Excessive Pallidal Beta-band Activity and Functional Connectivity: A Novel Intracranial Biomarker of Status Dystonicus
Arjun Balachandar1, Lindsey Vogt2, Karim Mithani2, Sebastian Coleman2, Mark Ebden2, Andrea Leblanc-Millar2, Sara Breitbart2, Alfonso Fasano1, Carolina Gorodetsky2, George Ibrahim2
1Toronto Western Hospital, 2The Hospital for Sick Children
Objective:

Characterize novel neural correlates of status dystonicus (SD) and assess their relation to clinical severity.

Background:

SD is an emergency with severe episodes of dystonia, necessitating urgent hospital admission. Deep brain stimulation (DBS) of the globus pallidus interna (GPi) is a treatment for refractory SD. Intracranial neural correlates to SD-states and corresponding clinical severity are unknown.

Design/Methods:

Methods:

Nine patients with SD (Hospital for Sick Children, Canada) were implanted with sensing-capable Medtronic Percept™GPi DBS (age: 7.8±3.6). Local Field Potentials (LFPs) were recorded at multiple time points during SD and after recovery in non-SD states longitudinally (6-36 months; range: 11-1155 days; average: 319±358 days) and Power Spectral Densities (PSDs) calculated (Welch-method). Analysis of PSD periodic and aperiodic components was performed using fitting-oscillations/one-over-f methods. Band-limited power (Theta: 3-7Hz; Alpha: 7-12.5Hz, Beta: 12.5-30Hz, Gamma: 30-60Hz) was calculated. Intra-pallidal functional connectivity in SD and non-SD was computed using magnitude squared coherence (MSC) between outer (contact 3-referenced-to-2) and inner (1-to-0) GPi. Mixed effects models (MEMs) assessed relations between LFP metrics and clinical scales, including Burke‐Fahn‐Marsden Dystonia Rating Scale (BFMDRS) and Pediatric Quality of Life Score (PedsQL).

Results:

Results:

Across all patient recordings at optimal contact points, the peak power of the periodic component of the LFP in the beta-band (p=0.01) and band-limited beta-band power (p<0.001) increased in SD compared to non-SD. GPi beta-band MSC (p<0.001) increased in SD (0.24±0.10) from non-SD (0.16±0.08). MEMs controlling for random effects of patient and time determined significant correlation (R2=0.80) between decreased PedsQL and increased beta power (p=0.004; intercept p=0.007). Results were beta-band specific with no significant associations with theta (p=0.793) or alpha-band power (p=0.877). Similar results were seen for PedsQL motor-subscores but not BFMDRS.

Conclusions:

Excessive pallidal beta-band activity and functional connectivity are newly described biomarkers of SD, correlating with clinical severity.

10.1212/WNL.0000000000208829
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.