0738 EFFECTS OF SLEEP DEPRIVATION ON BRAIN PERFUSION PATTERNS IN SLEEPWALKERS’ WAKEFULNESS AND SLOW WAVE SLEEP

Abstract

Several EEG-based studies have documented anomalies in the slow wave sleep (SWS) of adult sleepwalkers. Moreover, previous imaging studies have identified specific brain perfusion patterns in sleepwalkers during post sleep deprivation wakefulness as well as during a somnambulistic episode. However, neuroimaging has yet to be used to investigate sleepwalkers’ SWS. The present study measured regional cerebral blood flow (rCBF) with single photon emission computed tomography (SPECT) during sleepwalkers’ post sleep deprivation SWS and resting-state wakefulness. Following 24 hr period of sleep deprivation, 10 sleepwalkers (7F, 3M; mean age: 28.2 ± 6.9 years) and 10 sex and age-matched controls were injected with a unidose of 99mTc-ECD after 2 minutes of stable SWS within their first sleep cycle as well as during resting-state wakefulness. Participants were scanned after each injection with a high-resolution SPECT. Between group differences in rCBF were assessed using two-sample t-tests separately for SWS and wakefulness. Significance was set at p<0.005 at the voxel level uncorrected for multiple comparisons combined with >100 contiguous voxels by cluster. When compared to controls’ rCBF observed during SWS and resting-state wakefulness, sleepwalkers showed significant decreases in several bilateral frontal regions, including the superior frontal, middle frontal and medial frontal gyri. Most of these regions are included in the dorsolateral prefrontal cortex (DLPFC). During SWS, decreased rCBF was also found in sleepwalkers’ left postcentral gyrus, insula and superior temporal gyrus. During waking resting-state, decreased rCBF was also found in parietal and temporal regions of sleepwalkers’ left hemisphere. This study was the first to use neuroimaging to investigate sleepwalkers’ SWS. Decreased rCBF was found in sleepwalkers’ DLPFC and insula, two regions involved in consciousness and in the generation of slow wave activity. The data also reveal altered rCBF patterns during sleepwalkers’ resting-state wakefulness. These findings suggest that prefrontal and insular regions may be implicated in the pathophysiology of sleepwalking. This research was supported by a research grant from the Canadian Institutes of Health Research (CIHR).