Status dystonicus is a distinct state characterized by pallidal beta-band activity.

Abstract

Status dystonicus (SD) is a poorly known neurological emergency requiring urgent interventions, including deep brain stimulation (DBS) targeting the globus pallidus interna (GPi). The sensing capabilities of DBS electrodes provide an opportunity to study the pathophysiology of SD. Here, we study local field potentials (LFPs) from GPi-DBS electrodes implanted in a cohort of 10 children longitudinally during SD, recovery and relapse (recording range 11-1155 days). During SD, we report an increase in the periodic component of the power spectrum within the beta-band along with increases in burst amplitude compared to recordings in non-SD states. Furthermore, relapsed SD is characterized by a return of excessive beta signatures. Beta-specific LFP power is also significantly associated with worse quality-of-life scores (PedsQL, R² = 0.695). We identify circadian pallidal beta-band periodicity in one participant with chronic narrowband beta-power recordings over months, with significant increase in power during SD. These rare recordings in children with SD point to excessive pallidal beta-band activity as a biomarker of SD. Our findings further suggest that SD is a distinct state with important implications for understanding dystonia pathophysiology, tracking dystonia states from intracranial activity and potential adaptive DBS treatments.