Motor evoked potentials in patients with chronic whiplash-associated disorder grade II

It is common belief that psychological problems influence the persistence of complains in patients with so-called mild whiplash-associated disorders (WADs). The usefulness of motor evoked potentials (MEPs) is investigated in patients with grade II WAD and remaining complains for more than 6 months.

Twenty consecutive patients, aged between 24 and 58 years, with persistent neck pain for months after a car accident were included. All patients had a magnetic resonance imaging (MRI) of the cervical spine and cord. Central (CMCT) and peripheral motor conduction times (PMCT) were evaluated by registration in the biceps brachii muscle (C5-C6) and in the abductor digiti minimi muscle (C7-C8-Th1).

Thirteen patients had prolonged CMCT or/and PMCT compared to 7 with normal values. On MRI discus bulging C5-C6, without abnormal signal changes in the cervical spinal cord was observed in 6 of the patients with disturbed MEPs compared to 3 without. Out of 7 patients, who had repeated MEPs after 6 months, 3 of them had an improvement of their conduction time. The patients with prolonged MEP conduction times were older than those with normal values (p=0.007).

MEP examination has to be performed in all patients with persistent complains even in the absence of objective neurological signs and non-significant changes on imaging.