The terminology surrounding frailty is used in clinical settings, and in research and development for identifying processes of, and patients in, age-related physical decline. However, a framework suitable for age-related neurodegenerative diseases needs to (1) adequately account for the effects that the processes of aging have on neural decline and disease, and (2) be helpful in identifying relevant groups of users and patients. This is becoming increasingly necessary due to emerging possibilities to detect, prevent, and treat age-related neural decline and disease. Based on a number of relevant criteria, I distinguish four groups of patients and users: robust, non-frail, pre-frail, and frail. With the four groups defined, ethical assessments can be made on an individual basis regarding which medical technologies are best suited for a person who risks, or suffers from, age-related neurodegenerative disease.