The psychiatric disability shown by 670 patients with penetrating head injuries has been evaluated, and explored in relation to two measures of the extent of focal brain damage, representing depth and quantity of brain damage respectively.
"Psychiatric disability" has been specially defined to include all aspects of intellectual, emotional, and behavioural disturbance, and graded on a three-point scale for the period 1-5 years after injury. Psychiatric disability has been found to correlate to a statistically significant extent with both measures of brain damage, and this has been found to persist after controlling for the distribution of generalized intellectual impairment in the material. Service rank, age at wounding, and overall physical disability during the follow-up period, do not emerge as significant sources of bias for the results.
Evidence is presented which suggests that depth of brain damage and quantity of brain damage may each make relatively independent contributions to psychiatric disability as here defined.
The duration of post-traumatic amnesia and the incidence of post-traumatic epilepsy have been explored in 670 patients with penetrating head injury, with special reference to the degree of psychiatric disability shown during the 1-5 years after injury. In both cases significant correlations have been observed. Increasing duration of post-traumatic amnesia is associated with an increased incidence of psychiatric disability. Similarly, the development of epilepsy, especially if within one year of injury, is associated with increased psychiatric disability.
These results have been used to qualify and amplify the results reported in the preceding part of the paper.
The location of focal brain damage has been explored in 345 patients with penetrating head injury, with special reference to the degree of psychiatric disability shown during the one to five years after injury.
Left hemisphere lesions are more closely associated with psychiatric disability than right, and there is evidence to suggest that the relationship between psychiatric disability and extent of brain damage is more close within the left hemisphere than the right.
Temporal lobe wounds are more closely associated with psychiatric disability than frontal, parietal or occipital lobe wounds. This association is very largely due to injuries of the left temporal lobe. There is some suggestion that right frontal and left parietal lobe wounds may also show a slightly increased association with psychiatric disability.
Lesions which produce sensory motor defects are significantly related to psychiatric disability. This special association persists when attention is restricted to defects associated with shallow cortical wounds. It is due principally to defects originating within the left hemisphere, and especially within the left parietal lobe.
Lesions which produce visual field defects are significantly related to psychiatric disability. This is due mainly to defects which originate within the left parietal and left temporal lobes.
Lesions which produce dysphasia are significantly related to psychiatric disability. This applies equally to dysphasias of parietal or temporal origin.
The special association of left temporal lobe wounds with psychiatric disability persists after discarding cases with each of the above neurological symptoms in turn.
The component psychiatric symptoms have been examined in 114 patients with penetrating head injury in which psychiatric disability had been rated "severe" during one to five years after injury. The symptoms have been examined individually and when grouped into four main categories—intellectual disorders, affective disorders, behavioural disorders, and somatic complaints without demonstrable physical basis. In addition, two commonly described clinical syndromes have received special consideration—the "frontal lobe syndrome" and the "post-traumatic syndrome".
Intellectual disorders and behavioural disorders are shown to be closely related to indices of organic brain damage, as is also the "frontal lobe syndrome". Amongst intellectual disorders, difficulty in concentration is an exception in this regard. Affective disorders as a group do not show this association, though some component symptoms (apathy and euphoria) appear to be closely related to organic brain damage. Somatic complaints and the "post-traumatic syndrome" show no such association.
Intellectual disorders as a group occur more commonly after left hemisphere damage, while affective disorders, behavioural disorders and somatic complaints are more frequent after right hemisphere damage.
Intellectual disorders are especially associated with damage to the parietal and temporal lobes of the brain. They are less frequent after damage to the frontal lobes than after damage to other parts of the brain. Affective disorders, behavioural disorders, and somatic complaints are more frequent after frontal lobe damage than after damage elsewhere. All component symptoms among the group of behavioural disorders show this special frontal association, and sexual abnormalities and criminal behaviour are found almost exclusively after frontal wounds. Although the "frontal lobe syndrome" occurs, as expected, principally after wounds which involve the frontal lobes, it is also seen in a number of patients whose wounds have not apparently involved the frontal lobes at all.
The interrelationships between the different symptoms and symptom groups have been explored. The various symptoms without demonstrable association with extent of brain damage are seen to be closely associated one with another; they include difficulty in concentration, depression, anxiety, and irritability, the group of somatic complaints, and the "post-traumatic syndrome".
The results have been interpreted in relation to previous studies of psychiatric disability after head injury, and in the light of current concepts of regional brain function in relation to psychiatric disorder.