Bauke W Dijkstra1, Moran Gilat1, L Eduardo Cofré Lizama2, Martina Mancini3, Bruno Bergmans4,5, Sabine M P Verschueren6, Alice Nieuwboer1. 1. Neuromotor Rehabilitation Research Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium. 2. School of Allied Health, Human Services and Sports, La Trobe University, Victoria, Australia. 3. Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA. 4. Department of Neurology, AZ Sint-Jan Brugge-Oostende AV, Bruges, Belgium. 5. Department of Neurology, Ghent University Hospital, Ghent, Belgium. 6. Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
Abstract
BACKGROUND: People with Parkinson's disease and freezing of gait (FOG; freezers) suffer from pronounced postural instability. However, the relationship between these phenomena remains unclear and has mostly been tested in paradigms requiring step generation. OBJECTIVE: To determine if freezing-related dynamic balance deficits are present during a task without stepping and determine the influence of dopaminergic medication on dynamic balance control. METHODS: Twenty-two freezers, 16 non-freezers, and 20 healthy age-matched controls performed mediolateral weight-shifts at increasing frequencies when following a visual target projected on a screen (MELBA task). The amplitude and phase shift differences between center of mass and target motion were measured. Balance scores (Mini-BESTest), 360° turning speed and the freezing ratio were also measured. Subjects with Parkinson's disease were tested ON and partial OFF (overnight withdrawal) dopaminergic medication. RESULTS: Freezers had comparable turning speed and balance scores to non-freezers and took more levodopa. Freezers produced hypokinetic weight-shift amplitudes throughout the MELBA task compared to non-freezers (p = 0.002), which were already present at task onset (p < 0.001). Freezers also displayed an earlier weight-shift breakdown than controls when OFF-medication (p = 0.008). Medication improved mediolateral weight-shifting in freezers and non-freezers. Freezers decreased their freezing ratio in response to medication. CONCLUSION: Hypokinetic weight-shifting proved a marked postural control deficit in freezers, while balance scores and turning speed were similar to non-freezers. Both weight-shift amplitudes and the freezing ratio were responsive to medication in freezers, suggesting axial motor vigor is levodopa-responsive. Future work needs to test whether weight-shifting and freezing severity can be further ameliorated through training.
BACKGROUND: People with Parkinson's disease and freezing of gait (FOG; freezers) suffer from pronounced postural instability. However, the relationship between these phenomena remains unclear and has mostly been tested in paradigms requiring step generation. OBJECTIVE: To determine if freezing-related dynamic balance deficits are present during a task without stepping and determine the influence of dopaminergic medication on dynamic balance control. METHODS: Twenty-two freezers, 16 non-freezers, and 20 healthy age-matched controls performed mediolateral weight-shifts at increasing frequencies when following a visual target projected on a screen (MELBA task). The amplitude and phase shift differences between center of mass and target motion were measured. Balance scores (Mini-BESTest), 360° turning speed and the freezing ratio were also measured. Subjects with Parkinson's disease were tested ON and partial OFF (overnight withdrawal) dopaminergic medication. RESULTS: Freezers had comparable turning speed and balance scores to non-freezers and took more levodopa. Freezers produced hypokinetic weight-shift amplitudes throughout the MELBA task compared to non-freezers (p = 0.002), which were already present at task onset (p < 0.001). Freezers also displayed an earlier weight-shift breakdown than controls when OFF-medication (p = 0.008). Medication improved mediolateral weight-shifting in freezers and non-freezers. Freezers decreased their freezing ratio in response to medication. CONCLUSION: Hypokinetic weight-shifting proved a marked postural control deficit in freezers, while balance scores and turning speed were similar to non-freezers. Both weight-shift amplitudes and the freezing ratio were responsive to medication in freezers, suggesting axial motor vigor is levodopa-responsive. Future work needs to test whether weight-shifting and freezing severity can be further ameliorated through training.
Entities:
Keywords:
Parkinson disease; freezing of gait; levodopa; postural balance
Authors: Simon Lewis; Stewart Factor; Nir Giladi; Alice Nieuwboer; John Nutt; Mark Hallett Journal: Transl Neurodegener Date: 2022-05-01 Impact factor: 9.883