Prognosis and consequences of head injury

The consequences of traumatic brain injury are memory impairment, both retrograde and antegrade amnesia are possible. Post-concussion syndrome, usually following a significant concussion, includes headache, dizziness, fatigue, difficulty concentrating, various types of amnesia, depression, apathy and anxiety. Often observed are impairments or loss of smell (and, therefore, taste), sometimes hearing, less often vision. Symptoms usually disappear spontaneously within weeks or months.

A number of cognitive and neuropsychiatric problems may persist after severe or even moderate traumatic brain injury, particularly after significant structural damage. Typical sequelae of traumatic brain injury include amnesia, behavioral disturbances (e.g., excitability, impulsivity, disinhibition, lack of motivation), emotional lability, sleep disturbances, and decreased intellectual ability.

Late epileptic seizures (more than 7 days after injury) develop in a small percentage of cases, usually weeks, months, or even years later. Spastic movement disorders, gait disturbances, balance problems, ataxia, and sensory loss may also occur.

A persistent vegetative state may develop after traumatic brain injury with impaired forebrain cognitive function but with preservation of the brainstem. The capacity for self-induced mental activity is absent; however, autonomic and motor reflexes and the normal sleep-wake cycle are preserved. Some patients may recover normal nervous system function if the persistent vegetative state lasts for 3 months after injury, and almost none for 6 months.

Neurological function gradually improves over a period of 2 to several years after traumatic brain injury, with particular improvement in the first 6 months.

Prognosis of traumatic brain injury

In the United States, the mortality rate for adults with severe traumatic brain injury with treatment ranges from 25 to 33% and decreases with increasing Glasgow Coma Scale score. Mortality is lower in children over 5 years of age (<10% with a GCS score of 5 to 7). Children tolerate comparable trauma better than adults.

In the vast majority of patients, neurological status is fully restored after mild traumatic brain injury. After moderate and severe traumatic brain injury, the prognosis is not as good, but much better than is usually assumed. The Glasgow Outcome Scale is widely used for prognostic assessment. According to this scale, the following outcomes are possible:

• good recovery (defined as the absence of new neurological deficits);
• moderate disability (defined as new neurological deficits in patients who are able to care for themselves);
• severe disability (defined as the inability of patients to care for themselves);
• vegetative state (defined as the absence of cognitive function in patients);
• death.

More than 50% of adults with severe traumatic brain injury recover well or to a level of moderate disability. In adults, recovery after severe traumatic brain injury is most rapid in the first 6 months, with small improvements possible over several years. In children, recovery immediately after traumatic brain injury is better, regardless of the severity of the injury, and lasts for a longer period of time.

Cognitive deficits with impaired concentration and memory, as well as various personality changes, are considered more as causes of social adaptation disorders and employment problems than specific motor and sensory disorders. Posttraumatic anosmia and acute traumatic blindness rarely disappear after 3-4 months. Manifestations of hemiparesis and aphasia usually weaken in all patients, except for elderly people.

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