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Ba F, Sang TT, He W, Fatehi J, Mostofi E, Zheng B. Stereopsis and Eye Movement Abnormalities in Parkinson’s Disease and Their Clinical Implications. Front Aging Neurosci 2022; 14:783773. [PMID: 35211005 PMCID: PMC8861359 DOI: 10.3389/fnagi.2022.783773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 01/10/2022] [Indexed: 12/01/2022] Open
Abstract
Background Parkinson’s disease (PD) is not exclusively a motor disorder. Among non-motor features, patients with PD possess sensory visual dysfunctions. Depth perception and oculomotor deficits can significantly impact patients’ motor performance. Stereopsis and eye behavioral study using 3D stimuli may help determine their implications in disease status. Objective The objective of this study is to investigate stereopsis and eye movement abnormalities in PD with reliable tools and their correlation with indicators of PD severity. We hypothesize that patients with PD exhibit different eye behaviors and that these differences may correlate to the severity of motor symptoms and cognitive status. Methods Control and PD participants were first evaluated for visual acuity, visual field, contrast acuity, and stereo perception with 2D and Titmus stereotests, followed by the assessment with a 3D active shutter system. Eye movement behaviors were assessed by a Tobii X2-60 eye tracker. Results Screening visual tests did not reveal any differences between the PD and control groups. With the 3D active shutter system, the PD group demonstrated significantly worse stereopsis. The preserved cognitive function was correlated to a more intact stereo function. Patients with PD had longer visual response times, with a higher number of fixations and bigger saccade amplitude, suggesting fixation stabilization difficulties. Such changes showed a positive correlation with the severity of motor symptoms and a negative correlation with normal cognitive status. Conclusion We assessed stereopsis with a 3D active shutter system and oculomotor behaviors with the Tobii eye tracker. Patients with PD exhibit poorer stereopsis and impaired oculomotor behaviors during response time. These deficits were correlated with PD motor and cognitive status. The visual parameters may potentially serve as the clinical biomarkers for PD.
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Affiliation(s)
- Fang Ba
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Fang Ba,
| | - Tina T. Sang
- Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Wenjing He
- Surgical Simulation Research Lab, Department of Surgery, University of Alberta, Edmonton, AB, Canada
| | - Jaleh Fatehi
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Emanuel Mostofi
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Bin Zheng
- Surgical Simulation Research Lab, Department of Surgery, University of Alberta, Edmonton, AB, Canada
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Hanna-Pladdy B, Pahwa R, Lyons KE. Dopaminergic Basis of Spatial Deficits in Early Parkinson's Disease. Cereb Cortex Commun 2021; 2:tgab042. [PMID: 34738086 DOI: 10.1093/texcom/tgab042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 11/14/2022] Open
Abstract
Dopaminergic mechanisms regulating cognitive and motor control were evaluated comparing visuoperceptual and perceptuomotor functions in Parkinson's disease (PD). The performance of PD patients (n = 40) was contrasted with healthy controls (n = 42) across two separate visits (on and off dopaminergic medications) on computerized tasks of perception and aiming to a target at variable stimulus lengths (4, 8, 12 cm). Novel visuoperceptual tasks of length equivalence and width interval estimations without motor demands were compared with tasks estimating spatial deviation in movement termination. The findings support the presence of spatial deficits in early PD, more pronounced with increased discrimination difficulty, and with shorter stimulus lengths of 4 cm for both visuoperceptual and perceptumotor functions. Dopaminergic medication had an adverse impact on visuoperceptual accuracy in particular for length equivalence estimations, in contrast with dopaminergic modulation of perceptuomotor functions that reduced angular displacements toward the target. The differential outcomes for spatial accuracy in perception versus movement termination in PD are consistent with involvement of the direct pathway and models of progressive loss of dopamine through corticostriatal loops. Future research should develop validated and sensitive standardized tests of perception and explore dopaminergic selective deficits in PD to optimize medication titration for motor and cognitive symptoms of the disease.
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Affiliation(s)
- B Hanna-Pladdy
- Center for Advanced Imaging Research (CAIR), Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - R Pahwa
- Parkinson's Disease and Movement Disorder Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - K E Lyons
- Parkinson's Disease and Movement Disorder Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Bernardinis M, Atashzar SF, Patel RV, Jog MS. Abnormal Vision-Based Displacement Perception in Parkinson's Disease. Front Neurosci 2021; 15:676469. [PMID: 34393703 PMCID: PMC8359811 DOI: 10.3389/fnins.2021.676469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/02/2021] [Indexed: 11/30/2022] Open
Abstract
In this work, we investigate the effect of Parkinson’s disease (PD), and common corresponding therapies on vision-based perception of motion, a critical perceptual ability required for performing a wide range of activities of daily livings. While PD has been recognized as mainly a motor disorder, sensory manifestation of PD can also play a major role in the resulting disability. In this paper, for the first time, the effect of disease duration and common therapies on vision-based perception of displacement were investigated. The study is conducted in a movement-independent manner, to reject the shadowing effects and isolate the targeted perceptual disorder to the maximum possible extent. Data was collected using a computerized graphical tool on 37 PD patients [6 early-stage de novo, 25 mid-stage using levodopa therapy, six later-stage using deep brain stimulation (DBS)] and 15 control participants. Besides the absolute measurement of perception through a psychometric analysis on two tested position reference magnitudes, we also investigated the linearity in perception using Weber’s fraction. The results showed that individuals with PD displayed significant perceptual impairments compared to controls, though early-stage patients were not impaired. Mid-stage patients displayed impairments at the greater of the two tested reference magnitudes, while late-stage patients were impaired at both reference magnitudes. Levodopa and DBS use did not cause statistically significant differences in absolute displacement perception. The findings suggest abnormal visual processing in PD increasing with disease development, perhaps contributing to sensory-based impairments of PD such as bradykinesia, visuospatial deficits, and abnormal object recognition.
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Affiliation(s)
- Matthew Bernardinis
- School of Biomedical Engineering, Western University, London, ON, Canada.,Canadian Surgical Technologies and Advanced Robotics, London Health Sciences Centre (LHSC), London, ON, Canada.,London Movement Disorders Centre, LHSC, London, ON, Canada
| | - S Farokh Atashzar
- Electrical and Computer Engineering, Mechanical and Aerospace Engineering, New York University (NYU), New York, NY, United States
| | - Rajni V Patel
- School of Biomedical Engineering, Western University, London, ON, Canada.,Canadian Surgical Technologies and Advanced Robotics, London Health Sciences Centre (LHSC), London, ON, Canada.,Department of Clinical Neurological Sciences and Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Mandar S Jog
- School of Biomedical Engineering, Western University, London, ON, Canada.,London Movement Disorders Centre, LHSC, London, ON, Canada.,Department of Clinical Neurological Sciences and Electrical and Computer Engineering, Western University, London, ON, Canada
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Lopez A, Caffò AO, Bosco A. The impact of age and familiarity with the environment on categorical and coordinate spatial relation representations. Scand J Psychol 2021; 62:125-133. [PMID: 33404117 DOI: 10.1111/sjop.12703] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/21/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022]
Abstract
Retrieving spatial information is a crucial everyday ability that is affected by age-related changes. Previous research has shown that this change is mediated by familiarity with an environment. The present research uses a series of landmark location tasks to extend and deepen our understanding of the role of aging in spatial mental representations of more or less familiar environments, also disentangling the contribution of coordinate and categorical spatial relations. The study tested the following hypotheses: (1) younger adults only have an advantage over the elderly in less familiar environments; (2) the advantage for categorical over coordinate spatial relations is mainly found for less familiar environments; and finally; (3) interactions between age, familiarity, and spatial relations might reveal that the effects of age and familiarity take different trajectories for coordinate and categorical spatial relations. Results confirmed that: (1) young people outperform the elderly only in less familiar environments; (2) there is a reduction in the difference between coordinate and categorical accuracy with increasing familiarity with the environment; while (3) the interaction between age and level of familiarity did not significantly differentiate coordinate from categorical spatial relations. In conclusion, the present study provides new evidence for the role of familiarity with geographical areas and its impact on the representation of categorical and coordinate relations, with practical implications for the assessment of topographical disorientation in aging.
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Affiliation(s)
- Antonella Lopez
- Department of Educational Sciences, Psychology, Communication, University of Study Bari, Via Crisanzio 42, Bari, 70122, Italy
| | - Alessandro O Caffò
- Department of Educational Sciences, Psychology, Communication, University of Study Bari, Via Crisanzio 42, Bari, 70122, Italy
| | - Andrea Bosco
- Department of Educational Sciences, Psychology, Communication, University of Study Bari, Via Crisanzio 42, Bari, 70122, Italy
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Sensory focused exercise improves anxiety in Parkinson's disease: A randomized controlled trial. PLoS One 2020; 15:e0230803. [PMID: 32298270 PMCID: PMC7162490 DOI: 10.1371/journal.pone.0230803] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 03/06/2020] [Indexed: 12/13/2022] Open
Abstract
Anxiety has been implicated as one of the greatest influences on quality of life in Parkinson’s disease (PD). The etiology of anxiety is unclear, although previous work suggests that anxiety may be linked to sensory deficits that cause uncertainty in movement. Thus, the current study examined whether focusing attention on sensory feedback during goal-based exercise has the potential to provide benefits to anxiety in PD. Thirty-five participants with PD were randomized to either a Sensory Attention Focused Exercise (SAFEx) (i.e. internal focus of attention, n = 18) or Sham Exercise control (i.e. external focus of attention, n = 17) and completed 33 one-hour attention-based exercise sessions over 11-weeks. Before and after the program (pre and post), participants completed the Parkinson Anxiety Scale (PAS) questionnaire. The PAS includes three anxiety sections: persistent, episodic, and avoidance. Changes in the total PAS score and within each section of the PAS were subjected to two-factor mixed repeated measures ANCOVA. Significant group by time interactions demonstrated that from pre to post, total PAS scores (p = 0.007) and episodic anxiety scores (p = 0.010) significantly decreased in the SAFEx group only (ΔTotal PAS = -5.2, F(1,27) = 5.41, p = 0.028, ηp2 = 0.17; ΔEpisodic Score = -1.8, F(1,27) = 6.89, p = 0.014, ηp2 = 0.20). In conclusion, focusing attention on sensory feedback while completing goal-based exercises may provide significant benefits to improving anxiety in PD. As such, sensory attention focused exercise may be a critical adjunct therapy for improving anxiety, and ultimately quality of life in people with PD.
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Barbieri FA, Polastri PF, Gobbi LTB, Simieli L, Pereira VIA, Baptista AM, Moretto GF, Fiorelli CM, Imaizumi LFI, Rodrigues ST. Obstacle circumvention and eye coordination during walking to least and most affected side in people with Parkinson's disease. Behav Brain Res 2018; 346:105-114. [PMID: 29180136 DOI: 10.1016/j.bbr.2017.11.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 11/23/2017] [Accepted: 11/23/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND The mechanisms that contribute to gait asymmetry in people with Parkinson's disease (PD) are unclear, mainly during gait with greater environmental demand, such as when an obstacle is circumvented while walking. OBJECTIVE The aim of this study was to investigate the effects of obstacle circumvention of the least and most affected side on motor and gaze behavior in people with PD under/without the effects of dopaminergic medication. METHODS Fifteen people with PD and 15 matched-control individuals were instructed to walk along a pathway, at a self-selected velocity, and to circumvent an obstacle, avoiding contact with it. Each participant performed five trials for each side. Kinematic parameters, mediolateral and horizontal body clearance to the obstacle, strategy to circumvent the obstacle, and gaze behavior were calculated. Parameters were grouped according to the side that the obstacle was circumvented and compared by three-way ANOVAs. RESULTS Both people with PD and the control group presented asymmetry to circumvent an obstacle during walking, however this was exacerbated in people with PD. Individuals with PD presented safe strategies (largest mediolateral and horizontal body clearance to the obstacle, "lead-out" strategy, and higher number and time of fixations on the obstacle) during obstacle circumvention for the least affected side compared to the most affected side. In addition, positive effects of dopaminergic medication on body clearance, spatial-temporal parameters, and gaze behavior were evidenced only when the obstacle was circumvented to the least affected side. CONCLUSIONS The obstacle circumvention to the most affected side is risky for people with PD.
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Affiliation(s)
- Fabio Augusto Barbieri
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil.
| | - Paula Favaro Polastri
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - Lilian Teresa Bucken Gobbi
- São Paulo State University (Unesp), Campus Rio Claro, Posture and Gait Studies Laboratory (LEPLO), Department of Physical Education, Rio Claro, SP, Brazil
| | - Lucas Simieli
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - Vinicius Ignácio Alota Pereira
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - André Macari Baptista
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - Gabriel Felipe Moretto
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - Carolina Menezes Fiorelli
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil; Universidade Sagrado Coração, Bauru, SP, Brazil
| | - Luis Felipe Itikawa Imaizumi
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
| | - Sérgio Tosi Rodrigues
- São Paulo State University (Unesp) - Campus Bauru, Scholl of Science, Human Movement Research Laboratory (MOVI-LAB) and Laboratory of Information, Vision and Action (LIVIA), Department of Physical Education, Bauru, SP, Brazil
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The Cognition of Maximal Reach Distance in Parkinson’s Disease. PARKINSON'S DISEASE 2016; 2016:6827085. [PMID: 27597927 PMCID: PMC5002485 DOI: 10.1155/2016/6827085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/10/2016] [Accepted: 07/20/2016] [Indexed: 11/23/2022]
Abstract
This study aimed to investigate whether the cognition of spatial distance in reaching movements was decreased in patients with Parkinson's disease (PD) and whether this cognition was associated with various symptoms of PD. Estimated and actual maximal reaching distances were measured in three directions in PD patients and healthy elderly volunteers. Differences between estimated and actual measurements were compared within each group. In the PD patients, the associations between “error in cognition” of reaching distance and “clinical findings” were also examined. The results showed that no differences were observed in any values regardless of dominance of hand and severity of symptoms. The differences between the estimated and actual measurements were negatively deviated in the PD patients, indicating that they tended to underestimate reaching distance. “Error in cognition” of reaching distance correlated with the items of posture in the motor section of the Unified Parkinson's Disease Rating Scale. This suggests that, in PD patients, postural deviation and postural instability might affect the cognition of the distance from a target object.
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Fearon C, Butler JS, Newman L, Lynch T, Reilly RB. Audiovisual Processing is Abnormal in Parkinson’s Disease and Correlates with Freezing of Gait and Disease Duration. JOURNAL OF PARKINSONS DISEASE 2015; 5:925-36. [DOI: 10.3233/jpd-150655] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Conor Fearon
- Dublin Neurological Institute at the Mater Misericordiae University Hospital, Dublin, Ireland
- Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland
| | - John S. Butler
- Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland
- School of Mathematical Sciences, Dublin Institute of Technology, Kevin Street, Dublin, Ireland
| | - Louise Newman
- Dublin Neurological Institute at the Mater Misericordiae University Hospital, Dublin, Ireland
- Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland
| | - Timothy Lynch
- Dublin Neurological Institute at the Mater Misericordiae University Hospital, Dublin, Ireland
| | - Richard B. Reilly
- Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland
- School of Medicine, Trinity College Dublin, Dublin, Ireland
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Virtually-induced threat in Parkinson's: Dopaminergic interactions between anxiety and sensory-perceptual processing while walking. Neuropsychologia 2015; 79:322-31. [PMID: 26004056 DOI: 10.1016/j.neuropsychologia.2015.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/18/2015] [Accepted: 05/20/2015] [Indexed: 11/20/2022]
Abstract
Research evidence has suggested that anxiety influences gait in PD, with an identified dopa-sensitive gait response in highly anxious PD. It has been well-established that accurate perception of the environment and sensory feedback is essential for gait. Arguably since sensory and perceptual deficits have been noted in PD, anxiety has the potential to exacerbate movement impairments, since one might expect that reducing resources needed to overcome or compensate for sensory-perceptual deficits may lead to even more severe gait impairments. It is possible that anxiety in threatening situations might consume more processing resources, limiting the ability to process information about the environment or one's own movement (sensory feedback) especially in highly anxious PD. Therefore, the current study aimed to (i) evaluate whether processing of threat-related aspects of the environment was influenced by anxiety, (ii) evaluate whether anxiety influences the ability to utilize sensory feedback in PD while walking in threatening situations, and (iii) further understand the role of dopaminergic medication on these processes in threatening situations in PD. Forty-eight participants (24 HC; 12 Low Anxious [LA-PD], 12 Highly Anxious [HA-PD]) completed 20 walking trials in virtual reality across a plank that was (i) located on the ground (GROUND) (ii) located above a deep pit (ELEVATED); while provided with or without visual feedback about their lower limbs (+VF; -VF). After walking across the plank, participants were asked to judge the width of the plank they had just walked across. The plank varied in size from 60-100 cm. Both ON and OFF dopaminergic medication states were evaluated in PD. Gait parameters, judgment error and self-reported anxiety levels were measured. Results showed that HA-PD reported greater levels of anxiety overall (p<0.001) compared to HC and LA-PD, and all participants reported greater anxiety during the ELEVATED condition compared to GROUND (p=0.01). PD had similar judgment error as HC. Additionally, medication state did not significantly influence judgment error in PD. More importantly, HA-PD were the only group that did not adjust their step width when feedback was provided during the GROUND condition. However, medication facilitated a reduction in ST-CV when visual feedback was available only in the HA-PD group. Therefore, the current study provides evidence that anxiety may interfere with information processing, especially utilizing sensory feedback while walking. Dopaminergic medication appears to improve utilization of sensory feedback in stressful situations by reducing anxiety and/or improving resource allocation especially in those with PD who are highly anxious.
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Ehgoetz Martens KA, Ellard CG, Almeida QJ. Does manipulating the speed of visual flow in virtual reality change distance estimation while walking in Parkinson’s disease? Exp Brain Res 2014; 233:787-95. [DOI: 10.1007/s00221-014-4154-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 11/17/2014] [Indexed: 01/23/2023]
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Ehgoetz Martens KA, Ellard CG, Almeida QJ. A closer look at mechanisms underlying perceptual differences in Parkinson's freezers and non-freezers. Neuroscience 2014; 274:162-9. [PMID: 24857710 DOI: 10.1016/j.neuroscience.2014.05.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/13/2014] [Accepted: 05/13/2014] [Indexed: 11/24/2022]
Abstract
Parkinson's disease patients who suffer from freezing of gait (PD-FOG) may have sensory and/or perceptual deficits, although they are difficult to disentangle. This study evaluated whether visuospatial perception or self-motion perception were more impaired in PD-FOG, and whether distance estimation errors might be related to misperception of physical walking (compared to imagined). Finally, cognitive status was evaluated in order to evaluate whether cognitive status predicts any of the perception deficits identified. Nine PD-FOG and 15 PD-nonFOG were tested. In experiment 1, participants were shown a target, then the target was removed, before participants demonstrated the original position of the target in two different feedback conditions (pointing with a laser, or walking to its original position). In experiment 2, participants walked to a target (3, 4.5, 6m) and then imagined walking to that same target. The time to complete both of these tasks was measured and compared. Experiment 1 found a significantly greater judgment error in PD-FOG across both conditions (p=0.013) (compared to PD-nonFOG). Constant error revealed that both groups significantly underestimated during the self-motion condition only (p=0.01). Interestingly, results from experiment 2 demonstrated a significant discrepancy between the time it took to imagine walking compared to their actual movement times, specifically in PD-FOG (p=0.03). This mismatch as well as cognitive status significantly predicted judgment errors during the self-motion condition from experiment 1. Therefore, this study found evidence that PD-FOG have significantly greater sensory-perception deficits compared to PD-nonFOG. These findings have important clinical implications for further understanding FOG and developing new rehabilitative strategies for FOG symptoms.
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Affiliation(s)
- K A Ehgoetz Martens
- Sun Life Financial Movement Disorders Research and Rehabilitation Centre, Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario N2L 3C5, Canada; Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - C G Ellard
- Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Q J Almeida
- Sun Life Financial Movement Disorders Research and Rehabilitation Centre, Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario N2L 3C5, Canada.
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