| An immense amount of heterogeneity is observable within the aging population. Two measures addressing this are biological age, a measure of maturational status that accounts for the functional status of various body systems, and intraindividual variability, a measure of variability in cognitive functioning observed within an individual.; This study examined the potential relation between biological age and intraindividual variability in forty community dwelling adults between the ages of 65 and 85. Biological age was estimated by measures of physiological function (grip strength and peak expiratory flow rate), anthropometric status (body mass index), sensory function (close and distance corrected visual acuity and auditory acuity), biomedical health (diastolic and systolic blood pressure), and cognitive function (fluid reasoning and episodic memory tasks). Median reaction time (RT) and intraindividual variability (coefficient of variation, CV) were measured on a battery of reaction time tasks. Exploratory factor analyses were carried out on the biomarkers, RT and CV scores. The cognitive biomarker factor correlated significantly with CV factor containing n-back, LD, and MSIT (r=-.33, p=.053) and marginally with the CV factor containing SRT (r=-.31, p=.073). The median RT factor containing SRT, CRT, LD, and MSIT correlated significantly with the cognitive biomarker factor (r=-.45, p=.007) and the physiological biomarker factor (r=-.42, p=.011). These results indicated that the approximation of biological age containing measures of cognitive functioning was the only measure of biological age related to variability. |
