THE POST-CONCUSSIONAL STATE - NEUROPHYSIOLOGICAL ASPECTS

Background. Twenty-six young men admitted to an Accident and Emergency Department for observation following a minor closed head injury (post -traumatic amnesia (PTA) less than 12 hours) were investigated within 24 hours of admission (day 0) and followed up at 10 days, 6 weeks and 1 year after the trauma. Method. Investigations at day 0 included phys ical examination, completion of post-concussional symptom and stress-a rousal checklists, computerised EEG (CEEG) and auditory brainstem evok ed potential (BAEP) recordings. These were repeated at ten days and si x weeks. At 12 months follow-up. the Present State Examination (PSE) w as carried out and a further post-concussional symptom checklist compl eted. Results. Post-concussional symptomatology declined progressively from day 0 but half had residual symptoms at 1 year. Seventy-two per cent ran an acute course with recovery by 6 weeks, 8% a chronic unremi tting course and 20% initially improved but had an exacerbation of sym ptoms between 6 weeks and 12 months. The CEEG alpha-theta ratios decre ased significantly between days 0 and 10, reaching a baseline thereaft er. Measures of CEEG recovery from all channels correlated with sympto m counts at six weeks; the slower the recovery the greater the symptom s. A relative delay in left temporal recovery was associated with resi dual psychiatric morbidity (PSE ID scores) at 12 months. Prolonged cen tral brainstem conduction times occurred in 27% of patients at day 0. These correlated positively with PTA and degree of psychiatric morbidi ty (PSE ID scores) at 12 months. Conclusions. Symptom chronicity was a ccompanied by continuing brainstem dysfunction, while the degree of tr ansient cortical dysfunction appeared to have a direct influence in th e intensity of early organic symptom reaction to the trauma. Levels of perceived stress at the time of the injury, or afterwards, were not r elated to symptom formation.