(am-nē′zhă )

[Gr. amnēsia, amnēstia, oblivion, forgetfulness]
Loss of memory, whether partial, total, permanent, or transient. The term is often applied to episodes during which patients forget recent events although they may conduct themselves appropriately, and after which no memory of the period persists. Such episodes are often caused by strokes, seizures, trauma, senility, alcoholism, or intoxication. The cause is often unknown.

anterograde amnesia

Amnesia for events that occurred after a precipitating event or medication.
Short-term memory loss may be induced in people who use benzodiazepine drugs (such as triazolam, lorazepam, or flurazepam).

SYN: SEE: anterograde memory; SEE: anterograde memory loss

auditory amnesia

SEE: Word deafness.

dissociative amnesia

Amnesia for important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness.
SYN: SEE: psychogenic amnesia

immunologic amnesia

immunological amnesia Innate inhibition of cellular or humoral immune responses.

lacunar amnesia

Amnesia for isolated events.

post-traumatic amnesia

ABBR: PTA Amnesia, agitation, and confusion affecting a patient with traumatic brain injury (TBI) soon after the injury or on awakening from coma. Edema, hemorrhage, contusions, shearing of axons, and metabolic disturbances impair the ability of the brain to process information accurately, resulting in unusual behaviors that are often difficult to manage. Trauma patients with normal brain scans may have mild TBI and display some of the symptoms of PTA. Post-traumatic amnesia can last for months but usually resolves within a few weeks. During PTA, the patient moves from a cognitive level of internal confusion to a level of confusion about the environment.
SEE: Rancho Los Amigos Guide to Cognitive Levels

SYMPTOMS
Symptoms include restlessness, moaning or crying out, uninhibited behavior (often sexual or angry), hallucinations (often paranoid), lack of continuous memory, confabulation, combative behavior, confused language, disorientation, perseveration, and sleep disturbances. Problem-solving ability, reasoning, and carrying out planned motor movements (as in activities of daily living) may also be impaired.

PATIENT CARE
The patient is continually reoriented by a large calendar and clock within sight; each interaction with the patient begins with a repetition of who is in attendance, why the attendant is present, and what activity is planned; and the patient is kept safe and comfortable and is allowed as much freedom of movement as possible.

As the patient becomes confused, he or she may show agitation. Health care professionals can limit agitation and confusion by speaking softly in simple phrases, using gestures as necessary, and allowing time for the patient to respond. Regular visits from family are important; the family should be prepared for the patient's appearance and behavior; they should be encouraged to help the patient with activities of daily living.

Equipment for agitated patients is used; wrist restraints are avoided if possible. Urinary catheters may increase agitation due to physical discomfort (incontinence briefs can be used during the training period of a toileting program). The patient's swallowing function is evaluated as soon as possible to avoid feeding tubes, but swallowing precautions are observed. A list of stimulations that increase or decrease the patient's agitation is posted for the use of everyone in contact with the patient. Distance is maintained during aggressive outbursts. The patient's personal space should not be invaded without warning, e.g., the patient should be told in advance that his or her body parts are going to be touched or washed. The patient should be approached from the front, and items should be placed where the patient can best see them.

Health care professionals should watch closely for impulsive movement that can jeopardize the patient. They should warn others that the patient cannot monitor his or her own behavior and that words and actions may occur without awareness or forethought. Independent behavior and self-care are encouraged. The patient is engaged in short activities with a motor component. One action at a time should be monitored if the patient performs several actions that interfere with treatment. To promote abstract reasoning, humor should be used if the patient understands it. A consistent daily schedule provides structure. The patient is taught to use compensatory cues (a watch or written activity schedule) to aid memory. The patient is also assessed for posttraumatic headache, which is treated with prescribed medications.

psychogenic amnesia

SEE: Dissociative amnesia.

retrograde amnesia

Amnesia for events that occurred before a specific precipitating event (such as a drug overdose, surgical operation, stroke, or trauma).
SYN: SEE: retrograde memory

selective amnesia

Amnesia for events that occurred at the same time as other experiences that are recalled.

tactile amnesia

SEE: Astereognosis.

transient global amnesia

Short-term amnesia in otherwise healthy people. Remote memory is retained.

traumatic amnesia

Amnesia caused by sudden injury to the brain.

visual amnesia

Amnesia for the appearance of objects or for printed words.