To present an updated version of the ‘Post-acute Level Of Consciousness scale’ (PALOC-s), in accordance with the latest scientific insights.

Within the context of a research project, 20 years ago, the PALOC-s was developed for the purpose of following the development of the level of consciousness of young unconscious patients participating in a rehabilitation program. Meanwhile, the understanding of the behavior related to different levels of consciousness has developed and terminology has changed, resulting in the need to revise the PALOC-s. With the preservation of the original description of the eight hierarchical levels of PALOC-s, adaptations are made in the terminology and grouping of these levels.

This manuscript presents the revised version of PALOC-sr, which is suitable for use in clinical practice. The validation of this scale is recommended for its optimal use in future (international) research projects.

Despite a growing understanding of disorders of consciousness following severe brain injury, the association between long-term impairment of consciousness, spontaneous brain oscillations, and underlying subcortical damage, and the ability of such information to aid patient diagnosis, remains incomplete.

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.

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 the brainstem. Furthermore, we showed that the combination of demographics, encephalographic, and imaging data in an analytic framework can be employed to aid behavioral diagnosis.

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.