Investigation of unilateral facial weakness: magnetic stimulation of the proximal facial nerve and of the face-associated motor cortex

Summary Twenty-four patients with unilateral facial weakness of various aetiologies were investigated using a magnetic stimulator to stimulate the proximal segment of the facial nerve directly (short latency response) and also to activate the facial motoneurons bilaterally via corticonuclear pathways by placing the stimulating coil over the motor cortex (long latency responses). Electromyographic recordings were taken from both mentalis muscles using concentric needle electrodes. Seventeen patients were investigated at various times after onset of idiopathic facial palsy (Bell's palsy). In the acute stage (less than 5 days after onset) short and long latency responses on the paretic side were abnormal, being absent in all but one patient, in whom the short latency response was delayed. These abnormal responses were the earliest neurographic correlate for nerve conduction block. In 4 out of 9 patients seen up to 30 days after onset of palsy, trans-synaptically evoked long latency responses were absent. In patients examined more than 2 months after onset, long latency responses could always be obtained and, in 5 of 8 patients, short latency responses could also be elicited, indicating a return of the direct excitability of the nerve. Five patients with cerebral hemisphere lesions causing mild unilateral facial weakness had absent long latency responses when stimulating over the affected hemisphere, but normal bilateral long latency responses following stimulation over the unaffected cerebral hemisphere; short latency responses were normal. Magnetic stimulation of the brain and of the facial nerve can differentiate between central and peripheral causes of unilateral facial weakness and may prove useful in the early assessment of the degree of conduction block in Bell's palsy.Supported by the Deutsche Forschungsgemeinschaft     

Annualized incidence and spectrum of illness from an outbreak investigation of Bell's palsy

BACKGROUND: There are limited clinical and epidemiological data on patients diagnosed with Bell's palsy. While investigating an apparent clustering of Bell's palsy, we sought to characterize the spectrum of illness in patients with this diagnosis. METHODS: A telephone survey of persons with idiopathic facial (Bell's) palsy in the Greater Toronto Area (GTA, population = 4.99 million) and Nova Scotia (population = 0.93 million) from August 1 to November 15, 1997 collected information on subject demographics, neurological symptoms, constitutional symptoms, medical investigation and management. Information regarding potential risks for exposure to infectious agents, past medical history, and family history of Bell's palsy was also collected. Subjects with other secondary causes of facial palsy were excluded. RESULTS: In the GTA and Nova Scotia, 222 and 36 patients were diagnosed with idiopathic facial (Bell's) palsy, respectively. The crude annualized incidence of Bell's palsy was 15.2 and 13.1 per 100,000 population in the GTA and Nova Scotia, respectively. There was no temporal or geographical clustering, and symptomatology did not differ significantly between the two samples. The mean age was 45 years, with 55% of subjects being female. The most common symptoms accompanying Bell's palsy were increased tearing (63%), pain in or around the ear (63%), and taste abnormalities (52%). A significant number of patients reported neurological symptoms not attributable to the facial nerve. CONCLUSION: No clustering of cases of Bell's palsy was observed to support an infectious etiology for the condition. Misdiagnosis of the etiology of facial weakness is common. Patients diagnosed with Bell's palsy have a variety of neurological symptoms, many of which cannot be attributed to a facial nerve disorder.     

Reactivation of type 1 herpes simplex virus and varicella zoster virus in an immunosuppressed patient with acute peripheral facial weakness

We describe a 26-year-old man treated with azathioprine for myasthenia gravis who developed acute left-sided peripheral facial weakness. Brain magnetic resonance imaging (MRI) revealed enhancement in the left geniculate ganglion and in the intracanalicular and tympanic segments of the facial nerve. Analysis of cerebrospinal fluid (CSF) and serum revealed intrathecal synthesis of anti-varicella zoster virus (VZV) IgG antibody. Although previous analyses of saliva, blood mononuclear cells, serum antibodies, middle ear fluid, and auricular and geniculate zone skin scrapings have shown that a small but definite proportion of patients with idiopathic peripheral facial palsy ("Bell's palsy") have the Ramsay Hunt syndrome zoster sine herpete (RHS ZSH), this is the first confirmation of RHS ZSH by intrathecal synthesis of anti-VZV IgG antibody. In addition, herpes simplex virus (HSV)-1 DNA was found in saliva of the patient on 3 consecutive days. Simultaneous reactivation of two alphaherpesviruses (HSV-1 and VZV) in our immunosuppressed patient underscores the need to consider opportunistic infection as a cause of facial weakness.     

Bell's palsy with ipsilateral numbness

Bell's palsy is an idiopathic facial palsy of the peripheral type. A herpes virus is the most likely mechanism. We report a patient with the often encountered combination of a facial palsy with ipsilateral sensory changes. Magnetic resonance imaging showed had contrast enhancement in the greater petrosal nerve. Viral spread through anatomical connections could be an explanation for the association of facial palsy with numbness.     

Blink reflex recovery in facial weakness: an electrophysiologic study of adaptive changes

OBJECTIVE: To study the electrophysiologic effects of unilateral facial weakness on the excitability of the neuronal circuitry underlying blink reflex, and to localize the site of changes in blink reflex excitability that occur after facial weakness. BACKGROUND: Eyelid kinematic studies suggest that adaptive modification of the blink reflex occurs after facial weakness. Such adaptations generally optimize eye closure. A report of blepharospasm following Bell's palsy suggests that dysfunctional adaptive changes can also occur. METHODS: Blink reflex recovery was evaluated with paired stimulation of the supraorbital nerve at different interstimulus intervals. Comparisons were made between normal control subjects and patients with Bell's palsy who either recovered facial strength or who had persistent weakness. RESULTS: Blink reflex recovery was enhanced in patients with residual weakness but not in patients who recovered facial strength. Facial muscles on weak and unaffected sides showed enhancement. In patients with residual weakness, earlier blink reflex recovery occurred when stimulating the supraorbital nerve on the weak side. Sensory thresholds were symmetric. CONCLUSION: Enhancement of blink reflex recovery is dependent on ongoing facial weakness. Faster recovery when stimulating the supraorbital nerve on the paretic side suggests that sensitization may be lateralized, and suggests a role for abnormal afferent input in maintaining sensitization. Interneurons in the blink reflex pathway are the best candidates for the locus of this plasticity.     

Role of transcranial magnetic stimulation in clinical diagnosis: facial nerve neurography

Facial nerve neurography involving magnetic stimulation techniques can be used to assess the intracranial segment of the facial nerve and the entire facial motor pathway, as opposed to the traditional neurography, involving only extracranial electric stimulation of the nerve. Both our own experience and data published in the literature underline the value of the method in localising facial nerve dysfunction and its role in clinical diagnosis. It is non-invasive and easy to perform. Canalicular hypoexcitability has proved to be the most useful and sensitive parameter, which indicates the dysfunction of the nerve between the brain stem and the facial canal. This is an electrophysiological finding which offers for the first time positive criteria for the diagnosis of Bell's palsy. The absence of canalicular hypoexcitability practically excludes the possibility of Bell's palsy. The technique is also able to demonstrate subclinical dysfunction of the nerve, which can be of considerable help in the etiological diagnosis of facial palsies. For example, in a situation where clinically unilateral facial weakness is observed, but facial nerve neurography demonstrates bilateral involvement, etiologies other than Bell's palsy are more likely, such as Lyme's disease, Guillain-Barré syndrome, meningeal affections etc. Furthermore, the technique differentiates reliably between peripheral facial nerve lesion involving the segment in the brain stem or the segment after leaving the brainstem.     

Pathophysiological diagnosis of facial paralysis using 3-D MRI]

Bilateral facial paralysis(facial diplesia) is often observed in Guillain-Barré syndrome(GBS) and Fisher's syndrome (FS). We tried to observe injured facial nerves using three-dimensional(3-D) MRI in facial diplesia due to GBS and its variants and examined function of blood nerve barrier and clinical use of 3-D MRI for detecting injured facial nerves. In the four patients with GBS and its variants(GBS three cases, FS one case), while routine brain MRI did not show any abnormal findings, contrast-enhanced 3-D MRI revealed Gd-enhancement of the facial nerves. On the other hand, only one case showed visualization using contrast-enhanced 3-D MRI in twelve cases of Bell's palsy. Therefore, it may be presumed that the reason why the significantly higher rate of visualization in facial paralysis in GBS and its variants than in Bell's palsy is attributable to a difference in the mechanism of injury or the extreme seriousness of the disease. In conclusion, the observation of facial nerve using 3-D MRI was very useful to know the condition of the facial diplesia in GBS and its variants.     

Idiopathic trigeminal sensory neuropathy with gadolinium enhancement in the cisternal segment

The authors report two patients with idiopathic trigeminal sensory neuropathy who showed gadolinium enhancement of the cisternal segment of the corresponding trigeminal nerve in cranial MRI. The resolution of these lesions in a repeat MRI suggests a similarity to Bell's palsy.     

An alarming sign for serious diseases in children: bilateral facial paralysis

Facial paralysis in children is most often idiopathic, and isolated facial nerve palsy resulting from leukemic infiltration is a rare occurrence. We report a 13-year-old male with acute lymphoblastic leukemia presenting with bilateral facial palsy, who was previously diagnosed with idiopathic facial palsy and treated with steroids. This rare presentation of acute lymphoblastic leukemia should be kept in mind as a diagnostic possibility in a patient with bilateral facial nerve paralysis.     

Outcome of liver transplantation for transthyretin amyloidosis: follow-up of Japanese familial amyloidotic polyneuropathy patients

The majority of peripheral seventh cranial nerve palsy cases remain without an identified etiology and will eventually be diagnosed as idiopathic or Bell's palsy. Some features of this condition may be characteristic of a viral infection. Indeed, several herpes viruses have been implicated as potential causative pathogens. Besides varicella-zoster virus, shown to cause Bell's palsy under the Ramsay-Hunt syndrome, recent years have seen an increased interest and focus on the possible herpes simplex virus type 1 (HSV-1) etiology in idiopathic facial paralysis. We review the clinical, biological and virological basis for the potential herpetic cause of Bell's palsy and the rational for antiviral therapy in this condition.     

Clinical aspects and immunology of facial neuritis

A clinical and immunological study was carried out in 75 patients with facial neuritis. It was found that the concentration of serum IgG and IgA were increased. The frequency of CIC in blood was higher than normal. In comparison with the controls, the difference was statistically significant (P less than 0.01). However, IgM, Ch50 and C3 levels were not deviated from normals. It was suggested that immune functions of patients with facial neuritis were abnormal. The data presented might set a clue in exploring the pathogenesis of this disease. Of these 75 cases, 2 were bilateral simultaneous Bell's palsy, 11 unilateral recurrent and bilateral alternating Bell's palsy. They might be considered as special types of Bell's palsy.     

Idiopathic cranial polyneuropathies]

A series of 43 cases with multiple cranial nerve deficits was collected between 1972 and 1990. No diagnosis was established in 15 cases. The facial and the trigeminal nerves were most frequently affected. In 10 cases, a monophasic course was observed usually with recovery. Recurrence was present in 5 cases. An inflammatory mechanism was likely in 10 cases. Nosological relations between these cases and either Bell's palsy (idiopathic facial paralysis) or Tolosa-Hunt's syndrome are discussed.     

Bell's palsy in children: analysis of clinical findings and course

To evaluate treatment of Bell's palsy (acute idiopathic peripheral facial nerve paralysis) of children, the authors analyzed 38 cases (18 females, 20 males) of Bell's palsy in children aged below 16 years old. The mean age of all cases was 6.8 +/- 6.2 years old. All cases resulted in complete recovery within 6 months. Clinical score of facial motor functions were adapted to 17 patients who were more than 5 years old. They were divided into two groups: early recovery group (clinical symptoms recovered within 3 months; 10 cases) and later recover group (over 3 months; 7 cases). Clinical scores evaluated in the first week from the onset were not significantly different. Steroid therapy was used for 9 patients of early group and 6 patient of later group. All patients of this study were recovered, thus we could not evaluate effect of steroid therapy for Bell's palsy in children. Use of steroid therapy for Bell's palsy needs more concretely administration. We consider how the region locates near to the center is an important prognostic factor.     

Predisposing factors in Bell's palsy: a case-control study

Summary The frequency of diabetes mellitus reported in subjects affected by Bell's palsy varies widely. In this investigation, a case-control study, we encountered a frequency of 24.8%. In addition, arterial hypertension and lipid disturbances were found to affect subjects with Bell's palsy more frequently than controls. These findings appear to suggest a primarily ischaemic pathogenesis for most cases of idiopathic peripheral facial paralysis. Furthermore, the finding of significantly lower taste impairment in diabetics than in non-diabetics with Bell's palsy may support the hypothesis of a vascular rather than a metabolic pathogenesis in these cases also. In fact, the vessels supplying the distal portion of the facial nerve, probably more affected in the diabetic patients in order to preserve taste sensation, have such a particular anatomical configuration that this might favour the onset of a diabetic small vessel disease which, in turn, would represent a factor of easier decompensation.     

Diagnostic relevance of transcranial magnetic and electric stimulation of the facial nerve in the management of facial palsy.

OBJECTIVE: Earlier investigations have suggested that isolated conduction block of the facial nerve to transcranial magnetic stimulation early in the disorder represents a very sensitive and potentially specific finding in Bell's palsy differentiating the disease from other etiologies. METHODS: Stimulation of the facial nerve was performed electrically at the stylomastoid foramen and magnetically at the labyrinthine segment of the Fallopian channel within 3 days from symptom onset in 65 patients with Bell's palsy, five patients with Zoster oticus, one patient with neuroborreliosis and one patient with nuclear facial nerve palsy due to multiple sclerosis. RESULTS: Absence or decreased amplitudes of muscle responses to early transcranial magnetic stimulation was not specific for Bell's palsy, but also evident in all cases of Zoster oticus and in the case of neuroborreliosis. Amplitudes of electrically evoked muscle responses were more markedly reduced in Zoster oticus as compared to Bell's palsy, most likely due to a more severe degree of axonal degeneration. The degree of amplitude reduction of the muscle response to electrical stimulation reliably correlated with the severity of facial palsy. CONCLUSIONS: Transcranial magnetic stimulation in the early diagnosis of Bell's palsy is less specific than previously thought. While not specific with respect to the etiology of facial palsy, transcranial magnetic stimulation seems capable of localizing the site of lesion within the Fallopian channel. SIGNIFICANCE: Combined with transcranial magnetic stimulation, early electrical stimulation of the facial nerve at the stylomastoid foramen may help to establish correct diagnosis and prognosis.     

Ramsay Hunt syndrome

The strict definition of the Ramsay Hunt syndrome is peripheral facial nerve palsy accompanied by an erythematous vesicular rash on the ear (zoster oticus) or in the mouth. J Ramsay Hunt, who described various clinical presentations of facial paralysis and rash, also recognised other frequent symptoms and signs such as tinnitus, hearing loss, nausea, vomiting, vertigo, and nystagmus. He explained these eighth nerve features by the close proximity of the geniculate ganglion to the vestibulocochlear nerve within the bony facial canal. Hunt's analysis of clinical variations of the syndrome now bearing his name led to his recognition of the general somatic sensory function of the facial nerve and his defining of the geniculate zone of the ear. It is now known that varicella zoster virus (VZV) causes Ramsay Hunt syndrome. Compared with Bell's palsy (facial paralysis without rash), patients with Ramsay Hunt syndrome often have more severe paralysis at onset and are less likely to recover completely. Studies suggest that treatment with prednisone and acyclovir may improve outcome, although a prospective randomised treatment trial remains to be undertaken. In the only prospective study of patients with Ramsay Hunt syndrome, 14% developed vesicles after the onset of facial weakness. Thus, Ramsay Hunt syndrome may initially be indistinguishable from Bell's palsy. Further, Bell's palsy is significantly associated with herpes simplex virus (HSV) infection. In the light of the known safety and effectiveness of antiviral drugs against VZV or HSV, consideration should be given to early treatment of all patients with Ramsay Hunt syndrome or Bell's palsy with a 7-10 day course of famciclovir (500 mg, three times daily) or acyclovir (800 mg, five times daily), as well as oral prednisone (60 mg daily for 3-5 days). Finally, some patients develop peripheral facial paralysis without ear or mouth rash, associated with either a fourfold rise in antibody to VZV or the presence of VZV DNA in auricular skin, blood mononuclear cells, middle ear fluid, or saliva. This indicates that a proportion of patients with "Bell's palsy" have Ramsay Hunt syndrome zoster sine herpete. Treatment of these patients with acyclovir and prednisone within 7 days of onset has been shown to improve the outcome of recovery from facial palsy.     

Absence of Lyme borreliosis among patients with presumed Bell's palsy.

In a prospective study, 69 patients with a presumed idiopathic (Bell's) peripheral facial palsy were clinically and serologically evaluated for the presence of Lyme borreliosis. In addition, their clinical spectrum was compared with clinical manifestations collected retrospectively in nine patients with symptomatic peripheral facial palsy due to Lyme borreliosis. The seroprevalence of Borrelia burgdorferi antibodies, determined by flagellum enzyme-linked immunosorbent assay, among 69 patients with idiopathic peripheral facial palsy (6%) and 153 healthy controls (4.5%) was not significantly different (odds ratio, 1.28; 95% confidence interval, 0.27 to 5.25). None of the patients with idiopathic peripheral facial palsy had or experienced the development of Lyme borreliosis. All patients with Lyme peripheral facial palsy had additional manifestations not present in patients with idiopathic peripheral facial palsy. These findings show that patients with a Lyme peripheral facial palsy can be differentiated from patients with idiopathic peripheral facial palsy by clinical examination. Therefore, screening of antibodies to B burgdorferi among patients with idiopathic peripheral facial palsy without additional manifestations is not recommended.     

A case of Möbius syndrome presenting with symptoms of severe infantile form of congenital muscular disorder

M?bius syndrome is a rare disorder characterized by congenital bilateral facial nerve palsy. Abducent palsy or other cranial nerve palsy, facial malformations, limb malformations, and skeletal malformations are common features associated with this syndrome. We report a 9-month-old infant in whom congenital muscular disorder was previously suspected because of facial muscle involvement (mask-like face), respiratory and swallowing disturbances, and hypotonia since birth. After an improvement in the respiratory infection, she showed slightly exaggerated deep tendon reflexes and an improvement in muscle tone. The occurrence of combined facial nerve palsy, glossopharyngeal nerve palsy, vagus nerve palsy, and hypoglossal nerve palsy strongly suggested that she had M?bius syndrome. Finally, the absence of the roots of bilateral facial nerves on an MRI confirmed that the disorder was M?bius syndrome. We propose that a thin slice MRI should be obtained to observe the cranial nerves around the brain stem if patients show symptoms of congenital myopathy or congenital myotonic dystrophy as well as facial nerve and other cranial nerve paralyses.     

Alternating Bell's palsy associated with diabetes mellitus. A report of four cases.

Four diabetic patients are presented with alternating facial palsy. The term alternating is meant to imply facial nerve paralysis, the onset of which occurs at different points in time on both sides of the face. Clinical findings are presented and a short review of the literature is summarized. The authors conclude that alternating facial palsy is often associated with diabetes mellitus. Alternating facial palsy is an infrequent finding. This is in marked contrast to the unilateral form. Approximately every 13 minutes someone in the United States incurs idiopathic facial paralysis or Bell's palsy (20 persons per 100,000 per year). It is apparent that the majority of unilateral facial palsies fall into the idiopathic category. The alternating form of facial paralysis, however, appears to be an unusual finding in a symptom complex of several diseases which will be discussed. It is the diagnostic significance of this alternating facial paralysis and its occasional association with diabetes mellitus that prompts this report.     

Successful response of non-recovering Ramsay Hunt syndrome to intravenous high dose methylprednisolone

Ramsay Hunt syndrome (RHS) is a frequent cause of facial palsy. It is a consequence of the infection of geniculate ganglion by herpes zoster or herpes simplex virus. In the lack of randomized controlled trials, RHS is empirically treated by a combination therapy of antiviral agents and steroids given orally. However, RHS has, per se, a poorer prognosis than idiopathic facial palsy (Bell's palsy). We describe a case series of two patients with RHS unsuccessfully treated with antiviral drugs and oral corticosteroids, showing an almost complete recovery after late administration of intravenous (i.v.) high dose methylprednisolone. Both patients had all recognized negative prognostic factors including age of onset, a high grade facial weakness, absence of R1 and R2 response at blink reflex test, and in the first case, the involvement of greater superficial petrosal nerve. We propose that i.v. high dose methylprednisolone should be considered, even as a late treatment option, in patients with RHS non recovering after standard antiviral and oral steroid therapy as well as presenting clinical features suggestive of a poor prognosis.