Retrograde amnesia

Individuals with Retrograde amnesia (RA) are unable to recount incidents or experiences, preceding a specific event in time. Get detailed information about this memory disorder, including its causes, symptoms, diagnosis, and treatment approaches.

Retrograde amnesia Definition

This disorder exhibits a marked impairment of autobiographical memory – a memory system consisting of episodes recollected from the life of an individual – based on personal experiences and descriptive knowledge. The ailment is completely in contrast to anterograde amnesia, which refers to a deficit in consolidating new information subsequent to a traumatic event.

Retrograde amnesia Types

Severe cases of RA, causes individuals to undergo permanent memory loss and forget their own identity. However, such an extreme form of amnesia is rarely seen and most patients suffer from any one of the following:

Temporally graded retrograde amnesia

Systemic consolidation, which describes the processes involved in the retrieval of memory, becomes impaired for a temporary period of time. Traces of anterograde amnesia could be found in this type.

Pure retrograde amnesia

The type is marked by the absence of anterograde amnesia.

Focal retrograde amnesia

Physical abnormalities are usually not observed in this form of RA. This condition is more of a psychological type of memory loss with few traits of anterograde amnesia.

Isolated retrograde amnesia

This is an intense form of RA and affected patients normally have extreme difficulty recalling past information.

Retrograde amnesia Symptoms

Although patients are not able to remember specific events or situations of the past, most of them retain long-term declarative memory- the memory of meanings, understandings and other factual information. However, individuals who inflict serious injuries on the brain can exhibit problems like:

  • Improper organization and categorization of verbal material
  • Incorrect way of language formation
  • Long-term memory loss
  • Difficulty recollecting non-verbal information
  • Unplanned travel or wandering from home, or workplace

Retrograde amnesia Causes

RA is a complex disorder and clinical psychoanalysts have not been able to ascertain the cause of the amnesiatic condition. As aforementioned, the loss of episodic and declarative memory could be attributed to damage to certain components of the brain such as:

Hippocampus

It is the major portion of the brain responsible for storing and encoding both short-term and long-term information.

Diencephalon

This is the posterior section of the forebrain that relays sensory information between the cerebral hemispheres and controls functions of the peripheral nervous system.

Temporal lobes

These form a part of the cerebral cortex and are mainly involved in speech, language, memory, hearing, and high level visual processing.

The potential factors that could probably affect the vital areas of the brain include:

Traumatic injuries

Structural damage to the brain is predominantly caused by a hard blow to the head, or even due to a congenital brain anomaly. The brain may also get traumatically afflicted due to diffuse axonal injury- tearing of its nerve fibers and subsequent formation of extensive lesions. The severity of the damage is highly dependent on the impact of external forces and location of injury. Repetitive head injuries may also prove lethal to individuals who are into regular contact sports.

Psychologically disturbing events

As discussed earlier, focal retrograde amnesia does not have a neurological basis and is generally an outcome of a traumatic incident. In fact, recent studies have proved that regular episodes of mental stress and emotional fear can trigger the onset of RA.

Korsakoff syndrome

Chronic alcohol abuse as well as severe malnutrition can cause depletion of thiamine in the brain. The water-soluble vitamin is needed daily to facilitate the orderly functioning of the brain. Replacement of nutritional food with hard alcohol can gradually erode the brain and lead to amnesia.

Infectious conditions

Bacteria and viruses are the most common offenders of infecting the brain, spinal cord, and its surrounding structures. The infectious agents invade various regions of the brain and cause inflammation. A wide variety of disorders can occur depending on the location of infection. Some of the common ones include:

  • Meningitis
  • Myelitis
  • Encephalitis
  • Abscess

Surgery

Sometimes, a surgery of the brain can pose huge risks and may even be responsible for inactivating few essential parts of the organ. In an attempt to cure an existing brain disorder, surgeons often remove the hippocampus and temporal lobes that leads to loss of both episodic and declarative memory.

Psychiatric treatment

Psychological disorders normally warrant therapeutic methods that would aid in the treatment. However, the techniques have adverse effects on the brain and may clinically induce RA in the patients. Electroconvulsive therapy (ECT) is one such procedure, in which an electric current is passed through the brain to produce controlled convulsions. Individuals with significant depression and who are not responding to antidepressants undergo ECT. Despite the benefits, short-term memory loss is the most common side effect of the method.

Retrograde amnesia Diagnosis

The assessment of episodic and declarative memory is usually done by testing the factual knowledge of the patients. Autobiographical memory interview is a useful research tool for investigating RA. The test evaluates a patient’s recall of specific incidents that has occurred earlier. It assays the three broad time bands, which are the childhood, early adult life and recent facts. In this way, the test allows measurement of the pattern of autobiographical memory deficit as well as detection of any signs of anterograde amnesia. Neuroimaging studies, comprising of computed tomography and magnetic resonance imaging can produce high quality images of the brain structures for quick viewing of any traumatic injury. Electroencephalography enables health specialists to record the electrical activity along the scalp and infer the test. Abrupt decrease in brain activity is usually associated with large slow EEG waves, a possible indicator of a structural damage.

Retrograde amnesia Treatment

Treatment for RA will be individualized for each patient depending upon the specific underlying cause and the individual's situation. Diuretics, anti-seizure drugs and surgical resection are the options available for minimizing additional damage to the brain tissues in patients with traumatic injuries. In emergency cases, adequate oxygen and blood supply is a must to restore breathing and circulation. Antibiotics, steroids and anticonvulsants can control the spread of bacterial infection in the brain. Special antiviral drugs are used to treat brain infections caused by herpes strains. Alcoholic patients must be counseled and educated about the negative effects of heavy drinking. Replacement or supplementation of thiamine by intravenous or intramuscular injection, together with proper nutrition and hydration can hasten recovery. Psychotherapeutic techniques such as hypnotherapy conducted by experienced practitioners can be beneficial for individuals who are suffering from RA due to an emotionally traumatic event. Spontaneous recovery utilizes a method called classical conditioning, a form of learning in which a biologically significant stimulus elicits a response from the patient. The appearance and sudden extinction of the response may accelerate the activity of the brain and helps restore the autobiographical information.

Retrograde amnesia still requires a standardized test as many criminals claim to have the disorder in order to escape from a harsh punishment. If you or any of your family members is experiencing difficulty in recalling incidents prior to a sudden or progressive onset of brain damage, seek immediate aid from a mental health counselor. Regular counseling sessions with your doctor can help you bring back memories of the past and regain a normal life.