The relationship between knee extension strength and lower extremity functions in nursing home residents with dementia

Abstract

Purpose: To assess the relationships between knee extension strengths and lower extremity functions in subjects with dementia and to predict lower extremity functions using knee extension strength. Methods: Fifty-four nursing home residents with dementia were enrolled in the study. The strength of the knee extensor was measured using a hand-held dynamometer. To predict lower extremity functions, subjects were classified into two groups: those who could dress their lower body, toilet, transfer to bed/toilet/shower and walk independently, and those who required assistance. Knee extension strength was compared between the two groups. Results: Logistic regression analysis showed that the strength of the knee extensor muscles was a significant predictor of the ability to dress the lower body (odds ratio, 109.90; 95% CI, 7.60–1589.49), toileting (odds ratio, 18.29; 95% CI, 2.41–138.84), transferring to bed/toilet/shower (odds ratio, 39.70; 95% CI, 4.51–349.08), and gait performance (odds ratio, 12.77; 95% CI, 2.30–70.77). The curve of the negative and positive predictive values indicated that a cutoff score of 0.8 Nm/kg would provide the best balance for dressing the lower body and toileting; 1.2 Nm/kg for transferring to bed/toilet/shower; and 0.6 Nm/kg for gait performance. Conclusions: Knee extension strength was significantly related to the lower extremity functions in people with dementia. Moreover, threshold levels of strength existed that could predict lower extremity dysfunctions in people with dementia.

Implications for Rehabilitation

• Knee extension strength is related to the lower extremity functions such as gait, toileting and dressing the lower body in people with dementia.

• Threshold levels of knee extension strength exist that can predict lower extremity dysfunctions in people with dementia.

• Resistance training based on knee extension strength is needed for prevention and improvement of strength and functional decline in people with dementia.

Keywords::

• Dementia
• hand-held dynamometer
• lower extremity activities

Acknowledgements

The authors would like to acknowledge Ryosuke Yamamoto, Minako Nishikawa, Yuko Ishiguro, Masami Suzuki, and staff at the Setagaya Municipal Kitazawa En for helpful comments and suggestions in the study.

Declaration of interest: This work was supported by a Grant-in-Aid for Research Activity Start-up 21800066 from the Japan Society for the Promotion of Science (JSPS). The authors state no conflicts of interest in regard to this manuscript.