Amnesia

Amnesia is a human memory disorder that manifests itself as pathological loss of memories of life circumstances. Amnestic syndrome remains a common complication of neurological diseases, mental disorders, chronic intoxication or acute poisoning.

General information

The absence of memories of past events is not always considered by doctors as a pathology. Childhood amnesia is common. Most people cannot recount the events of the first three years of their lives.

The main clinical manifestation of amnesia is the loss by a person of previously available memories of significant events of the past or the circumstances of recent actions. Amnestic syndrome remains a common manifestation of neurological and psychiatric pathologies.

Causes of memory disorder

The most common causes of amnesia are changes in the structures of the patient's brain. Metabolic, morphological or bioelectrical disorders occur because of:

• traumatic brain injury,
• brain tumors,
• cerebral hypoxia,
• neuroinfections,
• intoxication,
• degenerative diseases of the central nervous system,
• epilepsy.

Psychological traumas (abductions, rapes, car accidents, terrorist attacks) have a significant impact on the state of memory. Loss of memory is a defensive reaction to the events that have occurred. Partial amnesia can result from alcohol delirium, dissociative disorder or schizophrenia.

Types of amnestic syndromes

The basis for the classification of pathology are the characteristics of its completeness, chronological orientation and course features. During the diagnosis, doctors take into account all the parameters, since the patient's treatment strategy depends on them.

Neurologists distinguish three types of amnesia in accordance with the completeness of memory loss:

• absolute,
• partial,
• local.

In the first case, a patient cannot remember any events in a certain period of the past. In the second case, a patient has vague and fragmentary memories. Local amnestic disorders are diagnosed when a patient loses a certain skill or ability.

An extended classification takes into account the temporal location of events forgotten by a person in relation to the moment of occurrence of amnesia. Basic information about these types of pathology is presented in the table.

The course of amnesia may be stationary (without dynamics), progressive or regressive. The latter becomes the basis for a favorable prognosis regarding a complete recovery of the patient.

Symptoms of pathology

Symptoms of amnesia depend on the clinical form of the disease identified in the patient. The basic symptom is the inability of a person to remember events from a certain time period. The sequence of memory loss is described in Ribot's law. First amnesic patients forget recent events, then facts of the recent past. At the last stage, there is a loss of memories of actions in the distant past. Memory recovery is restored in reverse order.

Often, adults and children diagnosed with amnesia are faced with confabulations - fictional memories. They reflect the patient's desire to fill in the gaps in his/her own memory.

Symptoms of the amnestic syndrome can be combined with manifestations of the underlying pathology that led to disorders in the cerebral structures. In alcoholic delirium, for example, there are severe mood swings accompanied by euphoric episodes and hysterics. The patient experiences thirst, nausea attacks and suffers from loss of muscle tone. Amnesia with alcoholic neurosis remains temporary.

Diagnosis

The diagnostic algorithm is individual for each patient. The set and sequence of actions of the neurologist is determined by the clinical picture of the pathology. A psychiatrist, narcologist, neurosurgeon and infectiologist may be involved as consultants. Advanced diagnostic plan includes:

• data collection for anamnesis;
• assessment of neurological status;
• assessment of psychiatric status;
• CSF examination;
• general and biochemical blood tests.

An important diagnostic procedure is an MRI of cerebral vessels. Cerebral hemodynamic study is performed when vascular genesis of amnesia is suspected.

Computed tomography of the brain is indicated for patients with traumatic brain injuries. The same method is used when doctors detect symptoms of malignant neoplasms in brain structures.

Treatment of the amnesic syndrome

Drug treatment is prescribed to the patient based on the symptoms identified during the physical examination and additional studies. Pharmacotherapy is based on the following drugs:

• vasodilators and antiplatelet agents;
• neuroprotectors and antioxidants;
• anticholinesterase agents;
• nootropics;
• memantines.

The substances listed are designed to improve cerebral blood flow, optimize metabolic processes in neurons, slow down the progression of dementia, restore memory and stimulate the cognitive abilities of patients. Treatment for amnesia may include psychotherapy and physical exercises. In the presence of brain tumors, the patient is prescribed surgical intervention.

Prognosis and preventive measures

The success of treatment depends on the age of the patient, the underlying pathology and the causes of amnesia. Traumatic memory disorders are reversible - therapy is successful in 85% of all cases. Degenerative changes in the central nervous system are characterized by a progressive course that excludes the possibility of a complete recovery of the patient.

Preventive measures involve the observance of safety precautions during work and rest. These actions will allow the patient to avoid head injuries. At the first signs of intoxication, infections or vascular disorders, adults and children should seek medical help.

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