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Phanthanourak AL, Adkin AL, Carpenter MG, Tokuno CD. Effects of postural threat on the scaling of anticipatory postural adjustments in young and older adults. Front Hum Neurosci 2023; 17:1267093. [PMID: 37841075 PMCID: PMC10568077 DOI: 10.3389/fnhum.2023.1267093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
Introduction The ability to scale anticipatory postural adjustments (APAs) according to the predicted size of the upcoming movement is reduced with aging. While age-related changes in central set may be one reason for this effect, an individual's emotional state might also contribute to changes in anticipatory postural control. Therefore, the purpose of this study was to determine whether an altered emotional state, as elicited through postural threat, alters the scaling of APAs during a handle pull movement in young and older adults. It was hypothesized that the presence of postural threat would lead to more homogenous APAs (i.e., less scaling of APAs) across a range of pulling forces. Methods Young (n = 23) and older adults (n = 16) stood on top of a force plate that was mounted to a motorized platform. From this position, participants performed a series of handle pull trials without (no threat) or with (threat) the possibility of receiving a postural perturbation in the form of an unpredictable surface translation. Handle pulls were performed at force levels between 50 and 90% of maximum force. For each trial, the magnitude and timing of the APA were quantified from center of pressure (COP) recordings as well as electromyographic (EMG) activity of the soleus and medial gastrocnemius. The scaling of APAs with respect to force exertion was then determined through regression analyses and by comparing APAs during pulls of lower versus higher force. Results and discussion As evidenced by their smaller slope of the regression line between various dependent measures (i.e., COP velocity, soleus EMG onset latency, and soleus EMG amplitude) and the pulled forces, older adults demonstrated less scaling of APAs than the young. However, increases in arousal, anxiety and fear of falling due to postural threat, only minimally altered the scaling of APAs. Regardless of age, the slope of the regressions for none of the measures were affected by threat while only the soleus and medial gastrocnemius EMG onsets demonstrated significant force × threat interaction effects. These results suggest that the decreased ability to scale APAs with aging is unlikely to be due to changes in emotional state.
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Affiliation(s)
| | - Allan L. Adkin
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Mark G. Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Craig D. Tokuno
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
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Theodosiadou A, Henry M, Duchateau J, Baudry S. Revisiting the use of Hoffmann reflex in motor control research on humans. Eur J Appl Physiol 2023; 123:695-710. [PMID: 36571622 DOI: 10.1007/s00421-022-05119-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 12/17/2022] [Indexed: 12/27/2022]
Abstract
Research in movement science aims at unravelling mechanisms and designing methods for restoring and maximizing human functional capacity, and many techniques provide access to neural adjustments (acute changes) or long-term adaptations (chronic changes) underlying changes in movement capabilities. First described by Paul Hoffmann over a century ago, when an electrical stimulus is applied to a peripheral nerve, this causes action potentials in afferent axons, primarily the Ia afferents of the muscle spindles, which recruit homonymous motor neurons, thereby causing an electromyographic response known as the Hoffmann (H) reflex. This technique is a valuable tool in the study of the neuromuscular function in humans and has provided relevant information in the neural control of movement. The large use of the H reflex in motor control research on humans relies in part to its relative simplicity. However, such simplicity masks subtleties that require rigorous experimental protocols and careful data interpretation. After highlighting basic properties and methodological aspects that should be considered for the correct use of the H-reflex technique, this brief narrative review discusses the purpose of the H reflex and emphasizes its use as a tool to assess the effectiveness of Ia afferents in discharging motor neurones. The review also aims to reconsider the link between H-reflex modulation and Ia presynaptic inhibition, the use of the H-reflex technique in motor control studies, and the effects of ageing. These aspects are summarized as recommendations for the use of the H reflex in motor control research on humans.
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Affiliation(s)
- Anastasia Theodosiadou
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Mélanie Henry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Jacques Duchateau
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Stéphane Baudry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium.
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Papavasileiou A, Hatzitaki V, Mademli L, Patikas DA. Temporal modulation of H-reflex in young and older people: Acute effects during Achilles tendon vibration while standing. Exp Gerontol 2022; 165:111844. [DOI: 10.1016/j.exger.2022.111844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 03/20/2022] [Accepted: 05/23/2022] [Indexed: 11/04/2022]
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Edwards N, Dulai J, Rahman A. A Scoping Review of Epidemiological, Ergonomic, and Longitudinal Cohort Studies Examining the Links between Stair and Bathroom Falls and the Built Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16091598. [PMID: 31067692 PMCID: PMC6540131 DOI: 10.3390/ijerph16091598] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 11/16/2022]
Abstract
Stair and bathroom falls contribute to injuries among older adults. This review examined which features of stairs and bathrooms have been assessed in epidemiological, ergonomic, and national aging studies on falls or their risk factors. Epidemiological and ergonomic studies were eligible if published from 2006-2017, written in English, included older persons, and reported built environment measures. The data extracted included the following: study population and design, outcome measures, and stair and bathroom features. National aging studies were eligible if English questionnaires were available, and if data were collected within the last 10 years. Sample characteristics; data collection methods; and data about falls, the environment, and assistive device use were extracted. There were 114 eligible articles assessed-38 epidemiologic and 76 ergonomic. Among epidemiological studies, 2 assessed stair falls only, 4 assessed bathroom falls only, and 32 assessed falls in both locations. Among ergonomic studies, 67 simulated stairs and 9 simulated bathrooms. Specific environmental features were described in 14 (36.8%) epidemiological studies and 73 (96%) ergonomic studies. Thirteen national aging studies were identified-four had stair data and six had bathroom data. Most epidemiologic and national aging studies did not include specific measures of stairs or bathrooms; the built environment descriptions in ergonomic studies were more detailed. More consistent and detailed environmental measures in epidemiologic and national aging studies would better inform fall prevention approaches targeting the built environment.
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Affiliation(s)
- Nancy Edwards
- School of Nursing, University of Ottawa, Ottawa, ON K1S 5L5, Canada.
| | - Joshun Dulai
- School of Nursing, University of Ottawa, Ottawa, ON K1S 5L5, Canada.
| | - Alvi Rahman
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC H3A 0G4, Canada.
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Johannsson J, Duchateau J, Baudry S. Modulation of the Hoffmann reflex in soleus and medial gastrocnemius during stair ascent and descent in young and older adults. Gait Posture 2019; 68:115-121. [PMID: 30472523 DOI: 10.1016/j.gaitpost.2018.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/09/2018] [Accepted: 11/15/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND The Hoffmann (H) reflex can provide relevant information on spinal control of leg muscles during locomotor tasks in young and older adults. RESEARCH QUESTION Is the H reflex in the leg muscles differently modulated during stair gait in young and older adults? METHOD The H reflex in soleus (SOL) and medial gastrocnemius (MG) (normalized to the maximal M-wave amplitude obtained during upright standing; Mmax) was recorded in 19 young and 18 older adults during upright standing, and stair ascent and descent of a 3-step staircase. RESULTS H-reflex amplitude during upright standing was greater in young than older adults for SOL (48% vs. 26% Mmax; p = 0.001) and MG (23% vs. 14% Mmax; p = 0.02). When data were averaged across groups during stair ascent, H-reflex amplitude in SOL increased from 15% Mmax at the beginning of the stance phase to 29% Mmax at mid-stance, then decreased to be 4% Mmax in the swing phase. During stair descent, H-reflex amplitude was maximal (20% Mmax) at the beginning of the stance phase, decreased to 5% Mmax at the end of stance, and increased to 11% Mmax in the swing phase. Similar adjustments were observed for the H reflex in MG for both ascent and descent. H-reflex modulation during gait cycle (relative to upright standing) is less pronounced in older adults (p < 0.05). However, no difference was observed between subgroups of young and older adults matched for H-reflex amplitude in upright standing. In both groups, H-reflex modulation was not associated with changes in background electromyographic activity. SIGNIFICANCE This study indicates that the H reflex is modulated within the stair gait cycle during ascent and descent. Although its magnitude was slightly reduced, the overall modulation of the H reflex is not affected in healthy older adults.
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Affiliation(s)
- Johanna Johannsson
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium
| | - Jacques Duchateau
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium
| | - Stéphane Baudry
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium.
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Miranda Z, Pham A, Elgbeili G, Barthélemy D. H-reflex modulation preceding changes in soleus EMG activity during balance perturbation. Exp Brain Res 2019; 237:777-791. [PMID: 30604019 DOI: 10.1007/s00221-018-5459-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 12/19/2018] [Indexed: 12/01/2022]
Abstract
When balance is compromised, postural strategies are induced to quickly recover from the perturbation. However, neuronal mechanisms underlying these strategies are not fully understood. Here, we assessed the amplitude of the soleus (SOL) H-reflex during forward and backward tilts of the support surface during standing (n = 15 healthy participants). Electrical stimulation of the tibial nerve was applied randomly before platform tilt (control) and 0, 25, 50, 75, 100 or 200 ms after tilt onset. During backward tilt, a significant decrease in H-reflex amplitude was observed at 75, 100 and 200 ms. The onset of the decreased H-reflex amplitude significantly preceded the onset of the SOL EMG decrease (latency: 144 ± 16 ms). During forward tilt, the amplitude of the H-reflex increased at 100 and 200 ms after tilt onset. The onset of H-reflex increase did not occur significantly earlier than the onset of the SOL EMG increase (127 ± 5 ms). An important inter-subject variability was observed for the onset of H-reflex modulation with respect to EMG response for each direction of tilt, but this variability could not be explained by the subject's height. Taken together, the results establish the time course of change in SOL H-reflex excitability and its relation to the increase and decrease in SOL EMG activity during forward and backward tilts. The data presented here also suggest that balance mechanisms may differ between forward and backward tilts.
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Affiliation(s)
- Zoé Miranda
- Faculty of Medicine, School of Rehabilitation, Université de Montréal, Pavillon du Parc, C.P.6128 Succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.,Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, CRIR, Montreal, Canada
| | - Annie Pham
- Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, CRIR, Montreal, Canada.,Department of Medicine, Université de Montréal, Montreal, Canada
| | - Guillaume Elgbeili
- Recherche en Schizophrénie et troubles neurodéveloppementaux, Institut universitaire en santé mentale Douglas, Montreal, Canada
| | - Dorothy Barthélemy
- Faculty of Medicine, School of Rehabilitation, Université de Montréal, Pavillon du Parc, C.P.6128 Succ. Centre-ville, Montreal, QC, H3C 3J7, Canada. .,Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, CRIR, Montreal, Canada.
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Tokuno CD, Keller M, Carpenter MG, Márquez G, Taube W. Alterations in the cortical control of standing posture during varying levels of postural threat and task difficulty. J Neurophysiol 2018; 120:1010-1016. [PMID: 29790833 DOI: 10.1152/jn.00709.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cortical excitability increases during the performance of more difficult postural tasks. However, it is possible that changes in postural threat associated with more difficult tasks may in themselves lead to alterations in the neural strategies underlying postural control. Therefore, the purpose of this study was to examine whether changes in postural threat are responsible for the alterations in corticospinal excitability and short-interval intracortical inhibition (SICI) that occur with increasing postural task difficulty. Fourteen adults completed three postural tasks (supported standing, free standing, or standing on an unstable board) at two surface heights (ground level or 3 m above ground). Single- and paired-pulse magnetic stimuli were applied to the motor cortex to compare soleus (SOL) and tibialis anterior (TA) test motor-evoked potentials (MEPs) and SICI between conditions. SOL and TA test MEPs increased from 0.35 ± 0.29 to 0.82 ± 0.41 mV (SOL) and from 0.64 ± 0.51 to 1.96 ± 1.45 mV (TA), respectively, whereas SICI decreased from 52.4 ± 17.2% to 39.6 ± 15.4% (SOL) and from 71.3 ± 17.7% to 50.3 ± 19.9% (TA) with increasing task difficulty. In contrast to the effects of task difficulty, only SOL test MEPs were smaller when participants stood at high (0.49 ± 0.29 mV) compared with low height (0.61 ± 0.40 mV). Because the presence of postural threat did not lead to any additional changes in the excitability of the motor corticospinal pathway and intracortical inhibition with increasing task difficulty, it seems unlikely that alterations in perceived threat are primarily responsible for the neurophysiological changes that are observed with increasing postural task difficulty. NEW & NOTEWORTHY We examined how task difficulty and postural threat influence the cortical control of posture. Results indicated that the motor corticospinal pathway and intracortical inhibition were modulated more by task difficulty than postural threat. Furthermore, because the presence of postural threat during the performance of various postural tasks did not lead to summative changes in motor-evoked potentials, alterations in perceived threat are not responsible for the neurophysiological changes that occur with increasing postural task difficulty.
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Affiliation(s)
- Craig D Tokuno
- Department of Kinesiology, Brock University , St. Catharines, Ontario , Canada
| | - Martin Keller
- Movement and Sport Sciences, Department of Neurosciences and Movement Sciences, University of Fribourg , Fribourg , Switzerland.,Department of Sport, Exercise and Health, University of Basel , Basel , Switzerland
| | - Mark G Carpenter
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Catholic University of Murcia , Murcia , Spain
| | - Wolfgang Taube
- Movement and Sport Sciences, Department of Neurosciences and Movement Sciences, University of Fribourg , Fribourg , Switzerland
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