Cognitive functioning following traumatic brain injury: A five-year follow-up

To describe the long-term prevalence and severity of cognitive deficits following significant (i.e., ventilation required for >24 hours) traumatic brain injury. To assess a comprehensive range of cognitive functions using psychometric measures with established normative, reliability, and validity data.

A group of 71 adults was assessed at approximately five years (mean = 66 months) following injury. Assessment of cognitive functioning covered the domains of intelligence, attention, verbal and visual memory, visual-spatial construction, and executive functions.

Impairment was evident across all domains but prevalence varied both within and between domains. Across aspects of intelligence clinical impairment ranged from 8-25% , attention 39-62% , verbal memory 16-46% , visual memory 23-51% , visual-spatial construction 38% , and executive functions (verbal fluency) 13% . In addition, 3-23% of performances across the measures were in the borderline range, suggesting a high prevalence of subclinical deficit.

Although the prevalence of impairment may vary across cognitive domains, long-term follow-up documented deficits in all six domains. These findings provide further evidence that while improvement of cognitive functioning following significant traumatic brain injury may be possible, recovery of function is unlikely.