Assessment of anosmia after traumatic brain injury: performance characteristics of the University of Pennsylvania Smell Identification Test.

OBJECTIVE

To examine the performance characteristics of two forms of the University of Pennsylvania Smell Identification Test (UPSIT) in a sample of persons with traumatic brain injury (TBI).

DESIGN

Analysis of consecutive admissions into a brain injury rehabilitation program.

SETTING

Midwestern medical center.

PARTICIPANTS

One hundred twenty-two adults diagnosed with TBI (49% severe TBI, 16% moderate TBI, 35% mild TBI).

MAIN OUTCOME MEASURES: University of Pennsylvania Smell Identification Test (UPSIT; 3- and 40-item versions).

RESULTS

Fifty-six percent of sample exhibited impaired olfaction on the full UPSIT; 40% of these patients were unaware of their deficits. Contrary to expectation, TBI patients detected dangerous odors (natural gas, gasoline, smoke) with high accuracy. Usefulness of a 3-item screening measure was examined: Missing even one item related to a 2:1 likelihood of being anosmic.

CONCLUSIONS

These findings support past investigations indicating that anosmia, and unawareness of olfactory dysfunction, are common in persons with TBI and related to injury severity. The use of the 3-item screening measure as a gross indicator was supported, although caution is advised, because nearly 20% of patients performing perfectly on the 3-item screen scored in the anosmic range on the full UPSIT.