Behavioural improvement in a minimally conscious state after caloric vestibular stimulation: Evidence from two single case studies.

Objective:To investigate whether caloric vestibular stimulation, a non-invasive form of neuro-modulation, alters the level of awareness in people residing in a minimally conscious state.Design:Single-case (n = 2), prospective, controlled (ABAB) efficacy study.Setting:Tertiary, neuro-rehabilitation inpatient ward within a university hospital.Participants:Two individuals in a minimally conscious state.Intervention:Left ear caloric vestibular stimulation was performed in two four/five-week blocks interleaved with two four/five-week blocks of sham stimulation. Session duration and frequency gradually increased within each block from once per day for 10 minutes (Week 1) to once per day for 20 minutes (Week 2) to 20 minutes twice per day in the remaining weeks.Measures:Wessex Head Injury Matrix, JFK Coma Recovery Scale – Revised.Results:Both participants’ Wessex Head Injury Matrix scores indicated a transition from involuntary (i.e. mechanical vocalization) to voluntary (i.e. gesture making, selective responses...