Isolated high-frequency jaw tremor relieved by botulinum toxin injections.

Jaw tremor can be seen as a component of various neurological disorders such as essential tremor, Parkinson's disease, dystonia, branchial myoclonus, hereditary geniospasm, task-specific tremor, and Whipple's disease, as well as in normal situations such as shivering, and subclinical physiological jaw tremor. In most of these conditions, the jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, and its frequency is lower than 12 Hz. Schrag and colleagues reported a patient with a high-frequency idiopathic jaw tremor, and they speculated it could be related to orthostatic tremor affecting the masseter muscles. We encountered a similar patient with intermittent rapid focal jaw tremor that was successfully treated with botulinum toxin injections to the masseters.     

Botulinum toxin A may be efficacious as treatment for jaw tremor in Parkinson's disease.

Jaw tremor in Parkinson's disease (PD) may not respond well to conventional treatment. It causes embarrassment and social handicap. We piloted the use of botulinum toxin (BTX) injections in three patients with PD jaw tremor. BTX A (Dysport; mean, 53 U; range, 30-100 U) was given into each masseter muscle. Outcome was assessed by subjective and clinical improvement and by video recording before and 4 to 9 weeks after injections. There was an excellent response in all without side effects. BTX injections into the masseter may effectively improve jaw tremor and be useful in PD and other conditions.     

Primary writing tremor: report of a case successfully treated with botulinum toxin A injections and discussion of underlying mechanism.

Primary writing tremor (PWT) is a rare motor disorder of unknown etiology, where tremor is elicited primarily or exclusively with writing. We describe a patient with PWT, present a video before and after successful treatment with botulinum toxin type A injections, and discuss a possible underlying dystonic mechanism.     

Botulinum toxin is effective and safe for palatal tremor

Palatal tremor (formerly palatal myoclonus) is an extremely rare, but potentially treatable cause, of objective tinnitus. The tinnitus is thought to be secondary to rhythmic involuntary movements of the soft palate. Its aetiology is variable and it remains difficult to treat. Many different medical and surgical remedies have been tried but none have demonstrated reproducible success. Botulinum toxin has been used in sporadic cases and seems to produce good results. Ten patients with palatal tremor have presented to this department over the last three years. After discussion with the patients with regard to the management of this condition and possible complications, five opted for botulinum toxin therapy and five declined further intervention. Clinical diagnosis was made on the confirmation of soft palate movements synchronous with an audible clicking noise. Five patients underwent botulinum toxin injection into the insertion of the levator and tensor veli palatini muscles. Of the five that were treated with toxin, four showed complete resolution of symptoms after a course of treatment. Only one patient reported transient side effects. This would suggest that botulinum toxin is a safe and effective first line treatment for palatal tremor.     

Reduced jaw opening from paradoxical activity of mandibular elevator muscles treated with botulinum toxin

The aim of the study was the effect of injections with botulinum toxin A (BTX-A) on reduced jaw opening, caused by paradoxical, antagonistic activity of jaw elevator muscles after brain stem lesions. The study included a male (51 years) and a female (69 years) patient. Subjective assessment, clinical recordings, muscle blocks and electromyography (EMG) were used to diagnose paradoxical activity, and to plan, guide and evaluate the treatment. The paradoxical innervation pattern was unilateral in the male and bilateral in the female. The paradoxical activity during jaw opening amounted to 24-109% of the level during maximum biting, and bursts of paradoxical activity were also present during chewing. EMG-guided blocks and later BTX-A injections of the affected muscles increased the opening by 9-23 mm from pre-treatment values of 15-18 mm, and normalized chewing. The study proved BTX-A to be an effective treatment for reduced jaw opening caused by paradoxical activity. Treatment was optimized by EMG evaluation of the current activity of the jaw elevator muscles, permitting individual treatment plans with longer intervals between BTX-A injections and lower doses than with conventional treatment for oromandibular dystonia. Thus the treatment only had to be repeated one to two times per year to maintain acceptable jaw mobility.     

The entity of jaw tremor and dystonia.

BACKGROUND: Jaw tremor in the context of dystonia is not well recognized. METHOD: We describe 7 women (average onset age 70) with jaw tremor and dystonia. RESULTS: All had features of primary dystonia. Applying MDS criteria for tremor, 3 had "dystonic jaw tremor"; 4 had "jaw tremor associated with dystonia". Drugs were unhelpful. Botulinum toxin injections proved effective in 1 case. CONCLUSION: We propose the entity of "jaw tremor and dystonia". It is distinct from jaw tremor due to other causes including Parkinson's disease and essential tremor.     

Efficacy and complication of botulinum toxin injection in palatal myoclonus: experience from a patient.

We report the outcome of botulinum toxin injection for essential palatal myoclonus, given on two occasions over a period of one year, in an eight-year-old boy, the youngest patient treated with botulinum toxin to date. Though there was significant relief of ear clicks each time after the injection, he developed severe palatal palsy following the second injection, which persisted for a month. We suggest that appropriate caution needs to be exercised when repeating botulinum toxin injections for palatal myoclonus in children.     

Influence of botulinum toxin on rabbit jaw muscle activity and anatomy

Introduction: Muscles can adapt their fiber properties to accommodate to new conditions. We investigated the extent to which a decrease in muscle activation can cause an adaptation of fiber properties in synergistic and antagonistic jaw muscles. Methods: Three months after the injection of botulinum toxin type A in one masseter (anterior or posterior) muscle changes in fiber type composition and fiber cross‐sectional areas in jaw muscles were studied at the microscopic level. Results: The injected masseter showed a steep increase in myosin type IIX fibers, whereas fast fibers decreased by about 50% in size. Depending on the injection site, both synergistic and antagonistic muscles showed a significant increase in the size of their fast IIA fibers, sometimes combined with an increased number of IIX fibers. Conclusion: Silencing the activity in the masseter not only causes changes in the fibers of the injected muscle but also leads to changes in other jaw muscles. Muscle Nerve, 2012     

The use of botulinum toxin type-B in the treatment of patients who have become unresponsive to botulinum toxin type-A -- initial experiences.

The increasing use of botulinum toxin type-A, especially for focal dystonia and spasticity has highlighted the issue of secondary non-responsiveness. Within the last few years botulinum toxin type-B (Myobloc/Neurobloc) has become commercially available as an alternative to type-A. This paper discusses our initial experience of botulinum toxin type-B in a total of 63 individuals who attended our botulinum clinic. Thirty-six patients had cervical dystonia and a secondary non-response to type-A toxin. Thirteen of these patients (36%) had a reasonable clinical response to Neurobloc and continue to have injections. The other 23 patients either had no response, or a poor response, or had unacceptable side effects and ceased treatment. A small number of people with blepharospasm, hemifacial spasm and foot dystonia also had a disappointing response to injection. Twenty patients with spasticity were also type-A resistant. Seven of these show some continuing response to type-B, without unacceptable side effects. These findings demonstrate that botulinum toxin type-B has a place in the management of patients who have become non-responsive to type-A, but overall the responses to type-B toxin were disappointing.     

Secondary nonresponsiveness to botulinum toxin type A in patients with oromandibular dystonia.

Intramuscular injection of botulinum toxin type A is the treatment of choice for most cases of oromandibular dystonia. We report on five patients with oromandibular dystonia that developed secondary nonresponsiveness to botulinum toxin type A following multiple injections over a 6-year period.     

Botulinum toxin type B in antibody-induced botulinum toxin type A therapy failure

Recently, it was reported that botulinum toxin type B complex (BoNT/B) (NeuroBloc®, Elan Pharmaceuticals) can produce an adequate therapeutic response in patients with antibody induced failure of botulinum toxin type A complex (BoNT/A) therapy. We wanted to study whether this effect is transient or sustained. For this, 10 consecutive patients (6 males, 4 females, age 54.6 ± 14.3 years, duration of illness 15.8 ± 7.0 years) with complete BoNT/A therapy failure and BoNT/A antibody titres in excess of 10mU/ml in the mouse diaphragm assay (MDA) received BoNT/B in an initial dose of 12370 ± 1804MU. After the first BoNT/B application the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) improved from 20.1 ± 3.0 to 11.9 ± 3.4. In all patients systemic anticholinergic side effects occurred. Three patients had stable continuous responses to two, three and five subsequent BoNT/B applications. Six patients showed complete secondary therapy failure to the second or third subsequent BoNT/B applications. Side effects did no longer occur. In four of them the BoNT/B doses were doubled without producing any therapeutic benefit or any side effects. In five of them MDA testing was performed and revealed BoNT/B antibody titres in excess of 1mU/ml. One patient lost half of her initial BoNT/B responsiveness indicating partial secondary BoNT/B therapy failure. This partial therapy failure was seen on two consecutive application series and has not proceeded to complete therapy failure so far. BoNT/B seems to be only temporarily effective in the majority of patients with BoNT/A antibody induced therapy failure. Whether the formation of BoNT/B antibody points to a high antigenic potency of BoNT/B, to an increased immunoreactivity in BoNT/A antibody carriers or whether it is due to the large amount of protein applied in BoNT/B therapy needs to be studied.     

Botulinum toxin restores presynaptic inhibition of group Ia afferents in patients with essential tremor

We studied the effect of botulinum toxin A injection on the abnormal presynaptic phase of reciprocal inhibition between forearm antagonist muscles in patients with essential tremor. Ten patients with essential tremor were investigated before and 1 month after botulinum injection. Reciprocal inhibition was studied by conditioning the H reflex in forearm flexors with a radial-nerve stimulus delivered at a range of time intervals. Botulinum toxin produced a significant functional improvement in tremor (about 20%). Before botulinum toxin injection, patients had a reduced presynaptic phase of reciprocal inhibition. After botulinum toxin this phase was significantly more pronounced. The normal early disynaptic phase of reciprocal inhibition was normal before and after botulinum treatment. Although botulinum treatment reduced the size of the H reflex and the M wave to a similar extent, it left the H/M ratio unchanged. These findings show that botulinum toxin treatment restores presynaptic inhibition between forearm antagonist muscles. The results are also consistent with botulinum toxin having a beneficial effect in patients with essential tremor. Both effects probably depend upon the toxin's concurrent action on the extrafusal and intrafusal motor end-plates, the latter resulting in decreased spindle afferent input to the spinal cord. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1701–1705, 1998     

Treatment of idiopathic hemifacial spasm with botulinum toxin

Twelve patients with idiopathic hemifacial spasm received treatment with botulinum toxin A over a period of 18 months. Of 76 treatments given, most (94.7%) led to successful relief of eyelid spasms and all treatments were successful for perioral and lower facial muscle spasms. An average dose of 9.3 units of toxin per session was given to produce a mean interval of relief of 10.8 weeks. Blepharoptosis was the only ocular side effect; it was mild, reversible and occurred in 2 patients. However, lower facial palsy was frequent (9 patients); it was mild to moderate in severity but only partially reversible in 8 patients. Dosage for lower facial muscles should therefore be reduced.     

Treatment of hemifacial spasm with botulinum toxin.

The effectiveness of botulinum toxin injections in 11 patients with hemifacial spasm was investigated in a prospective placebo-controlled blinded study. The patients were treated with four sets of injections to various facial muscles, selected by clinical evaluation. Three injections were with graded doses of toxin and one was with placebo. The order of injections was random and unknown to the patients. Results were scored both subjectively by patient assessment of symptoms and objectively by blinded review of videotapes made one month after each injection. Subjective improvement occurred after 79% of injections with botulinum toxin, regardless of dose of toxin. Only 1 patient improved after placebo. Objective improvement was seen after 84% of injections with botulinum toxin. No patient showed objective improvement after placebo injection. The most frequent side effect was facial weakness, seen after 97% of injections of botulinum toxin. Facial bruising (20%), diplopia (13%), ptosis (7%), and various other mild side effects were seen less frequently. Botulinum toxin appears to be an effective and safe method of therapy for hemifacial spasm.     

Severe amphethamine-induced bruxism: treatment with botulinum toxin

While chewing and grinding movements have been observed in amphetamine addicts, recognition and management of this problem have rarely been highlighted. Botulinum toxin (BTX) has previously been demonstrated to be effective for bruxism associated with movement disorders, such as cranial-cervical dystonia. However, there is little information on its use in tardive bruxism. Here we report an amphetamine addict who presented with medically intractable bruxism, and discuss its pathophysiology and successful treatment with BTX.     

Botulinum toxin antibody type A titres after cessation of botulinum toxin therapy.

In some patients, therapy with botulinum toxin type A (BT-A) becomes ineffective due to formation of antibodies (BT-A-AB). The time course of BT-A-AB titres after cessation of BT-A therapy was quantitatively studied to determine whether and when they might drop. Thirteen patients (eight women, five men) with various dystonic syndromes and complete secondary therapy failure (CSTF) were included in this study (age at initiation of BT-A therapy, 48.2 +/- 11.3 years; number of injection series, 7.7 +/- 2.9; treatment time, 678.8 +/- 385.6 days; mean interinjection interval, 90.4 +/- 35.5 days; mean single dose, 546.7 +/- 336.9 EMU; cumulative dose, 4185.1 +/- 3375.7 EMU [1 EMU = 1 botox MU = 3 dysport MU]). During a monitoring period of at least 750 days after occurrence of CSTF, two or more BT-A-AB tests using the quantitative mouse diaphragm assay were performed. Eight of 13 BT-A-AB titres decreased. The onset of decrease could be detected after between approximately 500 and 1,750 days. After 1,250 to 2,250 days they had dropped below a level of 0.002 U/ml, where CSTF is unlikely. Five of 13 BT-A-AB titres did not decrease. For three of these five, the monitoring period was less than 1,500 days; a chance to drop remained. The other two were monitored for up to 2,400 days. Patients with decreasing and nondecreasing BT-A-AB titres did not exhibit statistically significant differences in either clinical characteristics or treatment parameters. When BT-A therapy was stopped the majority of BT-A-AB titres eventually decreased, allowing reinitiation of BT-A therapy. Application of new BT-A preparations with low antigenic potency might then become an interesting treatment option.