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The study consisted of a prospective investigation of 45 consecutively admitted patients who had sustained a mild head injury. In all cases the duration of post-traumatic amnesia was less than 24 hours. Head injury patients had an average of three adverse life events in the year preceding injury compared with 1.5 for controls. Using the PSE, 39% of the group were diagnosed psychiatric cases at six weeks after the injury. For cases the mean level of chronic social difficulties (3.3) was four times that for non-cases (0.8). Six months after injury, 28% of the head injury group had three or more symptoms. These chronic cases were on average ten years older than those whose symptoms had remitted. Chronic cases had, on average, three social difficulties, twice as many as found among those whose symptoms had remitted. The emergence and persistence of the postconcussional syndrome are associated with social adversity before the accident. While young men are most at risk of minor head injury, older women are most at risk of chronic sequelae.

SUMMARY A four-choice reaction time test was carried out on 45 minor head injury cases, 24 hours after the injury and 6 weeks later. Twenty-eight subjects were re-tested after a six month interval. Reaction time measures were also obtained in a matched, general practice control group. The concussion cases displayed significantly poorer performances than the matched controls in four measures, at day 0 and at 6 weeks. The patients also showed serial improvement in these measures up to six months after the injury, when their scores excelled those of the matched controls.Gronwall and Wrightson' studied various groups of minor head injuries using the Paced Auditory Serial Addition Test (PASAT), as a measure of the rate of information processing. All the concussion patients showed a reduction of the PASAT score, which correlated with symptoms. The authors postulated that the symptoms were directly caused by this diminution of information processing, such as concentration difficulties resulting in stress with headache, and fatigue. However, other workers have found the PASAT to be difficult, tedious for the subject, and unreliable.After cerebral concussion, patients may also demonstrate a slowing of reaction time which is commonly assumed to reflect a diminution of central information processing. Both simple and choice reaction time measures have been used. Some workers have found the choice reaction time to be more specific.2-4 In addition, Millers demonstrated that increasing complexity correlated with increasing sensitivity to cerebral damage. Other workers68 reported that the simple reaction time test is as sensitive as the more complex choice reaction time procedure. The conflicting results may be because of the heterogenicity of the subjects in relation to the severity and nature of the lesion, and because of the differing time intervals between the brain insult and