Pallidal deep brain stimulation in the treatment of Meige syndrome

BACKGROUND

Pallidal deep brain stimulation (DBS) of globus pallidus internus (Gpi) has emerged as an effective treatment for dystonia. The experience is however limited concerning focal dystonias and to date only a few cases of pallidal DBS in the treatment of Meige syndrome have been published.

METHODS/RESULTS

We here present a patient with Meige syndrome in whom unilateral pallidal DBS failed to improve the axial symptoms, but bilateral stimulation resulted in a major improvement. The Burke-Fahn-Marsden score (BFM) improved by 71.5% and the patient's blepharospasm was abolished.

CONCLUSIONS

The results suggest bilateral pallidal DBS may be an effective treatment for Meige syndrome.

Sustained relief of dystonia following cessation of deep brain stimulation

We describe the unusual clinical course of a patient with cranial dystonia (i.e., Meige syndrome) and additional upper limb involvement, who developed sustained relief of motor symptoms following cessation of a prolonged course of bilateral pallidal deep brain stimulation (DBS). Early response to therapy proved titratable and reversible; however, the patient gained independence from DBS in the fifth postoperative year and has since been more than a year without treatment or exacerbation of motor symptoms. Among the potential explanations for these neurological benefits lies the intriguing possibility that DBS therapy may have the capacity to induce plastic change that lessens or obviates the need for further treatment in susceptible patients.

Pallidal deep brain stimulation in patients with cranial-cervical dystonia (Meige syndrome)

Idiopathic cranial-cervical dystonia (ICCD) is an adult-onset dystonia syndrome affecting orbicularis oculi, facial, oromandibular, and cervical musculature. ICCD is frequently difficult to treat medically. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is a highly effective treatment for idiopathic generalized dystonia, however less is known about the effect of GPi DBS on ICCD. In this article, we present the results from a pilot study assessing the effect of GPi DBS in a series of patients with ICCD. Six patients underwent bilateral stereotactic implantation of DBS leads into the sensorimotor GPi. Patients were evaluated with the Burke-Fahn-Marsden dystonia rating scale (BFMDRS) and Toronto western spamodic torticollis rating scale (TWSTRS) before surgery and 6 months postoperatively. At 6 months, patients showed a 72% mean improvement in the BFMDRS total movement score (P < 0.028, Wilcoxin signed rank test). The mean BFMDRS disability score showed a trend toward improvement (P < 0.06). The total TWSTRS score improved 54% (P < 0.043). Despite improvement in dystonia, mild worsening of motor function was reported in previously nondystonic body regions with stimulation in 4 patients. Although GPi DBS was effective in these patients, the influence of GPi DBS on nondystonic body regions deserves further investigation.

Oromandibular dystonia

Oromandibular dystonia (OMD) is a rare neuromuscular disorder characterized by involuntary repetitive muscular contraction affecting different parts of the oromandibular region. Its various physical manifestations can be extremely debilitating and socially disabling to affected patients. To date, there is no commonly accepted set of diagnostic criteria nor well-defined management pathways. This paper aims to discuss some aspects of clinical manifestations, diagnostic criteria, neurological mechanisms, and treatment options for OMD, with illustrations from 6 clinical cases.

Severe tongue protrusion dystonia: Clinical syndromes and possible treatment

We describe intermittent or sustained severe involuntary tongue protrusion in patients with a dystonic syndrome. Speech, swallowing, and breathing difficulties can be severe enough to be life threatening. Causes include neuroacanthocytosis, pantothenate kinase-associated neurodegeneration, Lesch-Nyhan syndrome, and postanoxic and tardive dystonia. The pathophysiology of intermittent severe tongue protrusion remains unknown. Tongue protrusion dystonia is often unresponsive to oral drugs but may benefit from botulinum toxin injections into the genioglossus muscle. Bilateral deep brain pallidal stimulation was beneficial in two cases.

Levetiracetam in Meige's syndrome

The spontaneous occurrence of blepharospasm and dystonic movements in face muscles, particularly those of the perioral and mandibular regions, has been named as Meige's disease which was first described by Henry Meige in 1910. We report the case of a woman with Meige's syndrome whose symptoms improved with the use of levetiracetam.

Meige syndrome and pallidal deep brain stimulation

The cause of primary Meige syndrome is unknown, and although gender and age predilections are different from idiopathic torsion dystonia, most investigators consider Meige syndrome a variant of that disorder. Interest in the use of stereotactic brain surgery for refractory forms of dystonia is thus increasing. There is little experience with the use of deep brain stimulation (DBS) in focal dystonias, and reports of its use in Meige syndrome are very rare. We report on a case of Meige syndrome successfully treated with bilateral pallidal DBS.

A comparison of jaw-closing and jaw-opening idiopathic oromandibular dystonia

Oromandibular dystonia (OMD) is a form of focal dystonia that affects masticatory, lower facial, and lingual muscles. We compared the clinical variables and response to treatment between patients with idiopathic jaw-closure C-OMD (n = 11) and jaw-opening dystonia O-OMD (n = 12) seen in our Movement Disorders clinic over the last 10 years. The co-existence of dystonia in other regions and sensory tricks were significantly more prevalent in O-OMD (P = 0.049 and 0.03, respectively). Male gender, orobuccolingual dyskinesias (facial grimacing, lip biting, tongue dyskinesias, platysma contractions and bruxism) and better response to botulinum toxin injections were more frequent in C-OMD but remained a trend.

Substantial improvement in a Meige's syndrome patient with levetiracetam treatment

We report on a woman with idiopathic Meige's syndrome whose dystonia improved with the use of levetiracetam (LEV, Keppra, UCB Pharma, Smyrna, GA). This report and data from an animal model of paroxysmal dystonia suggest that LEV might be helpful in the treatment of dystonia.

Staged Deep Brain Stimulation for Refractory Craniofacial Dystonia with Blepharospasm: Case Report and Physiology

OBJECTIVE AND IMPORTANCE

We report the intraoperative results, subsequent course, and 1-year follow-up evaluation of a patient with medication-refractory craniofacial dystonia for whom we planned bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) implantation but delayed the left GPi DBS implantation because of robust intraoperative effects of right GPi DBS.

CLINICAL PRESENTATION

A 47-year-old patient had a 5-year history of progressively severe, bilateral craniofacial dystonia with blepharospasm (Meige's syndrome) that was refractory to medications and to botulinum toxin (A and B) injections. Blepharospasm interfered with his ability to perform his duties as a Special Forces soldier and ended his military career.

INTERVENTION

Under stereotactic guidance (magnetic resonance imaging and computed tomographic image fusion, Cosman-Roberts-Wells frame, and University of Florida surgical navigation software) and with detailed microelectrode mapping (four microelectrode passes), a DBS electrode was implanted in the right posteroventral GPi. Microelectrode recordings were taken to document electrophysiological activity of neurons in the region, and intraoperative macrostimulation was performed. The patient was followed up for 6 months with right unilateral GPi DBS, and later a left GPi DBS electrode was placed.

CONCLUSION

Although DBS for primary generalized dystonia is commonly performed by simultaneously implanting bilateral GPi electrodes, it may be reasonable in cases of refractory blepharospasm and/or craniofacial dystonia to use a staged procedure for implantation in selected patients. Additionally, the physiology, especially that encountered in the striatum, may help to elucidate the pathophysiological basis for refractory blepharospasm and Meige's syndrome. More cases will be needed to determine the significance of the results reported in this article.

Sensory mapping of lip representation in brass musicians with embouchure dystonia

Embouchure dystonia is a focal task-specific disorder involving abnormal non-coordinated movements and involuntary muscle contraction around the mouth. In professional brass players it is often so disabling that patients have to limit or give up their occupation. We examined the somatosensory homuncular representation and measured gap detection sensitivity of the lips in eight former professional musicians affected by embouchure dystonia and eight control subjects. Relative to controls, the patients' digit, and especially the thumb, representations were shifted in a lateral direction towards the lip representational zone. Patients' upper lips showed decreased sensitivity compared to their lower lips (p < 0.01). This asymmetry result was absent in controls. Abnormal somatosensory reorganization may contribute to the disorder.

Treatment of perioral dystonia with botulinum toxin in 4 cases of Meige's syndrome

OBJECTIVE

We describe the treatment of 4 patients (median age, 53.5 years) with incapacitating perioral dystonia and insufficient response to peroral medication. Their general treatment with clonazepam and anticholinergics was supplemented by intramuscular injections with botulinum toxin A (20-40 U) in the orbicularis oris muscle, guided by electromyography (EMG).

STUDY DESIGN

Perioral dystonia and treatment effect were assessed by using subjective global and visual analog scales, examiner-based video movement counts and rating scales, and quantitative EMG. t Tests were used for statistical analysis.

RESULTS

The result of the intramuscular botulinum toxin A injections was characterized by the patients as "much improved"; correspondingly, dystonia was significantly reduced in visual analog scale scores, on examiner-based assessments, and in recordings of EMG. The side effects were few and short-lasting.

CONCLUSION

Incapacitating perioral dystonia in Meige's syndrome may be safely controlled by recurrent EMG-guided botulinum toxin A injections in the orbicularis oris muscle, in combination with general medication.

Three silent periods in the orbiculari oculi muscles of man: normal findings and some clinical vignettes

PURPOSE

To investigate how many true silent periods could be found in the orbiculari oculi muscles of man.

MATERIAL AND METHODS

10 subjects, clinically healthy (5 male, 5 female), with a mean age of 34 years-old (range: 23 to 48) were evaluated by mean of the blink reflex at resting and during contraction of the orbiculari oculi reflex according to protocols validated internationally.

RESULTS

Three responses called R1, R2 and R3 were obtained in the orbicular oculi muscle at resting state which had latencies and amplitudes within normal limits. What was new was to obtain three silent periods when the subjects were evaluated during muscle contraction. The duration of the first silent period was statistically longer than the second one (p < 0.004) and shorter than the third silent period (p < 0.0001). In addition, this test was found useful in detecting more specific findings in patients with hemifacial spasm and Meigge syndrome.

CONCLUSION

This is by the first time that three silent periods in the orbicular oculi muscles are consistently demonstrated. The refractoriness of the alpha motoneurons and the action of gamma-collateral activity seem to be the main conditions leasing to display the first two periods of muscle suppression. The modification of gamma motoneurons firing as well as a pause of muscle spindles in facial muscles due to the action of nociceptive stimuli traveling unmyelinated C fibers of the supraorbital nerve might be the most important mechanisms involved in the production of the third silent period. These results enables further clinical application of this test.

The natural history of embouchure dystonia

Focal task-specific dystonias are unusual disorders of motor control, often affecting individuals who perform complex repetitive movements. Musicians are especially prone to develop these disorders because of their training regimens and intense practice schedules. Task-specific dystonia occurring in keyboard or string instrumentalists usually affects the hand. In contrast, there have been few descriptions of musicians with task-specific dystonia affecting the muscles of the face and jaw. We report detailed clinical observations of 26 professional brass and woodwind players afflicted with focal task-specific dystonia of the embouchure (the pattern of lip, jaw, and tongue muscles used to control the flow of air into a mouthpiece). This is the largest and most comprehensively studied series of such patients. Patients developed embouchure dystonia in the fourth decade, and initial symptoms were usually limited to one range of notes or style of playing. Once present, dystonia progressed without remission and responded poorly to oral medications and botulinum toxin injection. Patients with embouchure dystonia could be separated by the pattern of their abnormal movements into several groups, including embouchure tremor, involuntary lip movements, and jaw closure. Dystonia not infrequently spread to other oral tasks, often producing significant disability. Effective treatments are needed for this challenging and unusual disorder.

Bilateral pallidal stimulation for idiopathic segmental axial dystonia advanced from Meige syndrome refractory to bilateral thalamotomy

Meige syndrome is an adult-onset dystonic movement disorder that predominantly involves facial muscles, while some patients with this syndrome develop spasmodic dysphonia and dystonia of the neck, trunk, arms, and legs. We report that all dystonic symptoms that had been refractory to both pharmacotherapy and bilateral thalamotomy were markedly alleviated by bilateral pallidal stimulation in a patient with segmental axial dystonia advanced from Meige syndrome.

Oral rehabilitation with osseointegrated implants in a patient with oromandibular dystonia with blepharospasm (Brueghel's syndrome): a patient history

Oromandibular dystonia with blepharospasm (also known as Brueghel's syndrome, Meige's syndrome, or idiopathic orofacial dystonia) is characterized by intense and involuntary spasms of the orofacial muscles, with a frequent loss of teeth and occlusal alterations that worsen the dystonic manifestations and cause mucosal lesions that can lead to complete edentulism. The history of a patient with oromandibular dystonia who was rehabilitated with mandibular overdentures supported by endosteal implants is presented. Oral rehabilitation with implant-supported overdentures improved the situation, despite serious problems with instability. Mandibular overdentures supported by endosteal implants were satisfactorily used to re-establish occlusion, ensuring prosthetic stability and improving the dynamics of the masticatory muscles.

Shortened cortical silent period in facial muscles of patients with cranial dystonia

OBJECTIVE

To study the cortical silent period (SP) in the orbicularis oculi and perioral muscles in 23 patients with cranial dystonia and 10 age-matched control subjects.

METHODS

High-intensity magnetic stimuli were delivered with a round coil centered at the vertex during a maximal muscle contraction. Electromyographic (EMG) responses were recorded from surface electrodes placed over the orbicularis oculi and perioral muscles.

RESULTS

SPs elicited in upper and lower facial muscles had a similar duration. Facial muscle SPs were significantly shorter in patients than in control subjects. Patients with blepharospasm plus oromandibular dystonia had shorter SPs than patients with blepharospasm alone. Although patients' recordings showed reduced voluntary and evoked EMG activity, neither activities correlated with the duration of the SP.

CONCLUSIONS

Silent period (SP) shortening depends neither on the level of electromyographic activity nor on segmentary mechanisms. The shortened SP in facial muscles reflects hypoexcitability of cortical inhibitory neurons in cranial dystonia.

Serial SFEMG studies of orbicularis oculi muscle after the first administration of botulinum toxin

Serial single fiber electromyography (SFEMG) examinations of orbicularis oculi muscle in patients with blepharospasm or hemifacial spasm treated with botulinum toxin injections were performed. The aim of the study was to evaluate the impairment of neuromuscular transmission, to follow reinnervation after botulinum toxin administration and to find out whether there was a relationship between SFEMG parameters and clinical symptoms. Examinations were performed before injection, during early and late remission of symptoms, and after recurrence of the involuntary movement. Severe impairment of neuromuscular transmission, as revealed by increased jitter and increased presence of abnormal potential pairs and pairs with blocking, was found in early remission, but fiber density remained unchanged when compared with pretreatment values. In late remission, increased fiber density was registered for the first time. The recurrence of involuntary movements was related to the further increase of fiber density and tendency to normalization of jitter parameters. The study therefore suggests that formation of new neuromuscular junctions and their functional maturation is responsible for muscle recovery after botulinum toxin administration.

[Meige's syndrome associated with basal ganglia and thalamic functional disorders]

Magnetic resonance imaging (MRI) or single positron emission computed tomography (SPECT) or both were performed and the responses of surface electromyography (EMG) were examined in seven cases of Meige's syndrome. MRI or SPECT or both demonstrated lesions of the basal ganglia, the thalamus, or both in five of the cases. Surface EMG revealed abnormal burst discharges in the orbicularis oculi and a failure of reciprocal muscular activity between the frontalis and orbicularis oculi in all the cases. These findings suggest that voluntary motor control and reciprocal activity in the basal ganglia-thalamocortical circuits are impaired in Meige's syndrome. In addition, good responses were seen to clonazepam, tiapride and trihexyphenidyl in these cases. Therefore, we conclude that dopaminergic, cholinergic, and gamma-aminobutyric acid (GABA) ergic imbalances in the disorders of the basal ganglia and thalamus in Meige's syndrome cause control in the excitatory and inhibitory pathways to be lost, resulting in the failure of integration in reciprocal muscular activity and voluntary motor control. This failure subsequently causes the symptoms of Meige's syndrome.

Spontaneous remission in patients with essential blepharospasm and Meige syndrome

PURPOSE

To determine the frequency of remission in patients with essential blepharospasm and Meige syndrome.

METHOD

Retrospective analysis of patients by means of questionnaire in an institutional setting.

RESULTS

Among 238 patients diagnosed in a single institution as having essential blepharospasm or Meige syndrome, 27 (11.3%) claimed to be symptom free without curative surgery. The average time between onset and resolution in the patients who claimed remission was 4.85 years (range, 3 months to 22 years). Among these patients, the duration of remission averaged 6.33 years (range, 1 year to 14 years).

CONCLUSION

Patients with essential blepharospasm or Meige syndrome have a small but definite potential for spontaneous remission of symptoms, particularly within the first 5 years after onset of symptoms.

Neuroleptic-induced Meige's syndrome following akathisia: pharmacologic characteristics

A 52-year-old schizophrenic patient acutely showed blepharospasm and oromandibular dystonia following neuroleptic-induced akathisia. She had suffered from schizophrenia and been treated with neuroleptics for 15 years and had manifested tardive dyskinesia 5 years ago. Following a change in her neuroleptic medication, severe akathisia developed. Two days after the appearance of akathisia, blepharospasm and oromandibular dystonia appeared. After the disappearance of akathisia, the disorder continued. The frequency of blepharospasm ranged from 30 to 40 (times/min). The oral administration of trihexyphenidyl (6 mg/day), perphenazine (12 mg/day), and fluphenazine (12 mg/day) significantly decreased the frequency of blepharospasm, whereas carbamazepine (600 mg/day) and sulpiride (1200 mg/day) did not. These results suggest that overactivity of both cholinergic and dopaminergic functions in the striatum may be involved in this patient. Our patient, who showed acute onset of Meige's syndrome following neuroleptic-induced akathisia, is of interest to those studying the pathogenesis of Meige's syndrome.

[Oromandibular dystonia and botulinum toxins]

The authors describe the Meige's Syndrome also known as blepharospasm or mandibulo-oral dystonia. This Syndrome rather known by Neurologists and Ophthalmologists than by Stomatologists actually benefits by a specific treatment based on botulin toxins.

Acquired blepharoptosis

A review is given of the aetiology and possible treatment of acquired (non-congenital), blepharoptosis, which is a common but not specific sign of neurological disease. The diagnostic categories of upper eyelid drooping are scheduled as (a) pseudo-ptosis due to a local process or overactivity of eye closure, including blepharospasm, and (b) true ptosis due to a paresis of the eyelid levators (m. tarsalis superior or m. levator palpebrae) or to a disinsertion of the m. levator palpebrae (aponeurotic ptosis). A paresis of the m. tarsalis is due to a lesion in the central, intermediate or peripheral neuron of the sympathetic chain and constitutes one of the components of Horner's syndrome. A paresis of the m. levator palpebrae may be due to a failure in central innervation, in oculomotor (n.III) function, in neuromuscular transmission or to a lesion in the muscle itself.

Blepharospasm and related facial movement disorders

The variable clinical features and the relatively good response of blepharospasm to botulinum-toxin type A are now well established. The etiology and pathophysiology of blepharospasm and related facial movement disorders are still poorly understood. Genetic and histopathologic studies over the last year have contributed to our understanding of this disease. The most significant progress has been made in the electromyographic studies of the the levator palpebrae and orbicularis oculi muscles. Subclassification based on the electromyographic abnormalities of these two muscles have begun to improve our understanding of the variable responses to botulinum-toxin type A. Further electromyographic studies may help identify the best sites of injection for optimal response and differentiate patients requiring limited or complete myectomy. The development of the limited myectomy has provided excellent functional and cosmetic results with quick recovery times in selected patients.

[Dystonia as the cause of pharyngolaryngeal motility disorders]

Dystonia as cause of pharyngo-laryngeal motility disorders has not been adequately considered in most clinical ENT practices. This case study of a patient with spasmodic torticollis, Meige's syndrome and pharyngo-laryngeal motility disorder was found to be due to dystonia as the underlying cause. The possibility of local symptomatic therapy with botulinum toxin injections has currently provided the physician with an effective means for alleviating the disorder.

The interaction of the somatosensory evoked potentials to simultaneous finger stimuli in the human central nervous system. A study using direct recordings

In order to investigate the interaction of sensory electrophysiologic fields arising from the adjacent second (II) and third (III) fingers and the distant second and fifth (V) fingers, direct recordings of somatosensory evoked potentials (SEPs) were performed from the sensory and motor cortices, the sensory thalamic nucleus (nucleus ventralis caudalis, VC) and the cuneate nucleus in humans during neurosurgical operations. Electrical stimulation was given to the II, III or V fingers individually, and also to pairs of either the II and III fingers or the II and V fingers simultaneously. The interaction ratio (IR) was devised as the ratio of amplitude attenuation caused by the simultaneous stimulation to two fingers compared with the amplitude of the arithmetically summed SEPs to the individual stimulation of two fingers. The IRs were calculated on N20 and P25 from the sensory cortex, P22 from the motor cortex, P17thal from the VC, and N16cune and P35cune from the cuneate nucleus. With both stimulations to the II and III fingers and the II and V fingers, P25 showed the greatest IR, followed by P22, then by P17thal, with N16cune exhibited the smallest IR. N20 and P35cune showed similar IRs and significantly greater IRs with II and III finger stimulation compared with II and V finger stimulation. These results thus indicate that the interaction of somatosensory impulses occurs in several structures along the sensory pathway in CNS, including the cuneate nucleus, the sensory thalamic nucleus, as well as sensory and motor cortices, with the greatest IRs in the cerebral cortices and the weakest ones in the brain-stem.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical features and factors related to the functional prognosis in Meige's syndrome]

To clarify the factors determining the amelioration of Meige's syndrome, changes of involuntary movements (IVMs) and functional disability, we examined 60 patients with Meige's syndrome during 5 years after the onset. On average, they showed gradual worsening of IVMs for approximately 2.1 years, then the IVMs ameliorated slowly. In many patients, blepharospasm appeared as the first symptom. Subsequent IVMs were seen in vicinity of the muscles of orbicularis oculi. Phasic involuntary contractions changed to tonic ones in some patients. Asynchrony of the IVMs in various facial or neck muscles may be originated from extensive pathological changes and high excitability in the brainstem. The factors determining the amelioration of functional disability are: (1) younger onset, (2) shorter duration from the onset to the period showing the worst symptoms, (3) mild IVMs when the symptoms were the worst, (4) shorter duration from the onset to the beginning of therapy, (5) synchrony of the IVMs between the muscles of orbicularis oculi and other muscles. Methylphenidate, trihexyphenidyl, and ceruletide showed a higher efficiency for IVMs than the other drugs. The drug therapy in Meige's syndrome should be started as early as possible.

Blink reflex and the masseter inhibitory reflex in patients with dystonia

The excitatory and inhibitory interneuronal pathways in the brainstem are tested by examining the blink reflex and the masseter inhibitory reflex, respectively. We studied the R2 component of the blink reflex and the SP2 component of the masseter inhibitory reflex and their recovery cycle in 56 patients with various forms of dystonia. In patients with cranial, cervical, and generalized dystonia, but not in patients with extracranial segmental dystonia, the recovery cycle of both reflexes was enhanced. The recovery cycle of R2 and SP2 can demonstrate subclinical changes in excitability of brainstem interneurons. The degree of enhancement of the recovery cycles did not correlate, however, with the severity of clinical facial muscle impairment. In addition, the recovery cycles correlated positively with each other, showing that excitatory as well as inhibitory interneuronal pathways in the brainstem are perturbed in dystonia. Study of the trigemino-facial and trigemino-trigeminal reflexes provides an objective tool for assessing functional abnormalities in dystonia.

Sensory symptoms in cranial dystonia: a potential role in the etiology?

Cranial dystonia is normally considered as a pure movement disorder. Sensory symptoms have not received much attention, but we found ill-defined pain, discomfort, distortion of sensory modalities, 'phantom' kinetic or postural sensations in the orofacial areas subsequently involved by the dyskinesia in all of 11 consecutive patients, preceding by weeks or months the motor syndrome. Physicians were often mislead, initially making diagnoses such as trigeminal neuralgia, dental problems, sicca syndrome, chronic conjunctivitis, glossitis or stomatitis. The patients reported that the orofacial movements were at first willingly performed in order to decrease the discomfort which was felt in these facial areas before the movements finally escaped voluntary control and became socially disturbing. We suspect that the sensory symptoms, for which no objective substrate could be found, and which were always reported before and in the exact location of the subsequent dyskinesia, could be the earliest manifestation of an evolving process in cranial and perhaps other focal dystonias.

Time course of distant effects of local injections of botulinum toxin

Botulinum toxin A (btx) is used to treat focal dystonias. From accidental intoxications it is known that btx can cause generalized pathologic single-fiber electromyography (SFEMG) findings. We monitored the onset and course of these disturbances in eight patients who received a small dose of btx (2-22 ng) for therapy of focal dystonias in the head/neck region for the first time via repeated SFEMG investigations at days 0, 3, 6, 9, 12, 28, and 56. Recordings were performed in the extensor digitorum brevis muscle, and in two patients additionally in the tibialis anterior muscle. In six of these patients we found an increase of jitter and blocking. The onset of these changes was in the range of 3-13 days after injection. Fiber density showed a tendency to increase. There was no correlation between SFEMG findings and the dose of injected btx. Possible mechanisms for these observations may be either a very efficient local uptake and retrograde axonal transport via the spinal motor neurons or a systemic distribution via the blood circulation.

Electrophysiological study on jaw-opening reflex recorded from digastric muscle in Parkinson's disease and primary cranial dystonias

We investigated digastric reflex excitability in normals and in patients with extrapyramidal disorders such as primary cranial dystonias and Parkinson's disease. Relationships between exteroceptive suppression of masseter muscle and digastric reflex were also investigated in some cases. Digastric reflex hyperexcitability was observed in dystonic patients when compared to normals and parkinsonian patients. Furthermore, some patients with cranial dystonia presented absence of exteroceptive suppression reflex in masseter muscle with enlarged digastric response. These results indicate hyperexcitability of the digastric reflex and abnormal agonist-antagonist muscle co-contraction in chewing reflexes of patients with cranial dystonias. This shows that digastric reflex is an important electrophysiological investigation to explore the physiopathological mechanisms of primary cranial dystonias.

Surface electromyographic study of idiopathic cranial dystonia focused on the orbicularis oculi muscles

We studied 115 Japanese patients with idiopathic cranial dystonia (Meige disease), using surface electromyography (EMG) focused on the orbicularis oculi muscles to classify the findings of the abnormal involuntary movements of this disease and to evaluate the pathophysiology of blepharospasm (BS). Surface EMGs at rest and at voluntary eyelid opening after eyelid closing were investigated. We found 62 (53.9%) patients exhibiting the overblinking type, 37 (32.2%) the tonic BS type, and 16 (13.9%) the normal type of behavior, considering the frequency of spontaneous blinking and presence of spasms. The present results suggest that BS is not a summation of blinking but a spatial and temporal extension of the orbicularis oculi muscle activity engaging in blinking, and the classification of the present study can support the investigation of the temporal characteristics of patients with this disease.

Sleep and cranial dystonia

A nocturnal polygraphic study was performed on 10 patients with cranial dystonia (blepharospasm (BS) and oromandibular dystonia (OMD)). All patients showed impaired sleep efficiency and reduced slow and REM sleep, more marked in subjects with severe dystonia. Abnormal muscular activity decreased progressively with deeper sleep and during the first hours of the night, without disappearing. A disordered hypnic++ pattern and impaired motor control even during sleep are typical features in cranial dystonia.

Neurophysiological observations on the effects of botulinum toxin treatment in patients with dystonic blepharospasm

Botulinum toxin treatment improves dystonic blepharospasm by inducing transient paresis of the orbicularis oculi muscle. It is not known if it also reduces the enhanced brainstem neuronal excitability found in this disorder. We have performed conventional electromyography (EMG) and blink reflex excitability studies on fifteen patients with blepharospasm before and after botulinum toxin treatment. Denervation signs were found with needle EMG in all treated muscles. Amplitude of the facial compound muscle action potential (CMAP) and R1 response was reduced after botulinum toxin injections. In blink reflex excitability studies, the recovery of R2 response was enhanced after treatment even when patients were tested at the time of maximal benefit from botulinum toxin injections. The results suggest that there is little influence of botulinum toxin treatment upon the enhanced excitability of brainstem interneurons in patients with blepharospasm.

[Modification of the blink reflex in hemidystonia]

With the aim of evaluating the excitability of the brain stem reflex centers, we studied the side-to-side differences in the EMG activity of the early and late components of the blink reflex, in subjects with unilateral dystonia without demonstrable brain lesions. We observed that both early and late responses of direct blink reflex were significantly higher in the affected side than in the contralateral one.

The effect of nocturnal physiological sleep on various movement disorders

Thirty-one subjects affected by different movement disorders underwent polygraphic and videotape monitoring during nocturnal sleep, to assess movement patterns during the night. It was possible to distinguish two categories of disorders according to their pattern of movements. In the largest group (Meige's syndrome, blepharospasm, amyotrophic choreoacanthocytosis, Tourette syndrome, tonic foot, hemiballism) abnormal movements were still present during sleep, but decreased in frequency and amplitude in all stages. The second group presented three syndromes (nocturnal paroxysmal dystonia, nocturnal myoclonus, restless legs syndrome), in which light non-rapid-eye-movement sleep induced a strong activation of abnormal movements, whereas rapid-eye-movement sleep suppressed them.

Diurnal variability in cranial dystonia

Eleven patients with cranial dystonia were investigated for diurnal variations in disability by means of video recordings. Disability increased significantly from morning to evening. The increase was not related to changes in vigilance levels assessed by dynamic electroencephalogram. Cranial movement disorders display diurnal fluctuations that are probably related to endogenous circadian rhythms.

Facial dystonia: clinical features, prognosis and pharmacology in 31 patients

The natural history and response to different treatments were assessed in 31 consecutive patients with blepharospasm (BS) and/or oromandibular dystonia (OMD). The mean age at onset was 52.4 years and there was a female preponderance of 2.5 to 1. Ocular symptoms preceded the onset of blepharospasm in more than 50% of the affected patients, whereas psychiatric and dental problems prior to the onset of focal dystonia were found in 10% and 13% of the cases respectively. Dystonia elsewhere, mainly in the craniocervical area, was found in 23% of patients and appeared to follow a somatotopic progression. The first 2-3 years of history were crucial for the spread of dystonia to other face and body parts. When OMD was the first symptom, a lower tendency of dystonia to progress elsewhere was observed. A putative cause was found in 14% of patients who showed clinical and radiographic evidence of basal ganglia or rostral brainstem-diencephalon lesions. The response to different drugs was inconsistent although transient improvement was induced by haloperidol in 6 patients, by L-Dopa plus deprenyl in 3 patients, by trihexyphenidyl in 2 patients and by clonazepam in 2 patients. One, apparently spontaneous, remission was observed. Botulinum A toxin was injected in the orbicularis oculi of 8 patients affected by BS: moderate to marked improvement lasting 5 to 30 weeks (mean 14.5 weeks) was achieved in all cases; transient ptosis, lasting 1 to 3 weeks, occurred in 3 cases.

Effects of anticholinergic agents on the excitability of the blink reflex in Meige syndrome

Blink reflex recovery cycle, before and after acute administration of orphenadrine chlorhydrate, was tested in Meige syndrome. Data here reported show, after the drug, a decrease of the unconditioned polysynaptic responses, without a significant modification of the blink reflex recovery curves. This fact rules out a specific effect of anticholinergic drugs on the pathological reduction of the inhibitory process, at an interneuronal level of these polysynaptic pathways, in Meige syndrome.

Meige syndrome: an unusual cause of involuntary facial movements

Dental and allied health professionals are on occasion confronted with patients who exhibit abnormal facial movements. These patients may be seeking a diagnosis or may relate a specific problem resulting from the uncontrolled and involuntary orofacial movements. A complete description of the various conditions associated with abnormal facial movements is beyond the scope of this article. Instead, these authors present a case with dental symptoms that were masking a more serious underlying progressive neurologic disorder. Appropriate referral to the neurology service is essential so that treatment of the underlying cause may precede, rather than follow, empiric management of these patients' symptoms.

Meige syndrome: neuropathology of a case

Primary Meige syndrome is a form of cranial dystonia of unknown cause. Only three postmortem studies have been reported, and the results of these studies have not been consistent. We have examined the brain of a 72-year-old man with typical primary Meige syndrome and found mild to moderate cell loss in the zona compacta of the substantia nigra, locus ceruleus, midbrain tectum, and dentate nucleus of the cerebellum. Also frequent Lewy bodies were present in pigmented nuclei of the brainstem. No abnormalities were detected elsewhere. These pathological findings support the notion that brainstem pathology is important in the pathophysiology of cranial dystonia.

Coexistent Meige's syndrome and myasthenia gravis. A relationship between blinking and extraocular muscle fatigue?

We studied five patients with a combination of Meige's syndrome (blepharospasm-oromandibular dystonia) and myasthenia gravis. The coexistence of two disorders impairing eyelid opening led to diagnostic confusion and delayed appropriate therapy. Detailed oculographic monitoring of one patient indicated that eye position drifting due to myasthenic oculomotor fatigue was corrected by eye blinks, and that blinks tended to occur with slower saccades. Our observations suggest that fatigue of extraocular muscles may lead to synkinetic blinking and perhaps eventually to autonomous blepharospasm.

Pathophysiology of blepharospasm and oromandibular dystonia

The pathophysiology of reflexes mediated by the fifth and seventh cranial nerves has been studied in 16 patients with blepharospasm and oromandibular dystonia compared with normal age-matched subjects. The EMG activity of the dystonic spasms in the periocular and jaw muscles was similar to that described in other muscles in patients with generalized torsion dystonia. The latency of the R1 and R2 components of the blink reflex and of the corneal reflex was normal. However, the amplitude and the duration of the R1 and R2 and the duration of the corneal reflex were increased. In some patients the R1 component was also present on the side contralateral to the stimulus, while in normal subjects it was present only on the ipsilateral side. The excitability cycle of recovery of the R2 component of the blink reflex after a prior conditioning shock was enhanced in the patients. There were no EEG potentials preceding blepharospasms in the patients, although a Bereitschaftspotential was seen beginning some 500 ms prior to voluntary blinks in the same individuals. Exteroceptive suppression in the contracting masseter and orbicularis oculi muscles was absent in 40 to 50 per cent of the patients. The jaw jerk was present in all the patients with normal latency. These results indicate that the neuronal arcs of the facial reflexes in blepharospasm and oromandibular dystonia are normal. However, there is an abnormal excitatory drive, perhaps from the basal ganglia, to the facial motoneurons and the interneurons which mediate the facial reflexes in the brainstem.

"Trick" movements in facial dystonia

Two patients with facial dystonia (blepharospasm and/or oromandibular dystonia) presented with an unusual "trick" movement. Both patients were able to inhibit blepharospasm and oromandibular dystonia by vocalizations including singing, reading, and speaking spontaneously. The significance of "trick" movements in facial dystonia is discussed.