Developed in collaboration with CASA Medical.
Transient global amnesia (TGA) is a clinical syndrome characterised by the sudden onset of anterograde amnesia, accompanied by repetitive questioning, sometimes with a retrograde component, lasting up to 24 hours, and without compromise of other neurologic functions. Ability to do routine tasks often remains intact despite during the episode of anterograde amnesia.
In many cases there are no known precipitating factors but some episodes of TGA have identifiable triggers such as:
- painful experience
- emotional stress
- physical exertion
- acute illness
- cold or hot water immersion
- sexual intercourse
- raised intrathoracic pressure such as during Valsalva or high-G manoeuvres
- medical procedures
TGA is a medical condition of safety relevance or aeromedical significance.
Pilot and controller information
- If pilots or controllers suspect they might have or have been diagnosed TGA they must ground themselves or stop operating immediately.
- Pilots and controllers must obtain a ME review or contact CCAA NZ AvMed for further advice
Aeromedical implications
Effect of aviation on the condition
Aviation related triggers for TGA include:
- Valsalva or anti-G straining manoeuvres, positive pressure breathing
- Physical exertion
- Emotional stress
- High altitude exposure
- Sudden temperature changes
Effect of the condition on aviation
Overt incapacitation from:
- Acute impairment of memory may impair ability to safely aviate, navigate, communicate, while operating an aircraft, or conducting air traffic control duties.
- Emotional distress
Subtle incapacitation:
- Distraction due to accompanying symptoms such as headache, nausea, dizziness, sleepiness, blurry vision, etc.
Effect of treatment on aviation
- There is no available known treatment for TGA
Approach to medical certification
Based on the condition
- Confirmed diagnosis of TGA, based on the account at the time of occurrence of the episode, including collateral eyewitness account
- Exclusion of other diagnoses
- transient ischaemic amnesia
- transient epileptic amnesia (TEA)
- post-concussion
- hypoglycaemia
- epilepsy
- migraine variants
- head injury
- toxic encephalopathy
- psychological/psychiatric disorder
- TGA has a known association with migraine
- Identified triggers, if any
Demonstrated stability
- Absence of any neurological symptoms and no recurrence of TGA for a period of at least 12 months
- Exclusion of any epileptic event or seizure episode
Risk assessment protocol - information required
New cases
A report from a neurologist, including:
- Confirmed diagnosis
- Clinical status
- History of condition
- Reliable eye-witness account of episode
- Symptoms, including any visual or neurological symptoms, loss of consciousness
- Onset, duration, extent of retrograde and anterograde amnesia
- Identified precipitating factors
- Any history of
- Head injury, faints, fits or funny turns
- Migraine (refer to the relevant Clinical Practice Guidelines)
- Cardiovascular or cerebrovascular disease
- Family history of epilepsy and / or migraine
- Personal or family history of psychiatric illness
- ED / hospital summaries
- Results of physical and neurological examination
- Progress
- Investigations conducted (EEG and brain imaging are useful)
- results of any imaging performed
- Follow-up plan.
CAA require a review from a Neurologist 12 months after the event with respect to:
- Confirmation of diagnosis following 12-month period of observation
- During the 12-month period of observation:
- any recurrent episodes of transient global amnesia
- any history of faints, fits or funny turns
- absence of any neurological symptoms
- exclusion of any epileptic event or seizure episode
- results of any additional investigations.
Additionally, cardiovascular risk assessment, including relevant investigations, is required to exclude arrhythmia or thromboembolic event.
Renewal
CAA require a review from a treating doctor (GP or neurologist) with respect to:
- Any recurrent episodes of transient global amnesia
- Any history of faints, fits or funny turns
- Absence of any neurological symptoms
- Results of any additional investigations
If all criteria in the table below for an applicant with cataracts are met, the applicant meets the acceptable criteria for certification by the ME. Evidence supporting the ME’s decision (for example reports and results) must be sent to CAA.
ME aeromedical decision guide
If ALL the following criteria are met MEs may issue the pilot or controller a medical certificate. MEs are to forward all the documentation for the assessment to CAA.
An AMC referral to CAA NZ Aviation Medicine teams is required if a pilot’s or controller’s condition does not meet all the above criteria and they consent to their condition being considered under flexibility to the CAR 67 rules.
ME letters
TGA medical certificate letter [DOCX 23 KB]
