Impaired Weight-Shift Amplitude in People with Parkinson’s Disease with Freezing of Gait

Article type: Research Article

Authors: Dijkstra, Bauke W.^{a; *} | Gilat, Moran^a | Cofré Lizama, L. Eduardo^b | Mancini, Martina^c | Bergmans, Bruno^{d; e} | Verschueren, Sabine M.P.^f | Nieuwboer, Alice^a

Affiliations: [a] Neuromotor Rehabilitation Research Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium | [b] School of Allied Health, Human Services and Sports, La Trobe University, Victoria, Australia | [c] Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA | [d] Department of Neurology, AZ Sint-Jan Brugge-Oostende AV, Bruges, Belgium | [e] Department of Neurology, Ghent University Hospital, Ghent, Belgium | [f] Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium

Correspondence: [*] Correspondence to: Bauke Wybren Dijkstra, Tervuursevest 101, Bus 1501, 3001 Leuven, Belgium. Tel.: +32 16 37 66 57; E-mail: [email protected].

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.

Keywords: Parkinson disease, freezing of gait, levodopa, postural balance

DOI: 10.3233/JPD-202370

Journal: Journal of Parkinson's Disease, vol. 11, no. 3, pp. 1367-1380, 2021