Executive function processes predict mobility outcomes in older adults.

ABSTRACT

OBJECTIVES: To examine the relationship between performance on executive function measures and subsequent mobility outcomes in community-dwelling older adults. DESIGN: Randomized controlled clinical trial. SETTING: Champaign-Urbana, Illinois. PARTICIPANTS: Community-dwelling older adults (N = 179; mean age 66.4). INTERVENTION A 12-month exercise trial with two arms an aerobic exercise group and a stretching and strengthening group. MEASUREMENTS Established cognitive tests of executive function (flanker task, task switching, and a dual-task paradigm) and the Wisconsin card sort test. Mobility was assessed using the timed 8-foot up and go test and times to climb up and down a flight of stairs. METHODS: Participants completed the cognitive tests at baseline and the mobility measures at baseline and after 12 months of the intervention. Multiple regression analyses were conducted to determine whether baseline executive function predicted postintervention functional performance after controlling for age, sex, education, cardiorespiratory fitness, and baseline mobility levels. RESULTS: Selective baseline executive function measurements, particularly performance on the flanker task (ß = 0.15-0.17) and the Wisconsin card sort test (ß = 0.11-0.16) consistently predicted mobility outcomes at 12 months. The estimates were in the expected direction, such that better baseline performance on the executive function measures predicted better performance on the timed mobility tests independent of intervention. CONCLUSION: Executive functions of inhibitory control, mental set shifting, and attentional flexibility were predictive of functional mobility. Given the literature associating mobility limitations with disability, morbidity, and mortality, these results are important for understanding the antecedents to poor mobility function that well-designed interventions to improve cognitive performance can attenuate.