Early recovery after closed traumatic head injury: somatosensory evoked potentials and clinical findings.

OBJECTIVE

To determine the ability of somatosensory evoked potentials (SEP) compared with clinical findings to monitor and predict recovery in patients suffering from closed head injury with predominantly diffuse axonal injury (DAI).

DESIGN

Prospective cohort study.

SETTING

Neurologic intensive care unit (ICU) of a university hospital.

PATIENTS

Serial SEP recordings were obtained from 31 consecutive patients with closed head injury. The first SEP was recorded within 48 hrs after trauma, followed by recordings after another 2 days, after which the time interval for each consecutive recording was doubled. Clinical examinations were performed every 6 hrs during the ICU stay and daily after transfer to a general neurologic ward.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-three of 31 patients demonstrated pathologic SEP findings at initial examination. Of these patients, 11 recovered clinically, two remained vegetative, and ten died. In all 11 patients with clinical recovery, SEP also recovered. In 8 of 31 patients, initial SEPs were normal and remained normal until discharge, all eight had a good outcome. Initial SEP findings were related with outcome at 6 months (p = .02), and follow-up studies increased the predictive value of SEP studies (p = .009). Other factors related to outcome included age, severity of DAI, and length of ICU/hospital stay. In the 11 patients with SEP and clinical recovery, early (day 2) and late (>or=2 months) recovery was documented. Early and reliable SEP indicators of improvement included N20-P25-Amplitudes (mean recovery, 8.5 days) and central conduction time (9.6 days). Pupillary light reaction (6.4 days), Babinski reflex (12.4 days), and Glasgow Coma Score (9.6 days) were the most valuable clinical findings. Recovery of the Glasgow Coma Score frequently coincided with reduction of sedatives. In most patients, recovery was detected with SEP before clinical recovery (7/11 patients, time difference 1 wk).

CONCLUSIONS

Initial SEP findings correlate with long-term outcome in patients with closed head injury with DAI. Initial bilaterally absent cortical responses in the SEP reliably predicted death, whereas completely normal SEP findings predicted good long-term outcome. Early recovery after DAI can be detected with serial SEP recordings despite sedative medications. Electrophysiologic recovery frequently precedes clinical recovery.