Using behavioral testing as a more accurate way to diagnose cognitive decline in dogs
Why Behavioral Testing in Dogs Is Necessary
If we take better care of our pets, they will live longer. However, even the best care doesn't protect them from common age-related diseases, including those affecting brain function.
As dogs age, their behavioral symptoms may be similar to those of aging humans, such as memory decline, decreased learning ability, and other signs of brain aging.
Cognitive Decline and Alzheimer's Disease do indeed have many similarities. In particular, the development of both conditions is related to the buildup of beta-amyloid protein in senile plaques in the brain.
Compare the Symptoms
Cognitive Decline in Dogs
Disorientation and confusion
Changes in behavior
Anxiety and restlessness
Alzheimer's Disease in Humans
Inability to learn new information
Difficulty with language, numbers, and organizing thoughts
Accurate cognitive decline detection is important
for proper dogs treatment
Cognitive dysfunction in dogs may not always be evident in their behavior, but it can lead to other changes, such as alterations in their sleep-wake cycle. This can then result in more significant physiological changes. Cognitive dysfunction is commonly seen in 20% of dogs over the age of 11 years.
Problems with Conventional Diagnostics
Diagnosing cognitive decline in dogs can be challenging, as it is often based on questionnaires filled out by owners in veterinary practice. This method is subjective and can result in inaccurate diagnoses, making it difficult to effectively diagnose and evaluate treatment effectiveness.
More accurate laboratory techniques are not feasible for everyday veterinary practice, as they are time-consuming and expensive.
Our Approach to Diagnosing of Cognitive Decline in Dogs: Behavioral Tests
In our study, we have selected a series of tests that can be used in a clinical setting to assess cognitive dysfunction in a large number of dogs in a short amount of time. We hope that our research will contribute to the development of a more effective method for the treatment and prevention of cognitive decline in dogs.
Behavioral tests enable us to:
Assess a dog's mental responsiveness by examining its interest in new objects
Evaluate its attentiveness, memory capacity, and problem-solving abilities
Link these traits to the dog's biochemical and physical states, such as blood neuro-markers and locomotor activity.
The Battery of Behavioral Tests
Our battery of behavioral tests consists of: Open Field, Mirror, Stranger Person, Curiosity, and Detour tests.
Why do we need multiple tests? Just like humans, dogs have varying personalities and temperaments. Some are more energetic, while others are more laid back. Some may have stronger memories, while others may have difficulty remembering things. Some dogs excel at problem-solving, while others are more observant, and others still may be easily distracted. These differences do not necessarily indicate age-related cognitive dysfunction.
Dogs have unique personalities, which is why it is not possible to diagnose cognitive decline with a single measurement. A comprehensive assessment, taking into account multiple parameters such as activity levels, curiosity, and problem-solving abilities, is necessary to make a definitive diagnosis. It is also important to consider the impact of other health issues on a dog's cognitive abilities, such as vision or joint problems, which may affect the dog's ability to recognize itself in a mirror or interact with toys. A longitudinal approach, tracking changes in each parameter over time, is the best way to make a diagnosis.
1. Open Field Test
The Open Field Test is a commonly used approach to studying spontaneous animal behavior. In this test, a dog is placed in an empty room to explore. Its behavior is recorded using a ceiling-mounted video camera.
The test assesses the dog's locomotor activity, vocalizations, willingness to explore the environment, and interest in new objects. The tests are repeated every nine months to evaluate changes in the dog's behavior and assess the effectiveness of treatments or social enrichment.
A dog with cognitive decline or dysfunction may show decreased exploratory activity, such as staying in one corner of the room for the entire test. Alternatively, the dog may display increased anxiety and become overly active, running randomly around the room. On the other hand, a healthy dog will typically explore all areas of the room, including the center.
This test provides objective measures of the dog's basic exploratory activity, including the number of squares the dog crosses in 3 minutes and the time the dog spends in different areas of the room.
2. Mirror Test
The Mirror Test is one of the indicators of cognitive activity and measures how a dog reacts to various stimuli.
Typically, a dog should not interact with its reflection in a mirror. In fact, dogs are able to recognize themselves well in the mirror and quickly lose interest in their reflection.
However, a dog with cognitive dysfunction may treat its reflection as another dog and engage in either aggressive or friendly behavior.
We observe and record the dog's level of interaction with the mirror and for how long it interacts with it. This information can provide valuable insight into the dog's cognitive abilities.
3. Stranger Person Test
(Human Interaction Test)
Dogs have been domesticated by humans for over 10,000 years, and they have evolved to interact effectively with humans. Their ability to interact with humans, even strangers, is a key aspect of their domestication.
When meeting a stranger, a healthy dog will try to make eye contact and gauge the stranger's behavior, using body language and other cues to determine whether the stranger is friendly or not. Typically, healthy dogs show their affection by looking into the stranger's eyes, wagging their tails, and allowing themselves to be petted.
However, dogs with cognitive decline may lose this ability to interact effectively with humans. They may become frightened or confused when meeting a stranger and may ignore or avoid the stranger altogether. This is why the Stranger Person Test is an important part of our battery of behavioral tests.
In this test, a stranger enters the room and remains motionless in a chair, avoiding any eye contact or interaction with the dog. This allows us to observe the dog's natural response to the stranger, without being influenced by the stranger's behavior. We then analyze the timing and manner in which the dog interacts with the stranger, as well as any differences in their behavior compared to other stimuli.
4. Curiosity Test
(Toy Interaction Test)
In this test, we evaluate the level of curiosity in dogs. New objects are introduced into the room, and the behavior of a healthy dog is to explore and investigate these objects. Some dogs may only sniff the objects, while others may play with plush toys or roll around with a Kong toy.
A dog with cognitive decline may not respond to the new objects or may react in an inappropriate manner, such as barking at them.
As in the previous tests, we record the amount of time the dog spends interacting with the toys and observe how this behavior changes over time.
5. Detour Task, or V-test
This test is also known as the problem-solving test, and it measures the dog's ability to solve a simple problem and find a way to a piece of food. Most dogs can perform this task with ease, but in the presence of cognitive dysfunction, the time it takes to complete the task increases or the dog may completely lose the ability to find the solution.
In this test, a treat is placed behind a transparent V-shaped barrier, and the dog must navigate around the barrier to reach the food. The test evaluates the dog's inhibitory control (the ability to resist a direct path to the goal), route planning, and learning. The dog is given three attempts, after which the V-shaped barrier is reversed, and another attempt is made in the opposite direction.
The V-test was adapted from Litchfield and Smith's article, "How Well Do Dingoes, Canis dingo, Perform on the Detour Task." Interestingly, captive wild dingoes outperform domestic dogs on this test.