[Prognostic assessment in peripheral facial nerve paralysis with particular reference to electroneurography (author's...

Electrophysiological investigations were carried out on 20 healthy controls and 130 patients with peripheral facial nerve paralysis. The aetiology was as follows: idiopathic (Bell's palsy) in 60 cases, viral in 29, traumatic in 18, postoperative in 4, in connexion with chronic otitis media in 6, diabetes mellitus in 4, positive rheumatological tests in 3, disturbed lipid metabolism in 2, the Melkersson-Rosenthal syndrome in 1, as a complication of pregnancy in 2, and in association with a tumour in 1 case. The compound action potential (CAP) of the orbicularis oris muscle was determinedi n 370 occasions in a right/left comparision, the record of the muscle response was intergrated over the time of action (IAR) on 32 occasions and trison of 255 occasions. The normal values are given in the first place and their dependence of the age of the subject. Then, the prognostic sifnficance of the above-mentioned parameters is investigated in cases of peripheral facial nerve paralysis. It is apparent that the determination of the CAP in a right/left comparison is a valuable prognostic guide as early as the 4th day, insofar as a decrease in this parameter of under 50% can be interpreted as a favourable sign and satisfactory reversal of the paralysis can be expected within 6-8 weeks. By contrast, a decrease of over 70% in the CAP is a bad prognostic sign, indicative of presumably only a poor trend to reversal of the paralysis. An intermediate depression of the CAP in the range of 50-70% signifies an expected moderate recovery within 6-8 weeks ahe case of CAP determination at the time of maximum amplitude depression (as opposed to the 4th day), then a decrease of less than 70% is taken to be indicative of satisfactory functional recovery within 6-8 weeks; a decrease of 95-100% signifies a bad prognosis, whilst a decrease amounting to between 70 and 95% carries an uncertain prognosis. The maximum decrease in amplitude was registered on the 8th day on average; the range lay between the 4th and the 14th day. An exception to these figures was the delayed response of the CAP in the case of 6 patients, 5 of whom showed a maximum decrease during the 3rd week and the last patient as late as the 4th week following the onset of facial nerve paresis. Similar reliance can be placed on the prognostic value of the IAR. however, the decrease in the IAR is smaller than that of the CAP measured on the same potential in a right/left comparison, so that a decrease in the IAR of over 60% can already herald a poor recovery. Repeated determination of the latency in cases of facial nerve paralysis showed that the mean latency value for the entire group of patients was slightly prolonged at the end of the 1st week, but the latency values obtained in any one particular patient are of no prognostic significance. A comparison between CAP and latency values obtained with the opposite (i.e...