EEG power spectra and subcortical pathology in chronic disorders of consciousness

Lutkenhoff, Evan S.; Nigri, Anna; Sebastiano, Davide Rossi; Sattin, Davide; Visani, Elisa; Rosazza, Cristina; D’Incerti, Ludovico; Bruzzone, Maria Grazia; Franceschetti, Silvana; Leonardi, Matilde; Ferraro, Stefania; Monti, Martin M.

Objective To determine (i) the association between long-term impairment of consciousness after severe brain injury, spontaneous brain oscillations, and underlying subcortical damage, and (ii) whether such data can be used to aid patient diagnosis, a process known to be susceptible to high error rates. Methods Cross-sectional observational sample of 116 patients with a disorder of consciousness secondary to brain injury, collected prospectively at a tertiary center between 2011 and 2013. Multimodal analyses relating clinical measures of impairment, electroencephalographic measures of spontaneous brain activity, and magnetic resonance imaging data of subcortical atrophy were conducted in 2018. Results In the final analyzed sample of 61 patients, systematic associations were found between electroencephalographic power spectra and subcortical damage. Specifically, the ratio of beta-to-delta relative power was negatively associated with greater atrophy in regions of the bilateral thalamus and globus pallidus (both left > right) previously shown to be preferentially atrophied in chronic disorders of consciousness. Power spectrum total density was also negatively associated with widespread atrophy in regions of the left globus pallidus, right caudate, and in brainstem. Furthermore, we showed that the combination of demographics, encephalographic, and imaging data in an analytic framework can be employed to aid behavioral diagnosis. Conclusions These results ground, for the first time, electroencephalographic presentation detected with routine clinical techniques in the underlying brain pathology of disorders of consciousness and demonstrate how multimodal combination of clinical, electroencephalographic, and imaging data can be employed in potentially mitigating the high rates of misdiagnosis typical of this patient cohort. Search terms disorders of consciousness, subcortical pathology, EEG, MRI.