Olfactory dysfunction in head injured workers

Olfactory dysfunction following trauma has been widely reported and is curr ently compensable according to existing American Medical Association guidel ines when it occurs in the occupational setting. Its presence and the risk factors for its development, however, have not been clearly delineated in o ccupationally head injured workers. In order to assess this phenomenon, a s eries of 365 consecutive head injured workers from 1993-1997 was assessed i n order to determine the incidence of post-traumatic olfactory dysfunction and its association with the severity of the head injury, the mechanism of injury and other neurotological abnormalities in the same cohort group. Olf actory dysfunction was identified in 13.7% (9.3% with anosmia, 4.4% with hy posmia/dysosmia). It was more likely where the loss of consciousness >1 h ( p < 0.002), in more severe head injuries (grades II-V) (p < 0.001) and when skull fracture (p < 0.001) occurred. The direction of the blow applied to the skull did not influence its presence, although radiologically confirmed skull fractures in the frontal, occipital, skull base and midface were twi ce as likely as temporal and parietal fractures to result in an olfactory c hange. From a neurotologic perspective, approximately 21.9% of head injured workers were determined to have recognizable evidence of cochleovestibular dysfunction. Olfactory dysfunction as a physical finding post-head injury compares favourably with the presence of post-traumatic benign positional p aroxysmal vertigo (BPPV) and its atypical variants in 11.2% of head injured workers.