The effect of age on cognitive performance of frontal patients

Abstract

Age is known to affect prefrontal brain structure and executive functioning in healthy older adults, patients with neurodegenerative conditions and TBI. Yet, no studies appear to have systematically investigated the effect of age on cognitive performance in patients with focal lesions. We investigated the effect of age on the cognitive performance of a large sample of tumour and stroke patients with focal unilateral, frontal (n=68), or non-frontal lesions (n=45) and healthy controls (n=52). We retrospectively reviewed their cross sectional cognitive and imaging data. In our frontal patients, age significantly predicted the magnitude of their impairment on two executive tests (Raven's Advanced Progressive Matrices, RAPM and the Stroop test) but not on nominal (Graded Naming Test, GNT) or perceptual (Incomplete Letters) task. In our non-frontal patients, age did not predict the magnitude of their impairment on the RAPM and GNT. Furthermore, the exacerbated executive impairment observed in our frontal patients manifested itself from middle age. We found that only age consistently predicted the exacerbated executive impairment. Lesions to specific frontal areas, or an increase in global brain atrophy or white matter abnormalities were not associated with this impairment. Our results are in line with the notion that the frontal cortex plays a critical role in aging to counteract cognitive and neuronal decline. We suggest that the combined effect of aging and frontal lesions impairs the frontal cortical systems by causing its computational power to fall below the threshold needed to complete executive tasks successfully.

Cognitive Reserve Proxies Do Not Differentially Account for Cognitive Performance in Patients with Focal Frontal and Non-Frontal Lesions

“…Age independently predicted performance on fluency and Trail-Making Part-A but not WAIS-III and GNT. This is in line with our previous work demonstrating that age and NART IQ influence performance on a range of cognitive measures in a smaller group of frontal patients, some of whom have also participated in the current study (Cipolotti et al, 2015b;MacPherson et al, 2017). However, age did not predict our frontal and non-frontal patients' intellectual abilities.…”

Cognitive neuropsychology and its vicissitudes: The fate of Caramazza's axioms

“…Some of the effects of nuisance variables can be reduced by statistical procedures such as analysis of covariance, but for effects of age, say, it can be shown that such partialling procedures may be insufficient (Cipolotti et al, 2015b), and they also do not deal with differences in patterns of aetiologies between subgroups. Again a way to partially guard against this problem is to carry out multiple tests on the same groups.…”

Impact of sociodemographic variables on executive functions

“…The executive functions involve the frontal lobe, particularly the pre-frontal cortex. 3 The development of EFs commences in the first year of life, and develops most between 6 and 12 years of age. 4 After complete maturation, the EFs remain stable until the onset of senescence, 3 being one of the first functions affected by the aging process, particularly working memory 5 and information processing speed.…”

“… 3 The development of EFs commences in the first year of life, and develops most between 6 and 12 years of age. 4 After complete maturation, the EFs remain stable until the onset of senescence, 3 being one of the first functions affected by the aging process, particularly working memory 5 and information processing speed. 6 With advancing age, hemodynamic changes in the whole brain can be expected, where these are most marked in the frontal, temporal and occipital lobes.…”

“…However, the cited studies remain limited and are largely based on screening tests. This scenario prompted the present study investigating executive functions sensitive to aging 3 and their relationships with sociodemographic variables by applying tests sensitive to EFs. Two tasks are often employed in EF assessments.…”