What can N100 and ASSR Assess in Patients with Disorders of Consciousness?

Auditory Evoked Potentials (AEP), particularly the N100 component and the auditory steady-state response (ASSR), have been utilized in the clinical assessment of patients with Disorders of Consciousness (DOC). However, the specific utility of these measures remains debated across studies. To clarify the roles of N100 and ASSR in evaluating auditory function and levels of consciousness in DOC patients, we recorded N100 and ASSR responses in 30 DOC patients and assessed their significance at the individual level through statistical analyses. Our findings indicate that, compared to N100, the significance of the ASSR response appears to be a more reliable marker of auditory function. However, neither N100 nor ASSR, at both response and microstate levels, could effectively distinguish between patients diagnosed with unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS). Additionally, we validated the role of ASSR using a portable EEG device in an independent cohort of 30 patients. In summary, our results suggest that ASSR holds promise for assessing auditory function in DOC patients, but its utility in differentiating levels of consciousness may require further consideration. These findings offer valuable insights for clinicians and neuroscientists in selecting and designing objective tools for DOC assessment.