Co-morbidity

The simultaneous presence of two or more medical conditions or disabilities in a single individual. In accessibility contexts, co-morbidity is a critical design consideration because many users, particularly older adults, experience multiple impairments simultaneously — for example, vision loss combined with hearing loss, reduced mobility, peripheral neuropathy, or cognitive decline. Designing for co-morbidities requires multimodal interfaces that do not rely on any single sensory or physical channel, and challenges the common practice of designing for single disability categories in isolation. The prevalence of co-morbidities increases significantly with age, making it especially relevant for the aging population.