Higher-Level Hand Motor Function in Aging and (Preclinical) Dementia: Its Relationship with (Instrumental) Activities of Daily Life – A Mini-Review

A causal relationship between physical activity such as walking and cognitive functions - particularly executive functions and memory - has been observed in elderly people with and without dementia. Executive functions play an important role in the (instrumental) activities of daily life [(I)ADL]. However, a close relationship has also been found between motor activity of the upper limb, particularly the hand, and (I)ADL. Indeed, in aging, a decline in hand motor function is related to a decrease in (I)ADL, an increase in functional dependency, admission to a nursing home, and even mortality. This review begins by addressing clinical studies on the effect of age on higher-level hand motor activity. It then discusses higher-level hand motor function in age-related neurodegenerative diseases such as mild cognitive impairment, Alzheimer's disease and vascular dementia. It concludes by discussing the contribution of higher-level hand motor function assessment to the diagnosis of the various subtypes of (preclinical) dementia and by addressing the clinical relevance of studying higher-level hand motor function, procedural learning, and (I)ADL in aging and (preclinical) dementia.