A temporary impairment of brain functions immediately following a severe blow to the head.The problem of head injury has been on the increase in recent years due to the huge number of automobile, industrial and home accidents. Fortunately, most cases are minor, even when they involve loss of consciousness, and few victims develop mental disorders severe enough to require hospitalization. At present these cases account for only .6 per cent of first admissions to mental hospitals. This number is small enough to belie the ancient notion that blows on the head are a major cause of mental disorder—a notion that is still widely accepted because it lays the “blame” for mental illness on physical factors rather than on the patient or his family.But though the number of mental cases due to head injury is small, it is nevertheless constantly increasing. These cases pose special difficulties of a legal nature, for they usually lead to claims for compensation. They also present knotty psychiatric problems, since traumatic injuries involve a mixture of psychogenic and organic factors that is extremely hard to untangle.Traumatic disorders due to head injury may be either acute or chronic. Acute reactions immediately follow the injury, and are of three types. In cerebral concussion the blow to the head disrupts brain functions and causes a momentary clouding or loss of consciousness. The typical case is the football player who meets his opponent head-on, or the boxer who receives a heavy blow to the head. If consciousness is lost, the victim is confused, disoriented, and has a severe headache when he comes to. There is usually a partial or total amnesia for the event, but there are seldom any residual symptoms. In one case a boxer who had received such a blow went down for count of nine, but got up and won his match. When his trainer congratulated him in the locker room, he expressed utter amazement. The blow had partially knocked him out, and he had gone on fighting automatically, but could not remember the end of the bout at all.In cerebral contusion the blow to the head is severe enough to displace the brain and bruise its surface. The period of unconsciousness or coma may last for hours or days, and is followed by restlessness, clouding of consciousness, and often delirium. When the state of confusion clears up, the patient usually complains of severe headaches, nausea, dizziness, weakness, and sensitivity to light and noise. These symptoms usually subside in a few days or weeks, but in some cases there is prolonged irritability and impairment of mental and motor functions.In cerebral laceration there is an actual rupture or lesion of brain tissue, usually due to penetration by pieces of bone, bullets or other objects. The symptoms are similar to those in contusion cases, but they are usually more severe and may be followed by permanent intellectual and motor defects. The coma may last for days or weeks, and if the patient survives he practically always develops a delirious reaction. In its mild form, the delirium is characterized by haziness, restlessness, and irritability, but in some cases the patient becomes acutely bewildered, fearful, noisy, talkative, and violent. These reactions, as well as the residual impairment of function, are dependent not only on the type of brain damage sustained by the patient, but on his basic, or “pre- morbid,” personality. Unstable individuals are far more likely to develop acute delirious states than stable individuals.Lacerations which cause heavy internal bleeding generally produce more lasting and disastrous effects than those followed by mild bleeding. Repeated blows on the head, however, may cause scattered spots of bleeding called “petechial hemorrhages.” Veteran prizefighters frequently develop these multiple hemorrhages, which accounts for the fact that these men are frequently afflicted with slight mental confusion, uncertain balance, inability to concentrate, and involuntary movements—a chronic condition that is technically termed boxer’s traumatic encephalopathy or, in extreme cases, boxer’s dementia— and popularly described as “punch drunk.” No cure for this disorder has been found. See also HEAD INJURY (CHRONIC TRAUMATIC DISORDERS).