title: Evaluation of tentorial length and angle in sleep-wake disturbances after mild traumatic brain injury.
abstract: OBJECTIVE
  The purpose of this study was to determine if there is an association between tentorial length and angle and sleep-wake disturbances in patients with mild traumatic brain injury (TBI).
  
  
  METHODS
  MRI examinations of the brain of 34 consecutive patients with mild TBI with sleep-wake disturbance and 30 patients with mild TBI without sleep-wake disturbance were retrospectively reviewed. The length of the tentorium on a sagittal T1-weighted image (tentorial length) and the angle formed between the tentorium and a line through the foramen magnum (tentorial angle) were measured. Results were correlated with both neuropsychologic testing and any sleep-wake disturbance.
  
  
  RESULTS
  No significant difference existed between patients with and without sleep-wake disturbances in terms of age (p=0.44), sex (p=0.13), Immediate Post-Concussion Assessment Cognitive Test total symptom score (p=0.10), verbal memory score (p=0.32), visual memory score (p=0.31), processing speed (p=0.15), or reaction time (p=0.84). Tentorial length in patients with mild TBI with sleep-wake disturbances was significantly longer than patients with mild TBI without sleep-wake disturbances (p<0.01), and tentorial angle was significantly smaller (p<0.01). Tentorial angle was inversely correlated with length of time to recovery (p=0.002), and tentorial length was directly correlated with length of time to recovery (p<0.001).
  
  
  CONCLUSIONS
  Among patients with mild TBI with similar cognitive function and symptom severity, those with sleep-wake disturbances have significantly longer tentorial length with a flatter angle than do patients with mild TBI without sleep symptoms, with length of time to recovery being directly correlated with tentorial length and indirectly correlated with tentorial angle. Direct impact between the tentorium and the pineal gland during mild TBI may lead to pineal gland injury, disruption of melatonin homeostasis, and sleep-wake disturbances.
authors.affiliation: 1 All authors: Department of Radiology, University of Pittsburgh Medical Center, 3950 Presby South Towers, 200 Lothrop St, Pittsburgh, PA 15213.
authors.forename: Karl
authors.initials: K
authors.lastname: Yaeger
authors.forename: Lea
authors.initials: L
authors.lastname: Alhilali
authors.forename: Saeed
authors.initials: S
authors.lastname: Fakhran
mesh_terms: D000293:Adolescent; D000328:Adult; D001930:Brain Injuries / Q000150:complications* / Q000473:pathology*; D002531:Cerebellum / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020178:Sleep Disorders, Circadian Rhythm / Q000209:etiology* / Q000473:pathology*; D055815:Young Adult