Summary about Disease
Wave-Associated Transient Global Amnesia (TGA) is a rare and poorly understood form of Transient Global Amnesia (TGA) where episodes of sudden, temporary memory loss are specifically triggered by exposure to ocean waves or other aquatic activities. The defining characteristic is the transient nature of the memory impairment and its association with water-related events. Individuals experiencing Wave-Associated TGA have difficulty forming new memories and recalling recent events, while typically maintaining awareness of their identity and basic cognitive functions.
Symptoms
Sudden onset of profound anterograde amnesia (inability to form new memories)
Retrograde amnesia (difficulty recalling recent past events)
Repetitive questioning, often about current location or situation
Preservation of personal identity and awareness
Preservation of cognitive functions (e.g., language, attention, motor skills)
Anxiety or agitation may be present due to disorientation.
Symptoms are specifically linked to exposure to ocean waves or other aquatic environments.
Causes
The exact cause of Wave-Associated TGA, and TGA in general, is still unknown. Several theories exist, but no single theory has been definitively proven. Some proposed causes include:
Migraine Variant: TGA may be related to a form of migraine.
Cerebral Ischemia: Temporary reduction of blood flow to certain brain regions (hippocampus, thalamus) is speculated, possibly triggered by physiological changes related to wave exposure.
Venous Congestion: Jugular valve incompetence could lead to transient venous congestion with Valsalva maneuver.
Emotional Stress: Although not wave-specific, high emotional stress is commonly linked to TGA.
Hyperventilation: Water exposure could trigger hyperventilation leading to changes in brain blood flow.
No Cause Found: In many cases, no specific cause can be identified.
Medicine Used
There is no specific medication used to treat TGA itself. Treatment focuses on managing any underlying conditions or triggers, and providing supportive care:
Anxiolytics: Medications to reduce anxiety if present.
Observation: Typically, the individual is monitored to ensure the symptoms resolve.
Management of Underlying Conditions: If an underlying cause like migraine or cardiovascular issues is identified, it will be treated.
Is Communicable
No, Wave-Associated TGA is not communicable. It is not an infectious disease and cannot be transmitted from person to person.
Precautions
Since the causes are not fully understood, there are no definitive precautions to completely prevent Wave-Associated TGA. However, individuals with a history of TGA or those who are prone to migraines, anxiety, or cardiovascular problems may consider the following:
Avoidance of Triggers: If specific water activities or wave conditions seem to trigger episodes, those should be avoided.
Stress Management: Techniques such as deep breathing or meditation can help manage stress.
Medical Consultation: Regular check-ups and discussion with a physician, especially if risk factors are present.
Awareness: Informing others (family, friends) about the condition so they can recognize and respond appropriately if an episode occurs.
How long does an outbreak last?
Wave-Associated TGA is not an outbreak. The term "outbreak" refers to the sudden occurrence of a disease in a community or region. TGA is a neurological condition affecting individuals, not an infectious disease. An episode of TGA typically lasts for a period of 1 to 24 hours, with most episodes resolving within 4 to 8 hours.
How is it diagnosed?
Diagnosis of Wave-Associated TGA is based on clinical criteria and exclusion of other conditions:
Clinical Evaluation: Neurological examination to assess memory, orientation, and cognitive function. Detailed history of the events preceding the amnesia, specifically focusing on exposure to ocean waves or aquatic environments.
Diagnostic Criteria: Fulfillment of established diagnostic criteria for TGA, including:
Witnessed event of sudden onset anterograde amnesia.
Loss of recall of recently learned information.
Clear sensorium during the event.
Absence of other neurological symptoms (e.g., seizures, weakness, language deficits).
Resolution of symptoms within 24 hours.
Exclusion of other causes of amnesia (e.g., stroke, head injury, epilepsy, substance abuse).
Neuroimaging: MRI of the brain to rule out other structural abnormalities (e.g., stroke, tumor). MRI can sometimes show small hippocampal changes.
EEG: Electroencephalogram to rule out seizure activity.
Exclusion of Other Conditions: Ruling out other causes of transient memory loss, such as transient ischemic attack (TIA), stroke, seizures, head trauma, or drug intoxication.
Timeline of Symptoms
The timeline of symptoms typically follows this pattern:
Sudden Onset: The amnesia begins abruptly, usually during or shortly after exposure to ocean waves or other aquatic activities.
Anterograde Amnesia: The individual is unable to form new memories from the point of onset. They may repeat questions or appear disoriented.
Retrograde Amnesia: There may be difficulty recalling events from the recent past (days to weeks prior to the event).
Preserved Cognitive Function: Language, attention, and motor skills are generally intact. The individual recognizes their identity.
Gradual Resolution: The memory gradually returns over a period of hours. Retrograde amnesia may improve, but there may be permanent memory loss for the period of the TGA episode.
Complete Resolution: Within 24 hours, the individual typically returns to their baseline cognitive function.
Important Considerations
Recurrence: While TGA is generally considered a benign condition, there is a small risk of recurrence (reported between 2-24%).
Underlying Conditions: It's important to investigate for underlying conditions that may be associated with TGA, such as migraines, cardiovascular disease, or psychiatric disorders.
Driving and Activities: Individuals should avoid driving or operating heavy machinery during and immediately following an episode until cleared by a physician.
Support and Reassurance: Providing a calm and supportive environment is essential during an episode of TGA, as the individual may be anxious or confused.
Differentiation from Stroke: It's crucial to differentiate TGA from more serious conditions such as stroke, especially transient ischemic attack (TIA), as TIA requires immediate medical intervention.