Table 1.
Scoring of individual deficits in adult and aged mice
| Body system* | Frailty index item | Deficit score | ||||
|---|---|---|---|---|---|---|
| 0 | 0.5 | 1.0 | ||||
| Integument | Alopecia | |||||
| Loss of fur colour | ||||||
| Dermatitis | ||||||
| Loss of whiskers | ||||||
| Coat condition | ||||||
| Physical/musculoskeletal | Tumours | |||||
| Distended abdomen | ||||||
| Kyphosis | ||||||
| Tail stiffening | ||||||
| Gait disorders | ||||||
| Tremor | ||||||
| Forelimb grip strength | ||||||
| Body condition score | ||||||
| Vestibulocochlear/auditory | Vestibular disturbance | |||||
| Hearing loss | ||||||
| Ocular/nasal | Cataracts | |||||
| Eye discharge/swelling | ||||||
| Microphthalmia | ||||||
| Corneal opacity | ||||||
| Vision loss | ||||||
| Menace reflex | ||||||
| Nasal discharge | ||||||
| Digestive/urogenital | Malocclusions | |||||
| Rectal prolapse | ||||||
| Vaginal/uterine/penile prolapse | ||||||
| Diarrhoea | ||||||
| Respiratory | Breathing rate/depth | |||||
| Discomfort | Mouse grimace scale | |||||
| Piloerection | ||||||
| 0 | 0.25 | 0.50 | 0.75 | 1.0 | ||
| Other† | Temperature | |||||
| Weight | ||||||
| Frailty index score‡ | ||||||
*Frailty scoring system, adapted from Whitehead et al. (2014). All deficits except temperature and weight were scored as 0 if absent, 0.5 if present but mild and 1.0 if present and severe.
†Temperature and weight were scored based on deviation from mean reference values from age‐matched mice. Values that differed from the reference by >1 SD were scored as 0.25, >2 SD were 0.5, >3 SD were 0.75 and >4 SD received a score of 1.
‡Deficit scores were added and divided by 31 (total number of items evaluated) to produce a frailty index score for each mouse.