0301 Sleep Deprivation Unmasks Performance Deficits Following Mild Traumatic Brain Injury

• Published in: Sleep (New York, N.Y.) N.Y.), 2018-04, Vol.41 (suppl_1), p.A115-A116
• Main Authors: St. Pierre, M, Grillakis, A, Campbell, C, Capaldi, V, Mantua, J, Brager, A, Yarnell, A
• Format: Article
• Language: English
• Subjects: Decision making; Sleep deprivation; Traumatic brain injury
• ISSN: 0161-8105; 1550-9109
• DOI: 10.1093/sleep/zsy061.300

Abstract Introduction Subjective cognitive complaints are common in the chronic stages (>3 months since injury) of mTBI, yet there is limited evidence of objective neurocognitive deficits in this population. Neuroimaging studies have demonstrated that although cognitive performance is similar between mTBI individuals and controls, mTBIs have broader utilization of frontal and parietal brain regions during cognitive testing. Therefore, it has been suggested cognitive performance is preserved following mTBI due to changes in neural resource allocation (i.e., compensatory processes). Sleep deprivation, which limits neural compensation capability, may therefore “unmask” cognitive difficulties in this population. Methods We compared psychomotor vigilance test (PVT) performance and decision making (via the Iowa Gambling Task [IGT]) following normal sleep, total sleep deprivation, and a recovery period in mTBI volunteers (n=6) and uninjured controls). We predicted mTBI individuals would lack compensatory capabilities during sleep deprivation, signified by poorer PVT and IGT performance relative to controls. Results For PVT measures, both groups performed worse during sleep deprivation than baseline and recovery, and, as predicted, there was a significant interaction between condition and group for several measures (e.g., false starts [F(2,43.29) = 4.58, p = 0.016], speed [F(4,49.87) = 4.43, p = 0.017], and minor lapses [F(2,35.12) = 3.47, p = 0.042]), such that the mTBI group had poorer performance during the sleep deprivation condition than controls. However, in contrast, neither sleep deprivation nor mTBI status impacted IGT performance. Conclusion Our results indicate, indeed, that sleep deprivation unmasks performance deficits in a chronic mTBI population, and that chronic mTBI, in conjunction with sleep loss, is detrimental for vigilance/alertness. Military populations, who are at a high risk for mTBI and who also frequently undergo bouts of sleep deprivation or sleep restriction, may be particularly vulnerable to these deficits. On the other hand, there was no detectable effect of sleep deprivation (or mTBI) on decision making, suggesting sleep deprivation may specifically unmask vigilance deficits rather than higher-order cognitive deficits in general. Support (If Any) Department of Defense Military Operational Medicine Program.