Acute stimulation with symmetric biphasic pulses induces less ataxia compared to cathodic pulses in DBS for essential tremor

• Published in: Parkinsonism & related disorders 2023-06, Vol.111, p.105435-105435, Article 105435
• Main Authors: Boogers, Alexandra, Peeters, Jana, Van Bogaert, Tine, Rusz, Jan, Bogaert-Miclaus, Camelia, Loret, Griet, De Vloo, Philippe, Vandenberghe, Wim, Nuttin, Bart, Mc Laughlin, Myles
• Format: Article
• Language: English
• Subjects: Ataxia; Ataxia - etiology; Biphasic stimulation; Deep brain stimulation; Deep Brain Stimulation - adverse effects; Dysarthria - etiology; Electrodes; Essential tremor; Essential Tremor - etiology; Essential Tremor - therapy; Humans; Pulse shapes; Treatment Outcome; Tremor - etiology; Ventral Thalamic Nuclei - surgery
• ISSN: 1353-8020; 1873-5126
• DOI: 10.1016/j.parkreldis.2023.105435

Symmetric biphasic pulses have been shown to acutely increase the therapeutic window of ventralis intermedius deep brain stimulation (Vim-DBS) for essential tremor (ET) compared to cathodic pulses. Acute supratherapeutic stimulation can induce ataxic side effects in Vim-DBS. To investigate the effect on tremor, ataxia and dysarthria of 3 h of biphasic stimulation in patients with DBS for ET. A randomized, doubled-blind, cross-over design was used to compare standard cathodic pulses with symmetric biphasic pulses (anode-first) during a 3-h period per pulse shape. During each 3-h period, all stimulation parameters were identical, except for the pulse shape. Tremor (Fahn-Tolosa-Marin Tremor Rating Scale), ataxia (International Cooperative Ataxia Rating Scale) and speech (acoustic and perceptual measures) were assessed hourly during the 3-h periods. Twelve ET patients were included. During the 3-h stimulation period, tremor control was equivalent between the two pulse shapes. Biphasic pulses elicited significantly less ataxia than cathodic pulses (p = 0.006). Diadochokinesis rate of speech was better for the biphasic pulse (p = 0.048), but other measures for dysarthria were not significantly different between the pulses. Symmetric biphasic pulses induce less ataxia than conventional pulses after 3 h of stimulation DBS in ET patients. •When compared for 3 h, at supratherapeutic thresholds:•Biphasic pulses induce less stimulation-induced ataxia compared to cathodic pulses.•Biphasic pulses induce equivalent tremor control compared to cathodic pulses.•Diadochokinesis rate of speech was better for biphasic than cathodic pulses.