Subtle visuomotor difficulties in preclinical A lzheimer's disease

Background Individuals with preclinical A lzheimer's disease ( P re‐ AD ) present nonimpaired cognition, as measured by standard neuropsychological tests. However, detecting subtle difficulties in cognitive functions may be necessary for an early diagnosis and intervention. Objectives A new computer‐based visuomotor coordination task ( VMC ) was developed to investigate the possible presence of early visuomotor difficulties in P re‐ AD individuals. Associations between VMC task performance and AD biomarkers were studied. The influence of A po E status on participants’ performance was addressed, as well as the relationship between performance and subjective cognitive decline ( SCD ). Methods Sixty‐six cognitively normal ( CN ) elders (19 P re‐ AD and 47 control participants [ CTR ]) and 15 patients with AD performed the VMC task, which consisted in executing visually guided goal‐directed movements that required the coordination of the visual and motor systems. All participants underwent A po E analysis and lumbar puncture. CN participants also completed an extensive standard neuropsychological battery. Results Despite presenting normal cognition in standard tests, P re‐ AD participants exhibited higher response times ( RT s) to complete the VMC task than CTR ( p  < .01). Besides, patients with AD showed higher RT s than CTR ( p  < .001) and Pre‐ AD ( p  < .05), and more errors than CTR ( p  < .005). RT s in A po E 4 carriers were higher than that observed in A po E 4 noncarriers ( p  < .01). In CN individuals, RT s were related to amyloid β‐protein 42 ( AB 42) biomarker ( p  < .01) and informant‐rated SCD ( p  < .01). Conclusions The VMC task is able to discriminate P re‐ AD from CTR individuals. Moreover, VMC results are associated with AB 42 levels in CN individuals, suggesting that visuomotor dysfunction may be a sensitive marker of P re‐ AD .