Retrospective analysis of sleep patterns in patients with chronic disorders of consciousness

Abstract

Analysis of sleep patterns in patients with chronic disorders of consciousness attracts attention from the perspective of the diagnosis and prognosis of the disease as well as the treatment. Yet, the very existence of normal sleep in patients in a vegetative or minimally conscious state is still a matter of debate. This paper presents a retrospective analysis of overnight polysomnographic records of 40 patients with chronic disorders of consciousness aimed at the possibility of establishing the connection between the degree of impaired consciousness and the presence and organization of polysomnographic graphical elements, associated with stages of sleep in normal individuals. Specialized software based on expert system artificial intelligence was developed to calculate indices and parameters that characterize sleep. It was shown that a remarkably low percentage of patients have a rhythmic change in sleep patterns, what indicates the prevalence of violations of the Sleep–Wake cycle in a vegetative state and minimally conscious state. Sleep spindles were not found in records, however, the absence can originate from the limitations of polysomnographic method applied to patients with severe brain damage. A positive correlation between the rhythmic change of sleep patterns, better outcome and CRS-R scores was confirmed.

Sleep and Circadian Disturbance in Disorders of Consciousness: Current Methods and the Way towards Clinical Implementation

“…Nekrasova and colleagues showed that automated software can detect sleep-related elements (e.g., sleep spindles, slow waves) to perform an R&K-like scoring in DoC patients. 54 This method showed that some organization of sleep stages was only present in 12.5% of 40 patients, none reached NREM2 or REM sleep and only 77.5% showed signs of wakefulness.…”

“…Prognosis did not increase with increased spindle activity and VS/UWS patients showed more NREM, increased fragmentation and slower activity in both NREM and REM compared to controls. Nekrasova and colleagues showed that automated software can detect sleep-related elements (e.g., sleep spindles, slow waves) to perform an R&K-like scoring in DoC patients 54 . This method showed that some organization of sleep stages was only present in 12.5% of 40 patients, none reached NREM2 or REM sleep and only 77.5% showed signs of wakefulness.…”

Study of Brain Circadian Rhythms in Patients with Chronic Disorders of Consciousness and Healthy Individuals Using Microwave Radiometry

“…The mere fact of alternating periods of sleep and wakefulness in VS patients is not evidence of the presence of circadian rhythm and remains a debatable issue, including in relation to MCS patients. Severe brain damage that caused the development of DOC (strokes, TBI, anoxic lesions) cannot but disrupt the activity of central oscillators, directly damaging them or destroying links with the periphery, and the level of preservation of circadian rhythms and the dynamics of their recovery can be an informative diagnostic criterion for assessing the patient’s condition [ 13 , 14 ].…”