Transient Global Amnesia (TGA)

Guidance for medical examiners when assessing a patient for either a general topic or condition - Transient Global Amnesia.

Aeromedical implications

Effect of aviation on condition

• Some episodes of TGA have identifiable triggers
• Known triggers for TGA that may be experienced in the aviation context include:
  • physical exertion
  • emotional stress
• Other triggers not normally associated with aviation include:
  • painful experience
  • medical procedures
  • cold or hot water immersion
  • sexual intercourse.

Effect of condition on aviation

• Overt incapacitation:
  • acute impairment of memory may impair ability to safely navigate and operate aircraft

Effect of treatment on aviation

• There is no treatment for TGA

Approach to medical certification

Based on the condition

• Confirmed diagnosis of TGA
• Exclusion of other diagnoses
  • transient ischaemic amnesia
  • transient epileptic amnesia
• Migraine is present in 25-33% of cases which may require treatment
• Avoidance of identified triggers.

Demonstrated stability

• Absence of symptoms of Transient Global Amnesia, Transient epileptic amnesia and Transient ischaemic amnesia for a period of one year
• Absence of recurrent episodes of TGA

Risk assessment protocol - information required

New cases

• CASA requires a report from a Neurologist with respect to:
• Diagnosis
• Clinical status
  • history of condition
  • 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 (see severe headache section)
    • cardiovascular or cerebrovascular disease
    • family history of epilepsy
  • cardiovascular risk factor assessment
  • hospital assessment
  • results of physical and neurological examination
  • progress
• Investigations conducted
  • results of any imaging performed
• Management
  • treatment and effectiveness
  • side-effects
  • monitoring
• Follow-up plan.

CASA requires a review from a Neurologist 12 months post-event with respect to:

• Diagnosis following 12 month period of observation
• During 12 month period of observation:
  • any recurrent episodes of transient amnesia
  • any history of faints, fits or funny turns
  • results of any additional investigations.

Renewal

CASA requires a review from a treating doctor (GP or neurologist) with respect to:

• Any recurrent episodes of transient amnesia
• Any history of faints, fits or funny turns
• Results of any additional investigations

Indicative outcomes

• Initial notification to CASA and grounding required on diagnosis for a minimum period of 12 months
• Clearance by CASA required before exercising privileges
• Due to the risk of recurrent TGA all classes of medical certificates may be subject to long term restriction (e.g.multi-crew or safety-pilot)

Unfavourable

• Any form of seizure disorder
• Transient epileptic amnesia
• Transient ischaemic amnesia

Pilot and controller information

• TGA is an aero-medically significant medical condition.
• There is no definitive test for TGA - it is a clinical diagnosis
• Pilots and controllers who have been diagnosed with TGA are required to ground themselves and notify this condition to their DAME or CASA
• Grounding required on diagnosis for a minimum period of 12 months for all classes
• After 12 months a restricted certificate (multi-crew or safety-pilot) may be possible