Canine Cognitive Dysfunction

[blanche]

Canine Cognitive Dysfunction
Stewart MacKenzie
2005
Watching the decline of your pet’s physical and/or mental health after years of vitality can be heart wrenching.  We often have fond memories of watching Fido playing fetch or watching Fluffy race around the house in apparent glee.  The concept of our pet’s senior years has changed drastically.  Old dog used to mean Fido was 7-10 years old.  Now pets are enjoying active healthy lifestyles well into their early teens, and it is not unheard of dogs living into their mid to late teens, and even early twenties!  With the increasing life-span of cats and dogs due to advances in healthcare, and nutrition, new health issues are moving to the forefront in small animal practices everywhere.  Where it used to be quite rare to deal with senior pet issues in clinics, there has been a shift in the practical dynamics of clinic work.  Increasingly practitioners include senior pet health exams as standard protocols, and the development of strategies to deal with existing issues and in prevention to ensure a better transition for pet and owner into their pet’s senior years.  An area of great concern for veterinarian and pet owner alike is the decline in a pet’s cognitive functioning as they get older.   Information will be relayed in the following context; what is “canine cognitive dysfunction”, how does it occur, and what are the prescriptive and non-prescriptive things that can be done to help pets in their senior years.
            Questions abound when owners first hear a diagnosis of “Canine Cognitive Dysfunction Syndrome” (CDS).  The first question usually asked is “Like Alzheimer’s”?   The answer is, yes; as dogs age, they can develop a form of neurodegenerative disease that has many similarities with the age relate cognitive disorder Alzheimer’s in humans.  More specifically, “like humans, canines naturally accumulate deposits of beta-amyloid (AB), a type of protein plaque, in the brain with age.  Further, canines and humans also share the same AB sequence that first show as deposits of the longer AB1–42 species followed by the deposition of AB1–40.  Aged canines like humans also show increased oxidative damage.  As a function of age, canines show impaired learning and memory on tasks similar to those used in aged primates and humans.  The extent of AB deposition correlates with the severity of cognitive dysfunction in canines” (Cotman etal 2002).  Ultimately the term Canine Cognitive Dysfunction Syndrome is now used to describe the above progressive neurodegenerative disorder in senior dogs.  It is generally marked by deficits in learning, memory, perception and awareness.  
            There are other disorders that can result in some of the same signs and symptoms, also seen in Canine Cognitive Dysfunction.  Such disease processes as “metabolic and endocrine disease, to painful conditions such as arthritis or dental disease” (Lansberg 2004) can result in some of the same behaviours as CDS, and it would be advisable to rule out any possibility that these are the root cause.  However, specific concerns of: house soiling, disobedience, confusion about previously regular habits, anxious pacing and panting (generalized anxiety) all indicate a primary concern of CDS.  Clinically, owners often describe pets with cognitive decline as having, increased anxiety, a decrease in general hygiene and grooming habits, altered appetite, decrease response to stimulus (such as going for a car ride) and problems with learning and memory.  These and other symptoms have lead clinicians to adopt the acronym DISHA to describe the following conditions “Disorientation, altered Interactions with people or other pets, Sleep-wake cycle alterations, House-soiling and altered Activity level (Lansberg 2004).  
With clear symptoms and signs of CDS, we move to the next step, getting a definitive diagnosis.  Although of great clinical value in the diagnosis of CDS (not many clinics have one), a Toronto General Testing Apparatus or TGTA is one way to get a clear cut definitive diagnosis of cognitive impairment.  Generally, the TGTA tests an animal’s ability to recognize, remember and choose objects based on similarities and differences, with the resulting proper choice being reinforced with a desired food reward.  It has been shown that while young dogs have little problem learning this task, older dogs are unable or have great difficulty in learning to recognize previously reinforced articles.  Fortunately, the average clinical practitioner can modify such tasks in the clinical setting, and along with curiosity tests (a basket full of toys, and the dog’s general interest and desire to explore and play with the toys), assign them a level of functioning based on observed outcomes.  “Using memory tasks, old dogs can be separated into three groups: unimpaired, impaired and severely impaired” (Lansberg 2004).  Assuming there is a definitive diagnosis of CDS, there are many different medically prescriptive and non-prescriptive treatment options available.  
The first type of treatment available to the aging dog is in the area of nutrition, or what is commonly known as “dietary therapy”.  “Widespread oxidative damage, extensive production of free radicals, and lowered vitamin E levels have all been identified in the brains of dogs with dementia” (Lansberg 2004).  It has been widely acknowledged (Milgram et al 2002), that antioxidants, such as vitamins E, C and other factors such as beta carotene, selenium along with mitochondrial co-factors such as L-carnitine, and DL-alpha-lipoic act synergistically to improve antioxidant defence, improve clearance of, reduce production and the effects of free radicals.  Free radicals are the toxic result of high rates of oxidative metabolism.  Levels of the above vitamins, minerals and co-factors can be improved through the supplementation of fruits and vegetables in the dog’s diet, or by using commercial preparations with these ingredients in them.  Interestingly there is also a new canine therapeutic diet available through veterinarians produced by Hill’s Pet Nutrition specifically formulated to treat CDS.  Called Canine b/d®, “the diet’s efficacy was assessed using neuropsychological testing procedures for more than 2 years” (Lansberg 2004), and was proven effective in improving performance on a number of cognitive tests.
The second area of treatment available are those that are medically prescriptive.  Drugs such as Selegiline and Anipryl ® are MAO (monoamine oxidase) inhibitors.  While it is still not clear how these drugs improve dogs with CDS, “enhancement of dopamine and other catecholamines in the cortex and hippocampus is presumed to be an important factor” (Lansberg 2002).  Dopamine and Catecholamine levels in the brains of dogs with CDS are significantly low.  The use of the drug Anipryl ® has had promising results.  Pfizer, the makers of Anipryl ® recommend that the dosage for oral administration for the control of clinical signs associated with CDS is 0.5–1.0 mg/kg once daily, preferably administered in the morning.  This is maintained for a month and then the dosage is adjusted accordingly until the desired balance/response is achieved.  It needs to be remembered however that there needs to be sufficient amount of time taken to instill a significant noticeable response in the dog.  
Ultimately decisions about aging pets are never easy to make.  Living with an animal diagnosed with CDS can be heart wrenching and difficult.  While there are things that can be done to alleviate some of the symptoms seen in aging pets, conditions may worsen, or new problems due to aging can materialize.  There is a wide choice of treatments available to clients willing to spend the time to find the right balance in treating their pet.  It needs to be remembered that a dog’s apparent misbehaviour is probably not intentional, but an effect of his condition.  While it is always desired that pets live full happy lives, with greater longevity, cognitive dysfunction in aging pets will be increasingly seen in clinics and by more practitioners.  All involved need to be aware of the options available to them in treating this disorder.
References:
Cotman, C. W. et al.  2002.  Brain Aging in the Canine: a Diet Enriched in Antioxidants
Reduces Cognitive Dysfunction.  Neurobiology of Aging 23: 809–818
Borra’s, D., Ferrer I., and Pumarola, M. 1999.  Age-related Changes in the Brain of the Dog.  Vet Pathol 36:202–211.
Dimakopoulos, A. C. and Mayer, R.J. 2001.  Aspects of Neurodegeneration in the Canine Brain.  Waltham International Symposium: Pet Nutrition Coming of Age.
Lansberg, G. 2005.  Therapeutic Agents for the Treatment of Cognitive Dysfunction Syndrome in Senior Dogs.  Progress in Neuro-Psychopharmacology and Biological Psychiatry 29: 471-479.
Milgram, N.W. et al. 2002 Landmark Discrimination Learning in the Dog: Effects of Age,
and Antioxidant Fortified Food, and Cognitive Strategy.  Neuroscience and Biobehavioral Reviews 26: 679–695.

[lmcpug]

Thank you, Blanche!
I'm sure that this will come in handy for some of us with seniors!!

Lori

[blanche]

I've had three dogs with CCD or CDS.  One years ago--before we knew anything about CCD and there were no options for him then.  And Bob had it, but it was complicated with him as he was having TIAs as well (mini strokes) so the Anipryl didn't work well for Bob.  
Maudie has now been diagnosed with it and she is doing well on the Anipryl.  There is also a food put out by Science Diet that is geared towards CCD.  However, it does have grains in it and so I haven't been able to use it with my oldsters, but I do know folks who have used it with great success.
I do supplement Maude's food (she's raw fed) with Wild Salmon Oil, an immune booster (Moducare) and am looking into whether I should be supplementing her with other things mentioned in the article above.
The reality is there is no cure for CCD and it is a personal judgement call as to when your dog has had enough.  I believe that I hung on too long with Bob and hope that I'll be braver with Maudie.  For now, she is happy, fairly oriented and doesn't show any increase in symptoms.  Her mental status does deteriorate during a full moon, interestingly.
It's hard to watch, but is also just a part of aging.

[blanche]

Food for thought: Keep your canine cognitive
By Cheryl S. Smith, ARTICLE, NUTRITION

Many of us have probably experienced the devastating impact of Alzheimer’s disease on an older relative, or the diminishing cognitive capacity of an aging dog, or both. In the continuing crossover between human and canine research, a study funded by the National Institutes of Health’s National Institute on Aging found new hope for Beagles – and probably all other dogs and possibly humans – to retain more of their mental faculties as they age.

The two-year longitudinal study was led by William Milgram, Ph.D., University of Toronto; Elizabeth Head, Ph.D., University of California, Irvine; and Carl Cotman, Ph.D., director of the Institute for Brain Aging and Dementia, UC Irvine. They divided a group of 48 Beagles, aged seven to 11 years, into those fed a regular diet and receiving standard care; those fed a special antioxidant-enriched diet while still receiving standard care; those fed a regular diet but receiving enriched care through socialization with other dogs, regular exercise and access to novel toys; and a group receiving both the antioxidant-enriched diet and enhanced care. The researchers also followed a group of young dogs (aged one to three), half of whom were fed a regular diet and half the antioxidant-fortified diet.

The antioxidant enrichment consisted of adding one per cent each of spinach, carrot granules, tomato pomace, citrus pulp and grape pomace, in place of corn. These additions, plus 800 International Units of dl-alpha tocopherol acetate (vitamin E) and 100 parts per million of ascorbyl monophosphate (vitamin C), increased the oxygen radical absorbance capacity (ORAC – a measure of the antioxidant capacity of a food) by 50 per cent.

Two mitochondrial cofactors – dl-Lipoic acid and l-carnitine – were also included. These chemical compounds help lower the reactive oxygen species (ROS) level, getting rid of destructive free radicals.
Enriched care included three 20-minute walks daily, a kennel mate, a variety of toys, and additional cognitive experiences.

As a baseline, researchers found that as task complexity increased, the error rate increased much more rapidly among aged dogs than with younger dogs. For the simplest task, young dogs made approximately 20 errors before performing as desired, while older dogs made closer to 70 errors. On the most involved task, young dogs made about 50 errors, while the old dogs soared to 130 errors. As an example, one of the tasks involved learning that a treat was hidden under either a black or white block, then a reversal of the task (so that the treat was under the opposite-coloured block).

Older dogs that received both the antioxidant-enhanced diet and enriched care showed the most marked improvement in learning. All 12 dogs in that group succeeded in the task-reversal discrimination. But either of the enhancements alone also had strong effects. Of the 12 older dogs receiving only the antioxidant diet, eight succeeded in the task reversal. In the enriched-care group, eight out of 10 dogs succeeded. In the control group (regular diet and standard care), only two of eight dogs managed to complete the task. In the control group of younger dogs, diet had no effect.

Dr. Cotman provided information focused specifically on the antioxidant-enriched diet. First, the positive effect became stronger as the difficulty of the task increased. At the simplest task, the control-group dogs made only about 15 more errors than the enhanced-diet dogs before reaching criteria. But on the most difficult task, the control group averaged a whopping 70 more errors to criteria.

Looking at the data over the entire span of the study, Dr. Cotman reported that performance continued to improve each year. While the combined diet and care enhancements produced the strongest effects, dietary enhancement alone was close behind and closed the gap significantly as the study progressed. By the end of the study, the control-group old dogs were making 250 errors before reaching criteria, while the dual-enhanced group was down to 120, and the antioxidant-diet group was at 130.

You’ve probably heard at least a bit about brain architecture as it relates to humans and Alzheimer’s disease – fragments of protein, called Beta-amyloids, accumulate to form plaques (rather than being broken down and eliminated). These plaques are one of the hallmarks seen in the brains of Alzheimer’s patients. In the aged dogs, those eating the antioxidant diet showed a markedly lower total amyloid load in three areas of the brain. Dietary intervention appears able to slow and even reverse age-related cognitive dysfunction.

Exercise and environmental enrichment provides a different effect, increasing the levels of BDNF (brain-derived neurotrophic factor). This protein is essential for the survival of existing neurons and growth of new synapses. It’s most active in areas involved with learning, memory and higher-level cognition. In Alzheimer’s patients, BDNF levels are much lower than normal.

While research is ongoing on both canine and human fronts, it seems clear that if you want your dog to stay as sharp as possible throughout his or her life, you should provide plenty of exercise and mental stimulation, and may want to acquaint yourself with the antioxidant capacity of your dog’s diet.

[lmcpug]

It is an aging thing, too true!

I wake up every morning to make sure that Pugman is still breathing and I'm constantly watching like a hawk  Cause I have gone through it with my girls, but it is something we eventually have to look at
 and we do come away, stronger for having made the decision and more knowledgable for the next one that ocmes along!  

Lori

[lmcpug]

Hmmm,
to the Cognitive Study!!

Perhaps, Pugman should have been a part of this study  it could be why he has made it so far and is still a going concern

The study makes for interesting reading Thanks Blanche for providing it to us!!

[keep on pugging]

Really interesting articles.

[Pugpillow]

There is also a good article in December, 2008's Whole Dog Journal, page 10-13.  It is called "Old and Confused" and was written by Lisa Rodier.  It is copyrighted but you can order it as a back issue at http://www.whole-dog-journal.com/

[blanche]

There is also a good article in December, 2008's Whole Dog Journal, page 10-13.  It is called "Old and Confused" and was written by Lisa Rodier.  It is copyrighted but you can order it as a back issue at http://www.whole-dog-journal.com/

Yes--I kept forgetting to mention that.  It is a really good article.  Now I'm trying to figure out to "mentally stimulate" Maude.  A tough gig with a dog who doesn't play, has no interest in toys, etc.  So we play hide the treat under a variety of objects.  Requires gating EVERYONE else off from the living room and involves lots of high decibel screaming by the gated off pugs.  I don't know if she's getting stimulated, but I usually need an aspirin after.

[Pugpillow]

Does she watch TV?  They have some doggy videos that are supposed to engage them.

[lmcpug]

There is also a good article in December, 2008's Whole Dog Journal, page 10-13.  It is called "Old and Confused" and was written by Lisa Rodier.  It is copyrighted but you can order it as a back issue at http://www.whole-dog-journal.com/

Yes--I kept forgetting to mention that.  It is a really good article.  Now I'm trying to figure out to "mentally stimulate" Maude.  A tough gig with a dog who doesn't play, has no interest in toys, etc.  So we play hide the treat under a variety of objects.  Requires gating EVERYONE else off from the living room and involves lots of high decibel screaming by the gated off pugs.  I don't know if she's getting stimulated, but I usually need an aspirin after.

:lol:  

Keep up the great work!!

Lori