Slowing of Alternating Forearm Movements Is Associated with Cognitive Impairment in Community-Dwelling Older People.

Background/Aims: Motor impairment is an important aspect of cognitive decline in older adults. It has been suggested that complex motor control is affected earlier than gross motor control. The aims were to investigate if complex hand motor function was more affected than gross motor function in cognitively impaired older subjects, and to present reference values. Methods: Alternating forearm movements and grip strength were studied in 301 cases, 419 intermediates and 1,207 controls, aged 60-93 years, controlling for demographic, health-related and functional factors and comorbidity. Global cognitive function was assessed by the Mini-Mental State Examination, and episodic memory by 3-word delayed recall. Grip strength was assessed by the Grippit(R). The frequency of alternating movements during 10 s was registered electronically. Results: Alternating movements but not grip strength was associated with cognitive impairment (right: p = 0.006; left: p = 0.022). The mean alternating movements for the 70-year-old male cases compared to the controls were 2.3 versus 2.5 Hz for the right, and 2.2 versus 2.4 Hz for the left arm (p < 0.05), and for the 60-year-old women 2.0 versus 2.3 Hz for the right arm (p < 0.05). Conclusion: Complex but not gross hand motor function is associated with early cognitive impairment.