The Italian Dystonia Registry: rationale, design and preliminary findings

The phenomenological approach in dentistry - a narrative review

PURPOSE

Phenomenology is a branch of philosophy that focuses on human lived experience. Illness including dental diseases can affect this living experience. Within the dental literature, there is very little reported on the use of phenomenology compared to other healthcare sciences. Hence, the aim was to review the literature and provide an overview of various applications of phenomenology in dental research.

METHODS

This study was a narrative review using literature in the last 10 years identified by web-based search on PubMed and Scopus using keywords. A total of 33 articles that were closely related to the field and application in dentistry were included. The methodology, main results, and future research recommendations, if applicable, were extracted and reviewed.

RESULTS

The authors in this study had identified several areas such as orofacial pain and pain control research, dental anxiety, dental education, oral healthcare perceptions and access, living with dental diseases and dental treatment experience in which the phenomenological method was used to gain an in-depth understanding of the topic.

CONCLUSIONS

There are several advantages of using the phenomenological research method, such as the small sample size needed, the diverse and unique perspective that can be obtained and the ability to improve current understanding, especially from the first-person perspective.

Exploration of potential immune mechanisms in cervical dystonia

BACKGROUND

Although there are many possible causes for cervical dystonia (CD), a specific etiology cannot be identified in most cases. Prior studies have suggested a relationship between autoimmune disease and some cases of CD, pointing to possible immunological mechanisms.

OBJECTIVE

The goal was to explore the potential role of multiple different immunological mechanisms in CD.

METHODS

First, a broad screening test compared neuronal antibodies in controls and CD. Second, unbiased blood plasma proteomics provided a broad screen for potential biologic differences between controls and CD. Third, a multiplex immunoassay compared 37 markers associated with immunological processes in controls and CD. Fourth, relative immune cell frequencies were investigated in blood samples of controls and CD. Finally, sequencing studies investigated the association of HLA DQB1 and DRB1 alleles in controls versus CD.

RESULTS

Screens for anti-neuronal antibodies did not reveal any obvious abnormalities. Plasma proteomics pointed towards certain abnormalities of immune mechanisms, and the multiplex assay pointed more specifically towards abnormalities in T lymphocytes. Abnormal immune cell frequencies were identified for some CD cases, and these cases clustered together as a potential subgroup. Studies of HLA alleles indicated a possible association between CD and DRB1*15:03, which is reported to mediate the penetrance of autoimmune disorders.

CONCLUSIONS

Altogether, the association of CD with multiple different blood-based immune measures point to abnormalities in cell-mediated immunity that may play a pathogenic role for a subgroup of individuals with CD.

Does thyroid diseases contribute to the natural history of idiopathic adult-onset dystonia? Data from the Italian Dystonia Registry

A few earlier observations and recent controlled studies pointed to the possible contribution of thyroid diseases in idiopathic adult-onset dystonia (IAOD). The aim of this study was to investigate the association between thyroid status and clinical characteristics of IAOD, focusing on dystonia localization, spread, and associated features such as tremors and sensory tricks. Patients were identified from those included in the Italian Dystonia Registry, a multicentre dataset of patients with adult-onset dystonia. The study population included 1518 IAOD patients. Patients with hypothyroidism and hyperthyroidism were compared with those without any thyroid disease. In the 1518 IAOD patients, 167 patients (11%; 95% CI 9.5-12.6%) were diagnosed with hypothyroidism and 42 (2.8%; 95% CI 1.99-3.74) with hyperthyroidism. The three groups were comparable in age at dystonia onset, but there were more women than men in the groups with thyroid disease. Analysing the anatomical distribution of dystonia, more patients with blepharospasm were present in the hyperthyroidism group, but the difference did not reach statistical significance after the Bonferroni correction. The remaining dystonia-affected body sites were similarly distributed in the three groups, as did dystonia-associated features and spread. Our findings provided novel information indicating that the high rate of thyroid diseases is not specific for any specific dystonia subpopulation and does not appear to influence the natural history of the disease.

Prevalence and temporal relationship of clinical co-morbidities in idiopathic dystonia: a UK linkage-based study

While motor and psychiatric phenotypes in idiopathic dystonia are increasingly well understood, a few studies have examined the rate, type, and temporal pattern of other clinical co-morbidities in dystonia. Here, we determine the rates of clinical diagnoses across 13 broad systems-based diagnostic groups, comparing an overall idiopathic dystonia cohort, and sub-cohorts of cervical dystonia, blepharospasm, and dystonic tremor, to a matched-control cohort. Using the SAIL databank, we undertook a longitudinal population-based cohort study (January 1st 1994-December 31st 2017) using anonymised electronic healthcare records for individuals living in Wales (UK), identifying those diagnosed with dystonia through use of a previously validated algorithm. Clinical co-morbid diagnoses were identified from primary health care records, with a 10% prevalence threshold required for onward analysis. Using this approach, 54,166 dystonia cases were identified together with 216,574 matched controls. Within this cohort, ten of the main ICD-10 diagnostic codes exceeded the 10% prevalence threshold over the 20-year period (infection, neurological, respiratory, gastrointestinal, genitourinary, dermatological, musculoskeletal, circulatory, neoplastic, and endocrinological). In the overall dystonia cohort, musculoskeletal (aOR: 1.89, aHR: 1.74), respiratory (aOR: 1.84; aHR: 1.65), and gastrointestinal (aOR: 1.72; aHR: 1.6) disorders had the strongest associations both pre- and post-dystonia diagnosis. However, variation in the rate of association of individual clinical co-morbidities was observed across the cervical, blepharospasm, and tremor dystonia groups. This study suggests an increased rate of specific co-morbid clinical disorders both pre- and post-dystonia diagnosis which should be considered during clinical assessment of those with dystonia to enable optimum symptomatic management.

Does sex influence the natural history of idiopathic adult-onset dystonia?

BACKGROUND

Several earlier studies showed a female predominance in idiopathic adult-onset dystonia (IAOD) affecting the craniocervical area and a male preponderance in limb dystonia. However, sex-related differences may result from bias inherent to study design. Moreover, information is lacking on whether sex-related differences exist in expressing other dystonia-associated features and dystonia spread.

OBJECTIVE

To provide accurate information on the relationship between sex differences, motor phenomenology, dystonia-associated features and the natural history of IAOD.

METHODS

Data of 1701 patients with IAOD from the Italian Dystonia Registry were analysed.

RESULTS

Women predominated over men in blepharospasm, oromandibular, laryngeal and cervical dystonia; the sex ratio was reversed in task-specific upper limb dystonia; and no clear sex difference emerged in non-task-specific upper limb dystonia and lower limb dystonia. This pattern was present at disease onset and the last examination. Women and men did not significantly differ for several dystonia-associated features and tendency to spread. In women and men, the absolute number of individuals who developed dystonia tended to increase from 20 to 60 years and then declined. However, when we stratified by site of dystonia onset, different patterns of female-to-male ratio over time could be observed in the various forms of dystonia.

CONCLUSIONS

Our findings provide novel evidence on sex as a key mediator of IAOD phenotype at disease onset. Age-related sexual dimorphism may result from the varying exposures to specific age-related and sex-related environmental risk factors interacting in a complex manner with biological factors such as hormonal sex factors.

Idiopathic cervical dystonia and non-motor symptoms: a pilot case-control study on autonomic nervous system

PURPOSE

Non-motor symptoms, such as sleep disturbances, fatigue, neuropsychiatric manifestations, cognitive impairment, and sensory abnormalities, have been widely reported in patients with idiopathic cervical dystonia (ICD). This study aimed to clarify the autonomic nervous system (ANS) involvement in ICD patients, which is still unclear in the literature.

METHODS

We conducted a pilot case-control study to investigate ANS in twenty ICD patients and twenty age-sex-matched controls. The Composite Autonomic System Scale 31 was used for ANS clinical assessment. The laser Doppler flowmetry quantitative spectral analysis, applied to the skin and recorded from indices, was used to measure at rest, after a parasympathetic activation (six deep breathing) and two sympathetic stimuli (isometric handgrip and mental calculation), the power of high-frequency and low-frequency oscillations, and the low-frequency/high-frequency ratio.

RESULTS

ICD patients manifested higher clinical dysautonomic symptoms than controls (p < 0.05). At rest, a lower high-frequency power band was detected among ICD patients than controls, reaching a statistically significant difference in the age group of ≥ 57-year-olds (p < 0.05). In the latter age group, ICD patients showed a lower low-frequency/high-frequency ratio than controls at rest (p < 0.05) and after mental calculation (p < 0.05). Regardless of age, during handgrip, ICD patients showed (i) lower low-frequency/high-frequency ratio (p < 0.05), (ii) similar increase of the low-frequency oscillatory component compared to controls, and (iii) stable high-frequency oscillatory component, which conversely decreased in controls. No differences between the two groups were detected during deep breathing.

CONCLUSION

ICD patients showed ANS dysfunction at clinical and neurophysiological levels, reflecting an abnormal parasympathetic-sympathetic interaction likely related to abnormal neck posture and neurotransmitter alterations.

Do cerebrovascular risk factors impact the clinical expression of idiopathic isolated adult-onset dystonia?

BACKGROUND

Although acquired dystonia may develop following ischaemic/haemorrhagic stroke, the relationship between cerebrovascular disease and idiopathic dystonia has been poorly investigated. This cross sectional study aimed at evaluating the impact of cerebrovascular risk factors on the clinical expression of idiopathic adult onset dystonia (IAOD), with reference to dystonia localization and dystonia-associated features.

METHODS

Data were obtained from the Italian Dystonia Registry. Patients with IAOD were stratified into two groups according to the presence of diabetes mellitus and/or arterial hypertension and/or dyslipidemia and/or heart disease. The two groups were compared for demographic features, dystonia phenotype, and dystonia-associated features (sensory trick, tremor, eye symptoms in blepharospasm, and neck pain in cervical dystonia).

RESULTS

A total of 1108 patients participated into the study. Patients who reported one cerebrovascular factor or more (n = 555) had higher age and longer disease duration than patients who did not. On multivariable logistic regression analysis, blepharospasm was the only localization, and sensory trick was the only dystonia-associated feature that was significantly associated with cerebrovascular risk factors. Linear regression analysis showed that the strength of the association between cerebrovascular factors and blepharospasm/sensory trick increased with increasing the number of cerebrovascular factors per patient.

CONCLUSIONS

Results of the present study showed that cerebrovascular risk factors may be associated with specific features of IAOD that is development of blepharospasm and sensory trick. Further studies are needed to better understand the meaning and the mechanisms underlying this association.

DYT-TOR1A dystonia: an update on pathogenesis and treatment

DYT-TOR1A dystonia is a neurological disorder characterized by involuntary muscle contractions and abnormal movements. It is a severe genetic form of dystonia caused by mutations in the TOR1A gene. TorsinA is a member of the AAA + family of adenosine triphosphatases (ATPases) involved in a variety of cellular functions, including protein folding, lipid metabolism, cytoskeletal organization, and nucleocytoskeletal coupling. Almost all patients with TOR1A-related dystonia harbor the same mutation, an in-frame GAG deletion (ΔGAG) in the last of its 5 exons. This recurrent variant results in the deletion of one of two tandem glutamic acid residues (i.e., E302/303) in a protein named torsinA [torsinA(△E)]. Although the mutation is hereditary, not all carriers will develop DYT-TOR1A dystonia, indicating the involvement of other factors in the disease process. The current understanding of the pathophysiology of DYT-TOR1A dystonia involves multiple factors, including abnormal protein folding, signaling between neurons and glial cells, and dysfunction of the protein quality control system. As there are currently no curative treatments for DYT-TOR1A dystonia, progress in research provides insight into its pathogenesis, leading to potential therapeutic and preventative strategies. This review summarizes the latest research advances in the pathogenesis, diagnosis, and treatment of DYT-TOR1A dystonia.

Phenotypic Variability in Acquired and Idiopathic Dystonia

Background

To date, a few studies have systematically investigated differences in the clinical spectrum between acquired and idiopathic dystonias.

Objectives

To compare demographic data and clinical features in patients with adult-onset acquired and idiopathic dystonias.

Methods

Patients were identified from among those included in the Italian Dystonia Registry, a multicenter Italian dataset of patients with adult-onset dystonia. Study population included 116 patients with adult-onset acquired dystonia and 651 patients with isolated adult-onset idiopathic dystonia.

Results

Comparison of acquired and idiopathic dystonia revealed differences in the body distribution of dystonia, with oromandibular dystonia, limb and trunk dystonia being more frequent in patients with acquired dystonia. The acquired dystonia group was also characterized by lower age at dystonia onset, greater tendency to spread, lower frequency of head tremor, sensory trick and eye symptoms, and similar frequency of neck pain associated with CD and family history of dystonia/tremor.

Conclusions

The clinical phenomenology of dystonia may differ between acquired and idiopathic dystonia, particularly with regard to the body localization of dystonia and the tendency to spread. This dissimilarity raises the possibility of pathophysiological differences between etiologic categories.

Thyroid disease in cervical dystonia

There are many possible etiologies for cervical dystonia (CD), but a cause cannot be identified in most cases. Most recent attention has focused on genetic causes, although a few prior studies have highlighted autoimmune mechanisms instead. Because autoimmune disorders frequently co-exist, the current study evaluated the hypothesis that autoimmune disorders might be more common in CD than neurological controls. The frequency of 32 common autoimmune disorders was evaluated using a systematic survey comparing 300 subjects with CD with 391 neurological controls. The frequency of thyroid disease was significantly higher in CD (20%) compared with controls (6%). Regression analyses that accounted for age and sex revealed an odds ratio of 4.5 (95% CI 2.5-8.1, p < 0.001). All other autoimmune disorders occurred with similar frequencies in CD and controls. Although these studies do not establish a mechanistic link between CD and autoimmune disease, they suggest the need for further attention to a potential relationship, and more specifically with thyroid disease.

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.

The Italian tremor Network (TITAN): rationale, design and preliminary findings

INTRODUCTION

The recently released classification has revised the nosology of tremor, defining essential tremor (ET) as a syndrome and fueling an enlightened debate about some newly conceptualized entities such as ET-plus. As a result, precise information of demographics, clinical features, and about the natural history of these conditions are lacking.

METHODS

The ITAlian tremor Network (TITAN) is a multicenter data collection platform, the aim of which is to prospectively assess, according to a standardized protocol, the phenomenology and natural history of tremor syndromes.

RESULTS

In the first year of activity, 679 patients have been recruited. The frequency of tremor syndromes varied from 32% of ET and 41% of ET-plus to less than 3% of rare forms, including focal tremors (2.30%), task-specific tremors (1.38%), isolated rest tremor (0.61%), and orthostatic tremor (0.61%). Patients with ET-plus were older and had a higher age at onset than ET, but a shorter disease duration, which might suggest that ET-plus is not a disease stage of ET. Familial aggregation of tremor and movement disorders was present in up to 60% of ET cases and in about 40% of patients with tremor combined with dystonia. The body site of tremor onset was different between tremor syndromes, with head tremor being most commonly, but not uniquely, associated with dystonia.

CONCLUSIONS

The TITAN study is anticipated to provide clinically relevant prospective information about the clinical correlates of different tremor syndromes and their specific outcomes and might serve as a basis for future etiological, pathophysiological, and therapeutic research.

Diagnostic Neurophysiologic Biomarkers for Task‐Specific Dystonia

Background

Task-specific dystonia (TSD) is a challenging clinical diagnosis with no objective diagnostic biomarkers.

Objective

The objective of this study was to test 2 neurophysiologic variables using transcranial magnetic stimulation as potential diagnostic biomarkers for TSD.

Methods

We tested (1) cortical silent period (CSP) and (2) dorsal inferior parietal lobule-motor cortex (dIPL-M1) physiologic connectivity in 9 patients with the writer's cramp form of TSD and 12 healthy volunteers on 2 separate sessions.

Results

CSP was significantly prolonged (P < 0.0001) in TSD and could classify TSD with high sensitivity and specificity with areas under the receiver operating characteristic curve (AUCs) = 0.94 and 0.90, respectively, for 2 separate sessions with an intraclass correlation = 0.79. dIPL-M1 interaction was notable for significant motor cortical inhibition in TSD compared with facilitation in healthy subjects (P < 0.0001) and could classify TSD with high sensitivity and specificity with AUCs = 0.96 and 0.86, respectively.

Conclusion

CSP and dIPL-M1 physiologic connectivity can classify TSD with high sensitivity, specificity, reproducibility, and reliability.

Sudden Onset, Fixed Dystonia and Acute Peripheral Trauma as Diagnostic Clues for Functional Dystonia

Background

The differentiation of functional dystonia from idiopathic dystonia may be clinically challenging.

Objective

To identify clinical features suggestive of functional dystonia to guide physicians to distinguish functional dystonia from idiopathic dystonia.

Methods

Patient data were extracted from the Italian Registry of Functional Motor Disorders and the Italian Registry of Adult Dystonia. Patients with functional and idiopathic dystonia were followed up at the same clinical sites, and they were similar in age and sex.

Results

We identified 113 patients with functional dystonia and 125 with idiopathic dystonia. Sudden onset of dystonia, evidence of fixed dystonia, and acute peripheral trauma before dystonia onset were more frequent in the functional dystonia group. No study variable alone achieved satisfactory sensitivity and specificity, whereas a combination of variables yielded 85% sensitivity and 98% specificity. A diagnostic algorithm was developed to reduce the risk of misclassifying functional dystonia.

Conclusion

Our findings extend the current diagnostic approach to functional dystonia by showing that clinical information about symptom onset, fixed dystonia, and history of peripheral trauma may provide key clues in the diagnosis of functional dystonia.

Second hit hypothesis in dystonia: Dysfunctional cross talk between neuroplasticity and environment?

One of the great mysteries in dystonia pathophysiology is the role of environmental factors in disease onset and development. Progress has been made in defining the genetic components of dystonic syndromes, still the mechanisms behind the discrepant relationship between dystonic genotype and phenotype remain largely unclear. Within this review, the preclinical and clinical evidence for environmental stressors as disease modifiers in dystonia pathogenesis are summarized and critically evaluated. The potential role of extragenetic factors is discussed in monogenic as well as adult-onset isolated dystonia. The available clinical evidence for a "second hit" is analyzed in light of the reduced penetrance of monogenic dystonic syndromes and put into context with evidence from animal and cellular models. The contradictory studies on adult-onset dystonia are discussed in detail and backed up by evidence from animal models. Taken together, there is clear evidence of a gene-environment interaction in dystonia, which should be considered in the continued quest to unravel dystonia pathophysiology.

Spread of segmental/multifocal idiopathic adult-onset dystonia to a third body site

BACKGROUND

Adult-onset focal dystonia can spread to involve one, or less frequently, two additional body regions. Spread of focal dystonia to a third body site is not fully characterized.

MATERIALS AND METHODS

We retrospectively analyzed data from the Italian Dystonia Registry, enrolling patients with segmental/multifocal dystonia involving at least two parts of the body or more. Survival analysis estimated the relationship between dystonia features and spread to a third body part.

RESULTS

We identified 340 patients with segmental/multifocal dystonia involving at least two body parts. Spread of dystonia to a third body site occurred in 42/241 patients (17.4%) with focal onset and 10/99 patients (10.1%) with segmental/multifocal dystonia at onset. The former had a greater tendency to spread than patients with segmental/multifocal dystonia at onset. Gender, years of schooling, comorbidity, family history of dystonia/tremor, age at dystonia onset, and disease duration could not predict spread to a third body site. Among patients with focal onset in different body parts (cranial, cervical, and upper limb regions), there was no association between site of focal dystonia onset and risk of spread to a third body site.

DISCUSSION AND CONCLUSION

Spread to a third body site occurs in a relative low percentage of patients with idiopathic adult-onset dystonia affecting two body parts. Regardless of the site of dystonia onset and of other demographic/clinical variables, focal onset seems to confer a greater risk of spread to a third body site in comparison to patients with segmental/multifocal dystonia at onset.

Neuroimaging in idiopathic adult-onset focal dystonia

We aimed to study the attitude of Italian neurologists in the use of conventional MRI in patients with idiopathic adult-onset focal dystonia. Patients were included in the Italian Dystonia Registry by experts working in different Italian centers. MRI was available for 1045 of the 1471 (71%) patients included in the analysis. Using logistic regression analysis, we found that MRI was more likely to be performed in patients with cervical dystonia, spasmodic dysphonia, or non-task-specific upper limb dystonia, whereas it was less likely to be performed in patients with blepharospasm or task-specific upper limb dystonia. We did not find differences in the number of MRIs performed between neurological centers in Northern, Central, and Southern Italy. We conclude that although the diagnosis of idiopathic adult-onset dystonia is mainly based on clinical grounds, many movement disorder experts rely on MRI to confirm a diagnosis of idiopathic dystonia. We suggest that neuroimaging should be used in patients with adult-onset focal dystonia to rule out secondary forms.

Shedding light on thyroid hormone disorders and Parkinson disease pathology: mechanisms and risk factors

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons. Dopaminergic system is interconnected with the hypothalamic-pituitary-thyroid axis. Dopamine (DA) upregulates thyrotropin releasing hormone (TRH) while downregulating thyroid stimulating hormone (TSH) and thyroid hormones. Moreover, TRH stimulates DA release. PD is associated with impaired regulation of TSH and thyroid hormones (TH) levels, which in turn associate with severity and different subtypes of PD, while levodopa and bromocriptine treatment can interfere with hypothalamic-pituitary-thyroid axis. Thyroid disturbances, including hypothyroidism, Hashimoto's thyroiditis (HT), hyperthyroidism and Graves' disease (GD) not only increase the risk of PD but also share some clinical signs with PD. Also, several genes including RASD2, WSB1, MAPT, GIRK2, LRRK2 and gene products like neurotensin and NOX/DUOX affect the risk for both PD and thyroid disease. Hypothyroidism is associated with obesity, hypercholesterolemia, anemia and altered cerebral blood flow which are associated with PD pathology. Herein we provide a comprehensive view on the association between PD and thyroid hormones regulation and dysregulations, hoping to provide new avenues towards targeted treatment of PD. We performed a comprehensive search in literature using Pubmed and Scopus, yielding to a total number of 36 original articles that had addressed the association between thyroid hormone disorders and PD.

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.

Motor and Sensory Features of Cervical Dystonia Subtypes: Data From the Italian Dystonia Registry

Introduction: Cervical dystonia (CD) is one of the most common forms of adult-onset isolated dystonia. Recently, CD has been classified according to the site of onset and spread, in different clinical subgroups, that may represent different clinical entities or pathophysiologic subtypes. In order to support this hypothesis, in this study we have evaluated whether different subgroups of CD, that clinically differ for site of onset and spread, also imply different sensorimotor features.

Methods: Clinical and demographic data from 842 patients with CD from the Italian Dystonia Registry were examined. Motor features (head tremor and tremor elsewhere) and sensory features (sensory trick and neck pain) were investigated. We analyzed possible associations between motor and sensory features in CD subgroups [focal neck onset, no spread (FNO-NS); focal neck onset, segmental spread (FNO-SS); focal onset elsewhere with segmental spread to neck (FOE-SS); segmental neck involvement without spread (SNI)].

Results: In FNO-NS, FOE-SS, and SNI subgroups, head tremor was associated with the presence of tremor elsewhere. Sensory trick was associated with pain in patients with FNO-NS and with head tremor in patients with FNO-SS.

Conclusion: The frequent association between head tremor and tremor elsewhere may suggest a common pathophysiological mechanism. Two mechanisms may be hypothesized for sensory trick: a gating mechanism attempting to reduce pain and a sensorimotor mechanism attempting to control tremor.

Demographic and clinical determinants of neck pain in idiopathic cervical dystonia

Cervical dystonia is associated with neck pain in a significant proportion of cases, but the mechanisms underlying pain are largely unknown. In this exploratory study, we compared demographic and clinical variables in cervical dystonia patients with and without neck pain from the Italian Dystonia Registry. Univariable and multivariable logistic regression analysis indicated a higher frequency of sensory trick and a lower educational level among patients with pain.

Risk of spread in adult-onset isolated focal dystonia: a prospective international cohort study

OBJECTIVE

Isolated focal dystonia can spread to muscles beyond the initially affected body region, but risk of spread has not been evaluated in a prospective manner. Furthermore, body regions at risk for spread and the clinical factors associated with spread risk are not well characterised. We sought here to prospectively characterise risk of spread in recently diagnosed adult-onset isolated focal dystonia patients.

METHODS

Patients enrolled in the Dystonia Coalition with isolated dystonia affecting only the neck, upper face, hand or larynx at onset of symptoms were included. Timing of follow-up visits was based on a sliding scale depending on symptom onset and ranged from 1 to 4 years. Descriptive statistics, Kaplan-Meier survival curves and Cox proportional hazard regression models were used to assess clinical characteristics associated with dystonia spread.

RESULTS

487 enrolled participants (68.3% women; mean age: 55.6±12.2 years) met our inclusion/exclusion criteria. Spread was observed in 50% of blepharospasm, 8% of cervical dystonia, 17% of hand dystonia and 16% of laryngeal dystonia cases. Most common regions for first spread were the oromandibular region (42.2%) and neck (22.4%) for blepharospasm, hand (3.5%) for cervical dystonia and neck for hand (12.8%) and laryngeal (15.8%) dystonia. Increased spread risk was associated with a positive family history (HR=2.18, p=0.012) and self-reported alcohol responsiveness (HR=2.59, p=0.009).

CONCLUSIONS

Initial body region affected in isolated focal dystonia has differential risk and patterns of spread. Genetic factors likely influence the risk of spread. These findings can aid clinical prognostication and inform future investigations into potential disease-modifying treatments.

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.

Sensorimotor Perceptive Rehabilitation Integrated (SPRInt) program: exercises with augmented movement feedback associated to botulinum neurotoxin in idiopathic cervical dystonia-an observational study

BACKGROUND

Idiopathic cervical dystonia (ICD) is a focal dystonia affecting neck muscles. Botulinum neurotoxin (BoNT) is the first-line treatment of ICD and different physical therapies (including exercise) are often proposed as adjunct treatments. However, the actual effectiveness of exercise in ICD is unclear. The aim of the current work is to assess the potential effectiveness of the Sensorimotor Perceptive Rehabilitation Integrated (SPRInt) exercise program as adjunct therapy for ICD.

METHODS

Fifteen ICD patients received BoNT injections in the neck muscles and, 12 weeks later, received BoNT a second time and SPRInt started. SPRInt consists in 18 exercise sessions in which augmented feedback of movement (including visual and acoustic feedback) is extensively used. Dystonia burden was measured by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). Patients were evaluated immediately before, 6 and 12 weeks after each BoNT injection.

RESULTS

Six weeks after the first BoNT injection (i.e., at BoNT peak effect), TWSTRS total score was better than baseline and remained improved at 12 weeks. TWSTRS disability domain slightly improved 6 weeks after the first BoNT injection, but after 6 more weeks returned to its baseline level. Disability improved more at SPRInt end (i.e., 6 weeks after the second BoNT injection), being even lower than after toxin alone. With a single-subject analysis, 4/10 patients who did not improve disability after BoNT improved after SPRInt plus BoNT.

CONCLUSIONS

SPRInt plus BoNT can be more effective than BoNT alone in improving cervical dystonia patients' difficulties in the activities of daily living.

TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier NCT03247868 (https://register.clinicaltrials.gov).

Peripheral trauma and risk of dystonia: What are the evidences and potential co-risk factors from a population insurance database?

Background

Dystonia is a neurological syndrome typically resulting in abnormal postures.

Objectives

We tested the role of physical injury as potential risk factor for development of dystonia using The National Health Insurance Research Database of Taiwan.

Methods

We identified 65704 people who were coded in the database as having had peripheral traumatic injuries (ICD-9-CM 807–848 and 860–959) in the year 2000. Patients with traumatic brain or spine injuries were excluded from analysis. We matched them using purposive sampling with 65704 people in the database who had not suffered peripheral trauma. We looked then at the incidence of dystonia occurring at least 1 year from the date of the peripheral trauma until 2011. Psychiatric symptoms (depression and anxiety) and sleeps difficulties have been investigated as potential covariates.

Results

We found 189 patients with dystonia (0.28%) in the trauma group, and 52 patients with dystonia (0.08%) in the non-trauma group. Trauma was independently associated with dystonia (adjusted HR = 3.12, 95% CI = 2.30–4.24). The incidence density of dystonia in the trauma group was 2.27 per 10000 person-years, while it was 0.71 per 10000 person-years in the non-trauma group Beyond the peripheral trauma, other variables associated to the incidence of dystonia included female sex, aged 40 years and above, depression and sleep disorders.

Conclusion

These data from a large population dataset support traumatic injury as a risk factor for the development of dystonia.

Pain in cervical dystonia and the antinociceptive effects of botulinum toxin: what is currently known?

Pain is the most common and disabling non-motor symptom in cervical dystonia (CD). Up to 88.9% of patients report pain at some point in the course of the disease. It is still a matter of debate whether CD-related pain originates only from prolonged muscle contraction. Recent data suggest that the alterations of transmission and processing of nociceptive stimuli play a crucial role in pain development. Botulinum toxin (BT) is the first-line therapy for CD. Despite fully elucidated muscle relaxant action, the antinociceptive effect of BT remains unclear and probably exceeds a simple decompression of the nerve fibers due to the reduction in muscle tone. The proposed mechanisms of the antinociceptive action of BT include inhibition of pain mediator release, inhibition of membrane sodium channels, retrograde axonal transport and impact on the other pain pathways. This article summarizes the current knowledge about the antinociceptive properties of BT and the clinical analgesic efficacy in the treatment of CD patients.

Remission in dystonia - Systematic review of the literature and meta-analysis

In isolated, sporadic dystonia, it has been occasionally reported that some patients might undergo symptom remission. However, the exact clinical characteristics of patients with remission remain understudied. Given the important prognostic and pathophysiological implications of dystonic remission, we here provide a systematic review of the literature and a meta-analysis to assess demographic and clinical features associated with this phenomenon. We also provide a list of operational criteria to better define dystonic remission. Using PubMed and Embase, we conducted a systematic literature search in March 2018. 626 records were screened, 31 studies comprising data of 2551 cases with reports predominantly from patients with cervical dystonia (n = 1319) or blepharospasm/Meige syndrome (n = 704) were included in qualitative analysis. Five studies reporting remission in cervical dystonia were eligible for meta-analysis. Complete remission was reported in 11.8% and partial remission for 4.4% of cases. Remission rates were higher in cervical dystonia than in blepharospasm/Meige (e.g. complete remission 15.4% vs. 5.8% respectively). Remission occurred on average 4.5 years after onset of dystonic symptoms. However, the majority of patients (63.8%) relapsed. Meta-analysis for cervical dystonia showed that patients with remission were significantly younger at symptom onset than patients without remission (mean difference -7.13 years [95% CI: 10.58, -3.68], p < 0.0001). Based on our findings, we propose that the degree, the conditions associated with the onset, and the duration of remission are key factors to be considered in a unifying definition of dystonic remission.

Expert recommendations for diagnosing cervical, oromandibular, and limb dystonia

BACKGROUND

Diagnosis of focal dystonia is based on clinical grounds and is therefore open to bias. To date, diagnostic guidelines have been only proposed for blepharospasm and laryngeal dystonia. To provide practical guidance for clinicians with less expertise in dystonia, a group of Italian Movement Disorder experts formulated clinical diagnostic recommendations for cervical, oromandibular, and limb dystonia.

METHODS

A panel of four neurologists generated a list of clinical items related to the motor phenomenology of the examined focal dystonias and a list of clinical features characterizing neurological/non-neurological conditions mimicking dystonia. Thereafter, ten additional expert neurologists assessed the diagnostic relevance of the selected features and the content validity ratio was calculated. The clinical features reaching a content validity ratio > 0.5 contributed to the final recommendations.

RESULTS

The recommendations retained patterned and repetitive movements/postures as the core feature of dystonia in different body parts. If present, a sensory trick confirmed diagnosis of dystonia. In the patients who did not manifest sensory trick, active exclusion of clinical features related to conditions mimicking dystonia (features that would be expected to be absent in dystonia) would be necessary for dystonia to be diagnosed.

DISCUSSION

Although reliability, sensitivity, and specificity of the recommendations are yet to be demonstrated, information from the present study would hopefully facilitate diagnostic approach to focal dystonias in the clinical practice and would be the basis for future validated diagnostic guidelines.