Design for Independent Living
Activity Demands & Older People's Capabilities
Author: Seidel, David
Supervisor: Brayne, Carol
Institution: Department of Engineering, University of Cambridge
Sensory, cognitive and motor capabilities decline with advancing age, affecting the ability to function independently in the community. Survey data show that many older people have difficulty performing activities necessary for independent living, such as cooking and shopping, due to a gap between the demands generated by the environment and their capacity to meet those demands. Identifying which components of an activity are difficult is crucial to designing products and services to delay the onset of disability. This thesis reports on the findings of three large population-based studies and one observational study. First, evidence from a cohort study of 12,186 individuals aged 65 years or over indicates that capabilities required for interacting with products and services are lost at different stages in later life. Locomotion was the first ability to be lost, then reaching, thinking, hearing, vision and dexterity. Second, a survey of 6,842 older people found that self-report and objective measures of motor capability both identify older people at greater risk of losing their independence in cooking, shopping and housework. Third, a survey was used to investigate how the demands associated with cooking, housework, laundry and shopping relate to the capabilities of 4,886 community-dwelling 55-93-year-olds. Most difficulties were attributable to limitations in bending/stooping, standing and reaching, whereas limitations in actions and hand function accounted for many fewer difficulties. Fourth, 27 men and women aged 75 years or over were recruited and observed during cooking and laundry in a home-like environment. Critical postures were frequently assumed, particularly by those with limited locomotion and reduced strength. To conclude, the studies are quite consistent in their findings across different settings and using different methods. The results can be used to prioritise the order in which design features are implemented at the population level.