Cognitive impairment decreases postural control during dual tasks in geriatric patients with a history of severe falls

OBJECTIVES: To investigate the influence of dual tasks, cognitive strategies, and fear of falling on postural control in geriatric patients with or without cognitive impairment and with a history of falls resulting in injury. DESIGN: Experimental three-group design. SETTING: Geriatric hospital. PARTICIPANTS: Twenty young healthy adults (mean age+/-standard deviation=25.4+/-4.4), 20 geriatric patients with a history of severe falls without cognitive impairment (mean age=82.6+/-5.5, mean Mini-Mental State Examination (MMSE) score=27.8+/-2.0) and 20 geriatric patients with a history of severe falls and cognitive impairment (mean age=83.2+/-5.5, mean MMSE=19.2+/-3.3). MEASUREMENTS: Motor performance: sway area and lateral and anterior-posterior sway angles. Cognition: semiautomated calculation steps (serial 2 forward) and nonautomated calculation derived from MMSE (serial 7 retro). Motor and cognitive performances were examined as single and dual tasks. Strategy decision, fear of falling, and subjective perception of motor and cognitive performance were assessed as covariates for dual-task performances. RESULTS: Motor performance decreased significantly during all dual tasks in geriatric patients with cognitive impairment and a history of falls resulting in injury. Cognitive performance was different depending on the task and group. Choice of cognitive strategies or fear of falling did not influence the dual-task performances. CONCLUSION: Even simple additional tasks substantially decrease postural stability due to attention-related cognitive deficits in cognitively impaired geriatric patients with a history of severe falls. The findings may help to explain the increased incidence and severity of falls in geriatric patients with cognitive impairment and a history of falls resulting in injury.