Neurology/geriatrics: Canine cognitive dysfunction syndrome

Canine cognitive dysfunction

„Dog dementia/senile dementia" is a geriatric disease, which develops progressively due to neurodegenerative processes. First mild symptoms can appear already at the age of 6-7 years.

Pathogenesis, incidence, and the DISHA(A) scheme

Similar to Alzheimer's disease in humans, lipofuscin and amyloid plaques infest the brain and lead to cognitive loss by limiting nerve cell function, as they can no longer be supplied with sufficient energy and oxygen. Consequences include progressive neuronal cell death and failure of interneuronal signal transmission. The density of the plaques correlates with the progression of the disease. Nevertheless, there are some pathogenetic differences to Alzheimer's disease and the disease cannot be compared 1:1.

The exact causes have not yet been clarified and need to be evaluated by further research. The influencing factors include not only age but also genetics, nutrition and other environmental factors.
Breed predispositions are not known so far, but can also not be excluded in principle. Female dogs and neutered animals seem to be affected more frequently.

In studies conducted, signs of senile dementia were found in 30-60% of dogs over 7 years of age. → Accordingly, great attention should be paid by both veterinarians and pet owners to raising awareness of dementia and this should be included as an anamnestic point in the regular senior check-up.

CDS is characterized by progressive deterioration of diverse cognitive functions. Based on the range of symptoms, the DISHA(A) scheme was developed. It lists the main symptoms of this syndrome and therefore serves as a guide for diagnosis.

D - Disorientation: standing in the corner/on the spot, staring (!), loss of reactions, familiar persons are no longer recognized
I - Altered social interaction: Behavioral changes in social behavior, loss of interest
S - Changes in sleep-wake rhythm: the "classic": turning night into day, strong nocturnal restlessness and vocalizations.
H - House soiling - changes in learned processes and memory such as loss of housetraining, apparent "disobedience".
A - changes in activity level: reduction and slowing down, aimless activities
A - increased signs of restlessness/anxiety, e.g., when left alone, due to external stimuli.

In addition, various Canine Cognitive Assessment/Rating Scales have now been devised to assess the severity of the condition using a scoring system. These are very suitable in practice as a preliminary questionnaire for the owner.

Diagnosis

An unambiguous diagnosis based on firmly defined parameters is not possible; in some cases, differentiation from normal aging processes is definitely a challenge.
Rather, the DISHAA scheme as well as diagnostic therapy by means of medication and dietary adjustment should be consulted for help. The most common symptoms are disorientation, loss of housetraining staring and nocturnal restlessness.

However, it is essential to exclude all other possible causes leading to similar symptoms beforehand, which very often include:

• Sources of pain: e.g. arthrosis, teeth (dental x-ray!),
• high blood pressure
• Heart diseases
• diseases of the urinary tract
• space-occupying processes in the abdominal cavity
• hypothyroidism

Vision and hearing tests can also be helpful to differentiate.

Regular check-ups are necessary to assess the course and early detection of other physical diseases.

Therapy

The goal of therapy is to slow the process and restore cognitive performance. This improves the quality of life of both dog and owner. A cure is not possible. It is important to start therapy as early as possible. The therapy is based on several pillars:

1) Behavior

Anything that promotes attention and concentration helps to counteract the process (even prophylactically), but the dog seniors must also not be overburdened. Doing exercises in the evening can promote sleeping through the night. If possible, maintain a fixed daily structure to which the four-legged friend can orientate itself.
Light physiotherapeutic exercises can be planned into the daily routine.

2) Dietetics

Both special complete feeds and dietary supplements (so-called nutraceuticals, combination preparations with ginkgo, B vitamins, etc.) and omega-3 fats are available and used with success.
In studies, the daily feeding of MCT oil also led to significant improvement in cognitive performance - this can be explained, among other things, by the fact that the medium-chain fatty acids (or the resulting ketone bodies) are a very good alternative source of energy for the brain, because in old age the brain's ability to utilize glucose decreases.

3) Medication

The choice of medication or combination of medications depends on the leading symptoms and often has to be tested out individually.

• Pain medication such as NSAIDs or gabapentin: diagnostic therapy if painful processes are suspected
• Selegiline (MAOI, antidepressant) - Important: onset of effect often only after 3-6 (8) weeks, but then often good to very good effect
• Benzodiazepines (diazepam, alprazolam)
• Propentofylline
• Melatonin: 1-2 x tgl. 3-6 mg/dog per os or 0.1 mg/kg per os every 8h (sleep promoting in case of nocturnal restlessness) - Attention: may potentiate the effect of benzodiazepines
• some veterinarians also report very good experiences with herbal products such as high-quality CBD oils, studies do not exist so far - important to know: The intake of CBD oil leads to a significant increase in alkaline phosphatase (AP) in the blood!
• Further: Pheromones (collars, plugs etc.), common supplementary feeds, which are supposed to have a calming effect.

4) Education and support of owners as a cornerstone of therapy - not to be neglected!

It is important, among other things, that owners show patience and understanding that the dog is not to blame for behavioral changes.
Rather, affected dogs need increased security and attention.
The environment can be adjusted according to age. For example, the nightly resting place can be equipped with a small night light, an extra water bowl, cozy and close to the owner, so the small details sometimes already help for calmer nights.

Bibliography: Upon request

Author of the article:

Veterinarian med. vet. Julia Brüner