Olfactory dysfunction in pediatric traumatic brain injury: a systematic review.

The neuropsychological outcomes of pediatric traumatic brain injury (TBI) have received increasing study over the past 20 years and are currently well delineated in the research literature. One outcome that has received little attention is that of olfactory dysfunction after pediatric TBI. This is despite literature indicating that anosmia and olfactory dysfunction are common after adult TBI and are likely to be linked to severity of injury, neuropathology, and executive dysfunction. At a clinical level, anosmia is known to be reported after pediatric TBI. Despite this, little is known about its prevalence and recovery. A systematic review was undertaken to provide objective information about olfactory dysfunction post-TBI in children. Despite broad inclusion criteria, only four published studies were identified. The studies found were limited by methodological weaknesses, variability in measures, small sample size, and difficulty of comparison across cohorts studied. Despite this, they reported consistent findings of anosmia and olfactory dysfunction in their TBI cohorts and identified a dose-response relationship between severity of injury and olfactory dysfunction. The results of the studies are discussed in terms of relevant findings, limitations, and areas requiring further exploration.