Oscillatory dynamics in isolated dystonia: five hundred hours of chronic invasive multisite motor network recordings

Dystonia is a movement disorder characterized by involuntary muscle contractions, often treated with bilateral pallidal deep brain stimulation (DBS). However, optimizing DBS therapy remains challenging due to delayed clinical effects and a lack of objective biomarkers in dystonia. Using an investigational sensing-enabled DBS device attached to both cortical and pallidal leads, we recorded over 500 h of neural activity in a patient with cervical dystonia before and during chronic stimulation therapy while the individual went about their normal daily life. During off-stimulation settings, we observed increased low-frequency power (3-12 Hz) and a distinct narrowband gamma oscillation (∼60 Hz) in the sensorimotor cortex, both of which correlated with the severity of dystonic head tremor. DBS suppressed both pathological low-frequency activity and narrowband gamma oscillations while inducing stimulation-entrained gamma oscillations at half the stimulation frequency (65 Hz). Reductions in low-frequency power and increases in entrained gamma power were associated with improvements in dystonia severity, as measured by blinded clinical assessments of home video and video-derived kinematics, including head tremor amplitude and head angle deviations. The amplitude of gamma entrainment depended on stimulation parameters, including amplitude, frequency, and electrode contact. These findings suggest that gamma oscillations and their entrainment by stimulation may serve as an objective marker of DBS effectiveness in dystonia.NEW & NOTEWORTHY We recorded over 500 h of neural activity in a patient with cervical dystonia using a sensing-enabled DBS device-the most extensive dataset to date. Multisite recordings were paired with wearable and kinematic analysis of 100+ home videos. Low-frequency and narrowband gamma oscillations correlated with tremor and were suppressed by DBS, which also induced entrained gamma oscillations. These neural changes tracked with clinical and kinematic improvements, suggesting potential biomarkers of DBS effectiveness.