Axonal Injury, Sleep Disturbances, and Memory following Traumatic Brain Injury

Abstract

AbstractObjectivesTraumatic brain injury (TBI) is associated with sleep deficits, but it is not clear why some report sleep disturbances and others do not. The objective of this study was to assess the associations between axonal injury, sleep, and memory in chronic and acute TBI.MethodsData were acquired from two independent datasets which included 156 older adult veterans (69.8 years) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) with prior moderate-severe TBIs and 90 (69.2 years) without a TBI and 374 participants (39.6 years) from Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) with a recent mild TBI (mTBI) and 87 controls (39.6 years), all who completed an MRI, memory assessment, and sleep questionnaire.ResultsOlder adults with a prior TBI had a significant association between axial diffusivity in the left anterior internal capsule (ALIC) and sleep disturbances [95% CI(5.0e+07, 1.7e+08), p ≤ .01]. This association was significantly different [95% CI(6.8e+07,2.2e+08), p=.01] from controls. ALIC predicted changes in memory over one-year in TBI [95% CI(−1.8e+08,-2.7e+07), p=.03]. We externally validated those findings in TRACK-TBI where ALIC axial diffusivity within two-weeks after injury was significantly associated with higher sleep disturbances in the TBI group at two-weeks [95% CI(−7.2e-06, −1.9e-04), p=0.04], six-months [95% CI(−4.2e-06,-1.3e-04), p≤ .01] and 12-months post-injury [95% CI(−5.2e-06, −1.2e-04), p=0.03]. These associations not seen in controls.InterpretationsAxonal injury to the ALIC is robustly associated with sleep disturbances in multiple TBI populations. Early assessment of ALIC damage following mTBI could identify those at risk for persistent sleep disturbances following injury.