Causes for treatment delays in dystonia and hemifacial spasm: a Canadian survey

Botulinum neurotoxin: A therapeutic powerhouse with broad clinical implications

ABSTRACT

Clostridium botulinum is a Gram-positive bacterium that produces one of the most deadly chemodenervating toxins in the world. To date, six distinct neurotoxins are available for prescription use in the United States. Decades of data across aesthetic therapeutic areas and therapeutic disease states support the safety and efficacy of C. botulinum, providing good symptom management and improved quality of life in appropriately chosen patients. Unfortunately, many clinicians are slow to progress patients to toxin therapy from more conservative measures, and others wrongly interchange the products despite characteristics unique to each. Commensurate with an improved understanding of the complex pharmacology and clinical implications of botulinum neurotoxins is the importance for clinicians to appropriately identify, educate, refer, and/or treat candidate patients. This article provides an overview of the history, mechanism of action, differentiation, indications, and uses for botulinum neurotoxins.

Validation of a guideline to reduce variability in diagnosing cervical dystonia

BACKGROUND

Cervical dystonia is characterized by a variable pattern of neck muscle involvement. Due to the lack of a diagnostic test, cervical dystonia diagnosis is based on clinical examination and is therefore subjective. The present work was designed to provide practical guidance for clinicians in confirming or refuting suspected cervical dystonia.

METHODS

Participants were video recorded according to a standardized protocol to assess 6 main clinical features possibly contributing to cervical dystonia diagnosis: presence of repetitive, patterned head/neck movements/postures inducing head/neck deviation from neutral position (item 1); sensory trick (item 2); and red flags related to conditions mimicking dystonia that should be absent in dystonia (items 3-6). Inter-/intra-rater agreement among three independent raters was assessed by k statistics. To estimate sensitivity and specificity, the gold standard was cervical dystonia diagnosis reviewed at each site by independent senior neurologists.

RESULTS

The validation sample included 43 idiopathic cervical dystonia patients and 41 control subjects (12 normal subjects, 6 patients with isolated head tremor, 4 with chorea, 6 with tics, 4 with head ptosis due to myasthenia or amyotrophic lateral sclerosis, 7 with orthopedic/rheumatologic neck diseases, and 2 with ocular torticollis). The best combination of sensitivity and specificity was observed considering all the items except for an item related to capability to voluntarily suppress spasms (sensitivity: 96.1%; specificity: 81%).

CONCLUSIONS

An accurate diagnosis of cervical dystonia can be achieved if, in addition to the core motor features, we also consider some clinical features related to dystonia mimics that should be absent in dystonia.

Clinical Implications of Dystonia as a Neural Network Disorder

Isolated dystonia is a neurological disorder of diverse etiology, multifactorial pathophysiology, and wide spectrum of clinical presentations. We review the recent neuroimaging advances that led to the conceptualization of dystonia as a neural network disorder and discuss how current knowledge is shaping the identification of biomarkers of dystonia and the development of novel pharmacological therapies.

Diagnostic Process in Rare Diseases: Determinants Associated with Diagnostic Delay

Many people living with rare disease (RD) report a difficult diagnostic process from the symptom onset until they obtain the definitive diagnosis. The aim of this study was thus to ascertain the diagnostic process in RDs, and explore the determinants related with having to wait for more than one year in this process (defined as “diagnostic delay”). We conducted a case–control study, using a purpose-designed form from the Spanish Rare Diseases Patient Registry for data-collection purposes. A descriptive analysis was performed and multivariate backward logistic regression models fitted. Based on data on 1216 patients living with RDs, we identified a series of determinants associated with experiencing diagnostic delay. These included: having to travel to see a specialist other than that usually consulted in the patient’s home province (OR 2.1; 95%CI 1.6–2.9); visiting more than 10 specialists (OR 2.6; 95%CI 1.7–4.0); being diagnosed in a region other than that of the patient’s residence at the date of symptom onset (OR 2.3; 95%CI 1.5–3.6); suffering from a RD of the nervous system (OR 1.4; 95%CI 1.0–1.8). In terms of time taken to see a specialist, waiting more than 6 months to be referred from the first medical visit was the period of time which most contributed to diagnostic delay (PAR 30.2%). In conclusion, this is the first paper to use a collaborative study based on a nationwide registry to address the diagnostic process of patients living with RDs. While the evidence shows that the diagnostic process experienced by these persons is complex, more studies are needed to determine the implications that this has for their lives and those of their families at a social, educational, occupational, psychological, and financial level.

Clinical Features and Evolution of Blepharospasm: A Multicenter International Cohort and Systematic Literature Review

Objective:

Blepharospasm is a type of dystonia where the diagnosis is often delayed because its varied clinical manifestations are not well recognized. The purpose of this study was to provide a comprehensive picture of its clinical features including presenting features, motor features, and non-motor features.

Methods:

This was a two-part study. The first part involved a systematic literature review that summarized clinical features for 10,324 cases taken from 41 prior reports. The second part involved a summary of clinical features for 884 cases enrolled in a large multicenter cohort collected by the Dystonia Coalition investigators, along with an analysis of the factors that contribute to the spread of dystonia beyond the periocular region.

Results:

For cases in the literature and the Dystonia Coalition, blepharospasm emerged in the 50s and was more frequent in women. Many presented with non-specific motor symptoms such as increased blinking (51.9%) or non-motor sensory features such as eye soreness or pain (38.7%), photophobia (35.5%), or dry eyes (10.7%). Non-motor psychiatric features were also common including anxiety disorders (34–40%) and depression (21–24%). Among cases presenting with blepharospasm in the Dystonia Coalition cohort, 61% experienced spread of dystonia to other regions, most commonly the oromandibular region and neck. Features associated with spread included severity of blepharospasm, family history of dystonia, depression, and anxiety.

Conclusions:

This study provides a comprehensive summary of motor and non-motor features of blepharospasm, along with novel insights into factors that may be responsible for its poor diagnostic recognition and natural history.

Oromandibular dystonia and temporomandibular disorders

BACKGROUND

The aim of this study was to characterize clinical features of patients with oromandibular dystonia (OMD) who had temporomandibular disorder (TMD) symptoms.

METHODS

A retrospective chart review of patients seeking treatment at a tertiary-level orofacial pain clinic from January 2015 through December 2020 was undertaken. The inclusionary criteria consisted of a diagnosis of OMD (International Classification of Diseases, Revision 10 code G24.4), which had been confirmed by a neurologist.

RESULTS

Eleven patients met the inclusion criteria. Focal dystonia and jaw deviation OMD were the most frequent diagnoses. A dental procedure was a triggering or aggravating factor in 36.4% of patients. All but 2 patients had a sensory trick, or tactile stimulus to a particular body part, and approximately one-half of the patients used an oral appliance as a sensory trick device. All but 1 patient had received a diagnosis of TMD, with myofascial pain of the masticatory muscles being the most prevalent diagnosis. Four patients had received a recommendation for orthodontic treatment. About one-half of the patients had undergone 1 or more invasive dental or maxillofacial surgical interventions to address their dystonia. Anxiety was the most common psychological comorbidity.

CONCLUSIONS

Because patients with OMD commonly experience TMD symptoms, they can receive a misdiagnosis of TMD while the OMD is overlooked.

PRACTICAL IMPLICATIONS

Owing to concomitant TMD symptoms, patients most often seek dental consultations and undergo treatments such as orthodontic interventions and temporomandibular joint surgeries. A dentist's competency in recognizing these patients can prevent unnecessary procedures and facilitate appropriate patient care.

Isolated Cervical Dystonia: Management and Barriers to Care

Background: Cervical dystonia (CD) is a rare disorder, and health care providers might be unfamiliar with its presentation, thus leading to delay in the initial diagnosis. The lack of awareness displays the need to highlight the clinical features and treatment in cervical dystonia. In our cohort, we have identified an earlier age of onset in men, despite an overall preponderance of affected women.

Objective: We aim to identify the prevalence, age of onset, spread, and treatment modalities of CD in the population. We also highlight the barriers which patients encounter related to diagnosis, follow-up, and treatment.

Methods: We reviewed 149 CD patients who attended specialized Dystonia Clinics over a 14-year period. Dystonia severity was rated using the Burke-Fahn-Marsden (BFM), Tsui, and Toronto Western Spasmodic Torticollis Rating Scales (TWSTRS). Mood and quality of life were assessed using Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and 36-Item Short Form Health Survey (SF-36).

Results: CD patients were majority White (91.3%) and more commonly female (75.8%). Men had an earlier median age of onset, 40.5 years (p = 0.044). BAI revealed a mean score of 7.2 (±6.4, n = 50) indicating minimal anxiety while BDI revealed a mean score of 7.30 (±7.6, n = 50) indicating minimal depression. The only SF-36 subscales associated with CD severity were physical functioning (p = 0.040) pain (p = 0.008) and general health (p = 0.014).

Conclusion: There appear to be gender differences in both the prevalence and age of onset of the disease. There was a 3-fold higher incidence in women than in men. CD patients of both sexes experience barriers to care, which can be reflected in their quality of life and time-to-diagnosis. In addition, males were less likely to experience an objective benefit with botulinum toxin treatment and more likely to discontinue care. Greater awareness of CD by health care providers is important to reduce the time-to-diagnosis.

Efficacy and Complications of Microsurgical Neurovascular Decompression in 55 Patients With Hemifacial Spasm

OBJECTIVE

To analyze the efficacy and complications of microvascular decompression for hemifacial spasm.

STUDY DESIGN

Retrospective study.

SETTING

Regional hospital.

METHODS

Fifty-five patients with hemifacial spasm were treated by microvascular decompression. All patients with hemifacial spasm who underwent retrosigmoid microvascular decompression from May 2004 to January 2017 were included. Patients with no conflict on preoperative magnetic resonance imaging or with an alternate diagnosis were excluded.

RESULTS

The overall cure rate was 83.64%, with an average follow-up of 7.4 years. A left-sided hemifacial spasm was a healing-promoting factor (P = .01). The median healing was 0.03 months, and the mean was 6 months. The efficacy remained high in the medium term (88% at 3 years), long term (90.24% at 5 years), and very long term (90.48% at 8 years). The recurrence rate was 9.8%. Favorable criteria included a right-sided spasm (P = .01) and an average age of 62 years (P = .03). The specific complications were permanent facial palsy (3.63%), unilateral deafness (5.45%), and hearing loss (3.63%). No death was reported. Regarding the quality of life of the patients, 94.7% had a modified HFS-8 postoperative score of 0 (Hemifacial Spasm 8 Quality of Life Scale).

CONCLUSION

Microvascular decompression for hemifacial spasm is an effective and lasting technique. Its low rate of complications and the considerable quality-of-life improvement should lead surgeons to propose it to patients as soon as botulinum toxin injections become ineffective or poorly tolerated.

A microstructural neural network biomarker for dystonia diagnosis identified by a DystoniaNet deep learning platform

This research identified a microstructural neural network biomarker for objective and accurate diagnosis of isolated dystonia based on the disorder pathophysiology using an advanced deep learning algorithm, DystoniaNet, and raw structural brain images of large cohorts of patients with isolated focal dystonia and healthy controls. DystoniaNet significantly outperformed shallow machine-learning pipelines and substantially exceeded the current agreement rates between clinicians, reaching an overall accuracy of 98.8% in diagnosing different forms of isolated focal dystonia. These results suggest that DystoniaNet could serve as an objective, robust, and generalizable algorithmic platform of dystonia diagnosis for enhanced clinical decision-making. Implementation of the identified biomarker for objective and accurate diagnosis of dystonia may be transformative for clinical management of this disorder.

Isolated dystonia is a neurological disorder of heterogeneous pathophysiology, which causes involuntary muscle contractions leading to abnormal movements and postures. Its diagnosis is remarkably challenging due to the absence of a biomarker or gold standard diagnostic test. This leads to a low agreement between clinicians, with up to 50% of cases being misdiagnosed and diagnostic delays extending up to 10.1 y. We developed a deep learning algorithmic platform, DystoniaNet, to automatically identify and validate a microstructural neural network biomarker for dystonia diagnosis from raw structural brain MRIs of 612 subjects, including 392 patients with three different forms of isolated focal dystonia and 220 healthy controls. DystoniaNet identified clusters in corpus callosum, anterior and posterior thalamic radiations, inferior fronto-occipital fasciculus, and inferior temporal and superior orbital gyri as the biomarker components. These regions are known to contribute to abnormal interhemispheric information transfer, heteromodal sensorimotor processing, and executive control of motor commands in dystonia pathophysiology. The DystoniaNet-based biomarker showed an overall accuracy of 98.8% in diagnosing dystonia, with a referral of 3.5% of cases due to diagnostic uncertainty. The diagnostic decision by DystoniaNet was computed in 0.36 s per subject. DystoniaNet significantly outperformed shallow machine-learning algorithms in benchmark comparisons, showing nearly a 20% increase in its diagnostic performance. Importantly, the microstructural neural network biomarker and its DystoniaNet platform showed substantial improvement over the current 34% agreement on dystonia diagnosis between clinicians. The translational potential of this biomarker is in its highly accurate, interpretable, and generalizable performance for enhanced clinical decision-making.

Cervical dystonia incidence and diagnostic delay in a multiethnic population

BACKGROUND

Current cervical dystonia (CD) incidence estimates are based on small numbers in relatively ethnically homogenous populations. The frequency and consequences of delayed CD diagnosis is poorly characterized.

OBJECTIVES

To determine CD incidence and characterize CD diagnostic delay within a large, multiethnic integrated health maintenance organization.

METHODS

We identified incident CD cases using electronic medical records and multistage screening of more than 3 million Kaiser Permanente Northern California members from January 1, 2003, to December 31, 2007. A final diagnosis was made by movement disorders specialist consensus. Diagnostic delay was measured by questionnaire and health utilization data. Incidence rates were estimated assuming a Poisson distribution of cases and directly standardized to the 2000 U.S. census. Multivariate logistic regression models were employed to assess diagnoses and behaviors preceding CD compared with matched controls, adjusting for age, sex, and membership duration.

RESULTS

CD incidence was 1.18/100,000 person-years (95% confidence interval [CI], 0.35-2.0; women, 1.81; men, 0.52) based on 200 cases over 15.4 million person-years. Incidence increased with age. Half of the CD patients interviewed reported diagnostic delay. Diagnoses more common in CD patients before the index date included essential tremor (odds ratio [OR] 68.1; 95% CI, 28.2-164.5), cervical disc disease (OR 3.83; 95% CI, 2.8-5.2), neck sprain/strain (OR 2.77; 95% CI, 1.99-3.62), anxiety (OR 2.24; 95% CI, 1.63-3.11) and depression (OR 1.94; 95% CI, 1.4-2.68).

CONCLUSIONS

CD incidence is greater in women and increases with age. Diagnostic delay is common and associated with adverse effects. © 2019 International Parkinson and Movement Disorder Society.

The Dystonias

PURPOSE OF REVIEW

This article provides a summary of the state of the art in the diagnosis, classification, etiologies, and treatment of dystonia.

RECENT FINDINGS

Although many different clinical manifestations of dystonia have been recognized for decades, it is only in the past 5 years that a broadly accepted approach has emerged for classifying them into specific subgroups. The new classification system aids clinical recognition and diagnosis by focusing on key clinical features that help distinguish the many subtypes. In the past few years, major advances have been made in the discovery of new genes as well as advances in our understanding of the biological processes involved. These advances have led to major changes in strategies for diagnosis of the inherited dystonias. An emerging trend is to move away from heavy reliance on the phenotype to target diagnostic testing toward a broader approach that involves large gene panels or whole exome sequencing.

SUMMARY

The dystonias are a large family of phenotypically and etiologically diverse disorders. The diagnosis of these disorders depends on clinical recognition of characteristic clinical features. Symptomatic treatments are useful for all forms of dystonia and include oral medications, botulinum toxins, and surgical procedures. Determination of etiology is becoming increasingly important because the number of disorders is growing and more specific and sometimes disease-modifying therapies now exist.

Consensus of the Iberoamerican Oculoplastic Society for diagnosis and management of facial dystonia

OBJECTIVE

To propose guidelines for the diagnosis and treatment of facial dystonia prepared by a group of experts in orbit and oculoplastics from the Iberoamerican Oculoplastic Society.

MATERIAL AND METHODS

An interactive discussion between the expert panel and those attending the 6th Iberoamerican Society of Oculoplastics Congress, which took place at the Hospital Nuestra Señora de la Luz in Mexico City on 22 October 2018, providing their personal experience based on evidence for diagnosis and treatment of facial dystonia. Around 200 ophthalmologists specialised in oculoplastics from North, Central and South America, Spain, and Portugal were involved. Discussion was focused on the following themes: pathophysiology, diagnosis, medical management, and surgical management.

CONCLUSIONS

Facial dystonia diagnosis is clinical; therefore, image studies are rarely needed. The ophthalmologist is generally the first physician to be consulted, and is able to be the treating physician, with the exception of specific cases of hemifacial spasm where management with neurosurgery may be beneficial. Botulinum toxin is the treatment of choice. Treatment with oral neuroleptics and myectomy of the orbicularis oculi muscle are reserved for refractory cases, since these do not have an adequate clinical response as first choice treatments. Persistent use of botulinum toxin does not modify the natural course of the disease.

Deep brain stimulation for dystonia: a novel perspective on the value of genetic testing

The dystonias are a group of disorders characterized by excessive muscle contractions leading to abnormal movements and postures. There are many different clinical manifestations and underlying causes. Deep brain stimulation (DBS) provides an effect treatment, but outcomes can vary considerably among the different subtypes of dystonia. Several variables are thought to contribute to this variation including age of onset and duration of dystonia, specific characteristics of the dystonic movements, location of stimulation and stimulator settings, and others. The potential contributions of genetic factors have received little attention. In this review, we summarize evidence that some of the variation in DBS outcomes for dystonia is due to genetic factors. The evidence suggests that more methodical genetic testing may provide useful information in the assessment of potential surgical candidates, and in advancing our understanding of the biological mechanisms that influence DBS outcomes.

Recent developments in dystonia

PURPOSE OF REVIEW

The dystonias are a family of related disorders with many different clinical manifestations and causes. This review summarizes recent developments regarding these disorders, focusing mainly on advances with direct clinical relevance from the past 2 years.

RECENT FINDINGS

The dystonias are generally defined by their clinical characteristics, rather than by their underlying genetic or neuropathological defects. The many varied clinical manifestations and causes contribute to the fact that they are one of the most poorly recognized of all movement disorders. A series of recent publications has addressed these issues, offering a revised definition and more logical means for classifying the many subtypes. Our understanding of the genetic and neurobiological mechanisms responsible for different types of dystonias also has grown rapidly, creating new opportunities and challenges for diagnosis, and identifying increasing numbers of rare subtypes for which specific treatments are available.

SUMMARY

Recent advances in describing the clinical phenotypes and determining associated causes have pointed to the need for new strategies for diagnosis, classification, and treatment of the dystonias.

Delays to the diagnosis of cervical dystonia

The diagnosis of cervical dystonia (CD) is based on physical examination and is therefore reliant on clinician experience. Due to variability of presenting symptoms it may be misdiagnosed, thus delaying the provision of effective treatment. We sought to determine the average time taken to make a diagnosis of CD in our clinical cohort and explore contributing factors to diagnostic delay. Forty-nine patients with a diagnosis of CD attending a movement disorder specialist for treatment completed a questionnaire regarding symptoms and clinical interactions at onset and diagnosis. The mean time from symptom onset to diagnosis was 6.8 years (range 0-53 years). More than 50% of patients sought physical therapies initially, prior to consulting their general practitioner. Only 40% of patients sought medical advice within the first 6 months of symptom onset and only 10% were given an initial diagnosis of CD. The first referral from the general practitioner was to a specialist other than a neurologist in 31% of patients. Patients were seen by a mean of three doctors (range one to nine) before being given the correct diagnosis of CD. Delay to diagnosis of CD may in part be due to lack of awareness of the condition amongst health care professionals. Improved diagnostic skill appears likely to have had a substantial impact on the delivery of appropriate treatment in this population.

Diagnosis and treatment of dystonia

The dystonias are a group of disorders characterized by excessive involuntary muscle contractions leading to abnormal postures and/or repetitive movements. A careful assessment of the clinical manifestations is helpful for identifying syndromic patterns that focus diagnostic testing on potential causes. If a cause is identified, specific etiology-based treatments may be available. In most cases, a specific cause cannot be identified, and treatments are based on symptoms. Treatment options include counseling, education, oral medications, botulinum toxin injections, and several surgical procedures. A substantial reduction in symptoms and improved quality of life is achieved in most patients by combining these options.

Diagnostic delay in adult-onset dystonia: data from an Italian movement disorder center

Adult-onset dystonia (AOD) may manifest in focal forms (as blepharospasm, oromandibular dystonia, cervical dystonia, laryngeal dystonia, and hand dystonia) or in segmental forms. Time from onset of dystonia to diagnosis can be an indicator of the quality of care received during the diagnosis of AOD, likely reflecting factors associated with both the patient and their health system. Three previously reported single-center studies showed that diagnosis of AOD may be delayed for several years. Here, we examined the time lapse between onset and diagnosis in patients with different forms of AOD from an Italian movement disorder center. We found the time lapse between dystonia onset and diagnosis was very long for patients who developed AOD before 1980; and even in the most recent years reaching a correct diagnosis required more than year in almost half of cases. Our results suggest that the delay in diagnosis of adult-onset focal and segmental dystonia has improved over time, but remains unacceptable. The findings are a promising indicator of improvements in care of this uncommon disorder. However, education of patients and doctors is still needed.

Descriptive epidemiology of cervical dystonia

Background

Cervical dystonia (CD), the most common form of adult-onset focal dystonia, has a heterogeneous clinical presentation with variable clinical features, leading to difficulties and delays in diagnosis. Owing to the lack of reviews specifically focusing on the frequency of primary CD in the general population, we performed a systematic literature search to examine its prevalence/incidence and analyze methodological differences among studies.

Methods

We performed a systematic literature search to examine the prevalence data of primary focal CD. Sixteen articles met our methodological criteria. Because the reported prevalence estimates were found to vary widely across studies, we analyzed methodological differences and other factors to determine whether true differences exist in prevalence rates among geographic areas (and by gender and age distributions), as well as to facilitate recommendations for future studies.

Results

Prevalence estimates ranged from 20–4,100 cases/million. Generally, studies that relied on service-based and record-linkage system data likely underestimated the prevalence of CD, whereas population-based studies suffered from over-ascertainment. The more methodologically robust studies yielded a range of estimates of 28–183 cases/million. Despite the varying prevalence estimates, an approximate 2:1 female:male ratio was consistent among many studies. Three studies estimated incidence, ranging from 8–12 cases/million person-years.

Discussion

Although several studies have attempted to estimate the prevalence and incidence of CD, there is a need for additional well-designed epidemiological studies on primary CD that include large populations; use defined CD diagnostic criteria; and stratify for factors such as age, gender, and ethnicity.

How long does it take to diagnose cervical dystonia?

BACKGROUND

Dystonia is a neurological disorder characterized by involuntary twisting movements and postures. The neck is among the most commonly affected regions, and diagnosis can be made readily through a simple clinical evaluation. The goal of this study was to explore how long it took patients to receive a diagnosis of cervical dystonia after symptom onset.

METHODS

A structured questionnaire was administered at outpatient clinics of a tertiary care academic medical center to 146 consecutively evaluated patients. The questionnaire addressed the length of time from symptom onset to diagnosis, the numbers and types of providers seen before reaching a diagnosis, and treatments attempted prior to receiving botulinum toxin.

RESULTS

A total of 108 patients saw a mean of 3.5 providers over a mean period of 44 months from symptom onset to diagnosis. For patients with symptom onset in the last decade only, patients saw a mean of 3.0 providers over a mean of 14 months.

CONCLUSIONS

Although cervical dystonia is the most common form of dystonia with clinical features readily identifiable by a simple history and examination, patients typically see multiple providers over more than a year before reaching a diagnosis and receiving optimal therapy. Improved awareness of the clinical features will enable patients to obtain appropriate therapy more rapidly.

Development and validation of a clinical guideline for diagnosing blepharospasm

OBJECTIVE

To design and validate a clinical diagnostic guideline for aiding physicians in confirming or refuting suspected blepharospasm.

METHODS

The guideline was developed and validated in a 3-step procedure: 1) identification of clinical items related to the phenomenology of blepharospasm, 2) assessment of the relevance of each item to the diagnosis of blepharospasm, and 3) evaluation of the reliability and diagnostic sensitivity/specificity of the selected clinical items.

RESULTS

Of 19 clinical items initially identified, 7 were admitted by content validity analysis to further assessment. Both neurologists and ophthalmologists achieved satisfactory interobserver agreement for all 7 items, including "involuntary eyelid narrowing/closure due to orbicularis oculi spasms," "bilateral spasms," "synchronous spasms," "stereotyped spasm pattern," "sensory trick," "inability to voluntarily suppress the spasms," and "blink count at rest." Each selected item yielded unsatisfactory accuracy in discriminating patients with blepharospasm from healthy subjects and patients with other eyelid disturbances. Combining the selected items, however, improved diagnostic sensitivity/specificity. The best combination, yielding 93% sensitivity and 90% specificity, was an algorithm starting with the item "stereotyped, bilateral, and synchronous orbicularis oculi spasms inducing eyelid narrowing/closure" and followed by recognition of "sensory trick" or, alternatively, "increased blinking."

CONCLUSION

This study provides an accurate and valid clinical guideline for diagnosing blepharospasm. Use of this guideline would make it easier for providers to recognize dystonia in clinical and research settings.

The focal dystonias: current views and challenges for future research

The most common forms of dystonia are those that develop in adults and affect a relatively isolated region of the body. Although these adult-onset focal dystonias are most prevalent, knowledge of their etiologies and pathogenesis has lagged behind some of the rarer generalized dystonias, in which the identification of genetic defects has facilitated both basic and clinical research. This summary provides a brief review of the clinical manifestations of the adult-onset focal dystonias, focusing attention on less well understood clinical manifestations that need further study. It also provides a simple conceptual model for the similarities and differences among the different adult-onset focal dystonias as a rationale for lumping them together as a class of disorders while at the same time splitting them into subtypes. The concluding section outlines some of the most important research questions for the future. Answers to these questions are critical for advancing our understanding of this group of disorders and for developing novel therapeutics.

Botulinum toxin clinic-based epidemiologic survey of adults with primary dystonia in East china

Background and Purpose:

Primary focal or segmental dystonia is a rare clinical condition. The clinical features of dystonia have not been evaluated in China. We performed a study to investigate the epidemiology of primary dystonia and its clinical variants in an adult population.

Methods:

A Botulinum Toxin Clinic-based study was conducted in the period 18 May through 8 October 2010 in East China. We identified 523 dystonia patients from the Movement disorders and Botulinum Toxin clinic Cases.

Results:

The most common focal dystonia were blepharospasm (59%), cervical dystonia (35%), limb dystonia (3%), oromandibular dystonia (2%) and laryngeal dystonia (1%). Males with primary dystonia were noted to have earlier age of onset. A female predominance was noted for most of the primary dystonias with a male to female ratio (M : F) ranging from 1 : 1.48 to 1 : 3.

Conclusions:

The epidemiological features of dystonia in East China we collected were similar to the report in Japan which contrasts partly with that reported in Europe.