title: Olfactory identification and its relationship to executive functions, memory, and disability one year after severe traumatic brain injury.
abstract: OBJECTIVE
  To explore the frequency of posttraumatic olfactory (dys)function 1 year after severe traumatic brain injury (TBI) and determine whether there is a relationship between olfactory identification and neuropsychological test performance, injury severity and TBI-related disability.
  
  
  METHODS
  A population-based multicenter study including 129 individuals with severe TBI (99 males; 16 to 85 years of age) that could accomplish neuropsychological examinations. Olfactory (dys)function (anosmia, hyposmia, normosmia) was assessed by the University of Pennsylvania Smell Identification Test (UPSIT) or the Brief Smell Identification Test (B-SIT). Three tests of the Delis-Kaplan Executive Function System (D-KEFS) were used to assess processing speed, verbal fluency, inhibition and set-shifting, and the California Verbal Learning Test-II was used to examine verbal memory. The Glasgow Outcome Scale-Extended (GOSE) was used to measure disability level.
  
  
  RESULTS
  Employing 2 different smell tests in 2 equal-sized subsamples, the UPSIT sample (n = 65) classified 34% with anosmia and 52% with hyposmia, while the B-SIT sample (n = 64) classified 20% with anosmia and 9% with hyposmia. Individuals classified with anosmia by the B-SIT showed significantly lower scores for set-shifting, category switching fluency and delayed verbal memory compared to hyposmia and normosmia groups. Only the B-SIT scores were significantly correlated with neuropsychological performance and GOSE scores. Brain injury severity (Rotterdam CT score) and subarachnoid hemorrhage were related to anosmia. Individuals classified with anosmia demonstrated similar disability as those with hyposmia/normosmia.
  
  
  CONCLUSIONS
  Different measures of olfaction may yield different estimates of anosmia. Nevertheless, around 1 third of individuals with severe TBI suffered from anosmia, which may also indicate poorer cognitive outcome.
authors.affiliation: Department of Research, Sunnaas Rehabilitation Hospital.
authors.forename: Solrun
authors.initials: S
authors.lastname: Sigurdardottir
authors.affiliation: Institute of Health and Society, Research Centre for Habilitation and Rehabilitation Models and Services (CHARM), Faculty of Medicine, University of Oslo.
authors.forename: Nada
authors.initials: N
authors.lastname: Andelic
authors.affiliation: Department of Physical Medicine and Rehabilitation, St. Olavs Hospital, Trondheim University Hospital.
authors.forename: Toril
authors.initials: T
authors.lastname: Skandsen
authors.affiliation: Department of Rehabilitation, University Hospital of North Norway.
authors.forename: Audny
authors.initials: A
authors.lastname: Anke
authors.affiliation: Division of Surgery and Clinical Neuroscience, Department of Physical Medicine and Rehabilitation, Oslo University Hospital.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Roe
authors.affiliation: Division of Surgery and Clinical Neuroscience, Department of Physical Medicine and Rehabilitation, Oslo University Hospital.
authors.forename: Oyvor Oistensen
authors.initials: OO
authors.lastname: Holthe
authors.affiliation: Department of Physical Medicine and Rehabilitation, Haukeland University Hospital.
authors.forename: Eike
authors.initials: E
authors.lastname: Wehling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000523:psychology*; D006233:Persons with Disabilities / Q000523:psychology*; D056344:Executive Function; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D000857:Olfaction Disorders / Q000209:etiology / Q000523:psychology*; D055696:Olfactory Perception; D012903:Smell