The identification of neuroapraxia, axonostenosis and trigger zone in facial nerve pathology

The classical electromyographic investigations and simultaneous recordings of voluntary activity and M responses from muscles of both the upper and lower branch of the facial nerve were carried out in 5 patients with Bell's palsy. R1 responses were also recorded. All investigations were extended to the healthy side. With the aim of localizing the point of axonostenosis with axonal atrophy we investigated the following parameters: conduction velocity (c.v.) in the fallopian canal, c.v. in the external facial nerve, side difference of R1-M. In one case of amyotrophic lateral sclerosis with previous Bell's palsy signs of collateral sprouting and of ephaptic transmission were detected.