Deep Brain Stimulation for Recovery of Consciousness in Minimally Conscious Patients After Traumatic Brain Injury: A Systematic Review

OBJECTIVES: Minimally conscious state (MCS) is a disorder of consciousness in which minimal but definite behavioral evidence of self-awareness or environmental awareness is demonstrated. Deep brain stimulation (DBS) of various targets has been used to promote recovery in patients with disorders of consciousness with varying results. The aim of this systematic review was to assess the effects of DBS in MCS following traumatic brain injury (TBI). MATERIALS AND METHODS: A systematic literature review was carried out using a number of electronic bibliographic data bases to identify relevant studies. We included all studies describing applications of DBS on patients in MCS following TBI. RESULTS: Eight studies were identified, including a total of ten patients, aged 15-58 years. The time from injury to stimulation ranged from 3 to 252 months, with the duration of follow-up post-DBS ranging from 10 to 120 months. Seven patients improved their postsurgical outcome score measures (three patients with the coma recovery scale, one with the near coma scale, and three with the Glasgow outcome score). A descriptive favorable outcome was reported in one patient. Two patients were reported not to have shown any improvements following the intervention. CONCLUSIONS: Current evidence is based on a small population of heterogeneous patients. The time from injury to stimulation was significantly variable and problematic, as spontaneous recovery can occur within the first year of injury. Although seven patients showed promising results in validated outcome measures, evidence supporting the use of DBS in MCS patients following TBI is lacking. There is need for controlled and randomized studies.