Cognitive dysfunction syndrome (CDS) is the degeneration of the nervous system in older pets, comparable to Alzheimer’s disease in people. Its four key signs are disorientation, changes in social relationships, a disrupted sleep cycle, and soiling inside the house. It is not simply “old age”: there is treatment that slows its progression, and the earlier it starts, the better.
Key facts:
- What it is: progressive degeneration of the central nervous system in geriatric animals. Diagnosed by exclusion.
- The 4 signs: disorientation; reduced social interaction; sleeping by day and pacing by night; soiling indoors.
- Causes: amyloid protein build-up, loss of neurons and myelin, free radicals, reduced cerebral blood flow.
- No cure, but early treatment slows its progression.
- Treatment: modifying the environment and behaviour, an antioxidant-rich diet, mental stimulation and cerebral vasodilator drugs.
Many owners assume that if their old dog becomes disoriented, barks at night or soils indoors, it is “just his age” and do not mention it to the vet. That is a mistake: those changes can stem from specific conditions, and there are treatments that reduce their progression.
What is cognitive dysfunction syndrome?
When behavioural changes appear in an elderly pet and cannot be explained by any other condition, we call it cognitive dysfunction syndrome. It is therefore diagnosed by exclusion: heart, kidney, prostate, joint pain, cataracts, deafness, dental disease and tumours — all of which alter behaviour — must be ruled out first.
It can be compared to Alzheimer’s disease in people, because both some of its signs and the underlying degenerative processes are similar.
What are the signs of CDS?
1. Disorientation. The animal struggles to recognise familiar people or places; it wanders aimlessly around the house until it bumps into a wall or a door. It may bark or whine for help.
2. Changes in social relationships. It interacts less with its owners, no longer plays, is more easily irritated and finds it harder to get on with other animals, so squabbles increase.
3. Changes in the sleep cycle. It sleeps less at night — wandering, whining, barking, scratching at the floor and doors — and more during the day.
4. Inappropriate elimination. A behaviour as well-learned as house-training seems to have been erased: it urinates and defecates indoors at any hour, without warning and without any underlying health problem.
What causes it?
Degenerative changes occur in the central nervous system: the build-up of amyloid protein in the brain — a neurotoxic substance similar to that found in Alzheimer’s patients, absent in younger animals, whose quantity correlates with the severity of the signs — the loss of brain mass and myelin with a reduced number of neurons, an increase in free radicals (which damage neurons and cause cell death), and a decline in the activity of several neurotransmitters and in cerebral blood flow.
How is it treated?
CDS is a gradual, progressive deterioration with no cure, so it is best to start treatment as early as possible to ease the symptoms. It works on several levels:
A suitable environment. Sometimes more water and food bowls are needed. Keep a strict routine so the animal can predict the day, and do not move the furniture, to avoid disorientation. Install padded ramps to aid movement, and make water and toilet areas easy to reach.
Mental stimulation. A stimulating environment keeps the mind active: simple, short games with a very rewarding pay-off (hiding treats the animal can find easily), short daily training exercises or short outings.
Nutrition. In old age the diet should be rich in antioxidants to combat free radicals and protect cell membranes. There are foods formulated for this. It also helps to reduce calories: this is known to increase life expectancy in most animals.
Medication. There are drugs that produce cerebral vasodilation, allowing greater blood flow and better oxygenation of the brain. Your vet will always recommend the most appropriate treatment.
How do I care for a senior pet?
Increase the number of vet visits. Watch for any change in physical condition or behaviour and report it. Do not overfeed. Check the mouth and teeth frequently. Adapt exercise to the animal’s physical condition. And, above all, give it plenty of affection and attention: make its life comfortable and happy.
Frequently asked questions
Does my old dog have dementia or is it just age?
If it becomes disoriented, sleeps by day and paces by night, stops interacting and soils indoors, it may be cognitive dysfunction. A vet must assess it and rule out other conditions.
Why does my elderly dog bark at night?
A disrupted sleep cycle is one of the four classic signs of CDS: they sleep less at night and wander the house.
Can cognitive dysfunction syndrome be cured?
No, but early treatment slows its progression: a stable environment, mental stimulation, an antioxidant diet and medication.
What can I do at home?
Do not move the furniture, keep fixed routines, make water and toilet areas easy to reach, and interact with it more throughout the day.
The senior years bring the highest vet spend: consultations, blood tests and lifelong medication. Petplan España (Petplan Ibérica, S.L.) reimburses 100% of the vet bill up to €3,100 a year, with a €45 excess, at any vet you choose, provided it is not a pre-existing condition. See the policy terms.
