An evaluation of the role of environmental factors in the disease penetrance of cervical dystonia.

BACKGROUND: Adult onset primary torsion dystonia (AOPTD) is a poorly penetrant autosomal dominant disorder; most gene carriers are non-manifesting despite having reached an adequate age for penetrance. It is hypothesised that genetic, epigenetic and environmental factors may exert protective or deleterious effects on penetrance of AOPTD. By examining environmental exposure history in cervical dystonia patients and their similarly aged unaffected siblings we aimed to determine the role of previous environmental exposures in relation to disease penetrance. METHODS: A case-control study of 67 patients with cervical dystonia and 67 of their age-matched unaffected siblings was performed. Past environmental exposures were assessed using a detailed 124-question standardised questionnaire. RESULTS: By univariate analysis, cervical dystonia patients, compared to their unaffected siblings, had an increased frequency of a history of car accidents with hospital attendance (OR 10.1, 95% CI 2.1 to 47.4, p=0.004) and surgical episodes (OR 6.5, 95% CI 1.76 to 23.61, p=0.005). Following multivariate analysis, car accidents with hospital attendance (OR 7.3, 95% CI 1.4 to 37.6, p=0.017) and all surgical episodes (OR 4.9, 95% CI 1.24 to 19.31, p=0.023) remained significantly associated with case status. CONCLUSIONS: Cervical dystonia patients had a history, prior to symptom onset, of significantly more frequent episodes of surgery and of car accidents with hospital attendance than their age-matched unaffected siblings. Soft tissue trauma appears to increase risk of development of cervical dystonia in genetically predetermined individuals.

Temporal discrimination, a cervical dystonia endophenotype: penetrance and functional correlates.

The pathogenesis of adult-onset primary dystonia remains poorly understood. There is variable age-related and gender-related expression of the phenotype, the commonest of which is cervical dystonia. Endophenotypes may provide insight into underlying genetic and pathophysiological mechanisms of dystonia. The temporal discrimination threshold (TDT)-the shortest time interval at which two separate stimuli can be detected as being asynchronous-is abnormal both in patients with cervical dystonia and in their unaffected first-degree relatives. Functional magnetic resonance imaging (fMRI) studies have shown that putaminal activation positively correlates with the ease of temporal discrimination between two stimuli in healthy individuals. We hypothesized that abnormal temporal discrimination would exhibit similar age-related and gender-related penetrance as cervical dystonia and that unaffected relatives with an abnormal TDT would have reduced putaminal activation during a temporal discrimination task. TDTs were examined in a group of 192 healthy controls and in 158 unaffected first-degree relatives of 84 patients with cervical dystonia. In 24 unaffected first-degree relatives, fMRI scanning was performed during a temporal discrimination task. The prevalence of abnormal TDTs in unaffected female relatives reached 50% after age 48 years; whereas, in male relatives, penetrance of the endophenotype was reduced. By fMRI, relatives who had abnormal TDTs, compared with relatives who had normal TDTs, had significantly less activation in the putamina and in the middle frontal and precentral gyri. Only the degree of reduction of putaminal activity correlated significantly with worsening of temporal discrimination. These findings further support abnormal temporal discrimination as an endophenotype of cervical dystonia involving disordered basal ganglia circuits.

The endophenotype and the phenotype: temporal discrimination and adult-onset dystonia.

The pathogenesis and the genetic basis of adult-onset primary torsion dystonia remain poorly understood. Because of markedly reduced penetrance in this disorder, a number of endophenotypes have been proposed; many of these may be epiphenomena secondary to disease manifestation. Mediational endophenotypes represent gene expression; the study of trait (endophenotypic) rather than state (phenotypic) characteristics avoids the misattribution of secondary adaptive cerebral changes to pathogenesis. We argue that abnormal temporal discrimination is a mediational endophenotype; its use facilitates examination of the effects of age, gender, and environment on disease penetrance in adult-onset dystonia. Using abnormal temporal discrimination in unaffected first-degree relatives as a marker for gene mutation carriage may inform exome sequencing techniques in families with few affected individuals. We further hypothesize that abnormal temporal discrimination reflects dysfunction in an evolutionarily conserved subcortical-basal ganglia circuit for the detection of salient novel environmental change. The mechanisms of dysfunction in this pathway should be a focus for future research in the pathogenesis of adult-onset primary torsion dystonia.

A Bespoke Electronic Health Journal for Monitoring Response to Botulinum Toxin in Treatment of Cervical Dystonia: Open-Label Observational Study of User Experience.

BACKGROUND: The mainstay of treatment for cervical dystonia (CD) is regular botulinum toxin injections every 3-4 months. Clinical evaluation of response is dependent on the patient's recall of how well symptoms responded to the previous injection. A mobile health app could assist both patients and health care professionals to monitor treatment benefits and side effects to assist with the selection of muscle and toxin dose to be injected at the next visit. The DystoniaDiary is a bespoke electronic health journal for monitoring symptoms of CD and response to treatment. OBJECTIVE: The objective of this study was to assess the acceptability and utility of the DystoniaDiary in patients with CD treated with botulinum toxins as part of their usual care. METHODS: In this open-label, single-center, single-arm observational study, patients attending a botulinum toxin injection clinic were invited to download the DystoniaDiary app. Patients selected up to 3 of their most troublesome CD symptoms (from a predefined list) and were prompted every 3 days to rate the control of these symptoms on a scale from 0 (very badly) to 100 (very well). Dates of onset and wearing off of response to injected botulinum toxin and responses to the Cervical Dystonia Impact Profile (CDIP-58) questionnaire at baseline and week 6 were also recorded in the app. RESULTS: A total of 34 patients installed DystoniaDiary. Twenty-five patients (25/34, 74%) recorded data for ≥12 weeks and 21 patients (21/34, 62%) for ≥16 weeks. Median time between the first and last data input was 140 days with a median of 13 recordings per patient. User experience questionnaires at weeks 4 and 12 (20 respondents) indicated that the majority of respondents found the DystoniaDiary app easy to install and use, liked using it, would recommend it to others (19/20), and wished to continue using it (16/20). A smaller proportion indicated that the DystoniaDiary gave a greater sense of control in managing their CD (13/20). There was interindividual variation in patients' perceptions of control of their symptoms after botulinum toxin injection. Response to treatment was apparent in the symptom control scores for some patients, whereas the severity of other patients' symptoms did not appear to change after treatment. CONCLUSIONS: This observational study demonstrated that the DystoniaDiary app was perceived as useful and acceptable for a large proportion of this sample of patients with CD attending a botulinum toxin clinic. Patients with CD appear to be willing to regularly record symptom severity for at least the duration of a botulinum injection treatment cycle (12-16 weeks). This app may be useful in monitoring and optimizing individual patient responses to botulinum toxin injection.

A Case of New Onset Cervical Dystonia in Pregnancy.

Background: Though uncommon, primary movement disorders can occur in pregnancy, the most common being restless legs syndrome and chorea gravidarum [1]. New onset dystonia in pregnancy has been reported four times previously with a resolution of symptoms within six months of delivery [2345]. Exacerbation of pre-existing movement disorders and the onset of de novo movement disorders during pregnancy support the hypothesis that female sex hormones play an important role in the regulation of basal ganglia circuitry. Case Report: Here we describe a case of new-onset cervical dystonia during pregnancy with persistence of symptoms after delivery. Discussion: The phenotypic overlap between this case and previously reported cases further establishes dystonia gravidarum as a distinct clinical entity.

Longitudinal EEG model detects antisense oligonucleotide treatment effect and increased UBE3A in Angelman syndrome.

Angelman syndrome is a neurodevelopmental disorder caused by deficiency of the maternally inherited UBE3A gene in neurons. Antisense oligonucleotide therapies are under development to reinstate UBE3A protein production. Non-invasive biomarkers to detect target engagement and treatment response are needed to support clinical trials. Delta power measured in the scalp EEG is a reliable biomarker for Angelman syndrome but varies widely across individuals and throughout development, making detection of a treatment effect using single measurements challenging. We utilized a longitudinal dataset of 204 EEG recordings from 56 subjects with Angelman syndrome to develop a natural history model of delta (2-4 Hz) power, with predictors of age, elapsed time, and relative delta power at an initial recording. Using this model, we computed the sample and effect sizes needed to detect a treatment effect in a human clinical trial with 80% power. We applied the same model structure to a mouse model of Angelman syndrome (n = 41) to detect antisense oligonucleotide-mediated treatment effects on absolute delta activity and Ube3a expression. In humans, delta power at a second time point can be reliably predicted using the natural history model. In mice, a treatment effect can be detected after antisense oligonucleotide treatment targeting the Ube3a-antisense transcript through at least 8 weeks post-treatment (P < 1e-15). Deviations in delta power from the expected natural history correlated with Ube3a expression in the mouse model (P < 0.001). Deviations in delta power from a human natural history model in Angelman syndrome can detect antisense oligonucleotide-mediated improvement in Ube3a expression in Angelman syndrome mice and may be relevant for human clinical trials.

A Case of GCH-1 Mutation Dopa-Responsive Dystonia Requiring High Doses of Levodopa for Treatment.

Background: Mutations in the GCH-1 gene are associated with Autosomal Dominant Dopamine Responsive Dystonia (DYT 5). One of the hallmarks of this condition is dramatic and sustained response to low doses of levodopa. Case Report: We present the case of a 22 year old female patient with genetically confirmed GCH-1 Dopa-Responsive Dystonia who had no response to low dose Levodopa but who achieved symptom control on a total dose of 900 mg/day. Discussion: Autosomal Dominant Dopa-Responsive Dystonia is a phenotypical heterogenous condition that, in some cases, may require high doses of levodopa for treatment response. Highlights: Mutations in the GCH-1 gene are associated with Autosomal Dominant Dopamine Responsive Dystonia which is typically defined by dramatic responses to low doses of levodopa. We report a patient with genetically confirmed Dopa-Responsive Dystonia who had no response to low dose Levodopa but who achieved symptom control with 900 mg/day.

Comparing endophenotypes in adult-onset primary torsion dystonia.

Adult-onset primary torsion dystonia (AOPTD) has an autosomal dominant pattern of inheritance with markedly reduced penetrance; the genetic causes of most forms of AOPTD remain unknown. Endophenotypes, markers of sub-clinical gene carriage, may be of use detecting non-manifesting gene carriers in relatives of AOPTD patients. The aim of this study was to compare the utility of the spatial discrimination threshold (SDT) and temporal discrimination threshold (TDT) as potential endophenotypes in AOPTD. Data on other published candidate endophenotypes are also considered. Both SDT and TDT testing were performed in 24 AOPTD patients and 34 of their unaffected first degree relatives; results were compared with normal values from a control population. Of the 24 AOPTD patients 5 (21%) had abnormal SDTs and 20 (83%) had abnormal TDTs. Of the 34 first degree relatives 17 (50%) had abnormal SDTs and 14 (41%) had abnormal TDTs. Discordant results on SDT and TDT testing were found in 16 (67%) AOPTD patients and 21 (62%) first degree relatives. TDT testing has superior sensitivity compared to SDT testing in AOPTD patients; although false positive TDTs are recognised, the specificity of TDT testing in unaffected relatives is not determinable. The high level of discordance between the two tests probably relates methodological difficulties with SDT testing. The SDT is an unreliable AOPTD endophenotype; TDT testing fulfils criteria for a reliable endophenotype with a high sensitivity.

Huntington's disease presenting as amyotrophic lateral sclerosis.

We present the clinical, electrophysiological and molecular genetic findings of a 58-year-old male with genetically confirmed Huntington's disease (HD) and concurrent clinically definite ALS by El Escorial criteria. The patient presented with asymmetric upper limb amyotrophy and weakness, and subsequently developed chorea and cognitive change. Genetic testing confirmed the presence of expanded trinucleotide repeats in huntingtin, consistent with a diagnosis of Huntington's disease. This case confirms the rare coexistence of Huntington's disease and motor neuron degeneration.

Formative evaluation of a telemedicine model for delivering clinical neurophysiology services part I: utility, technical performance and service provider perspective.

BACKGROUND: Formative evaluation is conducted in the early stages of system implementation to assess how it works in practice and to identify opportunities for improving technical and process performance. A formative evaluation of a teleneurophysiology service was conducted to examine its technical and sociological dimensions. METHODS: A teleneurophysiology service providing routine EEG investigation was established. Service use, technical performance and satisfaction of clinical neurophysiology personnel were assessed qualitatively and quantitatively. These were contrasted with a previously reported analysis of the need for teleneurophysiology, and examination of expectation and satisfaction with clinical neurophysiology services in Ireland. A preliminary cost-benefit analysis was also conducted. RESULTS: Over the course of 40 clinical sessions during 20 weeks, 142 EEG investigations were recorded and stored on a file server at a satellite centre which was 130 miles away from the host clinical neurophysiology department. Using a virtual private network, the EEGs were accessed by a consultant neurophysiologist at the host centre for interpretation. The model resulted in a 5-fold increase in access to EEG services as well as reducing average waiting times for investigation by a half. Technically the model worked well, although a temporary loss of virtual private network connectivity highlighted the need for clarity in terms of responsibility for troubleshooting and repair of equipment problems. Referral quality, communication between host and satellite centres, quality of EEG recordings, and ease of EEG review and reporting indicated that appropriate organisational processes were adopted by the service. Compared to traditional CN service delivery, the teleneurophysiology model resulted in a comparable unit cost per EEG. CONCLUSION: Observations suggest that when traditional organisational boundaries are crossed challenges associated with the social dimension of service delivery may be amplified. Teleneurophysiology requires a governance and management that recognises its socio-technical nature.

Formative evaluation of a telemedicine model for delivering clinical neurophysiology services part II: the referring clinician and patient perspective.

BACKGROUND: Feedback from service users will provide insight into opportunities for improvement so that performance can be optimised. In the context of a formative evaluation referring clinician and patient satisfaction with a teleneurophysiology service was examined during a 20 week pilot period. METHODS: Questionnaire surveys of referring clinicians and patients were conducted. RESULTS: Fifteen (58%) clinicians responded to the first part of a postal survey which examined their satisfaction with traditional clinical neurophysiology services. Nine (35%) responded to a second part which assessed their experience with the teleneurophysiology service. Teleneurophysiology improved satisfaction with waiting times, availability of results and impact on patient management. There was unanimous support from the clinicians for the permanent development of a teleneurophysiology service, although 2 cautioned this could delay establishing a neurology service in their region.Eighty-two percent (116/142) of patients responded to a survey of their satisfaction with teleneurophysiology. This was compared to a previous report of 322 patients' experience with traditional CN services in Ireland. Waiting times for appointment were shorter for the former group who supported the telemedicine model recognising that it reduced the travel burden and need for overnight journeys. The two groups were equally anxious about the investigation although the teleneurophysiology patients received more prior information. CONCLUSION: This study illustrates that teleneurophysiology is an acceptable model of service delivery for its primary customers. Their feedback is important in informing appropriate design and governance of such innovative models of health service provision.

Age-Related Sexual Dimorphism in Temporal Discrimination and in Adult-Onset Dystonia Suggests GABAergic Mechanisms.

BACKGROUND: Adult-onset isolated focal dystonia (AOIFD) presenting in early adult life is more frequent in men, whereas in middle age it is female predominant. Temporal discrimination, an endophenotype of adult-onset idiopathic isolated focal dystonia, shows evidence of sexual dimorphism in healthy participants. OBJECTIVES: We assessed the distinctive features of age-related sexual dimorphism of (i) sex ratios in dystonia phenotypes and (ii) sexual dimorphism in temporal discrimination in unaffected relatives of cervical dystonia patients. METHODS: We performed (i) a meta-regression analysis of the proportion of men in published cohorts of phenotypes of adult-onset dystonia in relation to their mean age of onset and (ii) an analysis of temporal discrimination thresholds in 220 unaffected first-degree relatives (125 women) of cervical dystonia patients. RESULTS: In 53 studies of dystonia phenotypes, the proportion of men showed a highly significant negative association with mean age of onset (p < 0.0001, pseudo-R (2) = 59.6%), with increasing female predominance from 40 years of age. Age of onset and phenotype together explained 92.8% of the variance in proportion of men. Temporal discrimination in relatives under the age of 35 years is faster in women than men but the age-related rate of deterioration in women is twice that of men; after 45 years of age, men have faster temporal discrimination than women. CONCLUSION: Temporal discrimination in unaffected relatives of cervical dystonia patients and sex ratios in adult-onset dystonia phenotypes show similar patterns of age-related sexual dimorphism. Such age-related sexual dimorphism in temporal discrimination and adult-onset focal dystonia may reflect common underlying mechanisms. Cerebral GABA levels have been reported to show similar age-related sexual dimorphism in healthy participants and may be the mechanism underlying the observed age-related sexual dimorphism in temporal discrimination and the sex ratios in AOIFD.

Complete right ventricular obstruction caused by a giant cardiac myxoid sarcoma.

Myxoid sarcoma is a very rare variant of primary malignant sarcoma of the heart, which presents like a myxoma. We describe the case of 21-year-old man with a giant myxoid sarcoma occupying most of the right ventricle. He underwent emergency surgery to resect the tumor and replace the tricuspid valve which was infiltrated. Chemotherapy and radiotherapy were given postoperatively.

Cervical dystonia: a disorder of the midbrain network for covert attentional orienting.

While the pathogenesis of cervical dystonia remains unknown, recent animal and clinical experimental studies have indicated its probable mechanisms. Abnormal temporal discrimination is a mediational endophenotype of cervical dystonia and informs new concepts of disease pathogenesis. Our hypothesis is that both abnormal temporal discrimination and cervical dystonia are due to a disorder of the midbrain network for covert attentional orienting caused by reduced gamma-aminobutyric acid (GABA) inhibition, resulting, in turn, from as yet undetermined, genetic mutations. Such disinhibition is (a) subclinically manifested by abnormal temporal discrimination due to prolonged duration firing of the visual sensory neurons in the superficial laminae of the superior colliculus and (b) clinically manifested by cervical dystonia due to disinhibited burst activity of the cephalomotor neurons of the intermediate and deep laminae of the superior colliculus. Abnormal temporal discrimination in unaffected first-degree relatives of patients with cervical dystonia represents a subclinical manifestation of defective GABA activity both within the superior colliculus and from the substantia nigra pars reticulata. A number of experiments are required to prove or disprove this hypothesis.

Motor training as treatment in focal hand dystonia.

Focal hand dystonia may arise as a result of aberrant plasticity from excessive repetitive use. Improvement might be possible with appropriate motor training. Focusing on trying to decrease abnormal overflow of movement to fingers not involved in a task, we developed a motor training program for individualized finger movements. Ten patients with writer's cramp participated in the motor training program. Evaluation was done with the Fahn dystonia scale, kinematic analysis of handwriting, transcranial magnetic stimulation (TMS), and electroencephalography (EEG). Clinical improvement of dystonia was significant using the Fahn dystonia scale, and 6 patients reported an improvement in writing. The handwriting analysis showed a trend for improvement after training in simple exercises. There were no changes in cortical excitability measured by TMS and EEG. Whereas this method of motor training for 4 weeks led to mild subjective improvement and some improvement in handwriting, it is not sufficient to reverse motor cortex abnormalities measured by TMS and EEG.

Effect of ethanol on the central oscillator in essential tremor.

We investigated the effects of ethanol and diazepam on the central, mechanical, and mechanical reflex components of tremor in patients with essential tremor (ET). A double-blind crossover study (ethanol or diazepam) was conducted on 2 separate days. Dose of ethanol or diazepam was calculated in each individual according to height, weight, and age in 10 patients with ET. The postural tremor amplitude at the wrist was recorded using a three-dimensional accelerometer placed on the dorsum of the hand. Electromyogram (EMG) was recorded with surface electrodes placed on the forearm extensors and flexors. To separate central and mechanical (reflex) components, a 500-g weight was placed on the dorsum of the hand during a second tremor measurement. Tremor recordings were done at baseline and 30, 60, 90, and 120 minutes after drug ingestion. Ethanol and diazepam blood levels were measured at baseline and after 20, 40, 80, and 120 minutes. Blood ethanol and diazepam levels were highest after 40 and 80 minutes. The amplitude of the central component 60 minutes after ingestion of ethanol was decreased significantly (P = 0.029) compared with diazepam. Our findings suggest that the improvement in tremor after ethanol ingestion was due, at least in part, to an effect on a central oscillator.