Data from: The use of functional data analysis to evaluate activity in a spontaneous model of degenerative joint disease associated pain in cats

Accelerometry is used as an objective measure of physical activity in
humans and veterinary species. In cats, one important use of accelerometry
is in the study of therapeutics designed to treat degenerative joint
disease (DJD) associated pain, where it serves as the most widely applied
objective outcome measure. These analyses have commonly used summary
measures, calculating the mean activity per-minute over days and comparing
between treatment periods. While this technique has been effective,
information about the pattern of activity in cats is lost. In this study,
functional data analysis was applied to activity data from client-owned
cats with (n=83) and without (n=15) DJD. Functional data analysis retains
information about the pattern of activity over the 24-hour day, providing
insight into activity over time. We hypothesized that 1) cats without DJD
would have higher activity counts and intensity of activity than cats with
DJD; 2) that activity counts and intensity of activity in cats with DJD
would be inversely correlated with total radiographic DJD burden and total
orthopedic pain score; and 3) that activity counts and intensity would
have a different pattern on weekends versus weekdays. Results showed
marked inter-cat variability in activity. Cats exhibited a bimodal pattern
of activity with a sharp peak in the morning and broader peak in the
evening. Results further showed that this pattern was different on
weekends than weekdays, with the morning peak being shifted to the right
(later). Cats with DJD showed different patterns of activity from cats
without DJD, though activity and intensity were not always lower; instead
both the peaks and troughs of activity were less extreme than those of the
cats without DJD. Functional data analysis provides insight into the
pattern of activity in cats, and an alternative method for analyzing
accelerometry data that incorporates fluctuations in activity across the
day.