Cognitive Disorders: Delirium, Dementia, Amnesia

Cognitive disorders significantly impair cognitive functions, especially problem solving, perception, and memory. Dementia, delirium, and amnestic disorder are the most direct cognitive disorders.

Other types of this disorder are anxiety disorders such as post-traumatic stress disorder (PTSD), panic disorders, phobias, generalized anxiety disorder, and obsessive-compulsive disorder. Mood disorders (bipolar disorder and depression) and psychotic disorders (delusional disorder and schizophrenia) are also classified as cognitive disorders.

What is dementia?

Dementia significantly impairs the intellectual functioning of a person, interfering with his or her normal relationships and activities. It also affects the solving problem skills and emotional balance of the person.

People who suffer from dementia often experience behavioral problems and personality changes such as agitation, hallucinations, and delusions. Dementia results from the loss of communication among nerve cells and/or death of these cells.

While memory loss is one of the most common symptoms of dementia, memory loss doesn’t necessarily mean that a person has this disorder. Dementia is diagnosed if two or more brain functions (perception, language skills, memory, or cognitive skills such as judgment and reasoning) are significantly damaged without the loss of consciousness.

What is delirium?

Delirium is a relatively sudden and acute decline in cognition, perception, and attention-focus. It is not the same as dementia although demented patients can have this as a symptom.

There are many possible causes of this disorder. The metabolic encephalopathy is the most common cause, which is responsible for about 20% to 40% of all delirium cases. This is often a result of organ failure, such as kidney or liver failure.

Other metabolic causes are hyperthyroidism and hypothyroidism, diabetes mellitus, and fluid and electrolyte imbalances in the blood, vitamin deficiencies, and severe dehydration.

Symptoms of delirium include: hallucinations, speech or language impairment, decreased or increased activity level, impairment of memory, and disorientation or confusion of time. A person suffering from this disorder may also have decreased awareness of his or her environment, misinterpreted stimuli and illusions, and mood disturbance.

What is amnesia?

Basically, amnesia is the loss of one’s ability to recall information stored in the memory. It is one of the symptoms of Alzheimer’s disease and other degenerative brain diseases. It may also result when the brain suffers from a traumatic injury, such as in a vehicular accident.

Brain cells cannot be replaced once they die, but the brain can recover several of its previous faculties depending on what caused the amnesia. Amnesia caused by an injury may be cured as the brain heals itself over time. However, amnesia caused by a degenerative illness are unlikely to be cured.


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