The Use of Functional Data Analysis to Evaluate Activity in a Spontaneous Model of Degenerative Joint Disease Associated Pain in Cats

Introduction and objectives: 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 and conclusions: 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.UCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Ciencias Económicas::Escuela de Estadístic

Impact of Optimized Breastfeeding on the Costs of Necrotizing Enterocolitis in Extremely Low Birthweight Infants

To estimate risk of NEC for ELBW infants as a function of preterm formula and maternal milk (MM) intake and calculate the impact of suboptimal feeding on NEC incidence and costs

Activity (A) and intensity (B) profiles for cats in the DJD group.

<p>Log transformed activity for all cats is shown in gray with time (in hours) along the horizontal axis. The group means for activity and intensity are shown for weekends (dark blue) and weekdays (light blue).</p

Pre-transformation range, quartiles, median, and mean of average per-minute activity counts across the 7 day period for each group of cats.

<p>Pre-transformation range, quartiles, median, and mean of average per-minute activity counts across the 7 day period for each group of cats.</p

Functional regression analysis for activity in the Normal group.

<p>Depicted are the smooth effects of Age (in years, left panels), BCS (middle panels) and AGE*BCS (standard deviations away from the mean, right panels) on the activity of Normal cats, when model (1) is assumed. Results are shown for weekends in the top row and weekdays in the bottom row, with functional coefficients in black, 95% confidence intervals in blue, and zero demarcated in red.</p

Functional regression analysis for activity in the DJD group.

<p>Depicted are the smooth effects of Age (in years), BCS, AGE*BCS (standard deviations away from the mean), standardized TDJD score and TPain score on the activity of DJD cats, when model (2) is assumed. Results are shown for weekends in the top row and weekdays in the bottom row, with functional coefficients in black, 95% confidence intervals in blue, and zero demarcated in red.</p

Activity (A and C) and intensity (B and D) profiles for cats in the Normal group (blue) and those with DJD (pink).

<p>Log transformed activity for all cats is shown in gray with time (in hours) along the horizontal axis. The group mean for activity and intensity are shown for weekends (A&B, respectively) and weekdays (C&D, respectively).</p

Demographic distribution for cats included in each of the studies.

<p>Results within a category that are designated by the same letter were not significantly different from one another.</p

FPCA for Intensity for the Normal cats for weekends (A) and weekdays (B).

<p>Hours of the day are shown across the horizontal axis. Variance about the mean that corresponds to each FPC is shown for weekends and weekdays with red (pluses) indicating the positive direction and blue (minuses) indicating the negative direction. Variance explained by each FPC: Weekends: 35.88%, 24.44%, 16.83%. Weekdays: 40.01%, 23.86%, 21.77%.</p