Background: There are no effective symptomatic treatments for progressive supranuclear palsy (PSP). Recent studies report benefits of spinal cord stimulation (SCS) for freezing of gait (FOG) and gait disorders in Parkinson's disease and atypical Parkinsonism patients. This is the first study to report therapeutic effects of SCS in Richardson's syndrome PSP (PSP-RS) patients.
Methods: Epidural SCS was implanted in three female PSP-RS participants (3.2 ± 1.3 years with disease). Six programs (300-400 µs/30-130 Hz) were randomly tested at suprathreshold intensity on separate days. The setting that best improved gait/FOG was used daily by each participant in the study. Protokinetics walkway captured spatiotemporal gait measures and FOG episodes (turning on the spot and while walking) and clinical scales including FOG questionnaire, UPDRS-III (OFF-/ON-L-dopa), and participant-perceived global impression of change (GISC) were collected at pre-SCS, and 3, 6, 12 months post-SCS.
Results: Participant #1 demonstrated the highest GISC score (6.5/10) with a consistent reduction of FOGs by 43.8%, UPDRS-III score (- 5 points), and improved step length and stride velocity (33.6%) while maintaining a L-dopa response of ~ 12% over the 12 months. Participant #2, walking FOG frequency and turning duration was reduced by 39.0% (OFF-L-dopa), and ON-L-dopa UPDRS-III score worsened (+ 5 points) at 12 months. Participant #3, FOG frequency reduced by 75% up to 6 months rating a GISC 3/10 score, however disease severity worsened at 12 months. Ambulatory gait parameters universally improved by 29.6% in all participants.
Conclusion: The results support the benefit of SCS for FOG and gait symptoms in PSP-RS and suggests early SCS intervention for dopaminergic-resistant gait should be considered.
Keywords: Atypical parkinsonian; Freezing of gait; Gait analysis; Gait dysfunction; Neuromodulation; Progressive supranuclear palsy; Spatiotemporal; Spinal cord stimulation.