Cognitive Dysfunction Syndrome

General Information:
Dogs in their twilight years present a true diagnostic challenge. Not only are senior dogs more likely to develop health problems, but they are inclined to develop multiple health problems and greater variability in their responses to stress, drugs and environmental factors. A very fine line exists between "normal" and "abnormal" for a particular age of dog.
In general the definition of Cognitive Dysfunction Syndrome (CDS) is geriatric onset behavioral changes (usually gradual) which are not entirely attributable to (other) general medical conditions. Historically, geriatric behavior problems have fallen into diagnostic categories similar to those in younger dogs. Based on two studies, those include: separation anxiety; breakdown of housetraining; aggression toward dogs; aggression toward people or dogs; excessive vocalization; phobia; and, night time waking where often no motivation is noted.

Let's go now to the most important part of the history - ensuring that the pet does have the clinical signs consistent with CDS.

Very seldom will a dog have an observable CDS problem during a visit to the veterinary hospital. Veterinarians must know all of the details about:

• what the problem is;
• when it started;
• its trend; and,
• any secondary problems.

  To get this depth of information goes beyond simply asking how the dog is doing. You, as Owners, need to be tell your vet about behavioral problems that have arisen and/or need changing. Without your help, the signs of CDS may be passed over because you mistakenly assume behavioral changes associated with CDS are "normal aging," and not signs of a disease or condition. The history is seldom volunteered in an appointment. As owners, you need to carefully record what clinical signs are present and this is done best by questionnaire. This questionnaire is available at Senior Dog Behavior History Form.
  Please print this form out, keep your records on it and give it to your vet when you visit next.
  An addition you may want to make is to rate each occurence of the abnormal behavior as 1 thru 10, with 1 being the very mild and 10 being very severe. Write this on the form and explain it to your vet.
  The Senior Dog Behavior History Form categorizes clinical signs into:

• Disorientation (confusion, wandering aimlessly, going to wrong side of doors; appearing to forget previously learned tasks getting "stuck" in corners and behind furniture);
• Activity/sleep behavior (Dogs often sleep more during the day, and much more deeply; they often are awake at times they "should" be sleeping, e.g. during the night. They may act restless and pace or wander inappropriately - hence we often state that they have an increase in purposeless activity, and a decrease in purposeful activity);
• Housetraining (inappropriate elimination in dogs previously well housetrained, or increased accidents in dogs that had occasional ones. These dogs are often disoriented and will, for example, signal to go outdoors, stand in the yard for a while and re-enter the house to urinate, often right in front of the owners); and,
• Interaction with family members (walking away from being petted, greeting owners less (or not at all) at the door; no longer initiating play or petting).
  Under each subheading it lists typical examples (not exhaustive however) of each category, about which you can document behavior changes over time.

  Let's review those signs one more time. Let's start with
  Disorientation: This would include getting lost in places where your pet should be familiar, wandering aimlessly, not being able to find entry/exit doors and staring into space.
  Activity and Sleep: It's not necessarily that these dogs are less active remember that the CHARACTER of the activity itself may be changed, i.e. increased pacing or wandering purposeless activity and sleep is increased, often very DEEP, and often at times the dog was previously awake. So you may think that your dog is MORE active than in the past (for example: my dog is now sleeping 21 hours a day, and pacing the other 3).
  Housetraining: these dogs may soil the home but may also signal, go out and not eliminate, fail to signal or go out, not eliminate and then come in and eliminate indoors.
  Change in Family Interactions: Dog social behavior changes. They tend to walk away while being petted, and generally initiate petting and play less (or none at all). Greeting behavior is decreased or gone. If you think about it these are qualities that people value in their dogs as members of the family.

   

  Hearing Loss vs. the Signs of CDS

  "Naturally" occurring hearing loss (that is, changes we expect to see as our dog, AND OURSELVES, for that matter, gets older) is gradual and dog's usually compensate in their actions and response to stimuli. With CDS the hearing loss can be present but there are elements of confusion, so that perhaps if you clap your hands to wake your dog, s/he may alert to the sound if s/he hears a little. If s/he does have CDS, s/he will be confused and not respond appropriately.
  

  Other Possibilities

  They can be divided into behavioral and medical. Another way of thinking of these is to consider primary behavior problems, and those secondary to medical problems which may mimic signs of CDS.
  Your vet needs to rule out medical conditions. The physical examination and neurological examination would be a key here as with any diagnostic dilemma, since your vet would see changes in the neuro exam similar to most neurological diseases. Remember that for the most part CDS is a "diagnosis of exclusion" - it cannot be confirmed in our patients until after death, so it is important to determine other possible causes.
  Medical diseases that are similar to cognitive dysfunction include:
• Any Central Nervous System disease, such as a tumor;
• Any disease that indirectly affects the Central Nervous System, such as end stage organ dysfunction like renal (kidney) or hepatic (liver) disease;
• Endocrine disorders, such as diabetes
• Conditions that affect circulation or blood supply (especially to the brain). Therefore anemia, hypertension cardiac disease, respiratory disease (and their causes) must be examined;
• Painful conditions can affect the pet's response to stimuli or increase irritability and perhaps aggression;
• Deafness - and blindness - technically fall into the "secondary" behavioral problem category. Dogs with sensory impairment though -- if they do not have CDS -- are very good at compensating for the impairment. Deaf dogs learn to recognize other signals; blind dogs find their way around fine, and learn (for example) by bumping into things, if it's gradual onset impairment. Often in real life, of course, we see dogs with both sensory failing and CDS.
• Any condition that affects the pet's mobility (arthritis, degenerative joint disease, etc.), or the pet's senses could also directly or indirectly affect behavior; and,
• If we are dealing with house soiling we have all of the rule outs from a medical standpoint, for polyuria, incontinence, increased frequency, etc. (such as urinary tract infection, kidnet disease, etc.).

  In fact between the neuro exam, the physical exam, the acute onset, and laboratory tests (Blood Chemistry, Complete Blood Count and Urinalysis, as a minimum), it should be possible to rule out cognitive dysfunction in many cases. With a slower onset, a progressive condition and no laboratory tests or physical findings on exam that would indicate a medical problem that might contribute to the clinical signs (behavioral), then your vet could consider CDS a diagnosis.
  

  Stepping back to the five "signs", is one sign enough to make diagnosis or do we need 3 of 5, or 5 of 5?
  In very general terms, this is a diagnosis based on MULTIPLE signs that could be within one category or in more than one. If a dog is showing just one (say, inappropriate elimination ) CDS should certainly be part of the possibilities (in an old dog with a problem that's gradual in onset ) but CDS is typically a syndrome with multiple signs.
  In general it is unlikely that, with a good behavioral history, you'd find aggression to be the sole sign of CDS. To answer more vaguely :) aggression is a very broad, very nonspecific sign, of anything from metabolic disease to osteoarthritis to intensified dominance aggression due to impaired vision and hearing. But aggression/irritability can occur (and does) as part of this syndrome in some dogs.
  Also, we can have concurrent medical problems AND CDS.
  In addition, there are other behavioral considerations.
  Primary behavior problems in dogs -- those not secondary to a medical condition -- may be either new or chronic. If an old dog exhibits behavior changes in one category (for example inappropriate elimination) but lacks any other signs of CDS, it is important to consider non-CDS related problems in your vet's behavioral differential. Some important primary behavior differentials include:

• Obsessive/compulsive disorders;
• Separation anxiety;
• Separation anxiety with destruction of property;
• Fear biting;
• Environmental phobia (e.g. noise/thunder);
• Inadequate housetraining (or breakdown of housetraining);
• Urine marking; and,
• Aggression of assorted varieties (dominance, fear, territorial). It must be determined whether or not these dogs are chronically predisposed to aggressiveness. Aggression is not particularly pathognomonic for CDS however.
  A point about separation anxiety since it may come up quite frequently as a possible diagnosis. In old dogs as in young, separation anxiety (without CDS) is classically a problem that occurs in the absence of owners and shortly after they depart (not 6 hours later) in direct response to departure, and at exit points (doors ) Most important, signs of disorientation are absent. As you look at at the clinical categories of CDS you may notice that all 4 categories involve disorientation to some degree (even inappropriate elimination in which dogs eliminate at their owners' feet).

  Your vet will also consider drug side effects when looking at symptoms and responses to therapy when diagnosing CDS.
  S/he me first try therapy and wait for response if you diagnose or suspect a medical problem. Sometimes s/he may even do drug trials before making the CDS diagnosis. If a pet is on drugs, s/he will also consider the side effect of those drugs. And even if a diagnosis of CDS is made, s/he will have to remember that these are older dogs and that other medical problems may soon develop.
  In fact, other medical problems are LIKELY to develop, in approximately 50% of older dogs. Moreover, another medical disorder (other than CDS) is likely to occur within the same year.
  Be aware that these signs are not necessarily those of normal aging. Consider also that controlling the signs of CDS can significantly improve quality of life for your dog and indirectly for the human family (and the relationship). Supportive care of your dog for other (concurrent) problems is also important in that you must have realistic expectations for management of a progressive disorder.

  Is it known if primary CDS dogs have a shorter life span than other geriatric dogs, in other words can it be considered a cause of death?
  Indirectly the answer appears to be yes -- because untreated or unresponsive CDS appears to accelerate the decision to euthanize.

  Does CDS occur in cats?
  It's not known for sure but so far there have been some of the physical changes characteristic of CDS found in cats are virtually identical to those seen in dogs, and these cats (3 in the study) had cognitive dysfunction type signs such as wandering and vocalizing. In another study of older cats (about 50 cats in the study), about 60% have been identified with at least one of the signs as seen in dogs.

  Treatment Information:
  Although there is no cure, your vet can help prolong the quality of your dog's life, and preserve his/her role in the family, by decreasing the behavioral problems resulting from the syndrome.
  There are some relatively simple steps to ease your dog's clinical signs. For example, environmental changes (in the home or yard) can help. Examples include placing baby gates in the house to prevent injury (stairs); also using leads and fences outdoors. Old dogs with CDS wander away from home and appear lost. In the home removing clutter can ease the dog's mobility. Dogs can also be restricted to areas easily cleaned if they are inappropriately eliminating It is important, however, not to socially isolate the dog.
  We can use house soiling as an example. Even if we were to treat control or perhaps resolve an underlying medical condition such as diabetes, a urinary tract infection or CDS, the problem may persist. For these dogs we may have to alter the environment, such as taking the pet out more frequently or confinement training but behavior modification in the form of reinforcing the appropriate behavior (with food and praise) and supervision and interruption of any indoor elimination.
  Although supervision and interruption with perhaps a leash and halter is important if the dog begins to eliminate indoors, punishment has no place. It causes fear, anxiety, and in these older dogs perhaps even injury.

  Medication:
  Your vet will send home L-Selegeline (Anipryl (R)) which has been recently approved for use in the clinical indication of cognitive dysfunction (CDS) in dogs.
  Generally - and remember, your vet will make a decision based on what's correct for YOUR INDIVIDUAL DOG - it's dosed at 0.5 to 1 mg/kg per day for about a month. The dose is once daily in the mornings (the best time to enhance cognitive function).
  While most dogs seem to improve within the first couple of weeks, there are some dogs that do not show improvement until the second month.
  The drug has few side effects. Occasionally, some mild gastrointestinal upset that usually resolves on its own in a few days, and there are occasional reports of increased activity, but that's about it. There are a few drug contraindications that your vet will discuss with you.
  Your vet may start with a tablet size (one of 2 mg, 5 mg, 10 mg, 15 mg, or 30 mg) that is at or above 0.5 mg/kg and after about a month if there is no significant response s/he may increase to the next tablet size if it is still within the dose range. If your dog were responding at 0.5 mg/kg for a while and then started to deteriorate, your vet might increase the dose for a month if your dog was not already at the maximum recommended dose.
  Generally the dogs that improve are on Anipryl for the balance of their lives, which in many cases will be until they develop a medical problem that leads to death or necessitates owner euthanasia. In some cases the cognitive dysfunction will progress to a point that the medication is no longer effective.

  We hope that you will find this information helpful in your quest for better pet care. 

  David E. Hammett, DVM
  and the Staff of All Creatures Veterinary Clinic, PC

In spite of our best efforts Miss Taffy went to the Rainbow Bridge on April 4, 2000. I am leaving all the information up that I have about her illness because so many people have seen it and written to me and have found it useful. She is always in our hearts and we miss her terribly.

The following is part of a letter I wrote to my friends about my Lhasa Apso, Miss Taffy. She is thought to be between 14 and 15 years old. I have had her 12 years and she has been a joy to live with for all these years but is starting to have serious problems. The letter explains the problems and below the letter there is a paper that my vet gave me to read that helps explain what is wrong with her. I am putting this web page up for those of you with older dogs who may be going through the same thing.

I wrote to my friends:
"Many of you know that Miss Taffy has been acting pretty strange for a few months now. We have been taking her to the vet and having tests done and having consultations with other Vets so on. Taffy is not actually sick. Her heart, lungs, liver and kidneys are in excellent shape but she has totally lost her mind! She has no idea who Mom and I are most of the time. She hides from us behind the couch or under a bed or what ever is handy. We have to tag team her to even get a hold on her to give her medicine and she bites us any time we pick her up or even try to. She wants nothing to do with us at all. Giving her any kind of care or grooming is major event. She is right now taking Elavil which they often give dogs who have severe separation anxiety. She has only been on it for a couple of days so we don't know really if it will help but we doubt it will. She has also been taking a new drug for senility but it has not helped and actually seemed to make things worse.

The vet gave me a paper to read and I have scanned it and will attach it to this email just in case any of you want to read it. The general consensus is that she has what is called Cognitive Dysfunction Syndrome which is progressive and irreversible. What it is in a nutshell is that her body is healthy and her brain is going to pot. I didn't scan the whole paper my Vet gave me but it had pictures of dogs brains showing how parts of them get smaller and smaller so that the dog basically can't function in a normal way. Signs of it are "changes in the usual sleep wake cycle, such as increased daytime sleeping and less nighttime sleeping. Changes in interaction with the owner such as decreased greeting behavior. Signs of disorientation, such as becoming trapped in a corner or behind furniture or staring into space. Impairment in normal housetraining, with loss of signaling to go outdoors and house soiling. " That is exactly how Taffy started out but she is much worse now.

Most of you know that when we got Taffy no one really knew her age but best guess by 2 different vets was between 2 1/2 and 3 and we have had her 12 years. It is very distressing, depressing and many other things to know that she does not remember those years. She doesn't remember snuggling together on the bed sleeping in late on Sat. morning or going for car rides or any of the things she use to love. Most of all and most hurtful of all she does not remember that she loved us or how much we love her. Where she use to be delighted to even see us now she runs in fear from us. I didn't quite realize how deeply upset I am till I started to write this letter to you all. It is very difficult for me.

I have no idea what will happen. I pray that one of the medications will at least relieve her fear and give her some peace. She roams the house all night long just panting and huffing and puffing from being so stressed out. There is no comfort that we can give her, nothing helps her, we can't even hold her. She is so physically healthy that this could go on for a very long time."

In dogs as in people, the medical implications of true aging are progressive and irreversible. Dogs reaching the final one-third of their lifespan undergo a variety of physical and metabolic changes that may cause them discomfort and/or change their behavior. For example, the acuity of the senses-sight, hearing, taste and smell-are reduced. Metabolism slows, immunocompetence decreases and tissues become dehydrated. Muscle and bone mass decline, and arthritis may affect the joints." There is an increased risk of cardiovascular disease, cancer and endocrine, renal and hepatic disorders.

The brain undergoes a series of changes that result in cognitive decline. It is generally believed-and studies have shown-that a dog's cognitive ability tends to decline with age. Cognitive function in dogs includes spatial orientation, housetraining, and recognizing and reacting to human family members. Cognitive Dysfunction Syndrome is the age-related deterioration of cognitive abilities characterized by behavioral changes in dogs that cannot be wholly attributed to general medical conditions such as neoplasia, infection or organ failure. CDS often is referred to by veterinarians as "old dog syndrome" or simply, "senility" and is manifested by one or more of the following five signs in the absence of any physical cause:

I. Disorientation/confusion
2. Decreased or altered responsiveness to family members
3. Disturbances of the sleep-wake cycle
4. Decreased activity level
5. Deterioration in housetraining

The progressive, degenerative course of canine CDS involves a gradual decline of cognitive ability sufficient to produce disfunctional ability in the home and/or as a family member. Dog owners may feel helpless, anxious and frustrated with the notion that the lifelong bonds they share with their canine companions are slipping away. While owners may be willing to tolerate some age-related behavioral problems associated with CDS, there eventually comes a time when those problematic behaviors become intolerable and euthanasia may be considered.

CDS Prevalence
Recently specialists have quantified the types and distribution of age-related behavior problems. An ongoing demographic study is being conducted at the University of California at Davis, investigating the incidence of signs associated with CDS in dogs between 11 and 16 years old. To date, a total of 139 dogs that had been patients at the Veterinary Medical Teaching Hospital have been evaluated: all were companion dogs that had received adequate veterinary care; the majority of males were neutered and the females spayed. It is important to note that none had a major debilitating general medical condition nor was undergoing drug therapy that might cause behavioral changes such as those being studied.

Following a screening interview, owners of the dogs were asked about the following:

I. Changes in the usual sleep-wake cycle, such as increased daytime sleeping and less nighttime sleeping
2. Changes in interactions with the owner such as decreased greeting behavior
3. Signs of disorientation, such as becoming trapped in corners or behind furniture or staring into space
4. Impairment in normal housetraining, with loss of signaling to go outdoors and house soiling

The UC-Davis CDS prevalence study revealed three major findings:
62% of 11- to 16-year-old dogs scored positively for one or more behavioral categories indicative of CDS. The prevalence of signs rose markedly with advancing age. No significant differences in incidence were seen between castrated males and spayed females within a given age group. From the data described above, we can assume that, as the population of older dogs increases, so will the number of CDS diagnoses made by veterinary practitioners. A 1998 market research study conducted by Pfizer Animal Health with dog owners supports the UC-Davis prevalence study findings. A total of 255 dog owners with dogs 8 years old and older were asked a detailed list of questions about their dog's behavior

The study found that:
48% of owners indicated their dog exhibited one or more clinical signs associated with CDS.
12% of surveyed pet owners described their dog as "senile."
73% of the remaining owners believed their dog "could develop senility."
81 % of dog owners who described their dog as senile indicated that their veterinarian was aware of the condition.

New Treatment
If your veterinarian has determined that your dog has CDS, a treatment for this disorder will probably be recommended. A new drug called Selegiline or L-Deprenyl, (brand name Anipryl), although not a cure, has been shown to alleviate a some of the symptoms of CCD. If the dog responds, he will need to be treated daily for the rest of his life. As with all medications, there are side effects and dogs with certain conditions should not be given Anipryl. For instance, if your dog is on Mitaban for external parasites, Anipryl is contraindicated.

Summary
As a result of advancements in veterinary medical care, dogs are living longer. In fact, an estimated 13.6 million pet dogs in the United States are 8 years old or older which means a substantial number of senior canines are at risk for developing age-related behavioral and medical disorders.

CDS is a common, recognizable condition in senior dogs. Because older dogs are integral to the lives of millions of families, it is important that clients understand the difference between "normal aging" and age-associated medical and behavioral conditions such as CDS. Finally, because the syndrome is manifested through behavioral signs, the client plays a key role in identifying its signs and in bringing them to their veterinarian's attention.

Is Your Dog's Mind Going to the Dogs?

A typical morning for me consists of quickly feeding the dogs, pouring a cup of coffee in my commuter mug, hunting frantically for my keys and rushing out the door-without the coffee. I run back inside to collect what I forgot the first time. Now I'm not only late, but I'm convinced I am losing my mind.

If you have an older dog, you might notice similar "absent mindedness" as he gets older. And if your mornings are anything like mine, perhaps you can relate to what your dog may be going through. While your brain lapse is more likely induced by the three extra times that the alarm clock's snooze button was hit, for a senior dog, it's a biochemical change that occurs in his brain as he ages. For you and me, slowing down-and waking up earlier-should resolve that forgetfulness. And there's help for old Madeline too.

Similar to aging people, geriatric dogs-and maybe elderly cats-can suffer from a "memory" disorder called cognitive dysfunction syndrome, or CDS. CDS has been compared with Alzheimer's disease in people because the changes that occur in the brain are similar and the signs-forgetfulness, disorientation, and not recognizing family members-are comparable.

In dogs with CDS, owners notice that their older animal seems more disoriented and confused. "Dogs may seem lost in their surroundings-get lost behind a couch, or stuck in a corner, or stand at the hinge side of the door," says Dr. Jo Ann Eurell, a veterinarian at the University of Illinois College of Veterinary Medicine in Urbana with an interest in behavior. "A senior pet may not recognize family members, or may sleep all day and be up pacing all night. The most notable sign is a deterioration in house training. A dog with CDS will have a lot of accidents."

The older a dog gets, the more likely cognitive dysfunction becomes. Because dogs, like people, are living longer, owners have to watch for age-related medical and behavioral disorders. "A lot of people write off signs of forgetfulness and disorientation in pets, thinking that it's just because they are old and nothing can be done," say Dr. Eurell. "But there is treatment available that may help dogs with CDS."

If your veterinarian suspects your senior canine is experiencing the effects of CDS, he will perform a thorough examination to look for an underlying medical problem that could be causing the behavior change. "As dogs age, their bodies undergo several different changes," says Dr. Eurell. "Aging dogs are particularly prone to problems with their hearing, smell, sight, and joints. They are also at a higher risk for heart problems and metabolic conditions."

Any of these problems can sometimes also cause signs similar to those in CDS, so a veterinarian will want to make sure a disoriented dog is not suffering from another systemic illness, hearing loss, or sight loss, before trying medication for CDS.

Annual exams, or bi-annual exams, are a very important part of keeping your best friend as healthy as possible so he can really enjoy his golden years. So the trick for owners, advises Dr. Eurell, is to be vigilant and to let your veterinarian know of any behavior changes, especially if your dog is entering the golden years. Don't just dismiss senile behavior as "old age." Your veterinarian may suggest medication that may solve the problem and have your old dog learning new tricks in no time.

For more information and if you suspect your senior canine may be showing signs of CDS, contact your local small animal veterinarian.

By Carrie Gustavson Information Specialist

Canine Cognitive Dysfunction Syndrome

Visit the Pfizer Animal Health website that explains much more about Canine Cognitive Dysfunction Syndrome.

This information is from Pfizer Animal Health, a world leader in animal health care development, and was printed in the September, 1998 Issue of DVM Newsmagazine.

A New Look at "Old Dog Syndrome"