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Purpose: Laryngeal dystonia is a chronic neurologic disorder characterized by intention-induced spasms of the vocal folds driven by aberrant central motor processing. The use of in-office transcervical botulinum toxin injection for the treatment of laryngeal disorders, such as laryngeal dystonia, has been deemed safe and efficacious. There is, however, no available data outlining the hemodynamic changes experienced by patients undergoing this frequently performed procedure., Methods: One hundred and one patients diagnosed with laryngeal dystonia were enrolled in this prospective study. These patients underwent transcervical laryngeal botulinum toxin injection to address their dysphonia. Vital signs where acquired prior to, and at the time of injection. Alterations in these parameters were then evaluated for statistical significance., Results: Statistically significant increases in mean heart rate (5.8 ± 10.8 bpm, P < 0.0001), systolic blood pressure and diastolic blood pressure (7.0 ± 9.5 mm Hg, P < 0.0001; 8.7 ± 14.7 mm Hg, P < 0.0001) were discovered. No statistically significant difference in oxygen saturation was noted and no patients in the study faced major adverse outcomes., Conclusions: Though these findings may not have related to clinically significant complication, our study demonstrates the importance of understanding potential stressors in a procedure routinely performed by laryngologists. This may result in more careful patient selection, alterations in procedure, and improved safety by acting in a timely fashion if alarming changes in hemodynamic parameters are noted., (Copyright © 2021 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: This article discusses the most recent findings regarding the diagnosis, classification, and management of genetic and idiopathic dystonia., Recent Findings: A new approach to classifying dystonia has been created with the aim to increase the recognition and diagnosis of dystonia. Molecular biology and genetic studies have identified several genes and biological pathways involved in dystonia., Summary: Dystonia is a common movement disorder involving abnormal, often twisting, postures and is a challenging condition to diagnose. The pathophysiology of dystonia involves abnormalities in brain motor networks in the context of genetic factors. Dystonia has genetic, idiopathic, and acquired forms, with a wide phenotypic spectrum, and is a common feature in complex neurologic disorders. Dystonia can be isolated or combined with another movement disorder and may be focal, segmental, multifocal, or generalized in distribution, with some forms only occurring during the performance of specific tasks (task-specific dystonia). Dystonia is classified by clinical characteristics and presumed etiology. The management of dystonia involves accurate diagnosis, followed by treatment with botulinum toxin injections, oral medications, and surgical therapies (mainly deep brain stimulation), as well as pathogenesis-directed treatments, including the prospect of disease-modifying or gene therapies., (Copyright © 2022 American Academy of Neurology.)

Background: Writer's cramp (WC) is a form of focal hand dystonia, for which focal botulinum neurotoxin (BoNT) injections are the current best therapy. Past studies have shown that some types of rehabilitative therapy can be useful. We hypothesized that BoNT together with a specific type of occupational therapy would be better than BoNT alone for treating WC patients comparing the effects with a patient-rated subjective scale., Methods: Twelve WC patients were randomized to two groups. Six received only BoNT therapy and 6 received BoNT & occupational therapy. The occupational therapy involved specific exercises of finger movements in the direction opposite to the dystonic movements during writing. BoNT was injected by movement disorders neurologists in the affected muscles under electromyography-guidance. The primary outcome was the patient-rated subjective scale at 20 weeks. Secondary exploratory outcomes included the writer's cramp rating scale (WCRS), writer's cramp impairment scale (WCIS), the writer's cramp disability scale (WCDS), handgrip strength and kinetic parameters., Results: The patient-rated subjective scale scores at 20 weeks were not significantly different between the two groups. Significant objective improvement was noted in the BoNT & occupational therapy group, as noted by the decrease (28%) in WCIS scores., Conclusions: Improvement of the primary outcome measure, the patient-rated subjective scale, was not achieved. However, significant improvement was found in the BoNT & occupational therapy group in a secondary measure of impairment. Our hypothesis-driven study results are likely limited by small sample size, and further large-scale studies of occupational therapy methods to improve the efficacy of BoNT seems worthwhile., (Published by Elsevier Ltd.)

Background: Chorea acanthocytosis is an extremely rare neurodegenerative condition characterized by neuropsychiatric disturbances, movement disorders, neuropathy, seizures, and acanthocytosis. In this case report, the authors will present the management of the oromandibular movement disorders associated with this disease., Case Description: This case report describes the focal management of the severe orofacial manifestations associated with this condition. The therapeutic approach adopted to reduce the severe oromandibular movements, dysphagia, and the numerous oral ulcers was selective electromyography (EMG)-guided botulinum toxin application to the inferior head of the lateral pterygoid muscles and masseters. This would be applied to control severe and sudden oromandibular dystonia., Results: Through this procedure, the authors were able to reduce these severe oral manifestations, which had a major impact on the patient's quality of life, and temporarily improve vital functions, such as mastication, deglutition, and speech articulation., Conclusions: Electromyography-guided botulinum toxin application may be a useful tool in the multimodal management of this condition.

Knowledge on dystonia has greatly improved recently, because of a renewed effort in understanding its cause, pathophysiology, and clinical characterization. Different drug classes traditionally have been used for the symptomatic treatment of dystonia, more recently surpassed by the introduction of botulinum neurotoxins and deep brain stimulation. No curative or disease-modifying treatments are available. Recent knowledge regarding the pathophysiology of inherited dystonias is highlighting new potential treatment strategies. We review therapeutic advances in dystonia that have been published over the last 3 years, particularly regarding oral medications, local injections of botulinum neurotoxins, deep brain stimulation, and transcranial or epidural brain stimulations. We discuss evidence of efficacy, highlight recent advances, and focus on key areas under development., (© 2015 International Parkinson and Movement Disorder Society.)

Objectives: to provide a revised version of earlier guidelines published in 2006., Background: primary dystonias are chronic and often disabling conditions with a widespread spectrum mainly in young people., Diagnosis: primary dystonias are classified as pure dystonia, dystonia plus or paroxysmal dystonia syndromes. Assessment should be performed using a validated rating scale for dystonia. Genetic testing may be performed after establishing the clinical diagnosis. DYT1 testing is recommended for patients with primary dystonia with limb onset before age 30, and in those with an affected relative with early-onset dystonia. DYT6 testing is recommended in early-onset or familial cases with cranio-cervical dystonia or after exclusion of DYT1. Individuals with early-onset myoclonus should be tested for mutations in the DYT11 gene. If direct sequencing of the DYT11 gene is negative, additional gene dosage is required to improve the proportion of mutations detected. A levodopa trial is warranted in every patient with early-onset primary dystonia without an alternative diagnosis. In patients with idiopathic dystonia, neurophysiological tests can help with describing the pathophysiological mechanisms underlying the disorder., Treatment: botulinum toxin (BoNT) type A is the first-line treatment for primary cranial (excluding oromandibular) or cervical dystonia; it is also effective on writing dystonia. BoNT/B is not inferior to BoNT/A in cervical dystonia. Pallidal deep brain stimulation (DBS) is considered a good option, particularly for primary generalized or cervical dystonia, after medication or BoNT have failed. DBS is less effective in secondary dystonia. This treatment requires a specialized expertise and a multidisciplinary team.

Importance of the Field: Dystonia is a neurological syndrome characterized by involuntary twisting movements and unnatural postures. It has many different manifestations and causes, and many different treatment options are available. These options include physical and occupational therapy, oral medications, intramuscular injection of botulinum toxins, and neurosurgical interventions., Areas Covered in This Review: In this review, we first summarize the treatment options available, then we provide suggestions from our own experience for how these can be applied in different types of dystonia. In preparing this review article, an extensive literature search was undertaken using PubMed. Only selected references from 1970 to 2008 are cited., What the Reader Will Gain: This review is intended to provide the clinician with a practical guide to the treatment of dystonia., Take Home Message: Treatment of dystonia begins with proper diagnosis and classification, followed by an appropriate search for underlying etiology, and an assessment of the functional impairment associated with the dystonia. The therapeutic approach, which is usually limited to symptomatic therapy, must then be tailored to the individual needs of the patient.

Botulinum toxin has several important properties that make it an ideal chemical denervator. These include its high degree of specificity for the neuromuscular junction, its ability to induce temporary and reversible denervation, and its limited degree of side effects and complications. Botulinum toxin is being used safely in a wide variety of clinical settings by many different specialists. In otolaryngologic practice, it is being administered for the treatment of at least a dozen conditions, including various dysphonias, dystonias, and spasms as well as torticollis, facial nerve paralysis, and hyperkinetic facial lines. Studies have shown that botulinum toxin injections have a high rate of success in temporarily relieving symptoms.

We report a 67-year-old hypertensive right-handed woman who developed severe pain and dystonia in her left upper and lower extremity after a thalamic infarction. She was well until 9 months prior to the present admission to our hospital, when she had an acute onset of left hemiparesis which turned out to have been caused by a thalamic infarct. Her hemiparesis showed nearly complete recovery during the next four months. She noted an onset of severe spontaneous pain and difficulty in using her left hand four months prior to the present admission. Neurologic examination on admission revealed an alert and well oriented Japanese woman. Cranial nerves were intact. Although she did not have weakness, her left hand showed thalamic posture, and upon standing, she showed a dystonic posture in which her left forearm took pronation and flexion at the elbow joint and her left lower extremity took extension in the knee joint and planter flexion in the ankle joint. Her dystonic posture increased during walking and disappeared in the supine position. She complained of severe spontaneous pain and tingling sensation in her left extremities. Position sense was diminished in her left leg. However other sensations were intact. She had slight ataxia on the left side. Deep tendon reflexes were symmetric, but the planter response was extensor on the left side. MRI revealed a small lacunar infarct involving the right posterolateral thalamic region. EMG with surface electrodes revealed non-reciprocal tonic discharges in the left biceps brachii and forearm flexor and extensor muscles. She responded poorly to various medications. Only trihexyphenidyl showed partial alleviation of her pain and dystonic posture. We thought her pain might be caused by dystonic contraction of the skeletal muscles, at least in part. We injected 25 IU of botulinus toxin as a total dose into her biceps brachii, triceps brachii, and wrist flexor muscles. A few days after the injection, her dystonic posture began to show marked improvement; as her dystonia improved, her pain also showed marked improvement. This patient appeared to represent a case of post-hemiplegic dystonia. Her pain was initially thought to be the thalamic pain. However, as her pain disappeared with improvement of her dystonia, her pain is most likely to have been caused by the dystonic muscle contraction. Botulinus toxin treatment appears to be useful for post-hemiplegic painful dystonia.

Over a 5-year period, 40 patients, 11 with musician's and 29 with writer's cramp, were treated with botulinum toxin A using a precise injection technique in which the hollow-bore electromyography (EMG) needle was positioned by both standard EMG and by muscle twitch evoked by stimulating current passed through it. Moderate to complete improvement in dystonia occurred in 28 patients (70%) after the first injection and in 34 patients (85%) after the second injection with better outcome in nonmusicians than in musicians. Of note, weakness of uninjected muscles, immediately adjacent to those injected, was found in 25/40 patients (63%). The most common patterns of toxin spread were from flexor digitorum sublimis to profundus, extensor carpi radialis to extensor digitorum communis, and extensor indicis proprius to extensor pollicis brevis. Spread to, and weakness of, adjacent uninjected muscles was a major factor contributing to suboptimal outcome in 6/39 (15%) such patients.

Dystonia is a neurologic disease characterized by involuntary repetitive muscular contractions which frequently causes torsion, spasmodic movements or abnormal postures. Pharmacologic and surgical treatment had been unsatisfactory in the majority of the cases. Intramuscular botulinic toxin application in focal dystonia disorders, achieve relief in approximately 90% of the cases by quimiodenervation. We included 35 patients with focal dystonia treated between November 1994 through June 1996: 14 facial hemispasm, nine blepharospasm, five cervical dystonia, two writer's cramps, one oromandibular dystonia and four patients with mixed focal dystonia. Improvement between 50-90% was observed in 32/34 (94%) of the patients; one case (2.8%) with therapeutic failure and one case (2.8%) never returned to quantify the response. Actually, botulinic toxin is the first choice treatment of focal dystonia and other diseases related to involuntary muscle spasm.

This paper reports the results of botulinum toxin A treatment in 13 children with cerebral palsy. All patients except one exhibited dynamic deformities in one hand or foot and changes in muscle tone of corticospinal and extrapyramidal origin. The primary purpose of the treatment was to improve the impaired skilled movements which resulted from dystonic limb posture and were the most disabling symptoms in the group studied. The study showed that the botulinum toxin treatment produced a significant improvement in functional disability in terms of amelioration of skilled hand movements and foot posture (p < 0.01). The injections took effect a few days after dystonic muscle infiltration, and the mean duration of improvement was 3.1 months (2.0-4.0 months). Side effects were negligible and transient; transitory muscle weakness was the most frequent. Botulinum toxin A provides a safe and effective adjuvant treatment of dystonic skilled movements and gait disorders in children with cerebral palsy.

The effects of botulinum toxin type A were studied in 33 patients with dystonia (12 blepharospasms, 10 hemifacial spasms and 11 spasmodic torticollis). A rate scale was used to evaluate the severity of the dystonic movements, before and two weeks after each injection. Among blepharospasm patients, eight were female and four were male; the mean age was 57.7 years; the mean time of the disease duration was four years. Three had familial history for similar disease; nine were essential and three had used neuroleptic drugs (tardive dystonia). The mean dose used was 51.3 U, with a mean time of beneficial effects of 2.8 months. For 22 injections and reinjections, 14 (63.7%) showed an excellent result, five (22.7%) good and three (13.6%) null. In the hemifacial spasm group, eight were female and two male; the mean age was 52.6 years; the mean time of the disease duration was 7.4 years; eight were essential and two post-paralytic. The mean dose used was 32 U. From the total of 15 injections and reinjections, all of them (100%) had an excellent result, with a mean time of beneficial effect of 3.4 months. Among the cervical dystonic patients, eight were male and three female; the mean age was 44.2 years; the mean time of the disease duration was 12.2 years; six had essential dystonia, three had used neuroleptic drugs and two had familial history for similar disease. The mean dose used was 238.6 U, with the mean duration of effect of 3.5 months. From the total of 20 injections and reinjections, 18 (90%) had good result, one (5%) mild and one (5%) null.(ABSTRACT TRUNCATED AT 250 WORDS)

We report on a six-month-old child with severe intermittent dystonic posture of both legs associated to a thoraco-lumbar myelomeningocele. The patient presented with a combination of progressive hypertonic knee extension and hip flexion. While the mobility of the right leg improved sufficiently after physiotherapy and splinting, satisfactory improvement of the left leg could be achieved only after local injections of botulinum A toxin, allowing for adequate functional motor development.

Objective: To determine the effectiveness of botulinum toxin injections for the management of hyperfunctional facial lines in patients with dystonia., Design: Twenty-six patients were included in the study: 24 patients had dystonic movement of the face as either a primary or secondary component, and two patients were treated for purely hyperfunctional lines. Botulinum toxin type A was injected via a monopolar hollow-bore Teflon-coated electromyography needle into the facial muscles associated with the hyperfunctional lines. Doses were divided into 1.25- to 10-U aliquots. Qualitative assessments by the patient and physician were made before injection and 2 to 3 weeks after injection., Patients: Twenty-six patients (two male and 24 female) with hyperfunctional lines were included. The ages were from 32 to 84 years with an average age of 59 years. Twenty had dystonia, four had hemifacial spasm, and two had pure hyperfunction without neuromuscular disease., Results: All of the patients had an effect of toxin within the first 24 to 72 hours. All of the patients experienced benefit from the toxin injections with partial or total resolution of painful contractions or unsightly hyperfunctional lines and spasms. The effects of the injection lasted 3 to 6 months. No systemic side effects were noted. Adverse effects included mild, temporary eyelid or lip weakness., Conclusion: Based on this initial pilot study, botulinum toxin may be an important new option for the treatment of patients with hyperfunctional facial lines.

Forty-six patients with hand dystonia, considered disabling despite optimal pharmacologic therapy, were injected in the forearm musculature with botulinum A toxin. Thirty of these patients were followed long enough to provide adequate data for analysis of 86 treatment sessions. There was a 63% female preponderance, with an average age at initial evaluation of 46 years and symptom duration of 7.9 years. Average baseline severity of dystonia was rated as 3.5 on a severity rating scale (0-4 rating; 4 = maximum severity). The average peak effect response for all injections (79 into wrist flexors and 29 into wrist extensors) was 2.2 for dystonia and 3.0 for pain (0-4 rating; 0 = no response, 4 = maximum benefit). The latency from injection to onset of effect averaged 5.6 days. Total response duration averaged 9.3 weeks and maximum improvement was 7.5 weeks. Only local complications occurred and consisted primarily of hand weakness (25 patients, 44 sessions). The results show that botulinum toxin injections effectively control hand dystonia in instances where other forms of therapy have failed.

We performed a longitudinal analysis of the effects of repeat botulinum toxin (BTX) injections in 42 patients with blepharospasm (BL) and 115 patients with cervical dystonia (CD) who received BTX injections between 1984 and 1992 in at least five separate treatment sessions. Although the BL patients were significantly older (59.8 years) than the CD patients (50.6 years; p < 0.001), there were no other demographic differences between the two groups. While the total dose per treatment session and the peak effect rating remained the same, the duration of benefit increased and the number of complications decreased during the course of treatment. We concluded that chronic treatment with BTX in patients with BL and CD is not associated with any decline in benefit, and that efficacy may improve slightly with repeat treatments.

Laryngeal dystonia is a condition characterized by involuntary spasms of the laryngeal muscles. In most patients this involves the adductor laryngeal muscles (adductor laryngeal dystonia). Treatment with a variety of therapies, including speech therapy and pharmacotherapy, have led to minimal improvement. Injections of botulinum-toxin (Botox) bilaterally into the vocalis muscles is a new treatment for adductor laryngeal dystonia. Since May 1991 we have treated 23 patients with adductor laryngeal dystonia with botulinum-toxin. In 74% of the patients the voice improved within 24-72 hours, and effect lasted for 2-14 months (average four months). Most of the patients got a breathy voice and a mild sensation of dysphagia during the first week after the injection.

The botulinum toxin is a highly potent neurotoxin, used since several years in the treatment of the focal musculary dystonias. We define the laryngeal dystonia as a clinical entity, which is represented by a spasmodic dysphonia or an inspiratory dyspnea without dysphonia, related to a specific dystonia of the thyroarytenoid muscles. The laryngeal functional exploration (i.e. fibroscopy, videostroboscopy, acoustic analysis, computerized voice analysis), the neurological and electrophysiological assessment allow to make diagnosis and evaluation of the therapeutical results of this rare laryngeal neurologic disease which was relatively misunderstood until now. There are several clinical types of spasmodic dysphonia: adductor form (with a jerky voice, pitch beaks, vocal arrests and pneumophonatory incoordination); abductor form (with a breathy voice of very low intensity) and mixed types which can be difficult to identify. Since 1989, we have treated 55 laryngeal dystonias with local intra-muscular botulinum toxin injection: 48 spasmodic dysphonia and 7 inspiratory dyspnea without dysphonia, with hyperactivity of the thyroaryténoïd muscles. We present our therapeutical protocol and results which are good in 87% of cases.

Focal dystonia and hemifacial spasms are difficult to treat. Medication and surgery may suppress the dystonic movements but the improvement is not satisfactory. The present article reviews use of Botulinum toxin in cases of focal dystonia. Injections of very small doses of Botulinum A toxin into the affected muscles is a new and efficient therapy for patients with focal dystonia. The toxin acts by inhibiting the release of acetylcholine from the nerve terminal, leading to a localized paralysis of the treated muscle. The effect is temporary and gradually diminishes, but the treatment can be repeated. The use of Botulinum toxin must be applied on the basis of a thorough knowledge of its effect and possible side effects.

Except in Wilson's disease, few secondary dystonias are susceptible to benefit from an aetiological treatment. The somatic distribution of dystonia often determines the therapeutic strategy. Thus, stereotactic surgery may be the treatment of choice for hemidystonia while anticholinergic medication may alleviate generalized dystonia, particularly in childhood. Finally, local infiltrations of botulinum toxin are particularly useful for various forms of local and segmental dystonia. Certain subsyndromes as myoclonic dystonia, levodopa sensitive dystonia and paroxysmal choreoathetosis may benefit from relatively specific treatment strategies.

Twenty-five writer's cramp patients have been attending the Movement Disorder Clinic at the Division of Neurology, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok during three years period (between January 1988 - January 1991). There were 17 male subjects and the male to female sex ratio was 2.125:1. The mean age of the patient was 36.80 (SD 10.21) years with the range of 18-60 years. The mean duration of illness of all patients was 5.88 (SD 7.14) years with the range of 1 to 30 years. Eighteen patients (72.0%) were classified as simple writer's cramp and seven patients (28.0%) were dystonic writer's cramp. The mean age of the patients of both groups was not different while the duration of illness in the dystonic group was statistically significantly longer than the simple group, i.e. 12.0 (SD 12.1) versus 3.9 (SD 3.1) years. Fourteen patients (56%) had associated pain during writing and 6 patients (24%) had hand tremor. All patients were right handed and had a history of various pharmacological treatments without any consistent benefit. They included muscle relaxants, tranquillisers, antiepileptic drugs, and betablockers. Fourteen patients from 17 available history records (82.4%) had been spending at least 4-10 hours writing each day. Twenty-one patients (84%) had botulinum toxin injections, 40-80 international mouse units were given in 2-4 divided doses over the overactive forearm muscles observed during writing without the electromyographic glidance. There was no loss to the follow-up. Fourteen of the 21 subjects (66.7%) showed definite improvement in hand writing, 4 patients (19.0%) improved minimally and 3 patients (14.3%) revealed no improvement. Arm pain in all 12 patients associated during writing was abolished after the injections. There were complications in 7 patients (33.3%) presented as transient finger drop (5 patients, 23.8%) and easily fatigued arm (2 patients, 9.5%). These preliminary results confirm that botulinum toxin injections is a successful treatment for many patients with writer's cramp without performing complex electromyographic recordings while the patients are writing. The constraints of this treatment are its high cost (i.e. 1 vial of 100 units costs 300 US dollars) and its benefit lasts for only 4-6 months.

Laryngeal dystonia is a syndrome characterized by action-induced, involuntary spasms of the laryngeal muscles. Most patients have involvement of the adductor laryngeal muscles producing uncontrolled spasms during phonation, and a "strain-strangle" speech pattern commonly termed "spastic dysphonia." Other patients have involvement of the abductor muscles producing "whispering dysphonia." Rare patients have paradoxical vocal cord motion during respiration with adductor spasms on inspiration. Over the past 5 years we have used botulinum toxin (BOTOX) to treat more than 200 patients with laryngeal dystonia. This group includes patients with adductor involvement (phonatory dystonia, recurrent laryngeal nerve section failure, respiratory dystonia) and those with abductor involvement (whispering dystonia). Patients received benefit within 24 to 72 hours, with sustained improvement for 2 to 9 months with an average of 4 months. Patients improved to an average of 90% of normal function. Clinically significant adverse effects included extended breathy dysphonia and mild choking on fluids. BOTOX has become our treatment of choice for dystonic conditions of the larynx.

Botulinum toxin therapy has emerged as a treatment modality for a variety of spastic- or contracture-related muscle diseases. Its safety has been proven for long-term use in the treatment of benign essential blepharospasm, hemifacial spasm, and certain types of strabismus. Recent approval from the Federal Drug Administration should make botulinum toxin available for use in a greater number of patients.

Except in Wilson's disease, few secondary dystonias are susceptible te benefit from an etiological treatment. The somatic distribution of dystonia often determines the therapeutic strategy. Thus, stereotactic surgery may be the treatment of choice for hemidystonia while anticholinergic medication may alleviate generalized dystonia, particularly in childhood. Finally, local infiltrations of botulinum toxin are particularly useful for various forms of local and segmental dystonia. Certain subsyndromes as myoclonic dystonia, levodopa sensitive dystonia and paroxysmal choreoathetosis may benefit from relatively specific treatment strategies.

We have studied the effect of botulinum toxin in patients with focal dystonia, not responding sufficiently to medical therapy. Injection of 5-100 units to the muscles, selected by EMG and clinical examination, invariably resulted in reduction of muscle tonus, although to a different degree depending on the dosage. The outcome after the first trial was best when dealing with small muscles in patients with blephalospasm or Meige's syndrome. In contrast, several attempts were required for the treatment of a large muscle as in torticollis, or multiple muscles as in writers' cramps. The effect lasted 1-3 months. With precise selection of the affected muscles and careful regulation of necessary dosages, this type of therapy may contribute to the treatment of focal dystonia.

In the past five years, 477 patients with various focal dystonias and hemifacial spasm received 3,806 injections of botulinum A toxin for relief of involuntary spasms. A definite improvement with a global rating greater than or equal to 2 on a 0-4 scale, was obtained in all 13 patients with spasmodic dysphonia, 94% of 70 patients with blepharospasm, 92% of 13 patients with hemifacial spasm, 90% of 195 patients with cervical dystonia, 77% of 22 patients with hand dystonia, 73% of 45 patients with oromandibular dystonia, and in 90% of 21 patients with other focal dystonia who had adequate follow up. While the average duration of maximum improvement lasted about 11 weeks after an injection (range seven weeks in patients with hand dystonia to 15 weeks in patients with hemifacial spasm), some patients benefited for over a year. Only 16% of the 941 treatment visits with follow up were not successful. Except for transient focal weakness, there were very few complications or systemic effects attributed to the injections. This study supports the conclusion that botulinum toxin injections are a safe and effective therapy for patients with focal dystonia and hemifacial spasm.

Injections of botulinum toxin into the main cervical muscles responsible for abnormal posture and movements in spasmodic torticollis reduced pain and attenuated dystonia for a period of 2 months on average. After several sessions 9 out of 36 patients (25 p. 100) felt they had improved by at least 50 percent, 16 (44 p.100) by 50 to 75 percent, and 6 (17 p. 100) by more than 75 percent. There were six failures.

Craniocervical dystonias are a major therapeutic problem, since in the majority of cases various drug regimens as well as surgical interventions either fail or are accompanied by serious side effects. Botulinum toxin, well known as a biological toxin which blocks the cholinergic neuromuscular synapse, proved to be a new and successful concept in the treatment of these disorders. In the present study, mechanisms of action, clinical indications and practical use of botulinum toxin are described.