Recent work by Manon Carrière and colleagues at the University of Liège (Belgium) has demonstrated that the ability to localize an auditory stimulus should be considered as a sign of consciousness.
They observed significant differences in survival rates at two-year follow-up and in brain function between unresponsive patients who could successfully localize sounds and those who couldn’t. Notably, higher EEG connectivity in the fronto-parietal network and secondary visual areas was found in the group of patients with auditory localization, as well as in the alpha band networks. In terms of FDG-PET and EEG measures, unresponsive patients with localization were closer to (minimally) conscious patients than their counterparts without auditory localization.
Based on these findings, the authors suggest the inclusion of auditory localization in the diagnostic criteria of the minimally conscious state, which would have major implications in patient care and end-of-life decisions.
Key Points:
- Localization to auditory stimulus may be considered as a new clinical sign of the minimally conscious state.
- Unresponsive patients who presented this behaviour demonstrated better survival rates at 2 years
- Higher EEG connectivity was observed in patients with auditory localization across fronto-parietal and visual networks.
- Brain metabolism assessed by FDG-PET was also higher in unresponsive patients with auditory localization, resembling the metabolic profile of minimally conscious patients.
References:
Manon Carrière, Helena Cassol, Charlène Aubinet, Rajanikant Panda, Aurore Thibaut, Stephen K Larroque, Jessica Simon, Charlotte Martial, Mohamed A Bahri, Camille Chatelle, Géraldine Martens, Srivas Chennu, Steven Laureys, Olivia Gosseries, Auditory localization should be considered as a sign of minimally conscious state based on multimodal findings, Brain Communications, Volume 2, Issue 2, 2020, fcaa195, https://doi.org/10.1093/braincomms/fcaa195