Amnesia

Amnesia
Synonyms	Memory loss
Pronounce	N/A
Specialty	Neurology, Psychiatry
Symptoms	Memory loss, difficulty recalling past events, inability to form new memories
Complications	N/A
Onset	Sudden or gradual
Duration	Can be temporary or permanent
Types	N/A
Causes	Brain injury, traumatic events, stroke, alcohol abuse, encephalitis, Alzheimer's disease
Risks	Head injury, substance abuse, psychological trauma
Diagnosis	Neuropsychological tests, brain imaging (MRI, CT scan)
Differential diagnosis	Dementia, delirium, depression, conversion disorder
Prevention	N/A
Treatment	Cognitive therapy, occupational therapy, medication
Medication	N/A
Prognosis	Varies depending on cause; some cases may improve over time, others may be permanent
Frequency	Common in cases of traumatic brain injury and neurodegenerative diseases
Deaths	N/A

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Obesity, Sleep & Internal medicine
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Amnesia
Synonyms	Amnesic syndrome
Pronounce	N/A
Specialty	N/A
Symptoms	Memory loss, confusion, inability to retain new information
Complications	Cognitive impairment, loss of autonomy, emotional distress
Onset	Sudden or gradual, depending on cause
Duration	Temporary or permanent
Types	Anterograde amnesia, Retrograde amnesia, Dissociative amnesia, etc.
Causes	Brain injury, stroke, neurodegenerative disorders, psychological trauma, alcohol abuse
Risks	Head trauma, epilepsy, encephalitis, substance use
Diagnosis	Neuropsychological testing, MRI, CT scan, EEG
Differential diagnosis	Dementia, Delirium, Depression
Prevention	Preventing head injuries, managing substance use, early intervention in infections
Treatment	Supportive care, cognitive rehabilitation, psychotherapy
Medication	Vitamin B1 in cases like Korsakoff's syndrome
Prognosis	Varies by type and cause
Frequency	Uncommon overall; varies with underlying condition
Deaths	Rarely fatal directly

Amnesia is a neurocognitive disorder characterized by partial or complete loss of memory, either short-term, long-term, or both. It can result from a variety of causes including neurological damage, psychological trauma, or toxic exposures. Individuals with amnesia may be unable to recall past experiences, form new memories, or both, depending on the type and extent of brain involvement.

Classification

Amnesia is broadly categorized based on the type of memory affected and the underlying cause.

Anterograde Amnesia

Anterograde amnesia is the inability to form new memories following the onset of the condition, often caused by damage to the hippocampus or related structures.

Retrograde Amnesia

Retrograde amnesia involves the loss of pre-existing memories prior to the onset of amnesia. It often spares older memories while more recent ones are affected.

Transient Global Amnesia

Transient global amnesia (TGA) is a sudden, temporary episode of memory loss not attributable to more common neurological conditions like epilepsy or stroke.

Dissociative Amnesia

Dissociative amnesia is typically psychological in origin, where individuals block out memories related to stressful or traumatic events. It is associated with post-traumatic stress disorder (PTSD) and dissociative disorders.

Traumatic Amnesia

Often seen after head injuries, traumatic amnesia may involve both retrograde and anterograde memory loss, depending on the severity of the traumatic brain injury.

Korsakoff's Syndrome

Korsakoff's syndrome is a chronic memory disorder caused by severe deficiency of vitamin B1 (thiamine), most often due to chronic alcoholism.

Lacunar Amnesia

Lacunar amnesia refers to memory loss of a specific event, leaving the rest of memory intact. It may occur in cases of stroke or localized brain trauma.

Fugue State

Also known as dissociative fugue, this condition involves sudden, unplanned travel away from home combined with memory loss regarding personal identity.

Infantile Amnesia

Also referred to as childhood amnesia, it is the normal inability of adults to recall memories from the early years of life, typically before age three.

Psychogenic Amnesia

Psychogenic amnesia is caused by emotional trauma or psychological conflict, without any detectable brain injury.

Source Amnesia

Source amnesia refers to the inability to remember the origin or source of learned information while retaining the factual content.

Alcohol-Induced Amnesia

Also called alcohol-induced blackouts, these are temporary memory lapses caused by excessive alcohol consumption.

Causes

Amnesia can arise from:

• Brain injury (trauma, surgery)
• Stroke
• Infections such as encephalitis
• Neurodegenerative diseases like Alzheimer's disease
• Psychological trauma
• Anesthesia or sedation
• Substance abuse, particularly alcohol

Damage to brain regions involved in memory processing — especially the hippocampus, thalamus, prefrontal cortex, and amygdala — is typically implicated in organic amnesia.

Diagnosis

Diagnosis involves a combination of:

• Detailed clinical history
• Neurological examination
• Neuropsychological tests
• MRI or CT scan
• EEG (to rule out seizures)

Treatment

Treatment depends on the cause:

• Reversible causes (e.g., vitamin deficiency or medication side effects) are treated by correcting the underlying condition.
• Cognitive therapy: Occupational therapy and memory training strategies can help patients adapt.
• Psychotherapy: Used in dissociative or psychogenic amnesia to uncover and address underlying trauma.
• Pharmacotherapy: In some cases, medications to treat underlying conditions (e.g., antidepressants for PTSD-related amnesia) may be used.

Prognosis

The outcome of amnesia depends on its cause and severity:

• Temporary amnesia (e.g., from minor head trauma or stress) often resolves completely.
• Chronic or progressive causes (e.g., Korsakoff‚Äôs syndrome, Alzheimer's) may lead to permanent memory loss.
• Psychological forms may improve with therapy.

See also

• Memory
• Hippocampus
• Neuropsychology
• Dementia
• Cognitive rehabilitation
• Wernicke‚ÄìKorsakoff syndrome
• Brain plasticity

External links

• National Institute of Neurological Disorders and Stroke ‚Äì Amnesia
• MedlinePlus ‚Äì Amnesia Overview