Assessment of postural balance in community-dwelling older adults - methodological aspects and effects of biofeedback-based Nintendo Wii training.

The overall purpose of this thesis was to examine selected methodological aspects and novel approaches for measuring postural balance older adults, and to examine the effects of biofeedback-based Nintendo Wii training on selected physiological, psychological and functional outcome variables in community-dwelling older adults. In Study I balance control was investigated using force plate analysis of Centre of Pressure (COP) excursion during static bilateral standing in 32 community-dwelling older adults at three different time-points (09:00, 12:30, and 16:00) throughout the day. An overall significant time-of-day effect was observed for all selected COP variables. The greatest change in all COP variables was observed (on average ~15%) between midday (12:30) and the afternoon (16:00), indicating that a systematic time-of-day influence on static postural balance exists in community-dwelling older adults. Consequently, longitudinal (i.e. pre-to-post training) comparisons of postural balance in in older adults with repeated assessments should be conducted at the same time-of-day. In Study II a novel approach for measuring postural balance (using the Nintendo Wii Stillness and Agility tests) was examined for reproducibility and concurrent validity in 30 community-dwelling older adults. While the Nintendo Wii Stillness test showed a high reproducibility, a systematic learning effect between successive sessions was observed for the Agility test. Moderate-to-excellent concurrent validity was seen for the Stillness test. In contrast, the Agility test revealed a poor concurrent validity. In conclusion, the Wii Stillness test seems to represent a low-cost objective reproducible test of postural balance in community-dwelling older adults and appears feasible in various clinical settings. A habituation (familiarization) period is necessary for the Wii Agility test to avoid a systematic learning effect between successive test sessions. Study III investigated the effect of ten weeks of biofeedback-based Nintendo Wii training on static postural balance, mechanical lower limb muscle function, and functional performance in 58 community-dwelling older adults. Additionally, the study investigated the participant motivation for this type of training (Exergaming). Marked improvements in maximal leg muscle strength, rapid force capacity and functional performance were observed following the period of biofeedback-based Nintendo Wii training. Unexpectedly, static bilateral postural balance remained unaltered following the period of intervention. The study participants perceived the Nintendo Wii training as enjoyable and highly motivating, which suggests that this type of exercise may be successfully implemented at senior citizens' centers and/or in the home of the elderly. The results presented in this thesis suggest that strict control of time-of-day is an important methodological aspect when evaluating postural balance in older adults, and an assessment protocol using the Nintendo Wii-Balance Board is reproducible and valid. Biofeedback-based Nintendo Wii exercise intervention appeared unsuccessful in improving static bilateral postural balance, most likely due to a test ceiling effect in the selected outcome measures, but the intervention elicited marked positive changes in various key risk factors associated to fall accidents. Notably, Wii based biofeedback exercise was perceived by the older adults as a highly motivating type of training.