Pallidal low-frequency activity in dystonia after cessation of long-term deep brain stimulation.

ABSTRACT

OBJECTIVE: This study investigates the association between pallidal low-frequency activity and motor sign severity in dystonia after chronic deep brain stimulation for several months. METHODS: Local field potentials were recorded in 9 dystonia patients at 5 timepoints (T1-T5) during an OFF-stimulation period of 5 to 7 hours in parallel with clinical assessment using Burke-Fahn-Marsden Dystonia Rating Scale. A linear mixed effects model was used to investigate the potential association of motor signs with local field potential activity in the low frequency (3-12 Hz) and beta range (13-30 Hz). RESULTS: A significant association of Burke-Fahn-Marsden Dystonia Rating Scale scores with low-frequency activity (3-12 Hz; b = 4.4; standard error = 1.5, degrees of freedom = 43, P = 0.006, 95% confidence interval, 1.3-7.5), but not beta activity (13-30 Hz) was revealed within participants across timepoints. CONCLUSION: Low-frequency activity is associated with dystonic motor sign severity, even months after chronic deep brain stimulation. Our findings corroborate the pathophysiological role of low-frequency activity in dystonia and highlight the potential utility as a biomarker for adaptive neuromodulation. © 2019 International Parkinson and Movement Disorder Society.