Can neuromuscular strength and function in people with dementia be rehabilitated using resistance-exercise training? Results from a preliminary intervention study.

Abstract

Neuromuscular weakness is a prominent symptom among people with central nervous system disorders, such as dementia, typically leading to disability in activities of daily life. We sought to evaluate the potential of resistance exercise to improve neuromuscular strength and function in the lower extremities among community-dwelling people with dementia. Twenty-eight subjects, aged 70-88 years and with an average Mini-Mental State Examination score of 17.8 +/- 7.2, were recruited from a population of adult daycare facility users. Subjects underwent pre- and postintervention assessment of strength and physical function consisting of determination of bilateral maximum strength of the knee extensor, hip flexor, dorsiflexor muscles, and handgrip; and evaluation of lower-extremity function based on repeated chair stands and gait speed. The intervention consisted of moderate-intensity progressive resistance training of the hip extensors, abductors, knee extensors and flexors, and dorsiflexors using the Theraband resistance system for up to 3 days weekly over a 6-week period. Subjects completed an average of 11.4 +/- 2.5 exercise sessions. Among those who exercised at least twice per week (> or = 12), they improved an average of 15.6% in quadriceps strength, 10.1% in handgrip strength, 22.2% in sit-to-stand (STS) time, 9.9% in usual gait time, 5.4% in fast gait time (p =.03), and 14.0% in the timed-up-and-go (TUG) test. Subjects demonstrated improvements in some areas of muscular capacity (quadriceps and handgrip) and most tests of lower-extremity function (STS, gait, TUG), yet declines in other areas (dorsiflexion and iliopsoas strength). Although strength or functional deficits in all domains were not remediable, these results suggest the potential of a resistance-exercise intervention of longer duration and/or greater intensity to produce beneficial effects on the neuromuscular functioning of people with dementia.