Psychology Facts

▲ Agnosia ▲

》Agnosias are a group of conditions where damage to your brain interferes with how it processes or understands information coming in from your senses. Your senses, such as vision or hearing, work fine, but your brain can't process the information. That can disrupt your ability to understand or navigate the world around you.

》Agnosias can happen to anyone at any age but tend to happen because of certain brain conditions. Some, but not all, of these conditions have a connection to your age or other age-related diseases.

》Agnosias are very rare overall. Less than 1% of people receiving care for a neurological (brain) condition have any type of agnosia.

》Agnosias are conditions that you can't explain away as a problem with a person's senses or memory. An example of this is a person who knows what a cat is and can see that there's a cat in the room with them, but can't tell you that it's a cat by looking at it (visual agnosia), or they can't identify that it's a cat from its meow (auditory agnosia).

》Agnosia comes in two main forms:

Apperceptive: This form involves a problem of perception. The person's senses work, but their brain can't process the information.

Associative: This type is a problem of recognition. The senses can pick up information and the brain can process it, but it can't recognize or make sense of the information coming in.

》The difference between these forms is slight but important. An example of this is to take multiple copies of the same picture of a cat and show it to people with the forms of agnosia. The person knows what a cat is in either form, but their brain can't recognize them by sight.

Apperceptive: If you show multiple copies of a picture of a cat to a person with apperceptive agnosia, they wouldn't be able to tell that it's a cat, and they can't tell that it's the same picture.

Associative: If you show the same pictures to someone with associative agnosia, they would recognize it's the same picture but wouldn't be able to tell that it's a cat.

》Agnosias are problems with your brain, not the senses themselves. Like any other part of your body, your brain is prone to injuries. These injuries, known as lesions, will have different effects depending on where in your brain they happen. Lesions can also happen suddenly or slowly over time, depending on the underlying cause.

》Potential conditions and causes of brain lesions leading to agnosias include, but aren't limited to, the following:

Alzheimer's disease.
Aneurysms.
Brain tumors (including cancerous and noncancerous growths).
Dementia.
Developmental disorders.
Head injuries such as concussions or traumatic brain injuries (TBIs).
Cerebral hypoxia (brain damage from lack of oxygen).
Infections (such as those that cause encephalitis).
Seizures and epilepsy.
Sleep apnea.
Stroke.
Toxins, such as carbon monoxide poisoning.

》Diagnosing agnosias involves tests and exams that'll ensure the following:

Sensory tests: These tests will make sure that the involved sense in question works as it should and rule out any sense-related problems or conditions.

Cognitive and mental status check: These tests ensure the problem isn't with the person's thinking, focusing or problem-solving abilities.

Memory and familiarity tests: These tests will verify that the person doesn't have a memory problem. They also make sure a person's lack of recognition isn't because of a lack of experience or familiarity with something.

Diagnostic and imaging tests: These tests look for lesions or signs of damage to the relevant part of your brain.

Types of Agnosia will be in the next chapter!!