title: Recovery of episodic memory subprocesses in mild and complicated mild traumatic brain injury at 1 and 12 months post injury.
abstract: Episodic memory complaints are commonly reported after traumatic brain injury (TBI). The contributions of specific memory subprocesses (encoding, consolidation, and retrieval), however, are not well understood in mild TBI (mTBI). In the present study, we evaluated subprocesses of episodic memory in patients with mTBI using the item-specific deficit approach (ISDA), which analyzes responses on list learning tasks at an item level. We also conducted exploratory analyses to evaluate the effects of complicated mTBI (comp-mTBI) on memory.
  
  
  
  We compared episodic verbal memory performance in mTBI (n = 92) at approximately 1 and 12 months post TBI, as well as in a healthy comparison (HC) group (n = 40) at equivalent time points. Episodic memory was assessed using the California Verbal Learning Test-2nd Edition (CVLT-II), and both standard CVLT-II scores and ISDA indices were evaluated.
  
  
  
  Compared to the HC group, the mTBI group showed significantly poorer encoding and learning across time, as measured by ISDA and CVLT-II. Further analyses of these mTBI subgroups [(noncomplicated mTBI (NC-mTBI, n = 77) and comp-mTBI (n = 15)], indicated that it was the comp-mTBI group who continued to demonstrate poorer encoding ability than the HC group. When the patient groups were directly compared, the NC-mTBI group improved slightly on the ISDA Encoding Deficit Index. While the comp-mTBI group worsened slightly over time, their poorer encoding ability was not likely clinically meaningful.
  
  
  
  These findings indicate that, while the NC-mTBI and HC groups' performances were comparable by 12 months, a primary, long-term deficit in encoding of auditory verbal information remained problematic in the comp-mTBI group.
authors.affiliation: a Department of Psychiatry, Section of Neuropsychiatry , Brain Imaging Laboratory, Geisel School of Medicine at Dartmouth , Lebanon , NH , USA.
authors.forename: Fadi M
authors.initials: FM
authors.lastname: Tayim
authors.affiliation: a Department of Psychiatry, Section of Neuropsychiatry , Brain Imaging Laboratory, Geisel School of Medicine at Dartmouth , Lebanon , NH , USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Flashman
authors.affiliation: b Department of Psychiatry and Biobehavioral Sciences , David Geffen School of Medicine at UCLA , Los Angeles , CA , USA.|c Department of Psychiatry, Division of Psychology , Harbor-UCLA Medical Center , Torrance , CA , USA.|d Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance , CA , USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Wright
authors.affiliation: a Department of Psychiatry, Section of Neuropsychiatry , Brain Imaging Laboratory, Geisel School of Medicine at Dartmouth , Lebanon , NH , USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Roth
authors.affiliation: a Department of Psychiatry, Section of Neuropsychiatry , Brain Imaging Laboratory, Geisel School of Medicine at Dartmouth , Lebanon , NH , USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: McAllister
mesh_terms: D000293:Adolescent; D000328:Adult; D001924:Brain Concussion / Q000150:complications / Q000523:psychology*; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000523:psychology*; D061212:Memory, Episodic; D008875:Middle Aged; D009483:Neuropsychological Tests; D020127:Recovery of Function; D055815:Young Adult
keywords: Neuropsychology; encoding; memory; postconcussion syndrome; traumatic brain injury