Validity of late-term electroneurography in Bell's palsy

Facial nerve electrodiagnostics for patients with facial palsy: a clinical practice guideline

PURPOSE

Facial nerve electrodiagnostics is a well-established and important tool for decision making in patients with facial nerve diseases. Nevertheless, many otorhinolaryngologist-head and neck surgeons do not routinely use facial nerve electrodiagnostics. This may be due to a current lack of agreement on methodology, interpretation, validity, and clinical application. Electrophysiological analyses of the facial nerve and the mimic muscles can assist in diagnosis, assess the lesion severity, and aid in decision making. With acute facial palsy, it is a valuable tool for predicting recovery.

METHODS

This paper presents a guideline prepared by members of the International Head and Neck Scientific Group and of the Multidisciplinary Salivary Gland Society for use in cases of peripheral facial nerve disorders based on a systematic literature search.

RESULTS

Required equipment, practical implementation, and interpretation of the results of facial nerve electrodiagnostics are presented.

CONCLUSION

The aim of this guideline is to inform all involved parties (i.e. otorhinolaryngologist-head and neck surgeons and other medical specialists, therapeutic professionals and the affected persons) and to provide practical recommendations for the diagnostic use of facial nerve electrodiagnostics.

Facial Palsy: A Retrospective Study of 416 Cases Based on Electrodiagnostic Consultation

Background:

Facial nerve palsy (FP) is a frequent neurological condition caused mostly by Bell´s Palsy (BP).

Objectives:

The main objective of this study is to describe electrophysiological parameters in a retrospective 28-year review of 416 cases of FP based on electrodiagnostic consultation.

Methods:

In total, 520 exams from 416 patients over a 28-year period were reviewed. Sex, age, etiology, comorbidities, and variables from electroneurography and needle electromyography were analyzed. Cases were grouped as BP (70.7%), injury (16.4%), iatrogenic (10.3%) and Ramsay Hunt syndrome (RHS) (2.6%).

Results:

The mean age was 41 years (3-82), 53.4% female. Diabetes was the most frequent comorbidity. Estimated Axon Loss (EAL), >90%, was found in 50% of the cases, mainly in the iatrogenic group. The amplitude drop of the Compound Muscle Action Potentials (CMAPs) was proportional in the Orbicularis Oculi, Orbicularis Oris and Nasalis muscles. The absence of CMAPs was more frequent in the iatrogenic group and less frequent in the BP one. Bell´s palsy associated with diabetes was more severe. The R1 latency (blink reflex) was significantly longer in the BP group (P>0.001). Synkinesis due to the misdirection of regenerating axons was much more frequent in the BP and RHS groups.

Conclusion:

Bell´s palsy was the most common cause. The EAL was equal in all facial branches. Facial nerve inexcitability was more frequent in the iatrogenic/injury groups. The R1 latency was found to be prolonged in the BP group and the only good prognosis indicator in a few cases. Misdirection reinnervation was more frequent in BP and RHS groups. There was no sex or side predominance.

Facial nerve paralysis associated with temporal bone masses

OBJECTIVE

To investigate the clinical and electrophysiological features of facial nerve paralysis (FNP) due to benign temporal bone masses (TBMs) and elucidate its differences as compared with Bell's palsy.

METHODS

FNP assessed by the House-Brackmann (HB) grading system and by electroneurography (ENoG) were compared retrospectively.

RESULTS

We reviewed 914 patient records and identified 31 patients with FNP due to benign TBMs. Moderate FNP (HB Grades II-IV) was dominant for facial nerve schwannoma (FNS) (n=15), whereas severe FNP (Grades V and VI) was dominant for cholesteatomas (n=8) and hemangiomas (n=3). The average ENoG value was 19.8% for FNS, 15.6% for cholesteatoma, and 0% for hemangioma. Analysis of the correlation between HB grade and ENoG value for FNP due to TBMs and Bell's palsy revealed that given the same ENoG value, the corresponding HB grade was better for FNS, followed by cholesteatoma, and worst in Bell's palsy.

CONCLUSIONS

Facial nerve damage caused by benign TBMs could depend on the underlying pathology. Facial movement and ENoG values did not correlate when comparing TBMs and Bell's palsy. When the HB grade is found to be unexpectedly better than the ENoG value, TBMs should be included in the differential diagnosis.