Results of the application of a set of functional MRI paradigms to diagnose “covert cognition” phenomenon in patients with prolonged disorders of consciousness

Abstract

   In recent years, the development of instrumental diagnostics has made it possible to identify a subgroup among patients with prolonged disorders of consciousness (PDoC) in which the phenomenon of “covert cognition” occurs, characterized by a dissociation between the clinical assessment and the data of instrumental diagnostic methods. To identify this phenomenon, we used a set of diagnostic paradigms developed at the Scientific Centre of Neurology in collaboration with a group of neuropsychologists from M.V. Lomonosov Moscow State University and tested on a cohort of healthy volunteers (n = 10) under the control of functional magnetic resonance imaging (fMRI).   Objective: to evaluate the results of applying a set of paradigms to diagnose the phenomenon of “covert cognition” in a Russian-speaking cohort of patients with PDoC.   Material and methods. In this fragment of a prospective study, after analyzing the medical records of 138 patients, 10 individuals with PDoC of various etiologies were included. Patients underwent a thorough neurological examination and a comprehensive neurophysiological and imaging study with emphasis on fMRI with paradigms.   Results. When analyzing the fMRI data, significant activation clusters were detected in five patients in response to some passive paradigms, some of which were comparable to those of healthy subjects.   Conclusion. Using the proposed set of fMRI paradigms, we demonstrated the possibility of identifying the phenomenon of “covert cognition” in a Russian-speaking cohort of patients in vegetative state / with unresponsive wakefulness syndrome (1/6), and confirmed by instrumental methods preservation of individual aspects of consciousness in patients in minimally conscious state “minus” (4/4).