[The effect of age on executive functioning after acquired brain injury in adults]

Executive functioning deficits have often been described in normal aging. They are also known to be a frequent sequel of traumatic brain injury, where patients may exhibit severe long-standing impairments in instrumental activities of daily living. One could therefore expect that cerebral lesions affecting executive functioning would result in more severe impairments in older patients. We previously developed an ecological assessment of executive functions, consisting of a cooking task, requiring multitasking abilities and known to be sensitive to a dysexecutive syndrome [Cortex 36 (2000) 649-669]. The aim of this study was to analyze the effect of age on the cognitive and ecological assessments of executive functions in a group of patients with acquired brain injury (ABI) resulting in a dysexecutive syndrome. Studies in this area usually focus on patients older than 60 or 65, but we chose to analyze the effect of age in a younger population. We hypothesized that older patients would have poorer performances on the cognitive and ecological tests of executive functioning, when compared to younger patients.

Forty-five patients with ABI resulting in frontal lesions and a dysexecutive syndrome participated in this study. Patients underwent a comprehensive battery of cognitive tests assessing executive functioning, as well as the cooking task. We also studied a group of 12 control subjects who performed the cooking task.

No effect of age was found on performance in the cooking task in the control group. Age was not related to demographic parameters or injury severity in the ABI group. Although the ABI group was relatively young (mean age: 40.3 years (S.D.=12.5), ranging from 17 to 63), results indicated a significant deleterious effect of age on the cognitive tests of executive functioning in the ABI group. We also highlighted a significant worsening of patients' performance in the cooking task with age, and this effect was found on several variables of task analysis: the number of errors and occurrence of dangerous behaviors.

Our study demonstrates the deleterious effect of aging on cognitive and ecological assessment of executive functioning after ABI. The strength of this study is that it deviated from the traditional age considered in studies of elderly populations and focused on younger patients. It is therefore important to consider the implication that this may have on a patient's rehabilitation program and postinjury discharge.