title: Recovery of cognitive function after traumatic brain injury: a multilevel modeling analysis of Canadian outcomes.
abstract: OBJECTIVE
  To ascertain patterns of cognitive recovery during the first year after traumatic brain injury (TBI). Specifically, differential recovery across cognitive domains was investigated.
  
  
  METHODS
  Prospective, longitudinal, naturalistic, 1-year follow-up study.
  
  
  METHODS
  Large, urban inpatient neurorehabilitation program.
  
  
  METHODS
  Patients (N=75) with moderate to severe TBI.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Patients with TBI were followed over the course of 1 year, during which participants' neuropsychological status was repeatedly evaluated at 3 time points (2, 5, and 12 months postinjury).
  
  
  RESULTS
  Multilevel modeling results were consistent with previous research, demonstrating that recovery in the first year postinjury is asymptotic in nature, with more accelerated recovery occurring during the first 5 to 6 months. Importantly, results also suggest that recovery is not uniform across cognitive domains. From 2 to 5 months postinjury, steeper recovery curves were revealed for indices of memory, speeded executive function, verbal abstraction, and manual dexterity relative to untimed tests of executive function and word knowledge. Recovery trajectories did not significantly vary as a function of cognitive domain over the course of the last 5 to 12 months.
  
  
  CONCLUSIONS
  These results are the first to explore trajectories of recovery directly as a function of multiple cognitive domains. They are expected to have implications for rehabilitative efforts as well as our understanding of the architecture of natural recovery after TBI.
authors.affiliation: Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Christensen
authors.forename: Brenda
authors.initials: B
authors.lastname: Colella
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Inness
authors.forename: Deborah
authors.initials: D
authors.lastname: Hebert
authors.forename: Georges
authors.initials: G
authors.lastname: Monette
authors.forename: Mark
authors.initials: M
authors.lastname: Bayley
authors.forename: Robin E
authors.initials: RE
authors.lastname: Green
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001930:Brain Injuries / Q000453:epidemiology / Q000534:rehabilitation*; D003071:Cognition / Q000502:physiology*; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D011379:Prognosis; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult