The association between cognition and dual-tasking among older adults: the effect of motor function type and cognition task difficulty

Abstract

Background

Dual-task actions challenge cognitive processing. The usefulness of objective methods based on dual-task actions to identify the cognitive status of older adults has been previously demonstrated. However, the properties of select motor and cognitive tasks are still debatable. We investigated the effect of cognitive task difficulty and motor task type (walking versus an upper-extremity function [UEF]) in identifying cognitive impairment in older adults.

Methods

Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal Cognitive Assessment (MoCA). Participants performed repetitive elbow flexion under three conditions: 1) at maximum pace alone (Single-task); and 2) while counting backward by ones (Dual-task 1); and 3) threes (Dual-task 2). Similar single- and dual-task gait were performed at normal speed. Three-dimensional kinematics were measured for both motor functions using wearable sensors.

Results

One-hundred older adults participated in this study. Based on MoCA score <20, 21 (21%) of the participants were considered cognitively impaired (mean age =86±10 and 85±5 for cognitively impaired and intact participants, respectively). Within ANOVA models adjusted with demographic information, UEF dual-task parameters, including speed and range-of-motion variability were significantly higher by 52% on average, among cognitively impaired participant (p<0.01). Logistic models with these UEF parameters plus age predicted cognitive status with sensitivity, specificity, and area under curve (AUC) of 71%, 81% and 0.77 for Dual-task 1. The corresponding values for UEF Dual-task 2 were 91%, 73% and 0.81, respectively. ANOVA results were non-significant for gait parameters within both dual-task conditions (p>0.26).

Conclusion

This study demonstrated that counting backward by threes within a UEF dual-task experiment was a pertinent and challenging enough task to detect cognitive impairment in older adults. Additionally, UEF was superior to gait as the motor task component of the dual-task. The UEF dual-task could be applied as a quick memory screen in a clinical setting.

Keywords:

• wearable motion sensor
• gait
• upper-extremity function
• biomechanics
• MCI
• Alzheimer’s disease

Acknowledgments

This project was supported by the Centers for Disease Control and Prevention Healthy Brain Research Network (CDC-HBRN). The CDC-HBRN is a Prevention Research Centers program funded by the CDC Healthy Aging Program-Healthy Brain Initiative. The project was also supported in part by award from the National Institute of Aging (NIA) (award number: 1 R21 AG055852-01). The findings of this manuscript are those of the authors and do not necessarily represent the official views of CDC-HBRN or NIA. Thanks to coordinators for their significant contribution in coordinating study staff, and to Banner Sun Heath Research Institute’s Longevity Study participants for their generous participation.

Disclosure

The authors report no conflicts of interest in this work. Mrs Kathy O’Connor, Dr Edward Zamrini, Dr Martha Jane Mohler, and Dr Nima Toosizadeh report grants from National Institute of Aging, during the conduct of the study.