Prognostic value of electrophysiological tests in bell's palsy

Abstract EN

Objective : To define the electrophysiological parameters carrying early prognostic potentials of the course and outcome of illness in Bell's palsy patients.

Methodology : our study included 60 patients presenting with Bell's palsy.

Motor evoked potential (MEP) and blink reflex (BR) were performed to all participants on the seventh, fourteenth and twenty first day of the onset of facial palsy.

They were assessed for amplitude (comparison of the affected side to none affected side and expressed as a percentage) and latency.

In order to estimate prognostic values of these electrophysiological parameters, they were correlated with the duration of recovery.

Results : Our results showed that, the most reliable prognostic data of MEP amplitude and latency occur after the fourteenth day following the onset of palsy, but that of the latency of blink reflex started earlier.

On the basis of these features, it is possible to predict duration of the clinical recovery and the unfavorable course of the illness.

The blink reflex is an early prognostic value from first week of palsy, the persistence or early return of an absent R1 component of the BR may qualitatively suggest a satisfactory functional outcome in facial paralysis.

If the percentage of surviving axons of MEP amplitude falls below 10 % within the first 14th day of onset of palsy, an incomplete recovery is suggested.

Conclusions : Electrophysiological tests in Bell's palsy can provide important quantitative information about the degree of axonal damage.

They may also predict the duration of clinical recovery and outcome of this disease.