Old before their time: Cognitive impairment and Idiopathic Epilepsy in dogs

An interesting set of three papers documenting the association between cognitive impairment and idiopathic epilepsy (IE) came out of the RVC this year. This is important as IE is the most common neurological condition in dogs with an onset of 6 months to 6 years. There is already evidence for increased anxiety and ‘ADHD-like behaviour’ in canine patients with IE but little in association with cognitive function. Research into this area could aid future treatment plans and improve owner expectations.

The PLoS ONE study with 4051 dogs showed good evidence that dogs with IE undergo cognitive decline with symptoms similar to canine cognitive disorder (CCD) or ‘canine dementia’. Dogs with IE exhibit a high risk at a low age which is in contrast to the normal and intuitive slow increase in risk through to middle age with an exponential increase in old age. This is illustrated nicely in the graphic below. This is a well recognised phenomenon in human medicine and in humans IE is also associated with an increased risk of co-morbidities such as dementia and Alzheimer’s disease in later life.

 

   Fig 1. Probability of being affected by canine cognitive dysfunction (CCD) by age in dogs with epilepsy (n = 286) and controls (n = 3765).  https://doi.org/10.1371/journal.pone.0192182

 Fig 1. Probability of being affected by canine cognitive dysfunction (CCD) by age in dogs with epilepsy (n = 286) and controls (n = 3765). https://doi.org/10.1371/journal.pone.0192182

Canine patients with IE were shown to be less trainable, more easily distracted, less likely to listen to their owners, have an increased failure to recognise familiar people, unintentional pacing and had increased difficulty finding food dropped on the floor. Those treated with traditional IE medication where also found to be worse in these metrics. This isn’t surprising as people in receipt of anti-epileptic drugs have long been shown to have a similar deterioration. To an owner this may present as a lack of obedience. The RVC has shown that owners in the face of this deterioration have resorted to using negative training devices. This illustrates our role to inform owners and prevent these negative training devices from being used.

The evidence also suggests that dogs with a previous history of obedience training before the onset of IE had less cognitive decline. Further investigation could assess a use case for cognitive guarding/prophylaxis in dogs and people by engaging in potentially neuroprotective mental training prior to the onset of IE.

Another interesting point from this data was that smaller dogs (<15kg) were shown to have a large increase in risk for canine cognitive dysfunction when compared to their heavier counterparts (Fig 2.).

 

 

 &nbsp; Fig 2. Probability of being affected by canine cognitive dysfunction (CCD) across weight (kg) in the control population.  https://doi.org/10.1371/journal.pone.0192182

 Fig 2. Probability of being affected by canine cognitive dysfunction (CCD) across weight (kg) in the control population. https://doi.org/10.1371/journal.pone.0192182