Biomedical subjects
Publications and source records attributed to S Egloff-Baer.
The antidromic impulse associated to the ephaptic response can produce a recurrent wave (Fe). Its latency, which is longer than that of the F wave, will augment if the site of stimulation is remote from the muscle. It is therefore a direct-indirect response. The 'Fe' wave is similar to the 'S' response described by Thorne, but the gamma-loop is not implicated. It can be misinterpreted as a desynchronized F wave.
Following the direct M response, peripheral nerve stimulation frequently evokes a second wave which shows all characteristics of an ephaptic response. The antidromic impulse or back response, which is always associated, is detected by a double stimulation technique. The ephaptic response seems not to be related to any specific nerve or muscle pathology, as it is also observed in normal subjects. It is therefore important to differentiate the ephaptic response from a late potential or a double discharge, the latter two having pathological significance.