We are all rusting away. Rusting is an oxidative reaction. All of our life systems are powered by oxidative reactions. It is the reason we breathe, to inhale more oxygen to keep those reactions going, burning fuel to provide energy for life. Sometimes they get out of control, especially when chemical by-products called free radicals are produced.

These are highly reactive compounds, often superoxides similar to hydrogen peroxide, the hair bleach. You may have seen this fizz and bubble on your skin.

Skin is tough, but cell membranes aren’t, so superoxides cause a lot of damage in our body. Not surprisingly, an organ like the brain that uses a lot of oxygen and has a lot of fat-rich cell membranes is particularly susceptible to superoxide damage. You can think of it as brain rust. Unfortunately the brain doesn’t have as much capacity for self-repair as most of our other organs.

Anyone over the age of fifty is already starting to notice the effects of this. Learning new things is becoming harder. Recall and memory is not as sharp. The first instances of the brain slipping out of gear start happening. “Ah, you’re having a senior moment,” is something you often hear.

It is happening to our pets too and is surprisingly common. In one study of dogs seven years and older, 75 percent of owners reported that their dog had showed one or more signs of brain ageing. However only one in eight had discussed it with their vet, perhaps because these changes are often considered to be ‘normal’. In a survey of 154 cats over 11 years of age brought to their vet for a routine annual check, 28 percent of those aged 11 to 15, and 50 percent of those over 15 years, showed signs of brain ageing. Also people think that it is normal for older pets to behave in this way.

The technical term for brain ageing is cognitive dysfunction syndrome (CDS). It is much better recognised and studied in dogs than cats and is sometimes termed ‘Dogzheimers’ because of some similarities with Alzheimer’s disease in humans. It is defined as a progressive neurodegenerative disorder, and characterised by gradual cognitive decline over months and years. It is easier to recognise early in dogs that are highly trained to perform difficult tasks. Slight deterioration in cognitive ability in these dogs is usually more readily noticed by their owners.

The signs of cognitive decline are often grouped using the acronym DISH.
•    Disorientation - Aimless wandering, ‘lost in space’ episodes, going to the wrong side (the hinge side) of the door, confusion, failure to recognise normal routines or surroundings.
•    Interaction – decreased greeting of family members or visitors, decreased interest in petting or attention, decreased interest in food and other stimuli.
•    Sleep pattern changes – restlessness, agitation or wandering at night; increased daytime sleeping.
•    Housetraining lapses – failure to ‘ask’ to go out; soiling in random places or in the presence of the owner; soiling inside shortly after going outside; incontinence.

However there are other signs too, including impaired ability to work or perform tasks, decreased responsiveness to familiar commands or tricks, and slower learning or even inability to learn new tasks.

Other behavioural and disease conditions can mimic or confuse the signs of CDS. Changes in the household such as a new baby, partner or pet can provoke behaviour changes similar to CDS. Older pets often have poorer hearing and vision and so may be less responsive. An arthritic pet may be more reluctant to perform familiar tasks, become irritable, grumpy, or start house-soiling simply because the pain of getting up and out overrides housetraining.

The pain of a dental abscess may cause apathy and loss of interest in food. Urinary tract infections can cause urinary incontinence that may be interpreted as loss of house-training due to senility. Changes in organ function are common with age and can impact on brain function and behaviour. Chronic liver disease is common in cats and dogs and can cause signs that mimic CDS.

So the first step to take if you suspect your pet may be showing signs of CDS is to get a vet check. Your vet will ask some probing questions; conduct a thorough physical exam and take urine and blood samples to check out organ function. CDS can only be diagnosed once other behavioural and medical causes have been ruled out.

Treatment options.

The treatment strategy has four components:
•    Deal with any other limiting factors such as osteo-arthritis, dental pain, liver disease, urinary tract infections, etc.
•    Nutritional therapies
•    Use drugs if necessary
•    Environmental enrichment and behavioural training

Nutritional therapies play a major role in the treatment of CDS, since a number of dietary components and supplements have been found to have beneficial effects on brain function.

The Omega 3 fatty acids DHA and EPA stabilise cell membranes and nourish brain tissue. Selenium and the vitamins C and E form part of the body’s own antioxidant defence mechanisms. Bioflavenoids and carotenoids from many fruits and vegetables have antioxidant effects, inactivate free radicals and stabilise cell membranes.

Hill’s have produced a prescription diet called b/d specifically to counter the symptoms of brain ageing in dogs. It contains all of the supplements mentioned above except PTDS. It has been shown in well-controlled trials to significantly improve pets with Dogzheimers. Responses are typically seen within four weeks of feeding b/d but marked improvements are sometimes seen much sooner, probably related to increased mitochondrial energy production. (See Billy’s story).

Aktivait is a nutritional supplement containing most of the discussed supplements. It has performed well in overseas trials and has recently become available from vets in New Zealand.

Drugs can also be used to help pets suffering from CDS.  Nicergoline (Fitergol) improves the circulation to the brain and so benefits those patients most who are suffering from poor cerebral circulation. Propentofylline (Karsivan) improves cardiac output but also decreases free radicals and inflammatory substances in the brain, improves synthesis of nerve growth factor, and has been shown to improve cognition. Selegiline inhibits the destruction of brain neurotransmitters, decreases brain cell death and increases nerve growth factor.

Because of their different modes of action varying results are seen with these drugs. Your vet may need to trial one or more, sometimes in combination.

Early detection and treatment of CDS can do a lot to help our old pets enjoy their last years with improved comfort and dignity. It helps us enjoy their last years a whole lot more too!