Prognostic value of combined stapedial muscle reflex [Acoustic reflex], electro-neuronography and facial nerve latency test in patients with Bell's palsy

ABSTRACT

In this study, 20 patients with idiopathic facial nerve palsy were evaluated by electroneuronography [ENOG], facial nerve latency test [FNLT] and stapedial muscle reflex [acoustic reflex]. The study aimed to define the value of these tests as prognostic tools in Bell's palsy. The ENOG test results indicated that when the amplitude of the compound muscle action potential varied between 51% and 95% of the normal value, the neuronal damage was slight. When the muscle action potential decreased to a value below 51% of normal values, the prognosis for recovery was worse. FNLT results indicated that as the latency time extended, the recovery grade of the facial nerve worsened. The comparison with the index of facial nerve functional recovery showed that these two tests had a high percentage of correctness. Acoustic reflex measurement helped in determining the site of lesion and in the follow up of the patients. A combination of test battery was important, so that the determination of the lesion may be as correct as possible