Seizure Risk Associated With the Use of Transcranial Magnetic Stimulation for Coma Recovery in Individuals With Disordered Consciousness After Severe Traumatic Brain Injury.

Objective: Repetitive Transcranial Magnetic Stimulation (rTMS) is emerging as a promising treatment for persons with disorder of consciousness (DoC) following traumatic brain injury (TBI). Clinically, however, there are concerns about rTMS exacerbating baseline seizure risk. To advance understanding of risks, this article reports evidence of DoC-TBI rTMS-related seizure risk.

Setting: Acute and sub-acute hospitals.

Participants: Persons in states of DoC 6.5 months to 15 years after TBI (n = 20) who received active rTMS (n = 17) or placebo rTMS (n = 3). After completing placebo procedures, placebo participants completed active rTMS procedures. These 3 participants are included in the active group.

Design: Meta-analysis of data from 3 clinical trials; 2 within-subject, 1 double blind randomized placebo-controlled. Each trial used the same rTMS protocol, provided at least 30 rTMS sessions, and delivered rTMS to the dorsolateral prefrontal cortex.

Main measures: During each study's rTMS treatment phase, seizure occurrences were compared between active and placebo groups using logistic regression. After stratifying active group by presence/absence of seizure occurrences, sub-groups were compared using contingency chi-square tests of independence and relative risk (RR) ratios.

Results: Two unique participants experienced seizures (1 active, 1 placebo). Post seizure, both participants returned to baseline neurobehavioral function. Both participants received antiepileptics during remaining rTMS sessions, which were completed without further seizures. rTMS-related seizure incidence rate is 59 per 1000 persons. Logistic regression revealed no difference in seizure occurrence by treatment condition (active vs placebo) or when examined with seizure risk factors (P > .1). Presence of ventriculoperitoneal shunt elevated seizure risk (RR = 2.0).

Conclusion: Collectively, findings indicate a low-likelihood that the specified rTMS protocol exacerbates baseline seizure rates in persons with DoC after TBI. In presence of VP shunts, however, rTMS likely elevates baseline seizure risk and mitigation of this increased risk with pharmacological seizure prophylaxis should be considered.