Treatment of dystonia

Dystonia may be a sign or symptom, that is comprised of complex abnormal and dynamic movements of different etiologies. A specific cause is identified in approximately 28% of patients, which only occasionally results in specific treatment. In most cases, treatment is symptomatic and designed to relieve involuntary movements, improve posture and function and reduce associated pain. Therapeutic options are dictated by clinical assessment of the topography of dystonia, severity of abnormal movements, functional impairment and progression of disease and consists of pharmacological, surgical and supportive approaches. Several advances have been made in treatment with newer medications, availability of different forms of botulinum toxin and globus pallidus deep brain stimulation (DBS). For patients with childhood-onset dystonia, the majority of whom later develop generalized dystonia, oral medication is the mainstay of therapy. Recently, DBS has emerged as an effective alternative therapy. Botulinum toxin is usually the treatment of choice for those with adult-onset primary dystonia in which dystonia usually remains focal. In patients with secondary dystonia, treatment is challenging and efficacy is typically incomplete and partially limited by side effects. Despite these treatment options, many patients with dystonia experience only partial benefit and continue to suffer significant disability. Therefore, more research is needed to better understand the underlying cause and pathophysiology of dystonia and to explore newer medications and surgical techniques for its treatment.

Differential diagnosis of common tremor syndromes

Tremor is one of the most common involuntary movement disorders seen in clinical practice. In addition to the detailed history, the differential diagnosis is mainly clinical based on the distinction at rest, postural and intention, activation condition, frequency, and topographical distribution. The causes of tremor are heterogeneous and it can present alone (for example, essential tremor) or as a part of a neurological syndrome (for example, multiple sclerosis). Essential tremor and the tremor of Parkinson's disease are the most common tremors encountered in clinical practice. This article focuses on a practical approach to these different forms of tremor and how to distinguish them clinically. Evidence supporting various strategies used in the differentiation is then presented, followed by a review of formal guidelines or recommendations when they exist.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.

Botulinum toxin therapy of laryngeal muscle hyperactivity syndromes: comparing different botulinum toxin preparations

Spasmodic dysphonia (SD) is a focal dystonia characterized by a strained, strangled voice. Botulinum toxin is a symptomatic treatment for SD and has become the mainstay of therapy over the last two decades. In this manuscript, we briefly review different laryngeal muscle hyperactivity syndromes, their injection techniques and toxins currently available. Adductor SD is the most common indication for botulinum toxin treatment in the larynx. All studies report similar results with regard to improvement, patient satisfaction and side effects. We describe different injection techniques to treat this disorder such as the percutaneous, transoral, transnasal, point-touch techniques. In abductor SD, a subtype of SD, the treatment is aimed at the posterior cricoarytenoid muscle. Other applications of botulinum toxin in the larynx include spasmodic laryngeal dyspnea and voice tremors. We also review injection techniques, the different toxin types used, and toxin doses.

Dystonia

BACKGROUND

Dystonia refers to a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. Although age at onset, anatomic distribution, and family history are essential elements in the evaluation of dystonia, new classification increasingly relies on etiologic and genetic data. In recent years, much progress has been made on the genetics of various forms of dystonia and its pathophysiology underlying the clinical signs. The treatment of dystonia has continued to evolve to include newer medications, different forms of botulinum toxin, and various surgical procedures.

REVIEW SUMMARY

In this article, the author reviewed and summarized the history of dystonia, its evolving classification, and recent genetic data, as well as its clinical investigation and treatment.

CONCLUSIONS

Recent advances in molecular biology have led to the discovery of novel dystonia genes and loci, updating classification schemes, and better understanding of underlying pathophysiology. Treatment strategies for dystonia have significantly been updated with the introduction of different forms of botulinum toxin therapy, new pharmacologic agents, and most recently pallidal deep brain stimulation. A systematic approach to the diagnosis and treatment evaluation of dystonic patients provides optimal care for long-term management.

State of the art: deep brain stimulation in Parkinson's disease

Surgical therapy for Parkinson's disease has a long history beginning in the 1930s with empirical exploration of different brain targets, such as resection of the primary motor cortex or extirpation of the caudate. Recently, there has been a renaissance of functional neurosurgery for the treatment of advanced Parkinson's disease, particularly deep brain stimulation (DBS). To date, DBS of the globus pallidus interna and subthalamic nucleus has been reported to relieve motor symptoms and levodopa-induced dyskinesia in patients with advanced Parkinson's disease. DBS also has different advantages over pallidotomy and subthalamotomy, including reversibility, decreased risk of reoperation and decreased morbidity. In addition to well-experienced neurologists and neurosurgeons, a multidisciplinary team approach is fundamental and critical to ensure success in the DBS procedure in individual patients. With the advances in neuroimaging, neurophysiology and localization techniques, it is increasingly likely that there will be more surgical targets in the future that can also improve cardinal features of Parkinson's disease, or even nonmotor manifestations of this condition.

Three brothers with a very-late-onset writer's cramp

Writer's cramp (WC) is a form of focal task-specific dystonia, which is brought on by writing. Although most cases are sporadic, a positive family history is present in 5% to 20% of cases. To date, WC has been reported in several families with primary torsion dystonia, including DYT7, a pure focal dystonia, and in the mixed dystonias, DYT1, DYT6, and DYT13. We describe a family of Bulgarian descent with three brothers presenting with a very-late-onset dystonic WC, compatible with linkage to chromosome 18p.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.

How useful is (123I) beta-CIT SPECT in the diagnosis of Parkinson's disease?

Because clinical features of parkinsonism can occur in other forms of parkinsonian syndromes in addition to Parkinson's disease, neuroimaging may have a role in determining true disease status. Iodine-123 ((123)I) (2beta-carboxymethoxy-3beta-[4-iodophenyl] tropane) or ((123)I) beta-CIT is a recently developed diagnostic biomarker of Parkinson's disease that provides in vivo information about nigrostriatal degeneration. In clinical trials, beta-CIT single photon emission computed tomography (SPECT) has been shown to be a highly sensitive diagnostic tool in differentiating clinically probable Parkinson's disease from normal subjects and essential tremor patients. As a tool for differentiating Parkinson's disease from atypical parkinsonian syndromes, ((123)I) beta-CIT SPECT may have more limited use because of more extensive postsynaptic pathology in the latter. Differentiating among various parkinsonian syndromes may be improved by methodological refinements, a combined strategy of imaging presynaptic and postsynaptic sites, or by metabolic imaging.

Late-Onset Friedreich Ataxia

BACKGROUND

Friedreich ataxia (FA), the most common hereditary ataxia, is caused by pathological expansion of GAA repeats in the first intron of the X25 gene on chromosome 9. Since the discovery of the gene, atypical features are increasingly recognized in individuals with FA, and up to 25% of patients with recessive or sporadic ataxia do not fulfill the Harding or Quebec Cooperative Study on Friedreich's Ataxia criteria for FA. Late-onset FA (LOFA) is defined as onset after age 25 years.

OBJECTIVES

To describe and further delineate the clinical and magnetic resonance imaging findings in patients with LOFA and to review the literature.

DESIGN

Clinical evaluation and comparison of clinical data and investigations.

SETTING

Ataxia clinics at UCLA and Cedars-Sinai Medical Center.

PATIENTS

Thirteen patients with LOFA with 13 sex-matched and Inherited Ataxia Progression Scale-matched patients with typical FA.

RESULTS

Gait and limb ataxias were seen in all the participants. Dysarthria, loss of vibration sense, and abnormal eye movements were also common in both groups. Patients with LOFA more often had lower limb spasticity (40% vs 0%; chi2 = 4.0; P = .04) and retained reflexes (46.1% vs 7.7%; chi2 = 3.46; P = .05). They had no complaint of sphincter disturbances, and there was no evidence of cardiomyopathy on echocardiograms (chi2 = 4.0; P = .04). Five of 9 patients with LOFA had cerebellar atrophy on neuroimaging.

CONCLUSIONS

Patients with gait and limb ataxias, dysarthria, loss of vibration sense, and fixational instability after age 25 years should be considered for molecular testing for GAA expansion in the FA gene. In contrast to previous studies, cerebellar vermian atrophy is not an uncommon finding.

Expanding use of botulinum toxin

Botulinum toxin type A (BTX-A) is best known to neurologists as a treatment for neuromuscular conditions such as dystonias and spasticity and has recently been publicized for the management of facial wrinkles. The property that makes botulinum toxin type A useful for these various conditions is the inhibition of acetylcholine release at the neuromuscular junction. Although botulinum toxin types A and B (BTX-A and BTX-B) continue to find new uses in neuromuscular conditions involving the somatic nervous system, it has also been recognized that the effects of these medications are not confined to cholinergic neurons at the neuromuscular junction. Acceptors for BTX-A and BTX-B are also found on autonomic nerve terminals, where they inhibit acetylcholine release at glands and smooth muscle. This observation led to trials of botulinum neurotoxins in various conditions involving autonomic innervation. The article reviews the emerging use of botulinum neurotoxins in these and selected other conditions, including sialorrhea, primary focal hyperhidrosis, pathological pain and primary headache disorders that may be of interest to neurologists and related specialists.

Tourette's syndrome: old syndrome, new insights and new treatment

Recognized for over 300 years, Tourette's syndrome was originally ascribed as a rare bizarre psychogenic illness. Because of recent advances in research on Tourette's syndrome, this disorder is not only the rarity once thought, but also a common, biological, genetic disorder with a spectrum of neurobehavioral manifestations that wax and wane during its entire natural course. In addition to standard neuroleptics, much progress in Tourette's syndrome research has widened its pharmacotherapy to include alpha2-adrenergic agonists and atypical neuroleptics as well as behavioral modification, adjustments, and different surgical approaches. Despite a myriad of reports, there are still many unresolved facts, which stimulate research into the underlying mechanisms of this complex neuropsychiatric disorder. We anticipate that continued success of research in this area will lead to molecular insights, identification of vulnerable genes, and eventually novel therapies that can target all aspects of this complex disorder.

Tourette's syndrome: old syndrome, new insights and new treatment

Recognized for over 300 years, Tourette's syndrome was originally ascribed as a rare bizarre psychogenic illness. Because of recent advances in research on Tourette's syndrome, this disorder is not only the rarity once thought, but also a common, biological, genetic disorder with a spectrum of neurobehavioral manifestations that wax and wane during its entire natural course. In addition to standard neuroleptics, much progress in Tourette's syndrome research has widened its pharmacotherapy to include alpha2-adrenergic agonists and atypical neuroleptics as well as behavioral modification, adjustments, and different surgical approaches. Despite a myriad of reports, there are still many unresolved facts, which stimulate research into the underlying mechanisms of this complex neuropsychiatric disorder. We anticipate that continued success of research in this area will lead to molecular insights, identification of vulnerable genes, and eventually novel therapies that can target all aspects of this complex disorder.

Improvement of cervical dystonia: possible role of transcranial magnetic stimulation simulating sensory tricks effect

Idiopathic cervical dystonia (ICD) is the most common form of focal dystonia. A characteristic and unique diagnostic feature is the presence of "sensory tricks", for example, a finger placed on the chin to neutralize the spasm. Although approximately 70% of patients with ICD experience effective sensory tricks, the exact mechanism of these tricks is still unknown. However, recent evidence suggests that higher sensorimotor integration processes are involved. A study using H2(15)O positron emission tomography demonstrated that the application of sensory trick stimulus, resulting in a near-neutral head position, led to an increased activation mainly of the superior and inferior parietal lobules (ipsilateral to head turn) and bilateral occipital cortex and to a decreased activity of the supplementary motor area and the primary sensorimotor cortex (contralateral to head turn). Since transcranial magnetic stimulation (TMS) is an experimental device with the ability to excite or depress the neural circuits, we hypothesize that the use of TMS of specific parameters to specific brain areas (as above) may produce an effect similar to sensory tricks resulting in the relief of spasms and the improvement of cervical dystonia.

Bilateral neurostimulation systems used for deep brain stimulation: in vitro study of MRI-related heating at 1.5 T and implications for clinical imaging of the brain

Deep brain stimulation (DBS) is used increasingly in the field of movement disorders. The implanted electrodes create not only a prior risk to patient safety during MRI, but also a unique opportunity in the collection of functional MRI data conditioned by direct neural stimulation. We evaluated MRI-related heating for bilateral neurostimulation systems used for DBS with an emphasis on assessing clinically relevant imaging parameters. Magnetic resonance imaging was performed using transmit body radiofrequency (RF) coil and receive-only head RF coil at various specific absorption rates (SARs) of RF power. In vitro testing was performed using a gel-filled phantom with temperatures recorded at the electrode tips. Each DBS electrode was positioned with a single extension loop around each pulse generator and a single loop at the "head" end of the phantom. Various pulse sequences were used for MRI including fast spin-echo, echo-planar imaging, magnetization transfer contrast and gradient-echo techniques. The MRI sequences had calculated whole-body averaged SARs and local head SARs ranging from 0.1 to 1.6 W/kg and 0.1 to 3.2 W/kg, respectively. Temperature elevations of less than 1.0 degrees C were found with the fast spin-echo, magnetization transfer contrast, gradient-echo and echo-planar clinical imaging sequences. Using the highest SAR levels, whole-body averaged, 1.6 W/kg, local exposed-body, 3.2 W/kg, and local head, 2.9 W/kg, the temperature increase was 2.1 degrees C. These results showed that temperature elevations associated with clinical sequences were within an acceptable physiologically safe range for the MR conditions used in this evaluation, especially for the use of relatively low SAR levels. Notably, these findings are highly specific to the neurostimulation systems, device positioning technique, MR system and imaging conditions used in this investigation.

Midbrain ataxia: an introduction to the mesencephalic locomotor region and the pedunculopontine nucleus

OBJECTIVE

Although gait ataxia is usually associated with cerebellar lesions, we review a less familiar cause. We present three patients with dorsal midbrain lesions and correlate these presentations with recent findings in the functional anatomy of the midbrain.

CONCLUSION

We suggest that these lesions involve a well-studied but generally unfamiliar area of the dorsal midbrain known as the mesencephalic locomotor region. More specifically, we hypothesize that involvement of the pedunculopontine nucleus, a major component of the mesencephalic locomotor region, may be at least partially responsible for producing midbrain ataxia.

Chorea and related disorders

Chorea refers to irregular, flowing, non-stereotyped, random, involuntary movements that often possess a writhing quality referred to as choreoathetosis. When mild, chorea can be difficult to differentiate from restlessness. When chorea is proximal and of large amplitude, it is called ballism. Chorea is usually worsened by anxiety and stress and subsides during sleep. Most patients attempt to disguise chorea by incorporating it into a purposeful activity. Whereas ballism is most often encountered as hemiballism due to contralateral structural lesions of the subthalamic nucleus and/or its afferent or efferent projections, chorea may be the expression of a wide range of disorders, including metabolic, infectious, inflammatory, vascular, and neurodegenerative, as well as drug induced syndromes. In clinical practice, Sydenham's chorea is the most common form of childhood chorea, whereas Huntington's disease and drug induced chorea account for the majority of adult onset cases. The aim of this review is to provide an up to date discussion of this disorder, as well as a practical approach to its management.

Cerebellar arteriovenous malformation presenting with bilateral proptosis mimicking caroticocavernous fistula

A 21-year-old man presented with a 3-year history of bulging and redness of his right eye associated with double vision. He had a history of facial trauma 5 years previously. These symptoms, which had progressed over the year preceding the presentation, were accompanied by a bilateral pounding headache and gait unsteadiness with veering to the right. On examination, he had bilateral pulsating exophthalmos that was more marked on the right with a loudly audible orbital bruit. Mild soft tissue swelling of the right eyelid along with dilated veins in the right conjunctival fornices was observed. His visual acuity was 20/20 and there was no papilloedema. Eye movement examination showed restricted up-gaze, in conjunction with skew deviation, the right eye being hypertropic. Although impaired convergence was observed, there was no convergence retraction nystagmus. Right lateral rectus palsy and right sensorineural hearing loss were noted. Coordination testing revealed right finger to nose and heel to shin ataxia associated with a slightly wide based gait.

The magnetic resonance images showed several findings of interest. There was a massive right cerebellar arteriovenous malformation, with a large tangle of vessels extending into the quadrigeminal plate and perimesencephalic cistern with mass effect on the right aspect of the midbrain (Figure 1). There was bilateral proptosis, significantly more pronounced on the right, with enlargement of the left lateral rectus muscle and bulging of the right cavernous sinus. Surprisingly, no significant enlargement of the right superior ophthalmic vein was noted (Figure 2). Cerebral angiography showed a massive right cerebellar arteriovenous malformation, fed by the bilateral posterior inferior cerebellar arteries, anterior inferior cerebellar arteries and superior cerebellar arteries, as well as direct branches from the basilar artery and right posterior cerebral artery. Superficial venous drainage was observed directly to the right transverse and sigmoid sinuses, as well as to the deep venous system, with an enlarged straight sinus, vein of Galen and internal cerebral veins. There was also retrograde forward-directed venous flow filling the right cavernous sinus and the inferior petrosal sinus. Emanating from the right cavernous sinus (Figure 3), there were two anterior directed veins: a smaller superior one, representing a cortical vein and a larger inferior vein, representing the right superior ophthalmic vein, which was only mildly dilated. The inferior ophthalmic vein was not visualized. No fistulous communication between the carotid artery and cavernous sinus was seen.