Do aetiology, age and cogntive reserve affect executive performance?

Abstract

Background: The behavioral effect of frontal lesions may be influenced by confounding factors such as aetiology, age and cogntive reserve. Yet no studies have investigated their effects on patients with focal lesions. Objective: Is the grouping of patients with frontal lesions caused by stroke or tumours methodologically appropriate; does age affect cognitive performance, can cognitive reserve protect against cognitive impairment? Patients and Methods/Material and Methods: Cognitive performance was compared across a large sample of frontal patients with stroke, high or low grade tumour, or meningioma. The effect of age, education and NART IQ on the cognitive performance of patients with focal lesions was investigated. Assessments of lesion location, volume, global brain atrophy and non-specific white matter changes were undertaken. Results: No significant difference in cognitive performance between the different aetiologies was found. Age of frontal patients significantly predicted the magnitude of their impairment on executive but not on nominal or perceptual tasks. In contrast, non frontal patients' age did not predict the magnitude of their impairments. After accounting for chronicity, age and severity of frontal lesion, NART IQ contributed to performance on the executive and naming tests whilst education contributed to fluid intelligence. The interactions between lesion severity and our CR proxies were not significant. Conclusion: The grouping of patients with frontal lesions caused by different aetiologies is a justified methodology that helps to further the understanding of frontal executive functions. The frontal cortex plays a critical role in aging to counteract cognitive and neuronal decline and when lesioned greater cognitive reserve does not better withstand neuropathology.