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

Boogers, Alexandra; Peeters, Jana; Bogaert, Tine Van; Rusz, Ján; Bogaert-Miclaus, Camelia; Loret, Griet; Vloo, Philippe De; Vandenberghe, Wim; Nuttin, Bart; Laughlin, Myles Mc

doi:10.1016/j.parkreldis.2023.105435

Cited by 1 publication

(4 citation statements)

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“…The ataxia scores were not significantly different in this study, contrary to what we published earlier ( 6 ). In our previous work, ataxia was intentionally provoked by stimulating at the ataxia threshold of the cathodic pulse.…”

Section: Discussioncontrasting

confidence: 99%

“…No adverse events were reported, but we are cautious with our conclusions considering the small sample size. In line with previous results ( 5 , 6 ), we documented that higher stimulation amplitudes are necessary when stimulating biphasically (symmetric active biphasic pulse with anodic phase first and no interphase gap) to obtain equivalent clinical responses as with cathodic stimulation. This increase in amplitude and the two active phases in symmetric biphasic pulses (active anodic and cathodic phase) theoretically entails an increase of energy consumption compared to the cathodic pulse.…”

Section: Discussionsupporting

confidence: 92%

“…Notably, this event is representative of patients with habituation in whom an increase in stimulation briefly leads to tremor control but is usually followed by increase of intentional tremor (as was documented in this patient, see Table 2 ) and balance problems due to overstimulation of cerebellar fibers ( 9 ). Overstimulation leading to falls is also seen in cathodic stimulation ( 13 ), even though we have previously shown that biphasic stimulation can decrease ataxia when compared to cathodic stimulation at the same amplitude ( 6 ). The falls could indicate that people with very small therapeutic windows may not safeguarded from overstimulation with biphasic pulses.…”

Section: Discussionmentioning

confidence: 99%

“…Symmetric biphasic pulses have been proposed as a solution to solve the problem of narrow therapeutic windows as these biphasic pulses have shown to mainly increase the side effect threshold compared to cathodic pulses ( 5 ). Furthermore, after three hours of symmetric biphasic stimulation, patients had equivalent tremor control but less stimulation-induced ataxia as with cathodic stimulation ( 6 ). The mechanisms behind these findings are yet to be determined.…”

Section: Introductionmentioning

confidence: 99%

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Testing of symmetric biphasic stimulation in Vim-DBS ET patients: a randomized-controlled pilot study

Boogers,

Peeters,

Van Bogaert

et al. 2024

Front. Neurol.

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IntroductionSymmetric biphasic pulses have been shown to increase the therapeutic window compared to standard cathodic pulses in ET Vim-DBS patients. Furthermore, three hours of stimulation with biphasic pulses caused less stimulation-induced ataxia compared to cathodic pulses. Therefore, an investigation of the longer-term safety of biphasic pulses is warranted.MethodsSeven ET patients were included in a randomized double-blind, cross-over design of one week home-use of symmetric biphasic stimulation (anodic phase first) versus cathodic stimulation. Amplitude was set in a double-blinded way, at the tremor arrest threshold. The primary outcome was safety assessed by documenting the adverse events. Secondary outcome parameters were stimulation amplitude, tremor (Fahn-Tolosa-Marin Tremor Rating Scale) and ataxia (International Cooperative Ataxia Rating Scale) severity, quality of life (Quality of Life in Essential Tremor Questionnaire) and cognition (Montreal Cognitive Assessment). Three patients continued in the open-label extension phase for 3 months, during which biphasic stimulation-only was further assessed by the same outcome parameters.ResultsDuring the 1 week testing, no adverse effects were reported. To obtain equivalent tremor control, the amplitude of the biphasic pulse was significantly higher compared to that of the cathodic pulse (p = 0.003). The other outcome parameters were not significantly different. During the open-label study, one patient used the remote control to increase the amplitude, leading to two falls caused by stimulation-induced ataxia. No other adverse effects occurred.Discussion and conclusionIn a small cohort, when tested for one week, symmetric biphasic pulses suggest to be safe, but require higher stimulation amplitudes. Further follow-up studies are needed to investigate long-term effects and safety.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionsupporting

confidence: 92%