Question

    Amnesia

    Amnesia is loss of memory that occurs due to psychological trauma or other conditions causing damage to the brain. Such a type of condition essentially does not cause loss of self identity.

    Presentation

    Individuals with amnesia usually find problems with short term memory. They are unable to remember recent or new information. Such individuals usually have sound memory about their childhood days or history. For example; such individuals can recall name of past presidents, but would unable to tell names of current ones. Also, they would find difficulty in telling what they had for breakfast.

    Individuals with retrograde amnesia are unable to recall past events or memories and those with anterograde amnesia find difficulty in learning new things [7]. However, individuals with such a kind of memory loss are still able to understand written and spoken words. In addition, affected individuals present with the following signs and symptoms:

    neurologic
  • more...
  • Workup

    At the preliminary level, various tests will be done to rule out underlying conditions that can be a cause of memory loss such as Alzheimer disease, dementia, brain tumor or depression. Thereafter, the following tests would be done to diagnose amnesia [8]:

    • Past medical history: A detailed medical history about illnesses and brain injury in the past is taken. The patient is also watched for signs of language problems, depressions, confusion and changes in personality. In addition, other information related to the pattern of memory loss is also gathered.
    • Neurological examination: Various tests are employed to assess the neurological and sensory functions such as reflexes, balance and psychological aspects.
    • Cognitive tests: In this, the individual’s memory, thinking and judgmental abilities are determined. Cognitive test will help determine the extent of memory loss which would in turn help in designing the treatment plan.
    • Imaging studies such as CT scan and MRI would also be done to determine presence of any brain abnormalities [9]. 
    • Blood tests will be done to analyze nutritional deficiencies and infections.

    Treatment

    The following methods are employed for treating amnesia [10]:

    • Occupational therapy: In this, individuals receive memory training, which includes several strategies to organize the information, so that it is easy to remember. Such a kind of technique improves the understanding of extended conversation, so that individuals with amnesia can get help in remembering such information.
    • Technological support: Individuals diagnosed with amnesia often find immense help from smart phones. These phones can help remind the individuals about important events and daily tasks.
    • Medications: Medications are basically administered for treating the underlying disease condition. As of now no medications have been developed that would help improve or correct memory loss in people with amnesia.

    Prognosis

    So far there is no specific treatment for amnesia. Affected individuals are treated for underlying disease conditions to manage the symptoms. Prognosis of the condition would greatly depend on the underlying disorder. Individuals who have developed amnesia due to brain injury, show signs of recovery over a period of several weeks to months. However, those with severe head injury have a poor prognosis.

    Complications

    Alzheimer Disease
    • Degenerative disease condition such as Alzheimer disease can cause amnesia.[symptoma.com]
    Transient Global Amnesia
    • Transient global amnesia occurs in about 5.2 cases per 100,000 populations.[symptoma.com]
    • Transient global amnesia is a well-described medical and clinical phenomenon.[en.wikipedia.org]
  • more...
  • Etiology

    Amnesia is attributable to all those factors that lead to brain damage. Such conditions include:

    • Encephalitis
    • Anoxia: Loss of oxygen supply to the brain can lead to temporary memory loss.
    • Degenerative disease condition such as Alzheimer disease can cause amnesia.
    • Emotional trauma during childhood is another significant cause of amnesia [3].
    • Medications: Certain medications such as benzodiazepines can also interfere with brain functioning leading to amnesia.

    Epidemiology

    Amnesia is of several types such as transient global amnesia, anterograde amnesia and retrograde amnesia. Transient global amnesia occurs in about 5.2 cases per 100,000 populations. The incidence is higher amongst those aged 50 years and above. It has been estimated that in individuals over 50 years, the condition strikes 23.5 cases per 100,000 populations [4].

    Sex distribution
    Age distribution

    Pathophysiology

    Under normal conditions, the function of memory employs several parts of the brain. Any type of situation, such as diseases, or trauma to these parts, significantly hampers the memory of the individual. The limbic system in the brain is responsible for memory functioning. This system includes the thalamus and the hippocampus. The hippocampus part of the brain is responsible for forming new memories and recovery of old memories. The cells of this part gets easily damaged and disrupted by diseases, trauma, injury, drugs and anoxia. In addition, stroke and infections can cause permanent damage to the brain [5] [6].

    Prevention

    Brain injury or damage to the brain from other disease is the root cause of amnesia. In view of this, it becomes necessary to adopt all steps to avoid brain damage. The following steps can be taken:

    • It is utmost important to protect head by wearing helmet while driving.
    • It is also necessary to avoid alcohol abuse.
    • Prompt treatment of infection is required to avoid its spread to the brain.
    • Any kind of sign that suggest onset of stroke or paralysis should receive immediate medical intervention to avoid further damage to the brain.

    Summary

    Individuals with amnesia face problems with forming new memories and remembering the old ones. With age, memory loss is a common phenomenon. However, when individuals experience significant loss of memory, then it is an indication of amnesia. It is a permanent condition that essentially occurs as a result of damage to the major areas of the brain. Unlike other form of amnesia, such as transient global amnesia, which causes temporary memory loss, amnesia is a permanent condition [1] [2].

    Patient Information

    Definition

    Amnesia is a condition characterized by memory loss due to damage to the parts of the brain that are responsible for memory function. There are several types of amnesia which include transient global amnesia, anterograde amnesia and retrograde amnesia. All these types define memory loss, but with different characteristics.

    Cause

    Damage to the thalamus and hippocampus region of the brain, are responsible for the memory function. Any damage to these parts, significantly affects the memory of the individuals. Factors such as underlying disease condition, brain injury, tumor, poor oxygen supply, alcohol abuse, trauma and stress can lead to amnesia.

    Symptoms

    Symptoms of amnesia include impaired ability of the individual to recall recent information, along with confusion and confabulation. Affected individuals can recall old information to a certain extent, but are pretty bad with new or recent information.

    Diagnosis

    A detailed medical history of the affected individual is gathered. Following this, neurological tests are carried out, to assess the extent of memory loss. In addition, CT scan and MRI are also done to determine damage to the brain.

    Treatment

    Affected individuals are treated through occupational therapy, and technological assistance to help them cope with memory loss. Certain medications are also given to treat the underlying condition.

    Self-assessment

    References

    1. Quinette P, Guillery-Girard B, Dayan J, et al. What does transient global amnesia really mean? Review of the literature and thorough study of 142 cases. Brain 2006; 129:1640.
    2. Tong DC, Grossman M. What causes transient global amnesia? New insights from DWI. Neurology. Jun 22 2004;62(12):2154-5.
    3. Briere J, Conte J. Self-reported amnesia for abuse in adults molested as children. J Trauma Stress 1993; 6:21.
    4. Matias-Guiu J, Blanquer J, Falip R, et al. Incidence of transient global amnesia in a Alcoi (Spain). Acta Neurol Scand. Aug 1992;86(2):221.
    5. American Psychiatric Association. Delirium, dementia, and amnestic and other cognitive disorders. In:Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Fourth Edition. Washington, DC: American Psychiatric Association; 1994:123-63.
    6. Chiang GC, Insel PS, Tosun D, et al. Hippocampal atrophy rates and CSF biomarkers in elderly APOE2 normal subjects. Neurology. Nov 30 2010;75(22):1976-81.
    7. Hennig-Fast K, Meister F, Frodl T, et al. A case of persistent retrograde amnesia following a dissociative fugue: neuropsychological and neurofunctional underpinnings of loss of autobiographical memory and self-awareness. Neuropsychologia 2008; 46:2993.
    8. KierschTA. Amnesia: a clinical study of ninety-eight cases. Am J Psychiatry 1962; 119:57.
    9. Liang JF, Shen AL, Lin SK. Bilateral hippocampal abnormalities on diffusion-weighted MRI in transient global amnesia: report of a case. Acta Neurol Taiwan. Jun 2009;18(2):127-9.
    10. Ruedrich SL, Chu CC, Wadle CV. The amytal interview in the treatment of psychogenic amnesia. Hosp Community Psychiatry 1985; 36:1045.

    • Learning set and facilitation of reversal learning after medial-temporal damage in rats: implications for an account of preserved learning abilities in amnesia - H Eichenbaum, A Fagan - The Journal of , 1986 - Soc Neuroscience


    Languages

    Self-assessment