Article
Gait alterations in Parkinson’s disease after deep brain stimulation – A ventrocaudal arrangement of “sweet” and “sour spots” within the subthalamic nucleus?
Gangstörungen bei M. Parkinson nach tiefer Hirnstimulation: Eine ventrokaudale Ausrichtung von „sweet“ und „sour spots“ im Nucleus subthalamicus?
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Published: | May 25, 2022 |
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Outline
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Objective: Impairment of mobility by gait disturbances is a common clinical problem in Parkinson’s disease after bilateral deep brain stimulation of the subthalamic nucleus. We aimed to describe subregions of the subthalamic space where neurostimulation has a positive effect on gait or provokes gait disturbances in Parkinson’s disease.
Methods: Seventy-eight patients were classified according to postoperative changes in gait: (1) gait improvement, (2) no change, (3) de-novo gait disturbances. We performed a segregation analysis for (1) and (3) by simulating volumes of tissue activated and comparing aggregated spatial data for the two groups. We also calculated a probability map of therapy effects on gait.
Results: Twenty patients experienced complete remission of presurgical gait problems after STN-DBS. Nine patients showed de-novo gait disturbances one year after implantation. We observed no differences in stimulation parameters and control of global motor symptoms between groups. Active contacts were more ventrally located for de-novo gait disturbances vs. gait improvement. Strong correlations were found between clinical alterations in gait and the individual stimulation volume within the probabilistic outcome atlas (R2=0.78; p=0.01). The heatmap allowed patients to be notified of the likelihood to experience long-term gait benefits based on their volume of tissue activated overlap.
Conclusion: Distinct areas within the subthalamic nucleus correlate with gait improvement vs. de-novo gait disorders after neurostimulation. Our heatmap model showed a high correlation for therapy outcomes, especially gait improvement. Interestingly, the concept of sweet spots or bad spots could not explain individual differences. The thin delineations between close substructures in the subthalamic nucleus correlated with individual changes in gait. The gait heatmap model may direct future re-programming approaches for more mobility in Parkinsonian patients.