What is Cognitive Dysfunction in Cats?

Almost twenty years ago when I left my residency and started out as a newly minted neurologist, feline cognitive dysfunction syndrome (CDS) was not on my radar. That has changed. As we learned more about aging in cats, CDS has become a more recognized disease by yours truly, as well as many others. If you're like me and need a Tidbit-Tuesday style refresher...read on!

What is cognitive dysfunction syndrome?
Cognitive dysfunction syndrome (CDS) is a term used to describe deterioration of mental capabilities associated with age.  Clinical signs of cognitive dysfunction can also be associated with other age-related illnesses (e.g. osteoarthritis, structural intracranial disease such as neoplasia, or cardiovascular disease) which makes it difficult to diagnose. See table 1 for an outline of behavior changes seen in cats with CDS.
The underlying etiology of CDS is yet unknown. Causes such as oxidative stress/damage, neurodegeneration  and vascular changes are among the leading hypothesis for human and canine CDS, and therefore suspected to be similar in feline CDS.  Deposits of extracellular B-amyloid and intracellular accumulation of microtubule-associated protein tau have been seen in human patients with cognitive dysfunction. Similarly,  B-amyloid deposits and increased tau have been detected in aged cats with cognitive decline, however the significance remains unclear. 

What are the clinical signs of cognitive dysfunction in cats?
There is a handy article, published in the Veterinary Clinics of North America in 2020 by Dr. Miele and associates that echoes what others have been reporting in a very concise little table. (See reference at bottom) I have replicated this table, with a few modifications, here. Note: There are other signs such as decreased appetite or thirst, that don't usually drive an owner or veterinarian to seek consultation from a neurologist so I haven't included them here. 

Table 1: Clinical behavioral changes associated with CDS in cats.Increased vocalization, especially at nightAltered social interaction and relationships, either with other or other pet. Altered sleep/wake patterHouse soilingSpatial Disorientation or confusion (i.e. forgetting the location of the litter box)Temporal disorientation (i.e. forgetting if they have been fed)Altered activity (i.e. aimless wandering)AnxietyLearning and memory dysfunction

How is CDS in cats diagnosed?
Oh, this is as tangled of a web as the tau proteins we chase. (A little CDS humor here...the tau proteins can cause the "tangles" seen in human CDS!). Currently, the diagnosis is made by ruling out structural brain disease and systemic causes for diseases that mimic CDS. This may include complete blood count, full biochemistry panel including thyroid screening, urinalysis, chest radiographs, blood pressure assessment, brain MRI and possibly a spinal tap. Imaging changes associated with canine CDS include increased depth of the sulci, dilation of ventricles secondary to neuronal loss (called ex vacuo hydrocephalus) and a measurably small interthalamic adhesion. Exclude everything else, and it's probably CDS.

How can we help these cats age easier?
Currently, there are no proven treatments for feline CDS.  The addition of antioxidants (B vitamins, vitamin C, other) as well as fish oil were evaluated for use in cats in one study and showed promise. The use of S-adenosyl-L-methionine (SAMe) has been recommended for cats based on a study that identified improved performance on cognitive testing. This study only found significant improvement in cognitive function testing in the least affected cats. In addition to medical management, environmental management with ready access to food, water, litter box and areas of comfort (beds, hiding spots) is recommended. Environmental stimulation with low impact toys, or bird feeders in which the cat can choose to ignore any activity if they do not feel inclined to engage, are recommended. Finally, focused veterinary visits can be important for cat owners to feel supported through the aging process. Focus your exam to specifically evaluate body weight, urine production (to assess for signs of dehydration), behavior changes and mobility.This may help detect signs earlier in the course of disease and to identify concurrent morbidity that may contribute to, or be confused with, cognitive dysfunction.

Did I forget anything? Most of you treat and see this more than I do. What have you used (successfully, or not) for treatment? 

Reference:
Miele A, Sordo L, Gunn-Moore DA. Feline Aging: Promoting Physiologic and Emotional Well-Being. Vet Clin North Am - Small Anim Pract. 2020;50(4):719-748. 

Canine Cognitive Dysfunction

Cognitive Dysfunction Syndrome in Dogs

Canine cognitive dysfunction syndrome (CDS) is reported to be a progressive disorder with specific characteristics. Many authors group canine CDS signs into specific categories such as:

• disorientation

• social interactions

• sleep-wake cycles

• house soiling, learning and memory

• activity and anxiety

There is a scoring system called the DISHAA Cognitive Dysfunction Evaluation Tool that utilizes these categories in forming a score, that has been shown by some to correlate to the level of impairment of the dog.

A recent study out of The Ohio State University by Dr. O'Brian et al, published in JAVMA (Sept 15, 2021), described the use of an educational 50 minute weekly class, as a means to controlling clinical progression of CDS. This is a case-control study with about 20 owner/dog pairs completing the class and 66 owner/dog pairs used as control. Scoring was performed at entrance to the study, as well as at 3, 6 and 12 months. During class the instructor spent part of the time informing the clients about a specific aspect of CDS, and the remainder of the time working on an interactive activity with the dog/owner pair geared towards cognitive enrichment and new learned tasks. The owners were asked to practice outside of class as well as in class. The most notable finding was a significant progression of clinical score, using the DISHAA scoring system, in the control group and a lack of progression in the class group. The only exception to this was the disorientation scores. These appeared to increase in the class group which, as the authors suggested, may be due to increased owner awareness by attending the class. The authors suggest that owner information, and structured interaction with the dog, is what slowed progression of all of the other markers of CDS.

What is the take away?

Well...maybe an information session (zoom or live) once monthly for all of your dogs over age 8 could increase awareness by clients and alert them to seek medical attention should signs arise. Or, maybe a senior class in your area (lead by a veterinarian or a trainer) might be the best answer for your clientele.

I hope you have a wonderful week! Please remember that I will be closed Monday-Thursday next week, with limited hours on Friday September 10th. Have a safe and happy Labor Day and Happy New Year, if you celebrate!

Cognitive Dysfunction Syndrome in Cats

What is Cognitive Dysfunction in Cats?

Sixteen years ago when I left my residency and started out as a newly minted neurologist, feline cognitive dysfunction syndrome (CDS) was not on my radar. That has changed. As we learn more about aging in cats, it has become a more widely recognized disease by yours truly, as well as many of you in practice. If you're like me and need a Tidbit-Tuesday style refresher...read on!

What is cognitive dysfunction syndrome?
Cognitive dysfunction syndrome (CDS) is a term used to describe deterioration of mental capabilities associated with age.  Clinical signs referred to cognitive dysfunction can also be associated with other age-related illnesses (e.g. osteoarthritis, structural intracranial disease such as neoplasia, or cardiovascular disease). See table 1 for an outline of behavior changes seen in cats with CDS.
The underlying etiology of CDS is yet unknown. Causes such as oxidative stress/damage, neurodegeneration  and vascular changes are among the leading hypothesis for human and canine CDS, and therefore suspected to be similar in feline CDS.  Deposits of extracellular B-amyloid and intracellular accumulation of microtubule-associated protein tau have been seen in human patients with cognitive dysfunction. Similarly,  B-amyloid deposits and increased tau have been detected in aged cats with cognitive decline, however the significance remains unclear. 

What are the clinical signs of cognitive dysfunction in cats?
There is a handy article, recently published in the Veterinary Clinics of North America by Dr. Miele and associates that echos what others have been reporting in a very concise little table. (See reference at bottom) I have replicated this table, with a few modifications, here. Note: There are other signs such as decreased appetite or thirst, that don't usually drive an owner or veterinarian to seek consultation from a neurologist so I haven't included them here. 

Table 1: Clinical behavioral changes associated with CDS in cats.Increased vocalization, especially at nightAltered social interaction and relationships, either with other or other pet. Altered sleep/wake patterHouse soilingSpatial Disorientation or confusion (i.e. forgetting the location of the litter box)Temporal disorientation (i.e. forgetting if they have been fed)Altered activity (i.e. aimless wandering)AnxietyLearning and memory dysfunction
How is CDS in cats diagnosed?
Oh, this is as tangled of a web as the tau proteins we chase. (A little CDS humor here...you see the tau proteins can cause the "tangles" seen in human CDS.). Currently, the diagnosis is made by ruling out structural brain disease and systemic causes for disease. This may include complete blood count, full biochemistry panel including thyroid screening, urinalysis, chest radiographs, blood pressure assessment, brain MRI and possibly spinal tap. Imaging changes associated with canine CDS include increased depth of the sulci, dilation of ventricles secondary to neuronal loss (called ex vacuo hydrocephalus) and a measurably small interthalamic adhesion. Exclude everything else, and it's probably CDS.

How can we help these cats age easier?
Currently, there are no proven treatments for feline CDS.  The addition of antioxidants (B vitamins, vitamin C, other) as well as fish oil were evaluated for use in cats in one study and showed promise. The use of S-adenosyl-L-methionine (SAMe) has been recommended for cats based on a study that identified improved performance on cognitive testing. This study only found significant improvement in cognitive function testing in the least affected cats. In addition to medical management, environmental management with ready access to food, water, litter box and areas of comfort (beds, hiding spots) is recommended. Environmental stimulation with low impact toys, or bird feeders in which the cat can choose to ignore any activity if they do not feel inclined to engage, are recommended. Finally, focused veterinary visits can be important for cat owners to feel supported through the aging process. Focus your exam specifically evaluating body weight, urine production (to assess for signs of dehydration), behavior changes and mobility.This may help detect signs earlier in the course of disease and to identify concurrent morbidity that may contribute to, or be confused with, cognitive dysfunction.

Did I forget anything? Most of you treat and see this more than I do. What do you see in practice? What have you used (successfully, or not) for treatment? Please reach out - I want to hear your perspective!

Reference:
Miele A, Sordo L, Gunn-Moore DA. Feline Aging: Promoting Physiologic and Emotional Well-Being. Vet Clin North Am - Small Anim Pract. 2020;50(4):719-748.