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Yacoubi B, Christou EA. Motor Output Variability in Movement Disorders: Insights from Essential Tremor. Exerc Sport Sci Rev 2024:00003677-990000000-00039. [PMID: 38445865 DOI: 10.1249/jes.0000000000000338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
ABSTRACT Findings on individuals with essential tremor suggest that tremor (within-trial movement unsteadiness) and inconsistency (trial-to-trial movement variance) stem from distinct pathologies and affect function uniquely. Nonetheless, the intricacies of inconsistency in movement disorders remain largely unexplored, as exemplified in ataxia where inconsistency below healthy levels was associated with greater pathology. We advocate for clinical assessments that quantify both tremor and inconsistency.
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Yacoubi B, Christou EA. RETHINKING FORCE STEADINESS: A NEW PERSPECTIVE. J Appl Physiol (1985) 2024. [PMID: 38299220 DOI: 10.1152/japplphysiol.00860.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Affiliation(s)
- Basma Yacoubi
- Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Evangelos A Christou
- Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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Kim JJ, Delmas S, Choi YJ, Hubbard JC, Weintraub M, Arabatzi F, Yacoubi B, Christou EA. Unique Neural Mechanisms Underlying Speed Control of Low-Force Ballistic Contractions. J Hum Kinet 2024; 90:29-44. [PMID: 38380304 PMCID: PMC10875691 DOI: 10.5114/jhk/182889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 01/20/2024] [Indexed: 02/22/2024] Open
Abstract
According to the speed-control hypothesis, the rate of force development (RFD) during ballistic contractions is dictated by force amplitude because time to peak force (TPF) remains constant regardless of changes in force amplitude. However, this hypothesis has not been tested at force levels below 20% of an individual's maximum voluntary contraction (MVC). Here, we examined the relationship between the RFD and force amplitude from 2 to 85% MVC and the underlying structure of muscle activity in 18 young adults. Participants exerted ballistic index finger abductions for 50 trials in each of seven randomly assigned force levels (2, 5, 15, 30, 50, 70, and 85% MVC). We quantified TPF, RFD, and various EMG burst characteristics. Contrary to the speed-control hypothesis, we found that TPF was not constant, but significantly varied from 2 to 85% MVC. Specifically, the RFD slope from 2 to 15% MVC was greater than the RFD slope from 30 to 85% MVC. Longer TPF at low force levels was associated with the variability of EMG burst duration, whereas longer TPF with higher force levels was associated with the EMG burst integral. Contrary to the speed-control hypothesis, we found that the regulation of TPF for low and high force levels was different, suggesting that neuronal variability is critical for force levels below 30% MVC and neuronal amplitude for force levels above 30% MVC. These findings present compelling new evidence highlighting the limitations of the speed-control hypothesis underscoring the need for a new theoretical framework.
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Affiliation(s)
- Joongsuk J. Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Stefan Delmas
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Yoon Jin Choi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Jessica C. Hubbard
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Michelle Weintraub
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Fotini Arabatzi
- School of Physical Education and Sports Science (Serres), Aristotle University of Thessaloniki, Serres, Greece
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A. Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
- Department of Neurology, Norman Fixel Institute of Neurological Disorders, University of Florida.Gainesville, FL, USA
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Kwon M, Christou EA. Visual Information Processing in Older Adults: Force Control and Motor Unit Pool Modulation. J Mot Behav 2023; 56:330-338. [PMID: 38155098 PMCID: PMC11006344 DOI: 10.1080/00222895.2023.2298888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 12/19/2023] [Indexed: 12/30/2023]
Abstract
Increased visual information about a task impairs force control in older adults. To date, however, it remains unclear how increased visual information changes the activation of the motor unit pool differently for young and older adults. Therefore, this study aimed to determine how increased visual information alters the activation of the motor neuron pool and influences force control in older adults. Fifteen older adults (66-86 years, seven women) and fifteen young adults (18-30 years, eight women) conducted a submaximal constant force task (15% of maximum) with ankle dorsiflexion for 20 s. The visual information processing was manipulated by changing the amount of force visual feedback into a low-gain (0.05°) or high-gain (1.2°) condition. Older adults exhibited greater force variability, especially at high-gain visual feedback. This exacerbated force variability from low- to high-gain visual feedback was associated with modulations of multiple motor units, not single motor units. Specifically, increased modulation of multiple motor units from 10 to 35 Hz may contribute to the amplification in force variability. Therefore, our findings suggest evidence that high-gain visual feedback amplifies force variability of older adults which is related to increases in the activation of motor neuron pool from 10 to 35 Hz.
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Affiliation(s)
- MinHyuk Kwon
- Department of Kinesiology and Health Promotion, California
State Polytechnic University, Pomona, CA, USA
- Department of Applied Physiology and Kinesiology,
University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology,
University of Florida, Gainesville, FL, USA
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Choi YJ, Chalatzoglidis G, Trapezanidou M, Delmas S, Savva E, Yacoubi B, Arabatzi F, Christou EA. Adolescent boys who participate in sports exhibit similar ramp torque control with young men despite differences in strength and tendon characteristics. Eur J Appl Physiol 2023; 123:965-974. [PMID: 36607415 PMCID: PMC10718087 DOI: 10.1007/s00421-022-05130-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE The goal of this paper was to determine if sports participation influences torque control differently for adolescent boys and young men during a slow ramp task. METHODS Twenty-one adolescent boys (11 athletes) and 31 young men (16 athletes) performed a slow ramp increase in plantar flexion torque from 0 to maximum. We quantified torque control as the coefficient of variation (CV) of torque during the ramp and quantified the Achilles tendon mechanical properties using ultrasonography. RESULTS Relative to adolescent boys, young men were taller, heavier, stronger, and had a longer and stiffer Achilles tendon. However, these characteristics were not different between athletes and non-athletes in adolescent boys. For the CV of torque, there was a significant interaction with sports participation, indicating that only adolescent boys who were non-athletes had greater variability than young men. The CV of torque of all participants was predicted from the maximum torque and torque oscillations from 1 to 2 Hz, whereas the CV of torque for adolescent boys was predicted only from torque oscillations from 1 to 2 Hz. CONCLUSION These findings suggested that adolescent boys who participate in sports exhibited lower torque variability during a slow ramp task, which was not explained by differences in Achilles tendon properties or strength.
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Affiliation(s)
- Yoon Jin Choi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - George Chalatzoglidis
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Martha Trapezanidou
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Stefan Delmas
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Evangelia Savva
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Fotini Arabatzi
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA.
- Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Lodha N, Patel P, Casamento-Moran A, Christou EA. Motor Training After Stroke: A Novel Approach for Driving Rehabilitation. Front Neurol 2022; 13:752880. [PMID: 35677325 PMCID: PMC9168025 DOI: 10.3389/fneur.2022.752880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 04/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background A key component of safe driving is a well-timed braking performance. Stroke-related decline in motor and cognitive processes slows braking response and puts individuals with stroke at a higher risk for car crashes. Although the impact of cognitive training on driving has been extensively investigated, the influence of motor interventions and their effectiveness in enhancing specific driving-related skills after stroke remains less understood. We compare the effectiveness of two motor interventions (force-control vs. strength training) to facilitate braking, an essential skill for safe driving. Methods Twenty-two stroke survivors were randomized to force-control training or strength training. Before and after training, participants performed a braking task during car-following in a driving simulator. We quantified the cognitive and motor components of the braking task with cognitive processing time and movement execution time. Results The cognitive processing time did not change for either training group. In contrast, the movement execution became significantly faster (14%) following force-control training but not strength training. In addition, task-specific effects of training were found in each group. The force-control group showed improved accuracy and steadiness of ankle movements, whereas the strength training group showed increased dorsiflexion strength following training. Conclusion Motor intervention that trains ankle force control in stroke survivors improves the speed of movement execution during braking. Driving rehabilitation after stroke might benefit from incorporating force-control training to enhance the movement speed for a well-timed braking response.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
- *Correspondence: Neha Lodha
| | - Prakruti Patel
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Evangelos A. Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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Paschaleri Z, Arabatzi F, Christou EA. Postural control in adolescent boys and girls before the age of peak height velocity: Effects of task difficulty. Gait Posture 2022; 92:461-466. [PMID: 35026628 DOI: 10.1016/j.gaitpost.2021.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/30/2021] [Accepted: 12/22/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Adolescent children experience a critical developmental period marked by rapid biological changes. Research question To describe the longitudinal changes in postural control that occur in adolescent boys and girls before the age of peak height velocity (PHV). METHODS Here, to address the gap of knowledge, we compared the postural control and activation strategies of the muscles that control the ankle joint in twenty-three boys (age 12.5 ± 0.29) and twenty-one girls (age 10.5 ± 0.32). They performed easy (two legs) and difficult (two legs-eyes closed; one leg) postural balance tasks at 18 and 9 months before PHV and at PHV. We quantified the center of pressure (COP) displacements in the anterior-posterior (AP) and mediolateral (ML) directions and electromyographic (EMG) activity of tibialis anterior (TA) and medial gastrocnemius (MG) muscles. RESULTS Boys exhibited greater AP and ML COP displacement than girls only for the one leg task (difficult task). Although boys and girls had similar postural control 18 months prior to PHV, girls exhibited lesser COP displacement at 9 months before PHV, which related to greater TA-MG coactivation (R2 = 0.26; p < 0.01). In contrast, postural control was not different between boys and girls with an easy balance task (two legs) performed with eyes open and closed. Rather, we found that all children improved their COP displacement in the ML direction with maturity and both AP and ML COP was significantly lower with eyes open. CONCLUSION These findings provide novel evidence that postural control is superior in early adolescent girls than boys 9 months prior to PHV, likely associated with an earlier maturation of muscle coordination.
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Affiliation(s)
- Zacharoula Paschaleri
- Department of Physical Education and Sport Science, Laboratory of Neuromechanics, Aristotle University of Thessaloniki, Serres, Greece
| | - Fotini Arabatzi
- Department of Physical Education and Sport Science, Laboratory of Neuromechanics, Aristotle University of Thessaloniki, Serres, Greece
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Clark DJ, Rose DK, Butera KA, Hoisington B, DeMark L, Chatterjee SA, Hawkins KA, Otzel DM, Skinner JW, Christou EA, Wu SS, Fox EJ. Rehabilitation with accurate adaptability walking tasks or steady state walking: A randomized clinical trial in adults post-stroke. Clin Rehabil 2021; 35:1196-1206. [PMID: 33722075 PMCID: PMC10416755 DOI: 10.1177/02692155211001682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To assess changes in walking function and walking-related prefrontal cortical activity following two post-stroke rehabilitation interventions: an accurate adaptability (ACC) walking intervention and a steady state (SS) walking intervention. DESIGN Randomized, single blind, parallel group clinical trial. SETTING Hospital research setting. SUBJECTS Adults with chronic post-stroke hemiparesis and walking deficits. INTERVENTIONS ACC emphasized stepping accuracy and walking adaptability, while SS emphasized steady state, symmetrical stepping. Both included 36 sessions led by a licensed physical therapist. ACC walking tasks recruit cortical regions that increase corticospinal tract activation, while SS walking activates the corticospinal tract less intensely. MAIN MEASURES The primary functional outcome measure was preferred steady state walking speed. Prefrontal brain activity during walking was measured with functional near infrared spectroscopy to assess executive control demands. Assessments were conducted at baseline, post-intervention (three months), and follow-up (six months). RESULTS Thirty-eight participants were randomized to the study interventions (mean age 59.6 ± 9.1 years; mean months post-stroke 18.0 ± 10.5). Preferred walking speed increased from baseline to post-intervention by 0.13 ± 0.11 m/s in the ACC group and by 0.14 ± 0.13 m/s in the SS group. The Time × Group interaction was not statistically significant (P = 0.86). Prefrontal fNIRS during walking decreased from baseline to post-intervention, with a marginally larger effect in the ACC group (P = 0.05). CONCLUSIONS The ACC and SS interventions produced similar changes in walking function. fNIRS suggested a potential benefit of ACC training for reducing demand on prefrontal (executive) resources during walking.
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Affiliation(s)
- David J. Clark
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL 32608, USA
- Department of Aging and Geriatric Research, University of Florida, 2004 Mowry Rd, Gainesville, FL 32611, USA
| | - Dorian K. Rose
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL 32608, USA
- Department of Physical Therapy, University of Florida, 101 Newell Dr, Gainesville, FL 32603, USA
- Brooks Rehabilitation, 3901 University Blvd S #101, Jacksonville, FL 32216, USA
| | - Katie A. Butera
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL 32608, USA
- Department of Physical Therapy, University of Florida, 101 Newell Dr, Gainesville, FL 32603, USA
| | - Brooke Hoisington
- Brooks Rehabilitation, 3901 University Blvd S #101, Jacksonville, FL 32216, USA
| | - Louis DeMark
- Brooks Rehabilitation, 3901 University Blvd S #101, Jacksonville, FL 32216, USA
| | - Sudeshna A. Chatterjee
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL 32608, USA
- Department of Physical Therapy, University of Florida, 101 Newell Dr, Gainesville, FL 32603, USA
| | - Kelly A. Hawkins
- Department of Physical Therapy, University of Florida, 101 Newell Dr, Gainesville, FL 32603, USA
| | - Dana M. Otzel
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL 32608, USA
| | - Jared W. Skinner
- VA Geriatric Research, Education and Clinical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA
| | - Evangelos A. Christou
- Department of Applied Physiology and Kinesiology, University of Florida, 1864 Stadium Rd, Gainesville, FL 32603
| | - Samuel S. Wu
- Department of Biostatistics, University of Florida, 2004 Mowry Rd, Gainesville, FL 32611, USA
| | - Emily J. Fox
- Department of Physical Therapy, University of Florida, 101 Newell Dr, Gainesville, FL 32603, USA
- Brooks Rehabilitation, 3901 University Blvd S #101, Jacksonville, FL 32216, USA
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Patel P, Casamento-Moran A, Christou EA, Lodha N. Force-Control vs. Strength Training: The Effect on Gait Variability in Stroke Survivors. Front Neurol 2021; 12:667340. [PMID: 34335442 PMCID: PMC8319601 DOI: 10.3389/fneur.2021.667340] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/17/2021] [Indexed: 11/21/2022] Open
Abstract
Purpose: Increased gait variability in stroke survivors indicates poor dynamic balance and poses a heightened risk of falling. Two primary motor impairments linked with impaired gait are declines in movement precision and strength. The purpose of the study is to determine whether force-control training or strength training is more effective in reducing gait variability in chronic stroke survivors. Methods: Twenty-two chronic stroke survivors were randomized to force-control training or strength training. Participants completed four training sessions over 2 weeks with increasing intensity. The force-control group practiced increasing and decreasing ankle forces while tracking a sinusoid. The strength group practiced fast ankle motor contractions at a percentage of their maximal force. Both forms of training involved unilateral, isometric contraction of the paretic, and non-paretic ankles in plantarflexion and dorsiflexion. Before and after the training, we assessed gait variability as stride length and stride time variability, and gait speed. To determine the task-specific effects of training, we measured strength, accuracy, and steadiness of ankle movements. Results: Stride length variability and stride time variability reduced significantly after force-control training, but not after strength training. Both groups showed modest improvements in gait speed. We found task-specific effects with strength training improving plantarflexion and dorsiflexion strength and force control training improving motor accuracy and steadiness. Conclusion: Force-control training is superior to strength training in reducing gait variability in chronic stroke survivors. Improving ankle force control may be a promising approach to rehabilitate gait variability and improve safe mobility post-stroke.
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Affiliation(s)
- Prakruti Patel
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
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Lodha N, Patel P, Shad JM, Casamento-Moran A, Christou EA. Cognitive and motor deficits contribute to longer braking time in stroke. J Neuroeng Rehabil 2021; 18:7. [PMID: 33436005 PMCID: PMC7805062 DOI: 10.1186/s12984-020-00802-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 12/20/2020] [Indexed: 01/13/2023] Open
Abstract
Background Braking is a critical determinant of safe driving that depends on the integrity of cognitive and motor processes. Following stroke, both cognitive and motor capabilities are impaired to varying degrees. The current study examines the combined impact of cognitive and motor impairments on braking time in chronic stroke. Methods Twenty stroke survivors and 20 aged-matched healthy controls performed cognitive, motor, and simulator driving assessments. Cognitive abilities were assessed with processing speed, divided attention, and selective attention. Motor abilities were assessed with maximum voluntary contraction (MVC) and motor accuracy of the paretic ankle. Driving performance was examined with the braking time in a driving simulator and self-reported driving behavior. Results Braking time was 16% longer in the stroke group compared with the control group. The self-reported driving behavior in stroke group was correlated with braking time (r = − 0.53, p = 0.02). The stroke group required significantly longer time for divided and selective attention tasks and showed significant decrease in motor accuracy. Together, selective attention time and motor accuracy contributed to braking time (R2 = 0.40, p = 0.01) in stroke survivors. Conclusions This study provides novel evidence that decline in selective attention and motor accuracy together contribute to slowed braking in stroke survivors. Driving rehabilitation after stroke may benefit from the assessment and training of attentional and motor skills to improve braking during driving.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Movement Neuroscience and Rehabilitation Laboratory, Colorado State University, Fort Collins, CA, 80523, USA.
| | - Prakruti Patel
- Department of Health and Exercise Science, Movement Neuroscience and Rehabilitation Laboratory, Colorado State University, Fort Collins, CA, 80523, USA
| | - Joanna M Shad
- Department of Health and Exercise Science, Movement Neuroscience and Rehabilitation Laboratory, Colorado State University, Fort Collins, CA, 80523, USA
| | | | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
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Kamieniarz A, Michalska J, Marszałek W, Stania M, Słomka KJ, Gorzkowska A, Juras G, Okun MS, Christou EA. Detection of postural control in early Parkinson's disease: Clinical testing vs. modulation of center of pressure. PLoS One 2021; 16:e0245353. [PMID: 33434235 PMCID: PMC7802937 DOI: 10.1371/journal.pone.0245353] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/28/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Little is known about the early stage balance changes in PD. Many clinicians assume that there are no postural issues in early PD because of failure to identify them on bedside and clinical testing. Here, we quantify balance changes in early and moderate stage PD and compared these values to healthy controls (HC) using clinical assessments of balance and posturography. METHODS We compared 15 HC with 15 early PD (PD-II; Hoehn and Yahr stage II) and 15 moderate PD (PD-III; H&Y stage III). Participants performed various clinical tests of balance and a standing postural task on a force platform. We quantified the spatiotemporal parameters of the center of pressure (COP), the sample entropy and power spectral density (PSD) of the COP. RESULTS The PSD of the COP differentiated PD-II from HC from 0-0.5 Hz and PD-II from PD-III from 0.5-1 Hz. Specifically, PD-II and PD-III manifested greater power than HC from 0-0.5 Hz, whereas PD-III exhibited greater power than PD-II and HC from 0.5-1.0 Hz (p<0.05). However, there were no significant differences between PD-II and HC in all clinical tests and in spatiotemporal parameters of the COP (p>0.05). Although the sample entropy was significantly lower in the PD groups (p<0.05), entropy failed to differentiate PD-II from PD-III. CONCLUSION The low-frequency modulation of the COP in this small cohort differentiated early PD from HC and from moderate PD. Clinicians should be aware that there are early balance deficits in PD. A larger sample size is needed to confirm these findings.
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Affiliation(s)
- Anna Kamieniarz
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Justyna Michalska
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Wojciech Marszałek
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Magdalena Stania
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Kajetan J. Słomka
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Agnieszka Gorzkowska
- Department of Neurorehabilitation, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Grzegorz Juras
- Institute of Sport Sciences, Academy of Physical Education, Katowice, Poland
| | - Michael S. Okun
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States of America
| | - Evangelos A. Christou
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States of America
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States of America
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Casamento-Moran A, Yacoubi B, Wilkes BJ, Hess CW, Foote KD, Okun MS, Wagle Shukla A, Vaillancourt DE, Christou EA. Quantitative Separation of Tremor and Ataxia in Essential Tremor. Ann Neurol 2020; 88:375-387. [PMID: 32418250 DOI: 10.1002/ana.25781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/19/2020] [Accepted: 05/10/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE This study addresses an important problem in neurology, distinguishing tremor and ataxia using quantitative methods. Specifically, we aimed to quantitatively separate dysmetria, a cardinal sign of ataxia, from tremor in essential tremor (ET). METHODS In Experiment 1, we compared 19 participants diagnosed with ET undergoing thalamic deep brain stimulation (DBS; ETDBS ) to 19 healthy controls (HC). We quantified tremor during postural tasks using accelerometry and dysmetria with fast, reverse-at-target goal-directed movements. To ensure that endpoint accuracy was unaffected by tremor, we quantified dysmetria in selected trials manifesting a smooth trajectory to the endpoint. Finally, we manipulated tremor amplitude by switching DBS ON and OFF to examine its effect on dysmetria. In Experiment 2, we compared 10 ET participants with 10 HC to determine whether we could identify and distinguish dysmetria from tremor in non-DBS ET. RESULTS Three findings suggest that we can quantify dysmetria independently of tremor in ET. First, ETDBS and ET exhibited greater dysmetria than HC and dysmetria did not correlate with tremor (R2 < 0.01). Second, even for trials with tremor-free trajectories to the target, ET exhibited greater dysmetria than HC (p < 0.01). Third, activating DBS reduced tremor (p < 0.01) but had no effect on dysmetria (p > 0.2). INTERPRETATION We demonstrate that dysmetria can be quantified independently of tremor using fast, reverse-at-target goal-directed movements. These results have important implications for the understanding of ET and other cerebellar and tremor disorders. Future research should examine the neurophysiological mechanisms underlying each symptom and characterize their independent contribution to disability. ANN NEUROL 2020;88:375-387.
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Affiliation(s)
- Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Bradley J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Christopher W Hess
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Kelly D Foote
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Michael S Okun
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Aparna Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.,Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
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Lodha N, Patel P, Harrell J, Casamento-Moran A, Zablocki V, Christou EA, Poisson SN. Motor impairments in transient ischemic attack increase the odds of a positive diffusion-weighted imaging: A meta-analysis. Restor Neurol Neurosci 2020; 37:509-521. [PMID: 31594263 DOI: 10.3233/rnn-190940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Unilateral motor impairment is a key symptom used in the diagnosis of transient ischemic attack (TIA). Diffusion-weighted imaging (DWI) is a promising diagnostic tool for detecting ischemic lesions. While both motor impairments and DWI abnormalities are linked to the diagnosis of TIA, the association between these prognostic factors is not well understood. OBJECTIVE To examine the association between unilateral motor impairments and the odds of a positive DWI in TIA. Further, to determine whether the time between symptom onset and neuroimaging (delay to scan) influences the odds of a positive DWI. METHODS We used PRISMA guidelines to conduct a systematic search from 1989 to 2018. We included studies that reported number of individuals with/without unilateral motor symptoms and a positive/negative DWI. RESULTS Twenty-four studies from North America, Australia, Asia, and Europe were submitted to a meta-analysis. A pooled odds ratio of 1.80 (95% CI, 1.45-2.24, p = 0.00; I2 = 57.38) suggested that the odds of a positive DWI are greater in TIA individuals who experience motor symptoms as compared with those who experience no motor symptoms. Further, increasing the time delay to scan from the symptom onset (>2 days) did not influence the odds of a positive DWI as compared with an earlier scan (≤2 days). CONCLUSIONS The current meta-analysis provides cumulative evidence from 6710 individuals with TIA that the presence of motor symptoms increases the odds of a positive DWI by two-folds. These findings transform the clinical perception into evidence-based knowledge that motor impairments elevate the risk for brain tissue damage. Unilateral motor impairments in a cerebrovascular event should increase a physician's suspicion of detecting brain infarctions. These findings may influence the clinical management of TIA by generating faster response to motor impairments in TIA and accelerating referral to specialized stroke clinic.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Prakruti Patel
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Jane Harrell
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | | | - Victoria Zablocki
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Sharon N Poisson
- Department of Neurology, University of Colorado, Aurora, CO, USA
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Christou GA, Mprikos SG, Christou KA, Christou MA, Christou EA, Nikas DN, Kiortsis DN. High Tolerability of Pitavastatin Therapy: A Case Report of Comparison with other Statins. Cardiology 2020; 145:421-424. [PMID: 32160627 DOI: 10.1159/000506394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/06/2020] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Myopathy is possibly the most clinically relevant statin-induced side effect. CASE PRESENTATION We report a case of a 63-year-old healthy male with mixed dyslipidemia. He developed bilateral myalgia of the forearms with fluvastatin 40 mg/day, pravastatin 20 mg/day, and combination of atorvastatin 10 mg and ezetimibe 10 mg/day. The only hypolipidemic treatment that was tolerable was the combination of pitavastatin 1 mg and ezetimibe 10 mg/day. DISCUSSION Pitavastatin demonstrated less potential for the development of myalgia compared to the so far considered most tolerable statins (i.e., fluvastatin and pravastatin). All the tested statins were used at the lowest approved dose for clinical use. CONCLUSION The combination of pitavastatin 1 mg and ezetimibe appears to be a promising treatment choice for individuals who are intolerant to statin therapy due to muscle complaints.
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Affiliation(s)
- Georgios A Christou
- Laboratory of Sports Medicine, Sports Medicine Division, Aristotle University of Thessaloniki, Thessaloniki, Greece,
| | | | | | | | | | - Dimitrios N Nikas
- First Cardiology Department, University Hospital of Ioannina, Ioannina, Greece
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15
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Wong JK, Hess CW, Almeida L, Middlebrooks EH, Christou EA, Patrick EE, Shukla AW, Foote KD, Okun MS. Deep brain stimulation in essential tremor: targets, technology, and a comprehensive review of clinical outcomes. Expert Rev Neurother 2020; 20:319-331. [PMID: 32116065 DOI: 10.1080/14737175.2020.1737017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Introduction: Essential tremor (ET) is a common movement disorder with an estimated prevalence of 0.9% worldwide. Deep brain stimulation (DBS) is an established therapy for medication refractory and debilitating tremor. With the arrival of next generation technology, the implementation and delivery of DBS has been rapidly evolving. This review will highlight the current applications and constraints for DBS in ET.Areas covered: The mechanism of action, targets for neuromodulation, next generation guidance techniques, symptom-specific applications, and long-term efficacy will be reviewed.Expert opinion: The posterior subthalamic area and zona incerta are alternative targets to thalamic DBS in ET. However, they may be associated with additional stimulation-induced side effects. Novel stimulation paradigms and segmented electrodes provide innovative approaches to DBS programming and stimulation-induced side effects.
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Affiliation(s)
- Joshua K Wong
- Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Christopher W Hess
- Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Leonardo Almeida
- Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | | | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Erin E Patrick
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, USA
| | - Aparna Wagle Shukla
- Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Kelly D Foote
- Fixel Institute for Neurological Diseases, Department of Neurosurgery, University of Florida, Gainesville, FL, USA
| | - Michael S Okun
- Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
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16
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Corti M, Casamento-Moran A, Delmas S, Bracksieck S, Bowman J, Meyer B, Norman S, Subramony S, Christou EA. Temporal but not spatial dysmetria relates to disease severity in FA. J Neurophysiol 2020; 123:718-725. [PMID: 31693434 DOI: 10.1152/jn.00165.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Friedreich's ataxia (FA) is an inherited disease that causes degeneration of the nervous system. Features of FA include proprioceptive and cerebellar deficits leading to impaired muscle coordination and, consequently, dysmetria in force and time of movement. The aim of this study is to characterize dysmetria and its association to disease severity. Also, we examine the neural mechanisms of dysmetria by quantifying the EMG burst area, duration, and time-to-peak of the agonist muscle. Twenty-seven individuals with FA and 13 healthy controls (HCs) performed the modified Functional Ataxia Rating Scale and goal-directed movements with the ankle. Dysmetria was quantified as position and time error during dorsiflexion. FA individuals exhibited greater time but not position error than HCs. Moreover, time error correlated with disease severity and was related to increased agonist EMG burst. Temporal dysmetria is associated to disease severity, likely due to altered activation of the agonist muscle.NEW & NOTEWORTHY For the first time, we quantified spatial and temporal dysmetria and its relation to disease severity in Friedreich's ataxia (FA). We found that FA individuals exhibit temporal but not spatial dysmetria relative to healthy controls. Temporal dysmetria correlated to disease severity in FA and was predicted from an altered activation of the agonist muscle. Therefore, these results provide novel evidence that FA exhibit temporal but not spatial dysmetria, which is different from previous findings on SCA6.
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Affiliation(s)
- Manuela Corti
- College of Medicine, Department of Pediatrics, University of Florida, Gainesville, Florida.,College of Medicine, Department of Neurology, University of Florida, Gainesville, Florida
| | - Agostina Casamento-Moran
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Stefan Delmas
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Samantha Bracksieck
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Jessica Bowman
- College of Medicine, Department of Pediatrics, University of Florida, Gainesville, Florida
| | - Blake Meyer
- College of Medicine, Department of Pediatrics, University of Florida, Gainesville, Florida
| | - Samantha Norman
- College of Medicine, Department of Pediatrics, University of Florida, Gainesville, Florida
| | - Sub Subramony
- College of Medicine, Department of Neurology, University of Florida, Gainesville, Florida
| | - Evangelos A Christou
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
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17
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Wilkes BJ, Wagle Shukla A, Casamento-Moran A, Hess CW, Christou EA, Okun MS, Vaillancourt DE. Effects of ventral intermediate nucleus deep brain stimulation across multiple effectors in essential tremor. Clin Neurophysiol 2019; 131:167-176. [PMID: 31794958 DOI: 10.1016/j.clinph.2019.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 09/04/2019] [Accepted: 10/14/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Essential tremor (ET) prominently affects the upper-limbs during voluntary movements, but can also affect the lower-limbs, head, and chin. Although deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of thalamus improves both clinical ratings and quantitative measures of tremor, no study has quantified effects of DBS on tremor across multiple body parts. Our objective was to quantify therapeutic effects of DBS across multiple body parts in ET. METHODS We performed quantitative assessment of tremor in ET patients who had DBS for at least one year. We assessed tremor on and off VIM-stimulation using triaxial accelerometers on the upper-limbs, lower-limbs, head and chin during seated and standing tasks. RESULTS VIM-DBS significantly reduced tremor, but there was no statistical difference in degree of tremor reduction across the measured effectors. Compared to healthy controls, ET patients treated with DBS showed significantly greater tremor power (4-8 Hz) across all effectors during seated and standing tasks. CONCLUSIONS VIM-DBS reduced tremor in ET patients. There was no significant difference in the degree of tremor reduction across the measured effectors. SIGNIFICANCE This study provides new quantitative evidence that VIM-DBS is effective at reducing tremor across multiple parts of the body.
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Affiliation(s)
- B J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - A Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - A Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - C W Hess
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - E A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - M S Okun
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - D E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
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18
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Park SH, Wang Z, McKinney W, Khemani P, Lui S, Christou EA, Mosconi MW. Functional motor control deficits in older FMR1 premutation carriers. Exp Brain Res 2019; 237:2269-2278. [PMID: 31161414 PMCID: PMC6679741 DOI: 10.1007/s00221-019-05566-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/23/2019] [Indexed: 02/05/2023]
Abstract
Individuals with fragile X mental retardation 1 (FMR1) gene premutations are at increased risk for fragile X-associated tremor/ataxia syndrome (FXTAS) during aging. However, it is unknown whether older FMR1 premutation carriers, with or without FXTAS, exhibit functional motor control deficits compared with healthy individuals. The purpose of this study, therefore, was to determine whether older FMR1 premutation carriers exhibit impaired ability to perform functional motor tasks. Eight FMR1 premutation carriers (age: 58.88 ± 8.36 years) and eight age- and sex-matched healthy individuals (60.13 ± 9.25 years) performed (1) a steady isometric force control task with the index finger at 20% of their maximum voluntary contraction (MVC) and; (2) a single-step task. During the finger abduction task, firing rate of multiple motor units of the first dorsal interosseous (FDI) muscle was recorded. Compared with healthy controls, FMR1 premutation carriers exhibited (1) greater force variability (coefficient of variation of force) during isometric force (1.48 ± 1.02 vs. 0.63 ± 0.37%; P = 0.04); (2) reduced firing rate of multiple motor units during steady force, and; (3) reduced velocity of their weight transfer during stepping (156.62 ± 26.24 vs. 191.86 ± 18.83 cm/s; P = 0.01). These findings suggest that older FMR1 premutation carriers exhibit functional motor control deficits that reflect either subclinical issues associated with premutations independent of FXTAS, or prodromal markers of the development of FXTAS.
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Affiliation(s)
- Seoung Hoon Park
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Zheng Wang
- Department of Occupational Therapy, University of Florida, Gainesville, FL, USA
| | - Walker McKinney
- Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS, USA
- Clinical Child Psychology Program, University of Kansas, Lawrence, KS, USA
- Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS, USA
| | - Pravin Khemani
- Department of Neurology, Swedish Neuroscience Institute, Seattle, WA, USA
| | - Su Lui
- Department of Radiology, Huaxi Magnetic Resonance Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Matthew W Mosconi
- Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS, USA.
- Clinical Child Psychology Program, University of Kansas, Lawrence, KS, USA.
- Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS, USA.
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19
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Chatterjee SA, Fox EJ, Daly JJ, Rose DK, Wu SS, Christou EA, Hawkins KA, Otzel DM, Butera KA, Skinner JW, Clark DJ. Interpreting Prefrontal Recruitment During Walking After Stroke: Influence of Individual Differences in Mobility and Cognitive Function. Front Hum Neurosci 2019; 13:194. [PMID: 31316360 PMCID: PMC6611435 DOI: 10.3389/fnhum.2019.00194] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
Background: Functional near-infrared spectroscopy (fNIRS) is a valuable neuroimaging approach for studying cortical contributions to walking function. Recruitment of prefrontal cortex during walking has been a particular area of focus in the literature. The present study investigated whether task-related change in prefrontal recruitment measured by fNIRS is affected by individual differences in people post-stroke. The primary hypotheses were that poor mobility function would contribute to prefrontal over-recruitment during typical walking, and that poor cognitive function would contribute to a ceiling in prefrontal recruitment during dual-task walking (i.e., walking with a cognitive task). Methods: Thirty-three adults with chronic post-stroke hemiparesis performed three tasks: typical walking at preferred speed (Walk), serial-7 subtraction (Serial7), and walking combined with serial-7 subtraction (Dual-Task). Prefrontal recruitment was measured with fNIRS and quantified as the change in oxygenated hemoglobin concentration (ΔO2Hb) between resting and active periods for each task. Spatiotemporal gait parameters were measured on an electronic walkway. Stepwise regression was used to assess how prefrontal recruitment was affected by individual differences including age, sex, stroke region, injured hemisphere, stroke chronicity, 10-meter walking speed, balance confidence measured by Activities-specific Balance Confidence (ABC) Scale, sensorimotor impairment measured by Fugl-Meyer Assessment, and cognitive function measured by Mini-Mental State Examination (MMSE). Results: For Walk, poor balance confidence (ABC Scale score) significantly predicted greater prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.003). For Dual-Task, poor cognitive function (MMSE score) significantly predicted lower prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.002). Conclusions: Poor mobility function predicted higher prefrontal recruitment during typical walking, consistent with compensatory over-recruitment. Poor cognitive function predicted lower prefrontal recruitment during dual-task walking, consistent with a recruitment ceiling effect. These findings indicate that interpretation of prefrontal recruitment should carefully consider the characteristics of the person and demands of the task.
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Affiliation(s)
- Sudeshna A. Chatterjee
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Emily J. Fox
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
- Brooks Rehabilitation, Jacksonville, FL, United States
| | - Janis J. Daly
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Dorian K. Rose
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Samuel S. Wu
- Department of Biostatistics, University of Florida, Gainesville, FL, United States
| | - Evangelos A. Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Kelly A. Hawkins
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Dana M. Otzel
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States
| | - Katie A. Butera
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Jared W. Skinner
- Geriatric Research, Education and Clinical Center, Malcom Randall VA Medical Center, Gainesville, FL, United States
| | - David J. Clark
- Brain Rehabilitation Research Center (BRRC), Malcom Randall VA Medical Center, Gainesville, FL, United States
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States
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Park SH, Wang Z, McKinney W, Christou EA, Mosconi MW. Functional Motor Control Deficits In Fragile X Mental Retardation 1 Gene Premutation Carriers. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561553.50534.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Lodha N, Patel P, Casamento-Moran A, Gauger K, Christou EA. Endpoint accuracy of goal-directed ankle movements correlates to over-ground walking in stroke. Clin Neurophysiol 2019; 130:1008-1016. [PMID: 31005051 DOI: 10.1016/j.clinph.2019.03.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/22/2019] [Accepted: 03/22/2019] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Goal-directed movements are essential for voluntary motor control. The inability to execute precise goal-directed movements after stroke can impair the ability to perform voluntary functions, learn new skills, and hinder rehabilitation. However, little is known about how the accuracy of single-joint, goal-directed ankle movements relates to multi-joint, lower limb function in stroke. Here, we determined the impact of stroke on the accuracy of goal-directed ankle movements and its relation to over-ground walking. METHODS Stroke (N = 28) and control (N = 28) participants performed (1) goal-directed ankle dorsiflexion movements to accurately match 9 degrees in 180 ms and (2) over-ground walking. During goal-directed ankle movements, we measured the endpoint error, position error, time error and the activation of the agonist and antagonist muscles. During over-ground walking, we measured the walking speed, paretic stride length, and cadence. RESULTS The stroke group demonstrated increased endpoint error than the controls. Increased endpoint error was associated with increased co-activation between agonist-antagonist muscles. Endpoint error was a significant predictor of walking speed and paretic stride length in stroke. CONCLUSIONS Impaired accuracy of goal-directed, ankle movements is correlated to over-ground walking in stroke. SIGNIFICANCE Quantifying accuracy of goal-directed ankle movements may provide insights into walking function post-stroke.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA.
| | - Prakruti Patel
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | | | - Katlyn Gauger
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
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Park SH, Kim C, Yacoubi B, Christou EA. Control of oscillatory force tasks: Low-frequency oscillations in force and muscle activity. Hum Mov Sci 2019; 64:89-100. [DOI: 10.1016/j.humov.2019.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/17/2019] [Indexed: 11/29/2022]
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Watanabe T, Nojima I, Sugiura H, Yacoubi B, Christou EA. Voluntary control of forward leaning posture relates to low-frequency neural inputs to the medial gastrocnemius muscle. Gait Posture 2019; 68:187-192. [PMID: 30497039 DOI: 10.1016/j.gaitpost.2018.11.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 10/18/2018] [Accepted: 11/18/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND Variability is an inherent feature of the motor output. Although low-frequency oscillations (<0.5 Hz) are the most important contributor to the variability of force during single-joint isolated force tasks, it remains unclear whether they contribute to the variability of a more complex task, such as a voluntary postural task. RESEARCH QUESTION Do low-frequency oscillations contribute to postural sway (center of pressure (COP) variability) when participants attempt to voluntarily maintain posture in a forward leaning position? METHODS Fourteen healthy young adults performed two tasks: 1) stand quietly (control condition); 2) leaned their body forward to 60% of their maximum lean distance by dorsiflexing the ankle joint. We recorded the COP and electromyographic (EMG) activity from the medial gastrocnemius (MG) and soleus (SL) muscles. We quantified the following: 1) COP variability as the standard deviation (SD) of anteroposterior COP displacements; 2) modulation of COP as the power in COP displacements from 0 to 2 Hz; 3) modulation of EMG bursting as the power in the rectified and smoothed EMG from 0 to 2 Hz; 4) modulation of the interference EMG as the power in the EMG from 10 to 35 and 35-60 Hz. RESULTS The SD of COP displacements related to the COP oscillations <0.5 Hz in both quiet standing and lean tasks. However, only for the lean task, the <0.5 Hz COP oscillations related to the EMG burst oscillations <0.5 Hz of the MG muscle. The EMG burst oscillations <0.5 Hz of the MG muscle further related to the interference EMG oscillations from 35 to 60 Hz for the lean task. SIGNIFICANCE Voluntary control of forward leaning posture relates to low-frequency neural inputs to the MG muscle.
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Affiliation(s)
- Tatsunori Watanabe
- Department of Physical Therapy, Nagoya University Graduate School of Medicine, Nagoya, Aichi, 461-8673, Japan; Japan Society for the Promotion of Science, Tokyo, Japan; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - Ippei Nojima
- Department of Physical Therapy, Nagoya University Graduate School of Medicine, Nagoya, Aichi, 461-8673, Japan
| | - Hideshi Sugiura
- Department of Physical Therapy, Nagoya University Graduate School of Medicine, Nagoya, Aichi, 461-8673, Japan
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Physical Therapy, University of Florida, Gainesville, FL, USA.
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Lodha N, Patel P, Casamento-Moran A, Hays E, Poisson SN, Christou EA. Strength or Motor Control: What Matters in High-Functioning Stroke? Front Neurol 2019; 9:1160. [PMID: 30687217 PMCID: PMC6333669 DOI: 10.3389/fneur.2018.01160] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/14/2018] [Indexed: 01/13/2023] Open
Abstract
Background: The two primary motor impairments that hinder function after stroke are declines in strength and motor control. The impact of motor impairments on functional capacity may vary with the severity of stroke motor impairments. In this study, we focus on high-functioning stroke individuals who experience mild to moderate motor impairments and often resume prior activities or return to work. These tasks require the ability to move independently, placing high demands on their functional mobility. Therefore, the purpose of this study was to quantify impairments in strength and motor control and their contribution to functional mobility in high-functioning stroke. Methods:Twenty-one high-functioning stroke individuals (Fugl Meyer Lower Extremity Score = 28.67 ± 4.85; Functional Activity Index = 28.47 ± 7.04) and 21 age-matched healthy controls participated in this study. To examine motor impairments in strength and motor control, participants performed the following tasks with the paretic ankle (1) maximum voluntary contractions (MVC) and (2) visuomotor tracking of a sinusoidal trajectory. Strength was quantified as the maximum force produced during ankle plantarflexion and dorsiflexion. Motor control was quantified as (a) the accuracy and (b) variability of ankle movement during the visuomotor tracking task. For functional mobility, participants performed (1) overground walking for 7 meters and (2) simulated driving task. Functional mobility was determined by walking speed, stride length variability, and braking reaction time. Results: Compared with the controls, the stroke group showed decreased plantarflexion strength, decreased accuracy, and increased variability of ankle movement. In addition, the stroke group demonstrated decreased walking speed, increased stride length variability, and increased braking reaction time. The multiple-linear regression model revealed that motor accuracy was a significant predictor of the walking speed and braking reaction time. Further, motor variability was a significant predictor of stride length variability. Finally, the dorsiflexion or plantarflexion strength did not predict walking speed, stride length variability or braking reaction time. Conclusions: The impairments in motor control but not strength predict functional deficits in walking and driving in high-functioning stroke individuals. Therefore, rehabilitation interventions assessing and improving motor control will potentially enhance functional outcomes in high-functioning stroke survivors.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Prakruti Patel
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Emily Hays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Sharon N Poisson
- Department of Neurology, University of Colorado, Aurora, CO, United States
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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25
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Kim C, Yacoubi B, Christou EA. Visual load and variability of muscle activation: Effects on reactive driving of older adults. Hum Mov Sci 2018; 63:172-181. [PMID: 30562674 DOI: 10.1016/j.humov.2018.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 11/25/2022]
Abstract
BACKGROUND The functional significance of the increase in motor output variability with increased visual information processing in older adults remains unclear. Here, we test the hypothesis that increased visual information processing increases muscle activation variability in older adults and impairs their ability to react as fast and as precisely as young adults during a simulated reactive driving task. METHODS Fourteen young and sixteen older adults performed a reactive driving simulation task that required responding to unexpected brake lights of the car ahead during a simple reaction time task (low visual information processing condition) and a choice reaction time task with "no go" trials condition (high visual information processing condition). We quantified the following: 1) reactive driving performance - combination of premotor response time, motor response time, and brake force error; 2) motor output variability - brake impulse variability; 3) muscle activation variability - variability in the tibialis anterior (TA) muscle activity. RESULTS The increase in information processing exacerbated the impaired reactive driving performance in older adults. The best predictor of this impairment was the increase in brake force error. The impaired reactive driving performance was related to brake impulse variability and variability in the TA activity. CONCLUSIONS This study provides novel evidence that increased information processing increases muscle activation variability in older adults with detrimental consequences to their ability to perform a simulated reactive driving task.
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Affiliation(s)
- Changki Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Physical Therapy, University of Florida, Gainesville, FL, USA
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Abstract
Presently, there is no evidence that magnification of visual feedback has motor implications beyond impairments in force control during a visuomotor task. We hypothesized that magnification of visual feedback would increase visual information processing, alter the muscle activation, and exacerbate the response time in older adults. To test this hypothesis, we examined whether magnification of visual feedback during a reaction time task alters the premotor time and the motor unit pool activation of older adults. Participants responded as fast as possible to a visual stimulus while they maintained a steady ankle dorsiflexion force (15% maximum) either with low-gain or high-gain visual feedback of force. We quantified the following: 1) response time and its components (premotor and motor time), 2) force variability, and 3) motor unit pool activity of the tibialis anterior muscle. Older adults exhibited longer premotor time and greater force variability than young adults. Only in older adults, magnification of visual feedback lengthened the premotor time and exacerbated force variability. The slower premotor time in older adults with high-gain visual feedback was associated with increased force variability and an altered modulation of the motor unit pool. In conclusion, our findings provide novel evidence that magnification of visual feedback also exacerbates premotor time during a reaction time task in older adults, which is correlated with force variability and an altered modulation of motor unit pool. Thus these findings suggest that visual information processing deficiencies in older adults could result in force control and reaction time impairments. NEW & NOTEWORTHY It is unknown whether magnification of visual feedback has motor implications beyond impairments in force control for older adults. We examined whether it impairs reaction time and motor unit pool activation. The findings provide novel evidence that magnification of visual feedback exacerbates reaction time by lengthening premotor time, which implicates time for information processing in older adults, which is correlated with force variability and an altered modulation of motor unit pool.
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Affiliation(s)
- MinHyuk Kwon
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida.,Exercise Science Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida.,Department of Physical Therapy, University of Florida , Gainesville, Florida
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27
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Delmas S, Casamento-Moran A, Park SH, Yacoubi B, Christou EA. Motor planning perturbation: muscle activation and reaction time. J Neurophysiol 2018; 120:2059-2065. [PMID: 29947595 PMCID: PMC6230771 DOI: 10.1152/jn.00323.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 12/15/2022] Open
Abstract
Reaction time (RT) is the time interval between the appearance of a stimulus and initiation of a motor response. Within RT, two processes occur, selection of motor goals and motor planning. An unresolved question is whether perturbation to the motor planning component of RT slows the response and alters the voluntary activation of muscle. The purpose of this study was to determine how the modulation of muscle activity during an RT response changes with motor plan perturbation. Twenty-four young adults (20.5 ±1.1 yr, 13 women) performed 15 trials of an isometric RT task with ankle dorsiflexion using a sinusoidal anticipatory strategy (10-20% maximum voluntary contraction). We compared the processing part of the RT and modulation of muscle activity from 10 to 60 Hz of the tibialis anterior (primary agonist) when the stimulus appeared at the trough or at the peak of the sinusoidal task. We found that RT ( P = 0.003) was longer when the stimulus occurred at the peak compared with the trough. During the time of the reaction, the electromyography (EMG) power from 10 to 35 Hz was less at the peak than the trough ( P = 0.019), whereas the EMG power from 35 to 60 Hz was similar between the peak and trough ( P = 0.92). These results suggest that perturbation to motor planning lengthens the processing part of RT and alters the voluntary activation of the muscle by decreasing the relative amount of power from 10 to 35 Hz. NEW & NOTEWORTHY We aimed to determine whether perturbation to motor planning would alter the speed and muscle activity of the response. We compared trials when a stimulus appeared at the peak or trough of an oscillatory reaction time task. When the stimulus occurred at the trough, participants responded faster, with greater force, and less EMG power from 10-35 Hz. We provide evidence that motor planning perturbation slows the response and alters the voluntary activity of the muscle.
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Affiliation(s)
- Stefan Delmas
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
| | | | - Seoung Hoon Park
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
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Ernster AE, Park SH, Yacoubi B, Christou EA, Casamento-Moran A, Singer ML, Humbert IA. Motor transfer from the corticospinal to the corticobulbar pathway. Physiol Behav 2018; 191:155-161. [PMID: 29678601 DOI: 10.1016/j.physbeh.2018.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 11/30/2022]
Abstract
There are multiple descending neural pathways, including the corticospinal pathway (CS) and the corticobulbar pathway (CB). The corticospinal pathway has been shown to exhibit within-pathway (CS-to-CS) motor transfer. However, motor transfer across each pathway (CS-to-CB or CB-to-CS) has yet to be studied in depth. The aim of the present study was to examine the effects of cross-pathway motor transfer between the ankle (CS) and tongue (CB) after training with a ballistic goal-directed motor task. Twelve healthy participants were recruited for this two-day experimental study. Six participants performed a ballistic goal-directed task with their ankle on Day 1 (ankle dorsiflexion), then tongue on Day 2 (elevate tongue against IOPI). The other 6 participants performed the same task with their tongue on Day 1, then ankle on Day 2. Both the ankle and tongue tasks (50 trials each) required matching force and time to a visual target. Our findings indicate that participants who underwent ankle training on Day 1 exhibited decreased tongue force error on Day 2 compared with participants who completed the tongue training on Day 1, with no prior ankle training (p = 0.02) (i.e. greater accuracy). This finding suggests that cross-pathway transfer from the corticospinal pathway to the corticobulbar pathway occurred with respect to force error. In other words, training of the ankle (CS) translated to improved training performance of the tongue (CB) through a reduction in force error. However, the reverse was not true - training the tongue did not elicit improved performance of the ankle. Nonetheless, if training with the corticospinal pathway can lead to improved corticobulbar pathway functioning, incorporating multi-pathway rehabilitation techniques might be valuable for clinicians across medical disciplines.
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Affiliation(s)
- Alayna E Ernster
- Swallowing Systems Core, Department of Speech, Language and Hearing Sciences, University of Florida, Gainesville, FL, United States.
| | - Seoung Hoon Park
- Neuromuscular Physiology Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Basma Yacoubi
- Neuromuscular Physiology Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Evangelos A Christou
- Neuromuscular Physiology Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Agostina Casamento-Moran
- Neuromuscular Physiology Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Michele L Singer
- Swallowing Systems Core, Department of Speech, Language and Hearing Sciences, University of Florida, Gainesville, FL, United States
| | - Ianessa A Humbert
- Swallowing Systems Core, Department of Speech, Language and Hearing Sciences, University of Florida, Gainesville, FL, United States
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Kim C, Yacoubi B, Christou EA. Speed but not amplitude of visual feedback exacerbates force variability in older adults. Exp Brain Res 2018; 236:2563-2571. [PMID: 29936533 DOI: 10.1007/s00221-018-5317-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/18/2018] [Indexed: 01/05/2023]
Abstract
Magnification of visual feedback (VF) impairs force control in older adults. In this study, we aimed to determine whether the age-associated increase in force variability with magnification of visual feedback is a consequence of increased amplitude or speed of visual feedback. Seventeen young and 18 older adults performed a constant isometric force task with the index finger at 5% of MVC. We manipulated the vertical (force gain) and horizontal (time gain) aspect of the visual feedback so participants performed the task with the following VF conditions: (1) high amplitude-fast speed; (2) low amplitude-slow speed; (3) high amplitude-slow speed. Changing the visual feedback from low amplitude-slow speed to high amplitude-fast speed increased force variability in older adults but decreased it in young adults (P < 0.01). Changing the visual feedback from low amplitude-slow speed to high amplitude-slow speed did not alter force variability in older adults (P > 0.2), but decreased it in young adults (P < 0.01). Changing the visual feedback from high amplitude-slow speed to high amplitude-fast speed increased force variability in older adults (P < 0.01) but did not alter force variability in young adults (P > 0.2). In summary, increased force variability in older adults with magnification of visual feedback was evident only when the speed of visual feedback increased. Thus, we conclude that in older adults deficits in the rate of processing visual information and not deficits in the processing of more visual information impair force control.
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Affiliation(s)
- Changki Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA. .,Department of Physical Therapy, University of Florida, Gainesville, FL, 32611, USA.
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Chung JW, Burciu RG, Ofori E, Coombes SA, Christou EA, Okun MS, Hess CW, Vaillancourt DE. Beta-band oscillations in the supplementary motor cortex are modulated by levodopa and associated with functional activity in the basal ganglia. Neuroimage Clin 2018; 19:559-571. [PMID: 29984164 PMCID: PMC6029579 DOI: 10.1016/j.nicl.2018.05.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/14/2018] [Accepted: 05/16/2018] [Indexed: 12/15/2022]
Abstract
We investigated the effect of acute levodopa administration on movement-related cortical oscillations and movement velocity in Parkinson's disease (PD). Patients with PD on and off medication and age- and sex-matched healthy controls performed a ballistic upper limb flexion movement as fast and accurately as possible while cortical oscillations were recorded with high-density electroencephalography. Patients off medication were also studied using task-based functional magnetic resonance imaging (fMRI) using a force control paradigm. Percent signal change of functional activity during the force control task was calculated for the putamen and subthalamic nucleus (STN) contralateral to the hand tested. We found that patients with PD off medication had an exaggerated movement-related beta-band (13–30 Hz) desynchronization in the supplementary motor area (SMA) compared to controls. In PD, spectral power in the beta-band was correlated with movement velocity. Following an acute dose of levodopa, we observed that the beta-band desynchronization in the SMA was reduced in PD, and was associated with increased movement velocity and increased voltage of agonist muscle activity. Further, using fMRI we found that the functional activity in the putamen and STN in the off medication state, was related to how responsive that cortical oscillations in the SMA of PD were to levodopa. Collectively, these findings provide the first direct evaluation of how movement-related cortical oscillations relate to movement velocity during the ballistic phase of movement in PD and demonstrate that functional brain activity in the basal ganglia pathways relate to the effects of dopaminergic medication on cortical neuronal oscillations during movement. Acute levodopa decreased beta-band desynchronization in the SMA, while improving movement velocity and muscle activity. Beta-band cortical activity during movement is positively correlated with upper limb movement velocity. fMRI in basal ganglia predicted the response of beta-band cortical activity to levodopa.
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Key Words
- BOLD, blood oxygen level dependent
- Ballistic movements
- DBS, deep brain stimulation
- ECoG, electrocorticography
- EEG
- EEG, electroencephalography
- EMG, electromyography
- ERSP, event-related power spectral perturbation
- FDR, false discovery rate
- HC, healthy control
- ICA, independent component analysis
- LFP, local field potential
- Levodopa
- M1, primary motor cortex
- MDS-UPDRS, Movement Disorder Society Unified Parkinson's Disease Rating Scale
- MEG, magnetoencephalography
- MPA, measure projection analysis
- MVC, maximum voluntary contraction
- MoCA, Montreal Cognitive Assessment
- PD, Parkinson's disease
- PD-OFF, off medication (levodopa) day
- PD-ON, on medication (levodopa) day
- PET, positron emission tomography
- Parkinson's disease
- ROI, regions of interest
- S1, primary somatosensory cortex
- SMA, supplementary motor area
- SNc, substantia nigra pars compacta
- STN, subthalamic nucleus
- Supplementary motor area
- fMRI
- fMRI, functional magnetic resonance imaging
- iEMG, integrated electromyography
- rCBF, regional cerebral blood flow
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Affiliation(s)
- Jae Woo Chung
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Roxana G Burciu
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Edward Ofori
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - Stephen A Coombes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Michael S Okun
- Department of Neurology and Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA
| | - Christopher W Hess
- Department of Neurology and Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology and Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
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31
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Casamento-Moran A, Fleeman R, Chen YT, Kwon M, Fox EJ, Yacoubi B, Christou EA. Neuromuscular variability and spatial accuracy in children and older adults. J Electromyogr Kinesiol 2018; 41:27-33. [PMID: 29723799 DOI: 10.1016/j.jelekin.2018.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/27/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022] Open
Abstract
Our ability to control movements is influenced by the developmental status of the neuromuscular system. Consequently, movement control improves from childhood to early adulthood but gradually declines thereafter. However, no study has compared movement accuracy between children and older adults. The purpose of this study was to compare endpoint accuracy during a fast goal-directed movement task in children and older adults. Ten pre-adolescent children (9.7 ± 0.67 yrs) and 19 older adults (71.95 ± 6.99 yrs) attempted to accurately match a peak displacement of the foot to a target (9° in 180 ms) with a dorsiflexion movement. We recorded electromyographic activity from the tibialis anterior (agonist) and soleus (antagonist) muscles. We quantified position error (i.e. spatial accuracy) as well as the coordination, magnitude, and variability of the antagonistic muscles. Children exhibited greater position error than older adults (36.4 ± 13.4% vs. 27.0 ± 9.8%). This age-related difference in spatial accuracy, was related to a more variable activation of the agonist muscle (R2: 0.358; P < 0.01). These results suggest that an immature neuromuscular system, compared to an aged one, affects the generation and refinement of the motor plan which increases the variability in the neural drive to the muscle and reduces spatial accuracy in children.
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Affiliation(s)
| | - Rebecca Fleeman
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Yen-Ting Chen
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - MinHyuk Kwon
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, FL, USA.
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA; Department of Physical Therapy, University of Florida, FL, USA.
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32
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Hawkins KA, Fox EJ, Daly JJ, Rose DK, Christou EA, McGuirk TE, Otzel DM, Butera KA, Chatterjee SA, Clark DJ. Prefrontal over-activation during walking in people with mobility deficits: Interpretation and functional implications. Hum Mov Sci 2018; 59:46-55. [PMID: 29604488 DOI: 10.1016/j.humov.2018.03.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 03/02/2018] [Accepted: 03/20/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND Control of walking by the central nervous system includes contributions from executive control mechanisms, such as attention and motor planning resources. Executive control of walking can be estimated objectively by recording prefrontal cortical activity using functional near infrared spectroscopy (fNIRS). OBJECTIVE The primary objective of this study was to investigate group differences in prefrontal/executive control of walking among young adults, older adults, and adults post-stroke. Also assessed was the extent to which walking-related prefrontal activity fits existing cognitive frameworks of prefrontal over-activation. METHODS Participants included 24 adults post-stroke with moderate to severe walking deficits, 15 older adults with mild gait deficits, and 9 young healthy adults. Executive control of walking was quantified as oxygenated hemoglobin concentration in the prefrontal cortex measured by fNIRS. Three walking tasks were assessed: typical walking, walking over obstacles, and walking while performing a verbal fluency task. Walking performance was assessed by walking speed. RESULTS There was a significant effect of group for prefrontal activity (p < 0.001) during typical and obstacles walking tasks, with young adults exhibiting the lowest level of prefrontal activity, followed by older adults, and then adults post-stroke. In young adults the prefrontal activity during typical walking was much lower than for the verbal fluency dual-task, suggesting substantial remaining prefrontal resources during typical walking. However, in older and post-stroke adults these remaining resources were significantly less (p < 0.01). Cumulatively, these results are consistent with prefrontal over-activation in the older and stroke groups, which was accompanied by a steeper drop in walking speed as task complexity increased to include obstacles (p < 0.05). CONCLUSIONS There is a heightened use of prefrontal/executive control resources in older adults and post-stroke adults during walking. The level of prefrontal resource utilization, particularly during complex walking tasks like obstacle crossing, may approach the ceiling of available resources for people who have walking deficits. Prior cognitive research has revealed that prefrontal over-activation combined with limited prefrontal resources can lead to poor cognitive performance. The present study suggests a similar situation influences walking performance. Future research should further investigate the extent to which prefrontal over-activation during walking is linked to adverse mobility outcomes.
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Affiliation(s)
- Kelly A Hawkins
- Department of Physical Therapy, University of Florida, PO Box 100154, Gainesville, FL 32610, USA.
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, PO Box 100154, Gainesville, FL 32610, USA; Brooks Rehabilitation, 3901 University Blvd S, Jacksonville, FL 32216, USA.
| | - Janis J Daly
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA; Department of Neurology, University of Florida, PO Box 100383, Gainesville, FL 32610, USA.
| | - Dorian K Rose
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA; Department of Physical Therapy, University of Florida, PO Box 100154, Gainesville, FL 32610, USA.
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, PO Box 118205, Gainesville, FL 32611, USA.
| | - Theresa E McGuirk
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA.
| | - Dana M Otzel
- VA Geriatric Research, Education and Clinical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA.
| | - Katie A Butera
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA; Department of Physical Therapy, University of Florida, PO Box 100154, Gainesville, FL 32610, USA.
| | - Sudeshna A Chatterjee
- Department of Physical Therapy, University of Florida, PO Box 100154, Gainesville, FL 32610, USA.
| | - David J Clark
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville, FL 32608, USA; Department of Aging and Geriatric Research, University of Florida, 2004 Mowry Rd, Gainesville, FL 32603, USA.
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Zukowski LA, Hass CJ, Shechtman O, Christou EA, Tillman MD. The effect of wheelchair propulsion style on changes in time spent in extreme wrist orientations after a bout of fatiguing propulsion. Ergonomics 2017; 60:1425-1434. [PMID: 28322620 DOI: 10.1080/00140139.2017.1303084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study compared how wheelchair propulsion styles affect changes in percentage of time spent in extreme wrist orientations, which have been associated with median nerve injury, after a fatiguing bout of propulsion. Twenty novice, non-disabled adult males learned arcing (ARC) and semicircular (SEMI) propulsion styles and utilised each to perform a wheelchair fatigue protocol. ARC and SEMI did not significantly differ in terms of changes after the fatigue protocol in percentage of time spent in extreme flexion/extension or radial/ulnar deviation at the push phase beginning or end. A pattern was observed, although not significant, of greater increases in percentage of time spent in extreme wrist extension and ulnar deviation during the push phase beginning and ulnar deviation during the push phase end while utilising SEMI relative to ARC. This study evinces that individual differences are greater than observed changes in extreme wrist orientations for both propulsion styles. Practitioner Summary: How wheelchair propulsion styles change with fatigue in terms of extreme wrist orientations was examined. This study evinces that individual differences are greater than observed changes in extreme wrist orientations for both propulsion styles and point towards the need for future research on individual differences utilising propulsion styles.
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Affiliation(s)
- Lisa A Zukowski
- a Division of Physical Therapy, Department of Allied Health Sciences , University of North Carolina at Chapel Hill , Chapel Hill , NC , USA
- b Department of Applied Physiology and Kinesiology , University of Florida , Gainesville , FL , USA
| | - Chris J Hass
- b Department of Applied Physiology and Kinesiology , University of Florida , Gainesville , FL , USA
| | - Orit Shechtman
- c Department of Occupational Therapy , University of Florida , Gainesville , FL , USA
| | - Evangelos A Christou
- b Department of Applied Physiology and Kinesiology , University of Florida , Gainesville , FL , USA
| | - Mark D Tillman
- b Department of Applied Physiology and Kinesiology , University of Florida , Gainesville , FL , USA
- d WellStar College of Health and Human Services , Kennesaw State University , Kennesaw , GA , USA
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Lodha N, Chen YT, McGuirk TE, Fox EJ, Kautz SA, Christou EA, Clark DJ. EMG synchrony to assess impaired corticomotor control of locomotion after stroke. J Electromyogr Kinesiol 2017; 37:35-40. [PMID: 28888972 DOI: 10.1016/j.jelekin.2017.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 06/14/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022] Open
Abstract
Adapting one's gait pattern requires a contribution from cortical motor commands. Evidence suggests that frequency-based analysis of electromyography (EMG) can be used to detect this cortical contribution. Specifically, increased EMG synchrony between synergistic muscles in the Piper frequency band has been linked to heightened corticomotor contribution to EMG. Stroke-related damage to cerebral motor pathways would be expected to diminish EMG Piper synchrony. The objective of this study is therefore to test the hypothesis that EMG Piper synchrony is diminished in the paretic leg relative to nonparetic and control legs, particularly during a long-step task of walking adaptability. Twenty adults with post-stroke hemiparesis and seventeen healthy controls participated in this study. EMG Piper synchrony increased more for the control legs compare to the paretic legs when taking a non-paretic long step (5.02±3.22% versus 0.86±2.62%), p<0.01) and when taking a paretic long step (2.04±1.98% versus 0.70±2.34%, p<0.05). A similar but non-significant trend was evident when comparing non-paretic and paretic legs. No statistically significant differences in EMG Piper synchrony were found between legs for typical walking. EMG Piper synchrony was positively associated with walking speed and step length within the stroke group. These findings support the assertion that EMG Piper synchrony indicates corticomotor contribution to walking.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Yen-Ting Chen
- Health Science Center, University of Texas, Houston, TX, USA
| | - Theresa E McGuirk
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; Brooks Rehabilitation, Jacksonville, FL, USA
| | - Steven A Kautz
- Ralph H. Johnson VA Medical Center, Charleston, SC, USA; Department of Health Sciences and Research and Division of Physical Therapy, Medical University of South Carolina, Charleston, SC, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - David J Clark
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA; Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA.
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Abstract
We describe the case of a 25-year-old athlete experiencing syncope during a 5-km running race. A thorough diagnostic workup reasonably excluded a cardiac disorder as the cause of syncope. The characterization of this episode of syncope as noncardiac appears to contradict the common belief that syncope during exercise has always a cardiac origin. Following a detailed history taking, it was revealed that the symptoms of the athlete started after a 180° turn of the route. This situation represents a setting relevant to a runner who stops suddenly after reaching the finish line and soon after experiences noncardiac syncope due to the abrupt cessation of muscle pump function of the lower limbs. Although the symptoms of the athlete in this report occurred during running, implying at a first glance the diagnosis of syncope occurring during exercise, a more detailed analysis of the circumstances indicated that these symptoms were in essence presenting after exercise from a pathophysiological view. The distinction between syncope occurring during and after exercise may be challenging enough for athletic activities involving a sudden stop of the running activity, such as for running races with sudden inversion of the route and sports characterized by rapid "starts and stops."
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Affiliation(s)
- Georgios A Christou
- Laboratory of Physiology, University of Ioannina Medical School, Ioannina, Greece
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Abstract
Background and purpose Transient ischemic attack (TIA) increases the risk for a subsequent stroke. Typical symptoms include motor weakness, gait disturbance, and loss of coordination. The association between the presence of motor impairments during a TIA and the chances of a subsequent stroke has not been examined. In the current meta-analysis, we examine whether the odds of a stroke are greater in TIA individuals who experience motor impairments as compared with those who do not experience motor impairments. Methods We conducted a systematic search of electronic databases as well as manual searches of the reference lists of retrieved articles. The meta-analysis included studies that reported an odds ratio relating motor impairments to a subsequent stroke, or the number of individuals with or without motor impairments who experienced a subsequent stroke. We examined these studies using rigorous meta-analysis techniques including random effects model, forest and funnel plots, I2, publication bias, and fail-safe analysis. Results Twenty-four studies with 15,129 participants from North America, Australia, Asia, and Europe qualified for inclusion. An odds ratio of 2.11 (95% CI, 1.67–2.65, p = 0.000) suggested that the chances of a subsequent stroke are increased by twofolds in individuals who experience motor impairments during a TIA compared with those individuals who have no motor impairments. Conclusion The presence of motor impairments during TIA is a significantly high-risk clinical characteristic for a subsequent stroke. The current evidence for motor impairments following TIA relies exclusively on the clinical reports of unilateral motor weakness. A comprehensive examination of motor impairments in TIA will enhance TIA prognosis and restoration of residual motor impairments.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Jane Harrell
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Stephan Eisenschenk
- Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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Casamento-Moran A, Hunter SK, Chen YT, Kwon MH, Fox EJ, Yacoubi B, Christou EA. Sex differences in spatial accuracy relate to the neural activation of antagonistic muscles in young adults. Exp Brain Res 2017; 235:2425-2436. [DOI: 10.1007/s00221-017-4968-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 04/24/2017] [Indexed: 12/20/2022]
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Wang Z, Kwon M, Mohanty S, Schmitt LM, White SP, Christou EA, Mosconi MW. Increased Force Variability Is Associated with Altered Modulation of the Motorneuron Pool Activity in Autism Spectrum Disorder (ASD). Int J Mol Sci 2017; 18:E698. [PMID: 28346344 PMCID: PMC5412284 DOI: 10.3390/ijms18040698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/20/2017] [Accepted: 03/22/2017] [Indexed: 11/20/2022] Open
Abstract
Force control deficits have been repeatedly documented in autism spectrum disorder (ASD). They are associated with worse social and daily living skill impairments in patients suggesting that developing a more mechanistic understanding of the central and peripheral processes that cause them may help guide the development of treatments that improve multiple outcomes in ASD. The neuromuscular mechanisms underlying force control deficits are not yet understood. Seventeen individuals with ASD and 14 matched healthy controls completed an isometric index finger abduction test at 60% of their maximum voluntary contraction (MVC) during recording of the first dorsal interosseous (FDI) muscle to determine the neuromuscular processes associated with sustained force variability. Central modulation of the motorneuron pool activation of the FDI muscle was evaluated at delta (0-4 Hz), alpha (4-10 Hz), beta (10-35 Hz) and gamma (35-60 Hz) frequency bands. ASD patients showed greater force variability than controls when attempting to maintain a constant force. Relative to controls, patients also showed increased central modulation of the motorneuron pool at beta and gamma bands. For controls, reduced force variability was associated with reduced delta frequency modulation of the motorneuron pool activity of the FDI muscle and increased modulation at beta and gamma bands. In contrast, delta, beta, and gamma frequency oscillations were not associated with force variability in ASD. These findings suggest that alterations of central mechanisms that control motorneuron pool firing may underlie the common and often impairing symptoms of ASD.
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Affiliation(s)
- Zheng Wang
- Schiefelbusch Institute for Life Span Studies, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Clinical Child Psychology Program, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Kansas Center for Autism Research and Training (K-CART), University of Kansas Medical School, Overland Park, KS 66213, USA.
| | - Minhyuk Kwon
- Schiefelbusch Institute for Life Span Studies, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Clinical Child Psychology Program, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Kansas Center for Autism Research and Training (K-CART), University of Kansas Medical School, Overland Park, KS 66213, USA.
| | - Suman Mohanty
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Lauren M Schmitt
- Schiefelbusch Institute for Life Span Studies, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Clinical Child Psychology Program, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Kansas Center for Autism Research and Training (K-CART), University of Kansas Medical School, Overland Park, KS 66213, USA.
| | - Stormi P White
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA.
| | - Matthew W Mosconi
- Schiefelbusch Institute for Life Span Studies, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Clinical Child Psychology Program, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
- Kansas Center for Autism Research and Training (K-CART), University of Kansas Medical School, Overland Park, KS 66213, USA.
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Kang N, Christou EA, Burciu RG, Chung JW, DeSimone JC, Ofori E, Ashizawa T, Subramony SH, Vaillancourt DE. Sensory and motor cortex function contributes to symptom severity in spinocerebellar ataxia type 6. Brain Struct Funct 2017; 222:1039-1052. [PMID: 27352359 PMCID: PMC6276122 DOI: 10.1007/s00429-016-1263-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/22/2016] [Indexed: 11/29/2022]
Abstract
Spinocerebellar ataxia type 6 (SCA6) is a genetic disease that causes degeneration of Purkinje cells, and recent evidence points to degeneration of Betz cells in the motor cortex. The relation between functional activity of motor cortex and symptom severity during a hand-grip motor control in vivo has not yet been investigated. This study explored both functional changes in the sensorimotor cortex and cerebellar regions and structural alterations in the cerebellum for SCA6 patients as compared to age-matched healthy controls using a multimodal imaging approach (task-based fMRI, task-based functional connectivity, and free-water diffusion MRI). Further, we tested their relation with the severity of ataxia symptoms. SCA6 patients had reduced functional activity in the sensorimotor cortex, supplementary motor area (SMA), cerebellar vermis, and cerebellar lobules I-VI (corrected P < 0.05). Reduced task-based functional connectivity between cortical motor regions (i.e., primary motor cortex and SMA) and cerebellar regions (i.e., vermis and lobules I-VI) was found in SCA6 (corrected P < 0.05). SCA6 had elevated free-water values throughout the cerebellum as compared with controls (corrected P < 0.05). Importantly, reduced functional activity in the sensorimotor cortex and SMA and increased free-water in the superior cerebellar peduncle and cerebellar lobule V were related to more severe symptoms in SCA6 (all pairs: R 2 ≥ 0.4 and corrected P < 0.05). Current results demonstrate that impaired functional activity in sensorimotor cortex and SMA and elevated free-water of lobule V and superior cerebellar peduncle are both related to symptom severity, and may provide candidate biomarkers for SCA6.
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Affiliation(s)
- Nyeonju Kang
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Roxana G Burciu
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Jae Woo Chung
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Jesse C DeSimone
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Edward Ofori
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA
| | - Tetsuo Ashizawa
- Department of Neurology, University of Florida, Gainesville, USA
| | | | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611-8205, USA.
- Department of Neurology, University of Florida, Gainesville, USA.
- Department of Biomedical Engineering, University of Florida, Gainesville, USA.
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Abstract
A less precise force output impairs our ability to perform movements, learn new motor tasks, and use tools. Here we show that low-frequency oscillations in force are detrimental to force precision. We summarize the recent evidence that low-frequency oscillations in force output represent oscillations of the spinal motor neuron pool from the voluntary drive, and can be modulated by shifting power to higher frequencies. Further, force oscillations below 0.5 Hz impair force precision with increased voluntary drive, aging, and neurological disease. We argue that the low-frequency oscillations are (1) embedded in the descending drive as shown by the activation of multiple spinal motor neurons, (2) are altered with force intensity and brain pathology, and (3) can be modulated by visual feedback and motor training to enhance force precision. Thus, low-frequency oscillations in force provide insight into how the human brain regulates force precision.
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Affiliation(s)
- Neha Lodha
- Department of Health and Exercise Science, Colorado State University Fort Collins, CO, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida Gainesville, FL, USA
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Casamento-Moran A, Chen YT, Lodha N, Yacoubi B, Christou EA. Motor plan differs for young and older adults during similar movements. J Neurophysiol 2017; 117:1483-1488. [PMID: 28077666 DOI: 10.1152/jn.00640.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/12/2016] [Accepted: 01/03/2017] [Indexed: 12/25/2022] Open
Abstract
Older adults exhibit altered activation of the agonist and antagonist muscles during goal-directed movements compared with young adults. However, it remains unclear whether the differential activation of the antagonistic muscles in older adults results from an impaired motor plan or an altered ability of the muscle to contract. The purpose of this study, therefore, was to determine whether the motor plan differs for young and older adults. Ten young (26.1 ± 4.3 yr, 4 women) and 16 older adults (71.9 ± 6.9 yr, 9 women) participated in the study. Participants performed 100 trials of fast goal directed movements with ankle dorsiflexion while we recorded the electromyographic activity of the primary agonist (tibialis anterior; TA) and antagonist (soleus; SOL) muscles. From those 100 trials we selected 5 trials in each of 3 movement end-point categories (fast, accurate, and slow). We investigated age-associated differences in the motor plan by quantifying the individual activity and coordination of the agonist and antagonist muscles. During similar movement end points, older adults exhibited similar activation of the agonist (TA) and antagonist (SOL) muscles compared with young adults. In addition, the coordination of the agonist and antagonist muscles (TA and SOL) was different between the two age groups. Specifically, older adults exhibited lower TA-SOL overlap (F1,23 = 41.2, P < 0.001) and greater TA-SOL peak EMG delay (F1,25 = 35.5, P < 0.001). This finding suggests that although subjects in both age groups displayed similar movement end points, they exhibited a different motor plan, as demonstrated by altered coordination between the agonist and antagonist muscles.NEW & NOTEWORTHY We aimed to determine whether the altered activation of muscles in older adults compared with young adults during fast goal-directed movements is related to an altered motor plan. For matched movements, there were differences in the coordination of antagonistic muscles but no differences in the individual activation of muscles. We provide novel evidence that the differential activation of muscles in older adults is related to an altered motor plan.
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Affiliation(s)
- Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Yen-Ting Chen
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Neha Lodha
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and .,Department of Physical Therapy, University of Florida, Gainesville, Florida
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Zukowski LA, Christou EA, Shechtman O, Hass CJ, Tillman MD. The Effect of Propulsion Style on Wrist Movement Variability During the Push Phase After a Bout of Fatiguing Propulsion. PM R 2016; 9:265-274. [PMID: 27390056 DOI: 10.1016/j.pmrj.2016.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/18/2016] [Accepted: 06/10/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Wheelchair propulsion has been linked to overuse injuries regardless of propulsion style. Many aspects of the arcing (ARC) and semicircular (SEMI) propulsion styles have been compared, but differences in intracycle movement variability, which have been linked to overuse injuries, have not been examined. OBJECTIVE To explore how ARC and SEMI affect changes in intracycle wrist movement variability after a fatiguing bout of propulsion. DESIGN Repeated measures crossover design. SETTING Wheelchair rollers and wheelchair fatigue course in a research laboratory. PARTICIPANTS Twenty healthy, nondisabled adult men without previous wheelchair experience. INTERVENTIONS Participants learned ARC and SEMI and used each to perform a wheelchair fatigue protocol. MAIN OUTCOME MEASUREMENTS Thirty seconds of propulsion on rollers were recorded by motion-capture cameras before and after a fatigue protocol for each propulsion style on 2 testing days. Angular wrist orientations (flexion/extension and radial/ulnar deviation) and linear wrist trajectories (mediolateral direction) were computed, and intracycle movement variability was calculated as standard deviations of the detrended and filtered values during the push phase beginning and end. Paired samples t tests were used to compare ARC and SEMI based on the percent changes from pre- to postfatigue protocol. RESULTS Both propulsion styles resulted in increased intracycle wrist movement variability postfatigue, but observed increases did not significantly differ between ARC and SEMI. CONCLUSIONS This study evinces that intersubject variability exceeded average changes in intracycle wrist movement variability for both propulsion styles. Neither propulsion style resulting in a greater change in intracycle movement variability may suggest that no single propulsion style is ideal for everyone. The large intersubject variability may indicate that the propulsion style resulting in the smallest increase in intracycle movement variability after a fatiguing bout of propulsion may differ for each person and may help explain why wheelchair users self-select to use different propulsion styles.
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Affiliation(s)
- Lisa A Zukowski
- Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Bondurant 3007, CB# 7135, Chapel Hill, NC 27599; and Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL(∗).
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL(†)
| | - Orit Shechtman
- Department of Occupational Therapy, University of Florida, Gainesville, FL(‡)
| | - Christopher J Hass
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL(§)
| | - Mark D Tillman
- WellStar College of Health and Human Services, Kennesaw State University, Kennesaw, GA; and Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL(¶)
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Larkin-Kaiser KA, Borsa PA, Baweja HS, Moore MA, Tillman MD, George SZ, Christou EA. Photobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner. Lasers Med Sci 2016; 31:1325-32. [DOI: 10.1007/s10103-016-1979-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/01/2016] [Indexed: 11/30/2022]
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Park SH, Kwon M, Solis D, Lodha N, Christou EA. Motor control differs for increasing and releasing force. J Neurophysiol 2016; 115:2924-30. [PMID: 26961104 DOI: 10.1152/jn.00715.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 03/09/2016] [Indexed: 11/22/2022] Open
Abstract
Control of the motor output depends on our ability to precisely increase and release force. However, the influence of aging on force increase and release remains unknown. The purpose of this study, therefore, was to determine whether force control differs while increasing and releasing force in young and older adults. Sixteen young adults (22.5 ± 4 yr, 8 females) and 16 older adults (75.7 ± 6.4 yr, 8 females) increased and released force at a constant rate (10% maximum voluntary contraction force/s) during an ankle dorsiflexion isometric task. We recorded the force output and multiple motor unit activity from the tibialis anterior (TA) muscle and quantified the following outcomes: 1) variability of force using the SD of force; 2) mean discharge rate and variability of discharge rate of multiple motor units; and 3) power spectrum of the multiple motor units from 0-4, 4-10, 10-35, and 35-60 Hz. Participants exhibited greater force variability while releasing force, independent of age (P < 0.001). Increased force variability during force release was associated with decreased modulation of multiple motor units from 35 to 60 Hz (R(2) = 0.38). Modulation of multiple motor units from 35 to 60 Hz was further correlated to the change in mean discharge rate of multiple motor units (r = 0.66) and modulation from 0 to 4 Hz (r = -0.64). In conclusion, these findings suggest that force control is altered while releasing due to an altered modulation of the motor units.
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Affiliation(s)
- Seoung Hoon Park
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - MinHyuk Kwon
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Danielle Solis
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Neha Lodha
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and Department of Physical Therapy, University of Florida, Gainesville, Florida
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Lodha N, Moon H, Kim C, Onushko T, Christou EA. Motor Output Variability Impairs Driving Ability in Older Adults. J Gerontol A Biol Sci Med Sci 2016; 71:1676-1681. [PMID: 26935111 DOI: 10.1093/gerona/glw013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 01/18/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The functional declines with aging relate to deficits in motor control and strength. In this study, we determine whether older adults exhibit impaired driving as a consequence of declines in motor control or strength. METHODS Young and older adults performed the following tasks: (i) maximum voluntary contractions of ankle dorsiflexion and plantarflexion; (ii) sinusoidal tracking with isolated ankle dorsiflexion; and (iii) a reactive driving task that required responding to unexpected brake lights of the car ahead. We quantified motor control with ankle force variability, gas position variability, and brake force variability. We quantified reactive driving performance with a combination of gas pedal error, premotor and motor response times, and brake pedal error. RESULTS Reactive driving performance was ~30% more impaired (t = 3.38; p < .01) in older adults compared with young adults. Older adults exhibited greater motor output variability during both isolated ankle dorsiflexion contractions (t = 2.76; p < .05) and reactive driving (gas pedal variability: t = 1.87; p < .03; brake pedal variability: t = 4.55; p < .01). Deficits in reactive driving were strongly correlated to greater motor output variability (R 2 = .48; p < .01) but not strength (p > .05). CONCLUSIONS This study provides novel evidence that age-related declines in motor control but not strength impair reactive driving. These findings have implications on rehabilitation and suggest that interventions should focus on improving motor control to enhance driving-related function in older adults.
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Affiliation(s)
- Neha Lodha
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville
| | - Hwasil Moon
- Department of Human Movement Science, Ewha Womans University, Seoul, Republic of Korea
| | - Changki Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville
| | - Tanya Onushko
- Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville.
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Park SH, Kim S, Kwon M, Christou EA. Differential contribution of visual and auditory information to accurately predict the direction and rotational motion of a visual stimulus. Appl Physiol Nutr Metab 2016; 41:244-8. [PMID: 26836352 DOI: 10.1139/apnm-2015-0390] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vision and auditory information are critical for perception and to enhance the ability of an individual to respond accurately to a stimulus. However, it is unknown whether visual and auditory information contribute differentially to identify the direction and rotational motion of the stimulus. The purpose of this study was to determine the ability of an individual to accurately predict the direction and rotational motion of the stimulus based on visual and auditory information. In this study, we recruited 9 expert table-tennis players and used table-tennis service as our experimental model. Participants watched recorded services with different levels of visual and auditory information. The goal was to anticipate the direction of the service (left or right) and the rotational motion of service (topspin, sidespin, or cut). We recorded their responses and quantified the following outcomes: (i) directional accuracy and (ii) rotational motion accuracy. The response accuracy was the accurate predictions relative to the total number of trials. The ability of the participants to predict the direction of the service accurately increased with additional visual information but not with auditory information. In contrast, the ability of the participants to predict the rotational motion of the service accurately increased with the addition of auditory information to visual information but not with additional visual information alone. In conclusion, this finding demonstrates that visual information enhances the ability of an individual to accurately predict the direction of the stimulus, whereas additional auditory information enhances the ability of an individual to accurately predict the rotational motion of stimulus.
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Affiliation(s)
- Seoung Hoon Park
- a Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - Seonjin Kim
- b Department of Physical Education, Seoul National University, Seoul, 151-748, Korea
| | - MinHyuk Kwon
- a Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - Evangelos A Christou
- a Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
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Bhullar A, Kang N, Idica J, Christou EA, Cauraugh JH. Increased visual information gain improves bimanual force coordination. Neurosci Lett 2015; 608:23-7. [PMID: 26455961 DOI: 10.1016/j.neulet.2015.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/21/2015] [Accepted: 10/01/2015] [Indexed: 11/19/2022]
Affiliation(s)
- Amitoj Bhullar
- Motor Behavior Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Nyeonju Kang
- Motor Behavior Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Jerelyne Idica
- Motor Behavior Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Evangelos A Christou
- Neuromuscular Physiology Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - James H Cauraugh
- Motor Behavior Laboratory, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
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Corti M, Smith BK, Falk DJ, Lawson LA, Fuller DD, Subramony SH, Byrne BJ, Christou EA. Altered activation of the tibialis anterior in individuals with Pompe disease: Implications for motor unit dysfunction. Muscle Nerve 2015; 51:877-83. [PMID: 25186912 DOI: 10.1002/mus.24444] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2014] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Pompe disease is a progressive disease that affects skeletal muscles and leads to loss of ambulation. We investigated the activation of the tibialis anterior (TA) in late-onset Pompe disease (LOPD) individuals during maximal voluntary contraction (MVC) and evoked involuntary responses. METHODS Four LOPD patients and matched control subjects performed MVC of the TA using dorsiflexion and TA evoked responses. Activation of the TA was recorded with surface electromyography. RESULTS The Pompe patients exhibited greater power at frequencies below 60 Hz and reduced power above 100 Hz. They also exhibited a reduced increase in M-wave and prolonged M-wave latency and duration in response to stimulation. CONCLUSIONS These results provide evidence that LOPD individuals have an altered activation pattern of the TA during maximal contractions. The observed activation pattern may reflect impairments in voluntary command, neuromuscular junction pathology, or compensatory drive due to a reduced number of functional motoneurons.
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Affiliation(s)
- Manuela Corti
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, Gainesville, Florida, USA
| | - Barbara K Smith
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physical Therapy, College of Public Health & Health Profession, University of Florida, P.O. Box 100296, Gainesville, Florida, 32610, USA
| | - Darin J Falk
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Lee Ann Lawson
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - David D Fuller
- Department of Physical Therapy, College of Public Health & Health Profession, University of Florida, P.O. Box 100296, Gainesville, Florida, 32610, USA
| | - S H Subramony
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Barry J Byrne
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Evangelos A Christou
- Department of Physical Therapy, College of Public Health & Health Profession, University of Florida, P.O. Box 100296, Gainesville, Florida, 32610, USA
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, Gainesville, Florida, USA
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Casamento-Moran A, Chen YT, Kwon M, Snyder A, Subramony SH, Vaillancourt DE, Christou EA. Force dysmetria in spinocerebellar ataxia 6 correlates with functional capacity. Front Hum Neurosci 2015; 9:184. [PMID: 25904859 PMCID: PMC4389656 DOI: 10.3389/fnhum.2015.00184] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/19/2015] [Indexed: 11/13/2022] Open
Abstract
Spinocerebellar ataxia type 6 (SCA6) is a genetic disease that causes pure cerebellar degeneration affecting walking, balance, and coordination. One of the main symptoms of SCA6 is dysmetria. The magnitude of dysmetria and its relation to functional capacity in SCA6 has not been studied. Our purpose was to quantify dysmetria and determine the relation between dysmetria and functional capacity in SCA6. Ten individuals diagnosed and genetically confirmed with SCA6 (63.7 ± 7.02 years) and nine age-matched healthy controls (65.9 ± 8.5 years) performed goal-directed isometric contractions with the ankle joint. Dysmetria was quantified as the force and time error during goal-directed contractions. SCA6 functional capacity was determined by ICARS and SARA clinical assessments. We found that SCA6 participants exhibited greater force dysmetria than healthy controls (P < 0.05), and reduced time dysmetria than healthy controls (P < 0.05). Only force dysmetria was significantly related to SCA6 functional capacity, as measured with ICARS kinetic score (R2 = 0.63), ICARS total score (R2 = 0.43), and SARA total score (R2 = 0.46). Our findings demonstrate that SCA6 exhibit force dysmetria and that force dysmetria is associated to SCA6 functional capacity. Quantifying force and time dysmetria in individuals with SCA6 could provide a more objective evaluation of the functional capacity and disease state in SCA6.
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Onushko T, Kim C, Christou EA. Reducing task difficulty during practice improves motor learning in older adults. Exp Gerontol 2014; 57:168-74. [DOI: 10.1016/j.exger.2014.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/21/2014] [Accepted: 06/05/2014] [Indexed: 01/22/2023]
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