Trigeminal nerve stimulation for disorders of consciousness: evidence from 21 cases

According to previous case reports, trigeminal nerve stimulation (TNS) can be successfully used to wake a non-responsive unconscious patient. However, no studies have comprehensively investigated the effect of TNS on patients with disorders of consciousness (DOC). Therefore, the present study aimed to assess the safety and efficacy of TNS in DOC patients recruited at the First Affiliated Hospital of Nanchang University. We used Coma Recovery Scale-Revised (CRS-R) scores to assess patients at baseline and after 1–4 weeks of TNS. The patients were further followed up for 4 weeks after the last stimulation to evaluate the safety of the procedure. The participant group comprised 21 DOC patients with an acquired brain injury who were more than 3 months post-injury. The participants were 44.29 ± 12.55 years old and 5.52 ± 1.83 months post-DOC onset, and included 12 patients who were in a vegetative state or had unresponsive wakefulness syndrome and 9 patients who were in a minimally conscious state. Compared with CRS-R scores at baseline, those at weeks 4 and 8 showed no significant improvements in any of the DOC patients. Nonetheless, CRS-R scores improved throughout the study period in 8 out of the 21 DOC patients. Among those with improved scores, two patients in a minimally conscious state had improved CRS-R scores at week 4, while five had improved scores at 4 weeks later. Only one patient with vegetative state/unresponsive wakefulness syndrome had recovered to a minimally conscious state at week 4. Importantly, no obvious treatment-related adverse events were considered to be related to TNS. Taken together, these data provide early evidence that TNS may be an effective and safe approach for promoting the recovery of consciousness in patients with neurological disorders.