Growing old is a natural process and a fact of life, for all of us, including our four-legged dog and cat family members. This is especially prevalent in dogs and cats since they age faster than us humanoids. Family members will probably be the first to notice the subtle changes of Canine Cognitive Dysfunction Syndrome or CDS. It may be more than just “getting old.”

Dogs with CDS may show signs of confusion, forgetfulness, less responsiveness, and/or other various behavioral changes that are not a normal part of aging. They are similar to dementia and senility in older people. These subtle signs might not be exhibited in the examination room so we may not see them during an examination.

An occasional dog have severe symptoms of CDS and fall down the stairs or have a similar type of accident. If you suspect your dog has this disease it needs to be watched closely for a serious injury.  The Long Beach Animal Hospital, staffed with emergency vets, is available until the evenings 7 days per week to help if your pet is having any problems, especially any injury related to CDS like a fracture of the bones or a concussion.

Think of us as your Long Beach Animal Emergency Center to help when you need us for everything from minor problems to major a major emergency. We serve all of Los Angeles and Orange county with our Animal Emergency Center Long Beach, and are easily accessible to most everyone in southern California via Pacific Coast Hwy or the 405 freeway.

If you have an emergency that can be taken care of by us at the Animal Emergency Hospital Long Beach always call us first (562-434-9966) before coming.  This way our veterinarians can advise you on what to do at home and so that our staff and doctor can prepare for your arrival. To learn more please read our Emergency Services page.

A common problem we encounter is an owner thinking their canine is getting old as it slows down and does not go as far and as fast on walks anymore. These dogs more often have arthritis than CDS, and this arthritis is treatable. Please read our Arthritis Page to learn more.

Xray of normal canine spine

This is a digital radiograph of a normal canine lower spine

Xray of arthritic canine spine

The painful arthritic areas are circled in this dog with arthritis of the spine called spondylosis


CDS is believed to be caused by physiological and chemical changes in the brain of aging dogs that affect brain function. These may include accumulation of B-amyloid, declining neurotransmitter activities, or increased activity of monoamine oxidase-B, an enzyme that may catalyze the metabolism of dopamine.1

In MRI (Magnetic Resonance Imaging) studies of the head, images show black and white cross-section “slices” of the brain. In MRI studies of older dogs with CDS, we see changes when compared to MRI studies of younger dogs. In the images below, note the ventricular space enlargement (V arrows) and hippocampus tissue shrinkage (H arrows) seen in the older dog image on the left, compared to the younger dog image on the right.1

MRI of dog brains

MRI of dog brains


Photo of dog showing typical CDS symptoms

(not due to vision or hearing loss)
Wanders aimlessly
Appears lost or confused in familiar surroundings such as the house or yard
Gets “stuck” in corners or under or behind furniture
Stares into space or at walls
Has difficulty finding the door
Stands at the wrong door to go outside
Stands at the “hinge” (wrong) side of the door
Does not recognize familiar people
Does not respond to verbal cues or their name
Appears to forget the reason for going outside
Activity and SleepSleeps more in a 24-hour day (overall)
Sleeps less during the night
Decrease in purposeful activity in a 24-hour day
Increase in aimless activity (such as wandering, and pacing) in a 24-hour day
Housetraining (for dogs previously housetrained)Has “accidents” (urinates or defecates) indoors
Has “accidents” indoors in view of family members
Has “accidents” indoors soon after being outside
Signals less to go outside (for dogs who previously signaled/asked to go outside)
Interaction with Family MembersSolicits attention less
Less likely to stand/lie for petting (walks away)
Less enthusiasm upon greeting
No longer greets family members (once the dog has realized that family members have arrived)


Since a biopsy of the brain is not usually a diagnostic option, a presumptive diagnosis can be made when there are clinical signs consistent with CDS and the absence of any underlying medical causes.

For a suspected case of CDS, as for any behavior problem, a history, physical examination, and diagnostic tests are needed to rule out the presence of any medical conditions that might affect behavior. These might include diseases of the internal organs, especially liver, kidney, and heart.

Additionally, primary and secondary behavioral problems need to be ruled out such as separation anxiety, noise phobias, or housesoiling.

Medical Conditions with Behavioral Components:

Medical conditionAssociated clinical signs

Sensory dysfunction

(loss of sight, hearing, smell)

Increased irritability, fear or aggression
Decreased appetite
Increased vocalization
Changes in sleep-wake cycle
Decrease in greeting behavior
Inattentive, decreased responsiveness to verbal commands

Urinary tract disease
Renal disease
Lower urinary tract infection

Incontinence, loss of housetraining
polyuria (urinating more)
polyphagia (eating more)
stranguria (painful urination, straining to urinate)
pollakiuria (urinating more frequently)


Weakness, reduced mobility and activity
Increased pain, irritability
Possibly inappropriate elimination


Decrease in activity
Increased irritability or aggression
Reduced tolerance to cold

Cushing’s disease

Polyphagia (eating more), polyuria (urinating more), restlessness
Decreased social interaction, responsiveness to commands and greeting behavior
Reduced activity
Loss of housetraining
Disrupted sleep-wake patterns

Neurological disorders

(primary or secondary
intracranial neoplasia)

Changes in sleep patterns, eating habits, housetraining, aggression, docility

To obtain a complete medical and behavioral history, we may ask many questions because signs of CDS may be subtle and not be exhibited in the examination room during during an examination. A printable Senior Dog Behavior History Form to aid in diagnosis of CDS is available by clicking here.

We will perform a thorough physical examination. In addition, a brief neurological examination will include assessment of cranial nerves, evaluation of postural reactions, especially conscious proprioception, and evaluation of the perineal reflex to assess sphincter function.

Typical diagnostic tests would include a serum chemistry profile, complete blood count (CBC), and urinalysis. Additional tests may be warranted based on the patient’s history and physical examination results.

Another method of diagnosis is response to therapy. If your dog improves when treated then there is a good chance he has this disease.


Anipryl® is a medication, in tablet form, generally given once a day. We will recommend the appropriate dose for each individual patient. You can learn much more about it by clicking on the link.

Return to Canine Diseases Page.

Additional Reading:

1. Cognitive Dysfunction Syndrome and Other Geriatric Behavior Problems; CE Advisor a supplement to Veterinary Medicine, Feb 1999.[view PDF format].
2. Controlling CDS with Anipryl®: Post Approval Field Research Results from Private Hospitals in the US; Pfizer Animal Health Technical Bulletin, Dec 2000. [view PDF format]

You will need the Adobe Acrobat Reader to view and print the bulletins and forms, which are in PDF format. If you already have Acrobat® Reader, you can immediately download and print the documents. If you need a copy of the Adobe® Acrobat® Reader®, click the icon below to download it free of charge from Adobe®.


  1. Adding New Science to the Practice of Medicine – Senior Dog Health, canine Cognitive Dysfunction Syndrome and anipryl® Senior Health Care advisor Program, Pfizer animal Health
  2. Campbell, S; Controlling CDS with anipryl®: Post approval Field Research Results from Private Hospitals in the US; Pfizer animal Health Technical Bulletin, Dec 2000.

Developed for Long Beach Animal Hospital, by Glenna M Gobar DVM, MPVM, MS, courtesy of Pfizer Animal Health; Sept 2001