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presents for medical certification. It is important to determine the nature and severity of injury as part of
the evaluation.
Medical history and medical records should allow determination of the nature of the injury. Varieties of
injury include simple concussion, traumatic subarachnoid haemorrhage, intracranial haematoma (epidural,
subdural, intraparenchymal), cerebral contusion, diffuse axonal injury (DAI), and penetrating injury with
laceration of cerebral tissue and supporting connective tissue.
Severity of injury can be assessed by records employing standardized measures of severity including the
Glasgow Coma Scale8 and the duration of Post Traumatic Amnesia (PTA - the amount of time between
the injury and the return of continuous memory). PTA of 0-1 hour constitutes mild TBI, 1-24 hours
moderate TBI, 1-7 days severe TBI, and beyond seven days very severe TBI.
Sequelae of TBI include post-concussion syndrome, focal neurological deficit, cognitive residual changes,
and posttraumatic epilepsy (PTE).
Post-concussion Syndrome
Post-concussion syndrome is characterized by a set of nonspecific symptoms including headache,
insomnia, irritability, a non-specific dizziness, poor concentration, memory loss and other complaints.
Neurological examination and imaging studies are normal. The condition is self-limited, generally
resolving in weeks or months. Symptomatic medications are often employed, precluding medical
certification until the condition subsides.
Focal Neurological Deficit
The major part of recovery from focal deficits such as hemiparesis, aphasia and other deficits takes place
within six months of injury, though further recovery occurs at a slower pace over two to three years.
Medical records and current neurological functioning will provide information regarding persistent
deficit.
Cognitive Residual Sequelae
The frontal lobes of the brain have to do with personality and behaviour, and the temporal lobes with
intellect and memory. Frontal deceleration is the most common mechanism of TBI, rendering these
structures more susceptible to injury than more cushioned posterior structures. When there has been
moderate to severe TBI, with Glasgow Coma Scale score of 9 or below or posttraumatic amnesia
exceeding 24 hours, the medical assessor should have a high index of suspicion for cognitive residual
8 Glasgow Coma Scale: a standardized system for assessing response to stimuli in a neurologically impaired patient;
reactions are given a numerical value in three categories (eye opening, verbal responsiveness, and motor
responsiveness), and the three scores are then added together. The lowest values represent the poorest clinical
scores. After Glasgow, in Scotland, where the scale was developed.
ICAO Preliminary Unedited Version — October 2008 III-10-12
effects. When indicated, detailed neuropsychological testing by a qualified examiner may document the
presence or absence of any cognitive residual sequelae.
Posttraumatic Epilepsy (PTE)
The risk of seizures following TBI is a major concern. With penetrating injuries involving violation of the
cranial vault, the risk is high and may approach 40 per cent. In more commonly occurring closed head
injuries, risk is a much lower five per cent. Risk increases with severity of injury. Cerebral contusion,
parenchymal haematoma, posttraumatic amnesia beyond one day, depressed skull fracture and subdural
haematoma confer increased risk. The presence of blood within the parenchyma is of major concern,
since PTE is believed to be an “iron driven” phenomenon.
A period of observation following TBI is often prescribed prior to medical certification, since risk of PTE
declines with the passage of time. Approximately 50 per cent of individuals, destined to develop PTE,
will experience their fist seizure within six months, about 75 per cent within the first year, and about 90
per cent within two years. With penetrating injuries 97 per cent of the risk will have been achieved in
three years, though some elevated risk still persists ten years after the injury.
Operational implications:
Traumatic brain injury is disqualifying for all classes of medical certification.
Aeromedical considerations:
Post-concussion syndrome is characteristically self-limited, and medical certification may be considered
within 3-6 months of symptom free observation. Depending upon severity, focal neurological deficit may
warrant a six months to two years period of observation for maximal neurological recovery. In
individuals with neuropsychological residual changes, usually indicating significant traumatic brain
injury, a one to five year observation period is warranted depending upon severity of cognitive
impairment. Careful cognitive evaluation for permanent impairment should then precede medical
　
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