Longitudinal cognitive changes in traumatic brain injury: a 30-year follow-up study

To evaluate longitudinal cognitive changes in patients over three decades following traumatic brain injury (TBI).

Two hundred ten patients with substantial TBI of variable severity were initially assessed between 1966 and 1972 at Turku University Hospital (Finland). Of these, 61 patients could be studied using the same assessments in the follow-up examination, on average 30 years after the TBI. The results of the follow-up assessment were also compared with an age- and education-matched control group. During each examination, patients were assessed with five subtests of the Wechsler Adult Intelligence Scale, three tests for episodic memory, and the general cognitive decline was determined.

The general pattern of slight cognitive decline during a 30-year follow-up contrasted with improvement in semantic memory. Women maintained their cognitive level, but men showed a decline during the follow-up, especially in visuospatial ability and visual memory. Younger patients were likely to maintain or even improve their cognitive functioning.

Most of the patients had mild cognitive decline during the follow-up, but this decline was influenced by gender and age at injury. Unlike the long-term course in the other domains of cognition, semantic memory showed good recovery potential after traumatic brain injury (TBI). The profile of long-term cognitive decline after TBI seems to be qualitatively different from the early signs of dementia of the Alzheimer type.