Functional tasks exercise for older adults with cognitive impairment at risk of Alzheimer's disease

Cognitive impairment is a common problem in older adults and increases in prevalence with age with or without the presence of pathology. Individuals with mild cognitive impairment (MCI) are at high risk of progressing to Alzheimer's diseases and other dementias. In the absence of pharmacological treatment for individuals with MCI, it is critical to explore the potential effects of non-pharmacological interventions. Studies have shown that combined cognitive-motor intervention is promising for improving cognitive functions in older adults. Daily functional tasks are innately cognitive-demanding and involve components of stretching, strengthening, balance and endurance as seen in a traditional exercise program. Functional task exercise programs, with an exercise component incorporated into performing everyday tasks and used as a means of combined cognitive-exercise intervention, may be more meaningful and practical for individuals with cognitive impairment. A structured functional tasks exercise program was subsequently developed as a combined cognitive-exercise intervention with the purpose to facilitate the cognitive functions of older persons with mild cognitive impairment. The aim of this thesis was to examine the feasibility of application and the potential effects of this newly developed functional task exercise program for improving the cognitive functions and functional status of older persons with mild cognitive impairment. A validation study was conducted to validate a Chinese version of the Problems in Everyday Living test (PEDL). The Chinese prototype of the PEDL (C-PEDL) was used for an outcome measurement in the pilot study which was conducted to initially test the feasibility as well as the effectiveness of the functional tasks exercise program for older adults with MCI. The pilot study used a single group repeated-measures design. A total of 11 participants (mean age 71.8 years) were recruited to participate in the intervention program for 10 weeks. All outcome measures were undertaken at baseline, post-intervention and 6-months follow-up using Neurobehavioral Cognitive Status Examination (NCSE), Category Verbal Fluency Test (CVFT), Chinese Version Verbal Learning Test (CVVLT), Lawton Instrumental Activities of Daily Living Scale (Lawton IADL) and C-PEDL. Data were analyzed using Repeated Measures Analysis of Variance. The Cohen's d effect size was calculated to assess the practical significant effects. At post intervention, the participants showed significant improvement in NCSE composite score (p < 0.000, d = 0.79), CVVLT total free recall (p < 0.0005, d = 0.76), CVFT (p = 0.014, d = 0.45), CVVLT 10-minute delayed free recall (p = 0.008, d = 0.40), Lawton IADL (p = 0.025, d = 0.60) and C-PEDL (p < 0.0005, d = 1.37). The improvements were also sustained at 6-months follow-up. Thus, the newly designed functional task exercise program demonstrated to be feasible and encouraged further investigation on the effects in a larger population. A randomized controlled trial was further conducted to compare the effects of a functional tasks exercise program to a cognitive training program in older adults with mild cognitive impairment. A total of 83 participants (mean age 73.8) were randomized to either a functional task exercise group (n = 43) or an active cognitive training group (n = 40) for 10 weeks. All outcome measures were undertaken at baseline, post-intervention and 6-months follow-up using NCSE, Trail Making Test A (TMT-A) and Chinese version Trail Making Test B (TMT-B) as well as the outcome measures performed in the pilot study. For data analysis, repeated measures Analysis of Variance (ANOVA) was performed to evaluate within-group effects and Analysis of Covariance (ANCOVA) to evaluate the between-group effects. Cohen's d was also calculated to estimate the between-group effect sizes. At post intervention, significant between-group differences were found in general cognitive functions (NCSE composite score; p = 0.001 and NCSE normal domains; p < 0.001), memory (CVVLT immediate recall; p = 0.028 and delayed recall; p = 0.022), executive function (TMT-B; p = 0.045 and CVFT; p = 0.029), everyday problem solving ability (C-PEDL; p < 0.001) and functional status (Lawton IADL; p = 0.049). During 6-months follow-up, significant between-group differences were still evident in the intervention group for general cognitive functions (NCSE composite score; p = 0.025 and NCSE normal domains; p = 0.034), memory (CVVLT delayed recall; p = 0.043), executive function (TMT-A; p = 0.011) and everyday problem solving ability (C-PEDL; p = 0.008). Overall, results from this thesis support the findings of previous studies that combined cognitive and exercise training is effective for influencing different cognitive domains and improving cognitive functions. The positive benefits of the intervention enhancing cognitive functions may ameliorate the progression of cognitive decline, which could potentially delay the conversion of pre-clinical stage to the clinical stages of AD or other dementias. In conclusion, findings from this thesis have shown that a functional tasks exercise program using simulated functional tasks as a cognitive-exercise intervention is feasible for improving cognitive functions and functional status of older adults with mild cognitive impairment. Moreover, the improvements can be sustained over time after completion of training. The present study contributes to the efficacy of combined cognitive-exercise interventions in populations with cognitive impairment.