Soluble neural cell adhesion molecule and behavioural recovery in minimally conscious patients undergoing transcranial direct current stimulation

Background: Transcranial direct current stimulation (tDCS) is used for therapeutic purpose in severely brain- injured patients. The relationship between the recovery after tDCS and potential biomarkers in plasma has been limitedly investigated in patients with minimal conscious state (MCS). Objective: To investigate soluble neuronal adhesion molecule (sNCAM) plasma levels in relation to tDCS and recovery processes in MCS. Methods: sNCAM was measured in plasma before (T−1,T0), during (T1) and after (T2, T3) tDCS sessions in eight patients with a post traumatic etiology and at least one year of chronic state. Results: While sNCAM levels were highly correlated overtime, no significant difference was observed in relation to tDCS. An inverse relation was observed between sNCAM levels at baseline and the tDCS long-lasting effects (T−1, r=−0.852, p= 0.007; T0, r=−0.787, p= 0.020). Conclusions: This exploratory research suggests the sNCAM levels, potentially associated with tDCS outcomes, as a candidate biomarker of neurobiological after-effects in MCS patients.