Correlation between neurobehavioural assessment and functional magnetic resonance imaging in the diagnosis of prolonged disorders of consciousness

Abstract

The misdiagnosis rate of prolonged disorders of consciousness remains at approximately 40%, owing to overlap between diagnostic criteria and inconsistencies in patient responses. Improved accuracy is essential for the appropriate provision of treatment and rehabilitation. Neuroimaging may provide additional diagnostic information to standard neurobehavioural assessment, enabling identification of higher levels of awareness. In this study, the Sensory Tool to Assess Responsiveness (STAR) neurobehavioural assessment was used to assess the level of awareness of 19 patients with prolonged disorders of consciousness. Patients also completed an fMRI diagnostic assessment. The degree of concordance between fMRI and STAR diagnoses was substantial, despite significant delays for some patients between the two assessments. Discrepant diagnoses may relate to this delay or to the inconsistency of responses which characterise the minimally conscious state. The findings indicate that fMRI neuroimaging and STAR neurobehavioural assessment, while largely concordant, may identify different facets of awareness in some patients, which supports the use of both types of assessment in forming a diagnosis. Recommendations for future research include minimal delays between neurobehavioural and neuroimaging assessment, larger patient cohorts, and the use of multiple shorter fMRI assessments which provide more opportunities for patients to exhibit relevant behaviours.

Keywords: Behavioural assessment; Brain injury; Disorders of consciousness; Minimally conscious state; Neurobehavioural assessment; Vegetative state.