The effects of chronic pain from spontaneous canine osteoarthritis on working memory and sleep

Abstract

In humans, chronic pain is associated with impaired working memory and sleep, however it is not known if this is the case in dogs. The aim of this thesis was to assess whether chronic pain from spontaneous osteoarthritis is associated with impaired working memory and sleep disturbance in dogs.

Initially, two behavioural assays (the holeboard and novel object recognition tasks) previously used in other species were adapted for rapid, single session use in osteoarthritic and healthy control dogs. Surprisingly, osteoarthritic dogs spent proportionally more time interacting with a novel object than a familiar one compared to control dogs, indicating possible increased non-spatial working memory or increased neophilia. However, dogs did not appear to successfully learn the holeboard task. Therefore a study was performed in dogs with no known health problems using a holeboard task with more trials to assess spatial working and reference memory, and a disappearing object task to assess spatial working memory, both of which dogs learned successfully. The spatial working memory of osteoarthritic and control dogs was compared using the disappearing object task, and dogs’ sleep was monitored for one month using proxy measures obtained from actigraphy and owner questionnaires.

Female (but not male) osteoarthritic dogs had a lower predicted probability of success in the disappearing object task compared to control dogs of the same sex. Osteoarthritic dogs spent less of the night resting than control dogs, though there were no significant differences between groups in scores on an owner questionnaire designed to measure sleep quality. These studies are the first to find evidence that a chronically painful condition impairs spatial working memory in dogs, and to find differences in night-time activity between osteoarthritic and healthy control dogs. However, further studies are required to confirm that these findings are generalisable to the wider canine population.

Date of Award	19 Mar 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Jo Murrell (Supervisor) & Michael T Mendl (Supervisor)