Contribution of the Synkinesis Assessment Questionnaire and the Sunnybrook Facial Grading System to the evaluation of synkinesis after peripheral facial palsy: A STROBE observational study

OBJECTIVES

The main aim of the study was to determine whether the perception of synkinesis by patients with peripheral facial palsy (PFP) matched their clinician's severity assessment. Secondary objectives comprised: (1) to determine whether objective measurement of synkinesis matched the patient's perception; and (2) is to identify factors influencing patients' perceptions.

METHODS

This retrospective study took place from January to May 2020. Forty patients (8 per PFP grade, I-V/VI; 20 women, 20 men) filled out the Synkinesis Assessment Questionnaire (SAQ) and were assessed on the Sunnybrook Facial Grading System (SFGS). Photographs were analyzed on MEEI-Facegram software.

RESULTS

Perceived synkinesis (total SAQ) matched objective grades (SFGS) (Z=2.89; P=0.004), especially for smiling (Z=3.84; P<0.001) and lip protrusion (Z=3.79; P<0.001). Synkinesis on lip protrusion was a more sensitive indicator of perceived synkinesis than synkinesis on smiling (Z=2.96; P=0.003). Duration (ρ=0.5137; P<0.001) and grade of PFP (Chi²=13.82; P=0.008) heightened the perception of synkinesis.

CONCLUSION

Patient-reported outcome measures (PROMs) such as the SAQ are relevant for clinical evaluation.

Quality of life after hemifacial spasm surgery: French versions of the HFS-8 and HFS-30 questionnaires

OBJECTIVES

The aim of the present study was to assess quality of life before and after surgery for hemifacial spasm, in order to validate two specific quality of life scales translated in French. Surgical results and complications were reported.

MATERIAL AND METHODS

Twenty-three patients with hemifacial spasm treated by microvascular decompression were retrospectively included. The HFS-8 and HFS-30 quality of life scales were translated from English into French using a forward-backward method and implemented on patients at least one year after surgery.

RESULTS

Median HFS-8 and HFS-30 values were respectively 16±12.5 (range: 8-20.5) and 38±38.5 (range: 23-61.5) before surgery and 0.5±4.5 (range: 0-4.5) and 5±17.5 (range: 1-18.5) after surgery, showing significant improvement in quality of life (P<0.001). The internal consistency of both scales was excellent (Cronbach's alpha>0.9), and they were significantly correlated (Pearson coefficient=0.95; 95% CI [0.91; 0.98]; P<0.0001). Success rates were 83% and 91%, respectively, after primary and revision surgeries. Complications were transient with minor consequences in 80% of cases, but could impact quality of life when lasting.

CONCLUSIONS

These results support the validity of the French versions of HFS-8 and HFS-30. Microvascular decompression is a safe and effective treatment for hemifacial spasm, and these scales are reliable tools to assess postoperative quality of life.

[Sequelae in bell's palsy: Prognostic factors for recovery]

OBJECTIVES

Facial palsy can be assessed using objective and subjective tools. The main purpose of this work was to use these tools to determine at 12 months the percentage of patients with sequelae and to specify the type of sequelae.

MATERIAL AND METHODS

Twenty-three patients with facial palsy were followed in this prospective and longitudinal study. They have been evaluated every 3 months during a year with the House and Brackmann grading scale and the Sunnybrook Facial Grading System. At 12 months, group A was composed of patients with complete recovery and group B, patients with sequelae.

RESULTS

At 3 months, in patients of group B, the House-Brackmann grading scale (P=0.0134), the Sunnybrook Facial Grading System global score (P=0.0283) and dynamic score (P=0.0148) were lower than group A. Moreover, the movement "brow lift" (P=0.0181) seems to be relevant to predict follow-up. Synkinesis on "brow lift" (P=0.0270) and the treatment delay (P=0.0384) increased for group B. Sex, age, paralyzed side and recurrence of facial palsy had no influence.

CONCLUSION

Objective and subjective tools determine thresholds and predictive scores of recovery with sequelae at 1 year. Nevertheless, it is relevant to assess clinically specific facial movements, such as "brow lift", to specify a recovery potential and to predict sequelae a year after the onset of facial palsy. As the treatment delay influences recovery, drug treatment should be recommended as early as possible.

French Society of ENT (SFORL) guidelines. Management of acute Bell's palsy

AQFThe authors present the guidelines of the French Society of ENT and Head and Neck Surgery (SFORL) regarding the management of Bell's palsy in adults. After a literature review by a multidisciplinary workgroup, guidelines were drawn up based on retrieved articles and group-members' experience, then read over by an independent group to edit the final version. Guidelines were graded A, B, C or "expert opinion" according to decreasing level of evidence. Thorough ENT and neurological clinical examination is recommended in all patients presenting with peripheral facial palsy to confirm diagnosis of Bell's palsy. MRI with gadolinium enhancement should explore the entire course of the facial nerve, if possible within the first month. ENMG should be performed to assess prognosis for recovery. In confirmed Bell's palsy, corticosteroid therapy should be implemented as early as possible (ideally within 72h) at a dose of 1mg/kg/day for 7-10 days. Antiviral therapy should be associated to steroids in patients with severe and early-onset disease and in Ramsay-Hunt syndrome. Isolated antiviral therapy is not recommended. To date, there is no evidence that surgical facial nerve decompression provides benefit.

[Tongue reconstruction by thoracodorsal perforator flap: A new harvesting technique to reduce morbidity]

The thoracodorsal artery perforator flap is increasingly used in head and neck reconstructions. One of its multiple advantages is the low donor site morbidity compared to the other free flaps usually used for this type of surgery, such as the radial forearm free flap and the anterolateral flap of the thigh. However, the current harvesting technique of the thoracodorsal artery free perforator flap needs a vertical incision rising high in the axillary hollow for the dissection of the pedicle, thus impeding optimal discretion of the donor site, especially for women. We describe an original technique to harvest a pure transversal skin paddle on its own perforator, leaving a horizontal scar thoroughly hidden in the bra and preserving the thoracodorsal pedicle. We detail the requirements for this new type of harvesting.

[Hypoglossofacial anastomosis for facial palsy treatment: Indications and results]

Hypoglossofacial anastomosis is a classical surgical procedure for the treatment of facial paralysis when the trunk of the facial nerve cannot be repaired and its peripheral branches are normal.

PATIENTS AND METHODS

Between 2004 and 2015, 77 patients were able to benefit from an hypoglossofacial anastomosis. The etiology of the paralysis was mainly the surgery of vestibular schwannoma, tumors of the facial nerve and diseases of the brainstem. A specific and premature speech therapy remediation was realized for all patients in order to preserve the tongue function and to upgrade the facial motricity.

RESULTS

Sixty-nine patients could be studied. The House Brackmann grading scale was used to appreciate the result. Thirty-one patients are grade III, 34 grade IV and in only one case the result is a grade V despite the anastomosis works. The main predictive factor for a good result is a small delay between the onset of the paralysis and the surgery for the rehabilitation. The specific physiotherapy upgrades the result with less side effects of the anastomosis.

CONCLUSION

Hypoglossofacial anastomosis is a simple and reliable surgical procedure for rehabilitation of paralysed face. The quality of the result is linked with an early surgery and a specific physiotherapy.

[Facial palsy rehabilitation: Assessment before surgery]

A patient who needs a surgery for facial rehabilitation must have a complete assessment. The etiology of the facial palsy must be clear. It is necessary to have a MRI of the facial nerve for the statement of the initial pathology or to search a lesion on the nerve. The facial palsy must be definite which is depending of the delay of the palsy and the etiology. An electromyography must be done. The choice of the procedure depends on the delay of the palsy, the site on the nerve, the associated diseases and the opinion of the patient after a good explanation.

[Smile "forced" smile versus "spontaneous": comparison of 3 techniques of reconstructive surgery of the face. Myoplasty temporal muscle, hypoglossal facial anastomosis and gracilis muscle free flap]

The facial palsy cause serious consequences for patients. Studies have also shown that in these patients, the inability to produce an appropriate and spontaneous smile would be a key factor of depression. When facial palsy is considered complete and the nerve cannot be repaired, the patient can benefit from palliative surgery to regain a better quality of life in the aesthetic, functional, and psychological aspects. The hypoglossal-facial anastomosis (AHF), temporal myoplasty (MAT) and gracilis transposition (TG) are the major surgeries currently used for this purpose. The aim of our study is to assess quantitatively and qualitatively the effects of each of these surgeries on the lip mobility and production of smile. From this perspective, we proposed a protocol of an evaluation of facial motricity, of quality of life, and more particularly on the quality and the analysis of the smile. The results underline that there is no significant difference in the recovery of the facial motricity according to the surgery. Only the slower, deferred deadline of recovery at the patients AHF and TG who have to wait several months, it is for the same levels as that of the patients' MAT. A premature and intensive rehabilitation such as the patients of our protocol benefited from it what is nevertheless essential to a good recovery whatever is the surgery.

[Lengthening temporalis myoplasty for facial palsy reanimation after parotid surgery]

AIM OF THE STUDY

Share our experience and our results of lengthening temporalis myoplasty (LTM) for facial palsy reanimation after parotid surgery.

MATERIALS AND METHODS

Study of 15 patients after they had had a lengthening temporalis myoplasty, in the same time or after a non conservative parotidectomy of facial nerve. 10 patients suffered from a parotid malignant tumor, one had a jugal epidermoid skin carcinoma invading the parotid, 2 patients had a facial palsy after removal of pleomorphic adenoma recurrence and two patients had a facial nerve schwannoma. 8 patients had a LTM surgery in the same time of the parotid tumoral removal.

RESULTS

No recurrence was observed on the 11 patients who had a carcinoma (average follow up: 27 months). The LTM surgery enabled us to obtain good results at rest for 14 patients (93%) and an intermediate result for one person. The ability to smile was described as good for 10 patients (66.6%), intermediate for 4 of them (26.6%) and unsatisfying for 1 person (6,6%). In the group rehabilitation, the results observed are similar, for the patients who had one or two surgical steps. In 3 cases, we noticed an infectious complication, which led us to operate again. In the 8 cases within lengthening was performed in the same time as parotidectomy, there was no additionnal surgical difficulty.

CONCLUSION

LTM surgery is an efficient method of rehabilitation. If possible, it should be performed in the same time as tumor removal. As the operational places are different, tumor checking-up and observation are not disturbed by this kind of rehabilitation.

[Prosodic analysis of speech of patient affected by peripheral facial paralysis]

INTRODUCTION

The aim of study of prosody in facial palsy is to assess the intensity of pathology in suprasegmental viewpoint in order to establish a proper rehabilitation.

METHODS

Patients were recorded during a reading and spontaneous speech test and a prosodic observation of speech spectrogram provided by Praat software.

RESULTS

The Accentual Groups lowering and significant dysprosodics elements (adverse effects and breaking balance) and a larger amount of disfluencies showed that the prosody of patients with facial palsy is altered because they need to swallow their saliva intentionally. Then, the decrease of Mean Length of Utterance (MLU) and the opinion of the jury highlight a decrease in desire to communicate and a loss of speech informativeness.

CONCLUSIONS

In patients with severe facial palsy, there is an impact of swallowing disorder (caused by salivary stasis) on the prosody of speech, with variations in the position of intonations boundaries and the intensity of prosodic marking. This also creates impact on fluency and on the perception of the message by the listener.

[Acoustic analysis of the articulatory disorders of patients affected by peripheral facial paralysis]

INTRODUCTION

The study of joint disorders in facial paralysis is an important element of support to guide rehabilitation.

MATERIAL

The material used for the registration of the database is a digital recorder Zoom H4N (way format, sample rate 44,100 Hz, 16 bit quantization). The microphone used is a Shure Beta 58, super cardioid. All recordings are made in a specific room.

METHODS

The annotation of the corpus is done using Praat software and its plug-in EasyAlign order to achieve alignment phonetics.

RESULTS

High frequency power ratio (HPR) is a good indicator of the setting in motion of the articulators as the number of explosions of bilabial phoneme was significantly related to the motor of the face and lips, and the score at dynamometer. The VOT was significantly shorter in patients with grade IV and V-VI than in control subjects. The results highlight a significant difference between the values of F3for the vowels /i/ and /y/, depending on the severity of the damage. There is even, for the most severe grades, there are a hundred Hertz difference between F3 of /i/ and that of /y/, which means that these two vowels becomes impossible to discriminate.

CONCLUSIONS

If these functional disorders are much discomfort for patients, however, these are not speaking of articulatory disorder in the strict sense, according to the definition of Borel Maisonny. We must therefore focus more specifically to the acoustic analysis of speech in order to check for spectral indices likely to identify these disorders.

[Termino-terminal hypoglossofacial anastomosis, indications, results]

OBJECTIVES

Retrospective study about the indications and the results of the end to-end hypoglossofacial anastomosis (AHF tt).

MATERIALS AND METHODS

Between 2004 and 2010, 38 patients were able to benefit from an AHF tt. It was about 13 men and 25 women. The mean age was of 40 years and the average deadline of coverage after facial paralysis was of 21.3 months. The etiology of the paralysis was in 47.7% of the cases a surgery for vestibular schwannoma and in 18% of the cases, of the facial nerve schwannoma. Besides the AHF tt, a golden weight was put to 6 of our patients. A specific and premature speech therapy remediation was realized at our all patient's.

RESULTS

The beginning of recovery was spread out between 3 and 9 months. The final result was a grade III HB (37%) and IV HB (60%). Only a case of grade VHB was observed. The complications often reported by the AHF tt were very widely decreased by the specific reeducation.

CONCLUSION

AHF tt is a particularly reliable technique, for rehabilitation of facial palsy, when the peripheral branches are intact and it, for the deadline 4-years-old subordinate except particular cases.

[The hypolossal-facial anastomosis in man. A model for studying peripheral and central nervous system plasticity]

Hypoglossal-facial anastomosis (HFA) is a cross-over between the proximal stump of the hypoglossal nerve (XII) and the distal one of the facial nerve (VII). The hypoglossal axons regrow within the sheaths of facial fibres, allowing the progressive reinnervation of the facial muscles. This model is interesting to study some mechanisms of plasticity of the nervous system for several reasons: 1) It is a quite simple and reproducible model of pathophysiological state. It allows the study of 2) the modifications of the nervous system induced by the HFA, both upwards and downwards to the lesion and 3) the modifications of reflex activities involving intrapontine connections such as the blink reflex. The electrophysiological features of the trigemino-facial (TF) and trigemino-hypoglossal (TG) connections demonstrated that a central reorganisation of the blink reflex (BR) was induced by HFA: the afferent volleys of the TF and TH reflexes elicited by cutaneous and mucosal trigeminal afferents respectively have been shown to project onto common interneurones located within the trigeminal principal sensory nucleus. A long-term prospective study showed: 1) a reinnervation of the facial muscles by the hypoglossal axons is a necessary perequisite for the central reorganisation of BR, 2) a hyperinnervation of the facial muscles by the hypoglossal axons, 3) a transient and regressive cross-innervation of paralyzed face by the healthy contralateral facial nerve.

Hypoglossal-facial nerve anastomosis: dynamic insight into the cross-innervation phenomenon

The authors investigated the evolution of the dynamic features of the cross-innervation process in patients with complete facial palsy due to facial nerve transection during surgery for acoustic neuroma removal followed by a hypoglossal-facial nerve anastomosis (HFA). Clinical and electrophysiologic investigations were carried out before and over a 3-year period after HFA. Cross-innervation had started by the 10th day, progressed to the seventh to eighth month, then decreased and finally disappeared by the 12th month after HFA. Ipsilateral reinnervation was observed by the fourth month, progressed to the 12th to 18th month, and remained stable for the remainder of the follow-up period.

[Parapharyngeal chondrosarcoma and Ollier's disease: a case report and review of the literature]

OBJECTIVES

Ollier's disease is a constitutional pathology of unknown etiology. It is characterized by bone dysplasia generating numerous enchondromas. The malignant degeneration of this dysplasia is well known. The aim of this article is to study the diagnostic, therapeutic and prognostic characteristics of these lesions.

MATERIAL AND METHODS

We report a case of parapharyngeal chondrosarcoma extended to the base of the skull in a patient with Ollier's disease. The treatment was a surgical removal by a cervicotransoral incision combined with a preauricular incision and with a mastoidectomy. It was therefore possible to control the skull base, the parapharyngeal space, the infratemporal fossa and the major neurovascular structures. The removal of the lesion was completed at the level of the clivus and sphenoid with optics (30 and 70 degrees ). We discuss this treatment and the follow up on the bases of literature data.

RESULTS

The neoplastic degeneration of enchondromas is estimated between 25 to 50% of cases. The most frequent location is the pelvic bones. Chondrosarcomas are slow growing tumors and their metastatic potential is less significant as we note it in our case report. Their diagnostic is essentially based on histological criteria's and their treatment is surgical.

CONCLUSION

Chondrosarcomas of the ENT area occurring with Ollier's disease is rare. Their prognostic is good if the surgical treatment is well done.

Prognostic value of mandibular involvement in oral cavity cancers

OBJECTIVES

The aim of the study was to determine, in a homogeneous population, the prognostic impact of mandibular involvement in oral cancers.

STUDY DESIGN

Retrospective study of 117 patients with T4 squamous cell carcinoma of the oral cavity treated by surgery and radiotherapy in the ENT Department of Bichat-Claude Bernard Hospital. All patients had histologically confirmed mandibular involvement. Patients with partial involvement of the mandible underwent rim mandibulectomy (RM) and those with extensive invasion underwent segmental mandibulectomy (SM).

METHODS

The local failure rate and the overall survival curves were calculated with respect to type of mandibulectomy. The causes of death were analysed.

RESULTS

The surgery was conservative in 55 cases (47%) and segmental in 62 patients (53%). The degree of mandibular involvement did not influence the local failure rate (29% and 25% in the RM and SM groups, respectively). On the other hand, it strongly influenced vital outcome, as five-year survival was only 25.4% after segmental mandibulectomy, compared to 40% after rim mandibulectomy. The metastases and the second primary tumors were more frequent in the SM group.

CONCLUSION

The degree of mandibular invasion influenced the survival rate of patients with squamous cell carcinoma of the oral cavity but this difference is not due to local failure.

[Treatment of Bell's palsy with acyclovir and methylprednisolone]

OBJECTIVE

An open therapeutic trial was conducted in patients with Bell's palsy. Results were compared with data in the literature.

MATERIALS AND METHODS

Between 1997 and 2000, 76 patients with Bell's palsy were treated with intravenous methylprednisolone (2 mg/kg/day) and acyclovir (5-10 mg/kg/8 hours) for 7 days. Treatment was initiated in all patients before the 14th day of illness. Severity of the palsy was scored on the first day of treatment and again one year later using the House and Brackman scale.

RESULTS

Grade II or III palsy were observed in 38% of the patients at initial presentation, grades IV to VI in 62%. After treatment, 92% of the patients had reverted to grades I and II (good outcome) and only 8% had sequelae at 1-year follow-up. All patients with initial grade I or II recovered completely. For patients with grade IV, V, or VI complete recovery at 1 year was observed in 94, 86 and 50% respectively.

CONCLUSION

Data in the literature suggest that corticosteroids should improve recovery in Bell's plasy. In our study, adjunction of acyclovir did not demonstrate any clear improvement in the cure rate. Benefit could depend on early prescription.

Midbrain deafness with normal brainstem auditory evoked potentials

The authors report two cases of patients with word deafness. The word deafness occurred after a head injury for the first patient and after an arterio venous malformation embolization for the second patient. MRI demonstrated bilateral lesions of the inferior colliculi but brainstem auditory-evoked potentials (BAEP) were within normal limits. These cases demonstrated that lesions involving the two inferior colliculi induced pure word deafness but do not affect BAEP.

Prognostic value of lymph node involvement in oral cancers: a study of 137 cases

OBJECTIVE

The aim of this study was to assess the prognostic value of lymph node involvement in patients with squamous cell carcinoma of the oral cavity.

STUDY DESIGN

Retrospective study of 137 patients with T4 squamous cell carcinoma of the oral cavity treated by surgery and radiotherapy (84 N0, 23 N1, 16 N2,14 N3). Twenty-three patients in the N0 group had a history of surgery or radiotherapy. One hundred fourteen patients underwent limited or radical neck dissection unilaterally or bilaterally.

METHODS

The histological charts were reviewed and correlated with preoperative lymph node clinical stage. The local failure rate and the overall survival curves were calculated with respect to clinical and histological stages. The causes of death were analyzed.

RESULTS

No evidence of lymph node metastasis was found in 47.4% of cases (54 of 114 patients). Among the node-positive (N+) patients, 39 had rupture of the lymph node capsule (R+). In the N0 group, 27.8% of patients were N+. Regional control rates after surgery and radiotherapy were 95% at 1 year and 85.4% at 5 years. The local failure rates were 6% in N0, 8.7% in N1, 31.2% in N2, 51.7% in N3, 9% in node-negative (N-), and 29% in N+R+ patients. The overall survival rates at 3 and 5 years were, respectively, 44.7% and 34.8% in the N0 group, 37.7% and 37.7% (same rate at 3 and 5 years) in the N1 group, and 31.2% and 15.8% in the N2 group. None of the patients in the N3 group survived beyond 2 years. The overall survival rates at 5 years were 42.8% and 17.5% in the N- and N+ groups, respectively.

CONCLUSIONS

In patients with locally advanced tumors (T4), clinical nodal status and histological nodal invasion were key prognostic factors. The presence of occult metastases in the N0 group justifies routine neck dissection.

Further evidence for a central reorganisation of synaptic connectivity in patients with hypoglossal-facial anastomosis in man

In normal subjects, electrical stimulation of trigeminal mucosal afferents (lingual nerve - V3) can elicit a short latency (12.5+/-0. 3 ms; mean+/-S.D.) reflex response in the ipsilateral genioglossus muscle (Maisonobe et al., Reflexes elicited from cutaneous and mucosal trigeminal afferents in normal human subjects. Brain Res. 1998;810:220-228). In the present study on patients with hypoglossal-facial (XII-VII) nerve anastomoses, we were able to record similar R1-type blink reflex responses in the orbicularis oculi muscles, following stimulation of either supraorbital nerve (V1) or lingual nerve (V3) afferents. However, these responses were not present in normal control subjects. Voluntary swallowing movements produced clear-cut facilitations of the R1 blink reflex response elicited by stimulation of V1 afferents. In a conditioning-test procedure with a variable inter-stimulus interval, the R1 blink reflex response elicited by supraorbital nerve stimulation was facilitated by an ipsilateral mucosal conditioning stimulus in the V3 region. This facilitatory effect was maximal when the two stimuli (conditioning and test) were applied simultaneously. This effect was not observed on the R1 component of the blink reflex in the normal control subjects. These data strongly suggest that in patients with XII-VII anastomoses, but not in normal subjects, both cutaneous (V1) and mucosal (V3) trigeminal afferents project onto the same interneurones in the trigeminal principal sensory nucleus. This clearly supports the idea that peripheral manipulation of the VIIth and the XIIth nerves induces a plastic change within this nucleus.

[Prognostic influence of cutaneous involvement in malignant tumors of the oral cavity]

The aim of this study was to assess the prognostic influence of cutaneous involvement in T4 squamous cell carcinoma of the oral cavity. The population was a homogeneous group of 137 patients. Cutaneous tumor localizations were observed in 20 of them. Surgery and radiotherapy were given in 103 cases and salvage surgery was performed in 34. Local control at 5 years was achieved in 68.5 % of the patients. Carcinologic failure rate was 55 % and 27.3 % in patients with and without cutaneous involvement respectively (p =0. 013). 5-year survivor rate was also correlated with cutaneous involvement: 10 % versus 32.2 % (p <0.0001).

Reflexes elicited from cutaneous and mucosal trigeminal afferents in normal human subjects

It has been shown that in patients in whom the central stump of the hypoglossal nerve has been anastomosed to the peripheral stump of a lesioned facial nerve, supraorbital nerve stimulation can elicit a short-latency reflex (12.5+/-0.6 ms; mean+/-S.D.) in facial muscles similar to the R1 disynaptic blink reflex response, but not followed by an R2 blink reflex component46. Thus in addition to replacing the facial neurons at peripheral synapses, these hypoglossal nerves contribute to a trigemino-hypoglossal reflex. The aim of this work was to study the type of reflex activities which can be elicited in both facial and tongue muscles by electrical stimulation of cutaneous (supraorbital nerve) or mucosal (lingual nerve) trigeminal (V) afferents in normal subjects. The results show that although stimulation of cutaneous V1 afferents elicits the well-known double component (R1-R2) blink reflex response in the orbicularis oculi muscles, it does not produce any detectable reflex response in the genioglossus muscle, even during experimental paradigms designed to facilitate the reflex activity. Conversely, stimulation of mucosal V3 afferents can elicit a single reflex response of the R1 type in the genioglossus muscle but not in the orbicularis oculi muscles, even during experimental paradigms designed to facilitate the reflex activity. These data are discussed in terms of two similar but separate circuits for the R1 responses of cutaneous (blink reflex) and mucosal (tongue reflex) origins. They suggest that in patients with hypoglossal-facial (XII-VII) nerve anastomosis, the short-latency trigemino-'hypoglossal-facial' reflex of the R1 blink reflex type observed in facial muscles following supraorbital nerve stimulation could be due to changes in synaptic effectiveness of the central connectivity within the principal trigeminal nucleus where both cutaneous and mucosal trigeminal afferents project.

Electrophysiological determination of the site involved in generating abnormal muscle responses in hemifacial spasm

In patients with hemifacial spasm (HFS), abnormal muscle responses due to abnormal cross-transmission are observed in facial muscles. However, the site in the facial nerve responsible for the cross-transmission remains a matter of controversy. We have developed a model in which by considering the electrophysiological parameters involved in producing the abnormal muscle response, we can determine the site of the abnormal cross-transmission within the facial nerve. This model was applied to HFS patients with three different etiologies: idiopathic, post-Bell's palsy, and post-XII-VII anastomosis. Our data show that: in idiopathic HFS, the cross-transmission may occur in the facial nerve at the level of the pontocerebellar angle; in post-Bell's palsy, it is inside the petrous bone; and in XII-VII anastomosis, it must be in the extracranial part of the facial nerve. The possible mechanisms for this cross talk are discussed in terms of ephaptic transmission or of a central hyperexcitability in the facial motor nucleus.