Can a Single Night of Sleep Deprivation Unmask Human Sleep and Neurophysiobehavioral Impairments During the Post-Acute Phase of Mild Traumatic Brain Injury?

The purpose of this study was twofold: (a) to determine whether, and the extent to which, the challenge of a single night of total sleep deprivation (TSD) unmasks lingering brain health-related deficits in individuals who within the past 3 to 12 months had been diagnosed (yet medically cleared) with a mild traumatic brain injury (mTBI+), and (b) to determine whether mTBI+ results in any neurophysiobehavioral deficits in the ability to recover from TSD. Seven previously concussed (mTBI+) adults (24.5 ± 5.3 years old) and six non-concussed control (mTBI-) adults underwent 24 h TSD preceded by 8 h baseline sleep (BSL) and followed by 8 h recovery sleep (REC). Study measures included the psychomotor vigilance test (PVT) across the entire study and polysomnography during nighttime sleep and daytime nap tests. mTBI+ (vs mTBI-) subjects exhibited more minor lapses on the PVT across all study phases. NREM (N3) sleep and total sleep time (TST) amounts were lower and wake after sleep onset (WASO) was higher in mTBI+ subjects (vs mTBI) at baseline and REC. mTBI+ (vs mTBI-) subjects showed no main effects in maintenance of wakefulness across TSD. Although there is some evidence that TSD may unmask latent performance deficits in mTBI+ subjects, a definitive conclusion was precluded by differences in baseline sleep in mTBI+ (vs mTBI-) subjects, suggesting that they may habitually carry a relatively elevated sleep debt (vs mTBI- controls). Reversal of TSD-induced neurophysiobehavioral deficits following recovery sleep were comparable for both groups, revealing no significant abnormalities in the responsivity of the sleep homeostat in the mTBI+ subjects.