APEX1 and fragile X-associated tremor/ataxia syndrome: Ultimately, due to the relatively small effect sizes of ApEn interactions, it will be important to systematically assess sustained sensorimotor control targeting premutation carriers at the younger age range of our sample (i.e., 45–60 years) and in relation to FXTAS symptoms over time to determine the power of our objective measures of sensorimotor behavior to track FXTAS progression and risk.