Altered saccade control reveals executive dysfunction in late-life depression

Abstract

Late-life depression (LLD) is frequently accompanied by executive dysfunction, which is associated with poorer clinical outcomes but remains difficult to assess objectively in older adults. Saccadic eye movements provide a rapid and non-invasive approach for probing executive-control processes supported by frontal–subcortical circuits. This study examined executive functioning in LLD by assessing saccade performance in an interleaved pro-saccade and anti-saccade task. Video-based eye tracking was used to characterize saccade responses in older adults with LLD ( N = 29) and age-matched healthy controls (CTRL; N = 19). Measures included direction errors, saccade latencies, short-latency saccades, saccade metrics, and voluntary override time (VOT). Cognitive status and depression severity were assessed with the Montreal Cognitive Assessment (MoCA) and the Geriatric Depression Scale-15 (GDS-15), respectively. Individuals with LLD showed a significantly higher rate of direction errors in anti-saccade trials compared with CTRL. Short-latency short-latency pro-saccades were also faster in the LLD group, whereas saccade metrics did not differ reliably between groups. Within the LLD group, MoCA scores were significantly associated with anti-saccade error rates and VOT, while GDS-15 scores were not correlated with these oculomotor measures. LLD is associated with selective alterations in executive-control-dependent saccade behavior. These findings provide preliminary evidence that saccade-based measures may help characterize executive dysfunction in LLD, although larger studies are needed to establish their reliability and clinical utility. Not applicable.