Detection of behavioural and cognitive dysfunction in mucopolysaccharidosis IIIA affected dogs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University, Palmerston North, New Zealand
This study investigated whether behavioural and cognitive dysfunction caused by
mucopolysaccharidosis (MPS) IIIA can be detected early in affected dogs’ lives, and to
describe the behaviours of these dogs. No other scientific papers have been published
on this topic and the population of dogs examined in this study are the only MPS IIIA
affected dog colony available worldwide for study.
Three main tests were performed on the population of MPS IIIA affected dogs.
Physical behavioural assessment tests were performed at six and eight weeks of age and
from twenty weeks of age a cognitive function task was taught and then tested to
measure the dogs’ performance. A previously validated questionnaire, the canine
behavioural assessment and research questionnaire (C-BARQ), was completed at three,
six and twelve months of age. The researchers in these studies were blinded to the MPS
IIIA status of the dogs examined.
The behaviours shown by the MPS IIIA puppies at six and eight weeks of age were not
significantly different from the behaviours of the unaffected puppies. This finding
supported the research of other MPS IIIA studies and suggests that clinical behavioural
changes do not occur at such a young age. The behaviours shown by the MPS IIIA
affected puppies appeared to be normal puppy behaviours similar to those described in
previous research on puppies.
The C-BARQ measured the behaviours shown by the MPS IIIA affected and unaffected
dogs. Most of the MPS IIIA affected dogs’ behaviours were not significantly different
from the unaffected dogs’ behaviours, but MPS IIIA affected dogs did retrieve
significantly more than unaffected dogs at three months of age, and were less
distractible at twelve months of age. It would be worth investigating these findings
further to decide whether it suggests a subtle alteration in brain functioning.
The cognitive function test showed a significant decrease in the success of the MPS IIIA
affected dogs in the final maze test. This is the first study on dogs affected with MPS
IIIA to find a decline in cognitive function before the occurrence of cerebellar clinical
signs and this new knowledge may lead to future developments measuring therapy
response and disease progression. The T-shaped maze testing may be valuable in future
research on cognitive function in dogs with other diseases such as epilepsy. Thus this
thesis provides valuable information on canine MPS IIIA and provides a foundation for
future disease investigations.