Effect of age on visuomotor functional MR imaging

Rationale and Objectives. We sought to determine the effect of age on functional MR imaging experiments performed with visual and motor stimulation. We hypothesized that there would be a diminution in the amplitude of fMRI activation with increasing subjects' age. Materials and Methods. We used fixed effects models to study the amplitude of activation during a block design visuomotor task in three different age groups: old (mean: 75 years; standard deviation: 6 years), middle-aged (mean: 52 years; standard deviation: 9 years) and young (mean: 29 years; standard deviation: 5 years). Each group included 7 subjects. Regions of interest (ROI) were left primary motor area (LM1), supplementary motor area (SMA), and right and left occipital (RO, LO) visual areas. Individual subjects and group statistical parametric maps (SPMs) were generated for each ROI, and then the mean amplitude of activation was compared using the group analysis and t test. Results. The young age group showed higher amplitude of activation than middle and old age groups in all ROI (P < 0.01 uncorrected). Unpaired two tailed t test results between the groups showed significant differences between middle and young, and old and young age groups in all ROIs (P ≤ 0.05), with the exception of old and young age groups in RO region (P= 0.11). Conclusion. The group analysis, and unpaired t test results reveal higher amplitude of fMRI activation in the young versus the old and middle-aged groups.