Abstract
Disorders of consciousness (DOC) are often accompanied by aberrant oscillatory neural activity in the thalamus and cerebral cortex. Patient-friendly non-invasive treatments targeting this functional anomaly are still missing. We propose and validate a novel approach that aims to restore DOC patients’ thalamocortical oscillations by combining rhythmic trigeminal-nerve stimulation (TNS) with comodulated musical stimulation. In a cluster-randomized, placebo-controlled, double-blinded, pretest-posttest clinical study, we show that application of this multisensory approach for 40 min on five consecutive days reliably leads to long-lasting improvements in DOC patients’ consciousness (assessed with Coma Recovery Scale-Revised) and oscillatory brain activity at the musical-electric TNS frequency (assessed with electroencephalography and a novel rhythmic auditory-speech paradigm). We found diagnostic improvement in 47% of patients in minimally conscious state and a positive relationship between patients’ behavioral and neural improvements. Based on this evidence we argue that non-invasive musical-electric TNS may serve as an effective patient-friendly DOC treatment and suggest frequency-specific oscillatory neural enhancement as its mode of action.
EXTERNAL TRIGEMINAL NERVE STIMULATION (ETNS) FOR EPILEPSY
