Neuropsychological significance of anosmia following traumatic brain injury.
OBJECTIVE
To investigate the incidence of anosmia following traumatic brain injury (TBI) using a standardized instrument and to test hypotheses that post-TBI anosmics perform significantly more poorly than do post-TBI normosmics on measures of executive skills and functional outcome.


METHODS
Prospective quasi-experimental between-groups design.


METHODS
Sixty-eight adults diagnosed with TBI.


METHODS
Brain injury rehabilitation program based at a Midwestern medical center.


METHODS
University of Pennsylvania Smell Identification Test (UPSIT), selected neuropsychological measures of executive skills, the Disability Rating Scale (DRS), and the Community Integration Questionnaire (CIQ).


RESULTS
Forty-four subjects (65%) demonstrated impaired olfaction; only 13 (30%) acknowledged smell dysfunction. Anosmic and normosmic groups did not differ in demographics, IQ, chronicity, or admission Glasgow Coma Scale (GCS). Anosmics had longer coma (P =. 01), more severe deficits in complex attention (Trailmaking Test, Part B, P =.01), new learning/memory (California Verbal Learning Test Trial V [CVLT-V], P =.001), and problem solving (Wisconsin Card Sorting Test [WCST], P =.001), leading to greater functional impairment (Disability Rating Scale [DRS], P =.003). No differences emerged on the CIQ.


CONCLUSIONS
Anosmia is a common sequela of TBI, although only a minority of patients are aware of this deficit. Further, anosmics demonstrated greater impairment in a variety of frontal-lobe mediated executive functions, as well as greater functional disability.
Callahan
C D
CD
Center for Neuromuscular Sciences, Memorial Medical Center, Springfield, Illinois 62781, USA. callahan.chuck@mhsil.com
Hinkebein
J
J
D000328:Adult; D001288:Attention / Q000502:physiology; D001930:Brain Injuries / Q000150:complications* / Q000503:physiopathology; D003128:Coma / Q000209:etiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D015600:Glasgow Coma Scale; D006801:Humans; D015994:Incidence; D007360:Intelligence; D008297:Male; D008568:Memory / Q000502:physiology; D008606:Mental Processes / Q000502:physiology; D009484:Neuropsychology; D000857:Olfaction Disorders / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D011340:Problem Solving / Q000502:physiology; D011446:Prospective Studies; D012903:Smell / Q000502:physiology; D012917:Social Adjustment; D013997:Time Factors; D014706:Verbal Learning / Q000502:physiology