Eye-Closure Rate Modulation in Blepharospasm.

Background: Blepharospasm (BSP) is a type of focal dystonia and a number of patients with BSP have relatives also affected by BSP. The objective of this study was to quantify eye closure rates during activities of daily living in individuals with BSP and individuals without BSP with and without a first-degree relative with BSP. Methods: 37 patients with BSP (BSP group), 10 asymptomatic volunteers with a first-degree relative with BSP (RELATIVES group) and 25 asymptomatic volunteers without relatives with BSP (HV group) were recruited. The number of eye closures for each task were counted per 60 seconds, with a video recording. Within and between groups statistical comparisons of eye-closure rates were performed. Results: The eye-closure rates of the RELATIVES group were not different from the BSP group for the majority of the tasks (except for watching television), and the HV group (for all tasks). The rate of eye closures in the BSP group compared to HV, was significantly increased in two tasks, resting and watching television. Discussion: Eye closure rate varies considerably during activities of daily living in all groups. Individuals with first degree relative with BSP are more likely to have increased eye closure rate at rest.

Identification of genetic risk loci and causal insights associated with Parkinson's disease in African and African admixed populations: a genome-wide association study.

BACKGROUND: An understanding of the genetic mechanisms underlying diseases in ancestrally diverse populations is an important step towards development of targeted treatments. Research in African and African admixed populations can enable mapping of complex traits, because of their genetic diversity, extensive population substructure, and distinct linkage disequilibrium patterns. We aimed to do a comprehensive genome-wide assessment in African and African admixed individuals to better understand the genetic architecture of Parkinson's disease in these underserved populations. METHODS: We performed a genome-wide association study (GWAS) in people of African and African admixed ancestry with and without Parkinson's disease. Individuals were included from several cohorts that were available as a part of the Global Parkinson's Genetics Program, the International Parkinson's Disease Genomics Consortium Africa, and 23andMe. A diagnosis of Parkinson's disease was confirmed clinically by a movement disorder specialist for every individual in each cohort, except for 23andMe, in which it was self-reported based on clinical diagnosis. We characterised ancestry-specific risk, differential haplotype structure and admixture, coding and structural genetic variation, and enzymatic activity. FINDINGS: We included 197 918 individuals (1488 cases and 196 430 controls) in our genome-wide analysis. We identified a novel common risk factor for Parkinson's disease (overall meta-analysis odds ratio for risk of Parkinson's disease 1·58 [95% CI 1·37-1·80], p=2·397 × 10-14) and age at onset at the GBA1 locus, rs3115534-G (age at onset ß=-2·00 [SE=0·57], p=0·0005, for African ancestry; and ß=-4·15 [0·58], p=0·015, for African admixed ancestry), which was rare in non-African or non-African admixed populations. Downstream short-read and long-read whole-genome sequencing analyses did not reveal any coding or structural variant underlying the GWAS signal. The identified signal seems to be associated with decreased glucocerebrosidase activity. INTERPRETATION: Our study identified a novel genetic risk factor in GBA1 in people of African ancestry, which has not been seen in European populations, and it could be a major mechanistic basis of Parkinson's disease in African populations. This population-specific variant exerts substantial risk on Parkinson's disease as compared with common variation identified through GWAS and it was found to be present in 39% of the cases assessed in this study. This finding highlights the importance of understanding ancestry-specific genetic risk in complex diseases, a particularly crucial point as the Parkinson's disease field moves towards targeted treatments in clinical trials. The distinctive genetics of African populations highlights the need for equitable inclusion of ancestrally diverse groups in future trials, which will be a valuable step towards gaining insights into novel genetic determinants underlying the causes of Parkinson's disease. This finding opens new avenues towards RNA-based and other therapeutic strategies aimed at reducing lifetime risk of Parkinson's disease. FUNDING: The Global Parkinson's Genetics Program, which is funded by the Aligning Science Across Parkinson's initiative, and The Michael J Fox Foundation for Parkinson's Research.

Genome-wide Association Identifies Novel Etiological Insights Associated with Parkinson's Disease in African and African Admixed Populations.

Background: Understanding the genetic mechanisms underlying diseases in ancestrally diverse populations is a critical step towards the realization of the global application of precision medicine. The African and African admixed populations enable mapping of complex traits given their greater levels of genetic diversity, extensive population substructure, and distinct linkage disequilibrium patterns. Methods: Here we perform a comprehensive genome-wide assessment of Parkinson's disease (PD) in 197,918 individuals (1,488 cases; 196,430 controls) of African and African admixed ancestry, characterizing population-specific risk, differential haplotype structure and admixture, coding and structural genetic variation and polygenic risk profiling. Findings: We identified a novel common risk factor for PD and age at onset at the GBA1 locus (risk, rs3115534-G; OR=1.58, 95% CI = 1.37 - 1.80, P=2.397E-14; age at onset, BETA =-2.004, SE =0.57, P = 0.0005), that was found to be rare in non-African/African admixed populations. Downstream short- and long-read whole genome sequencing analyses did not reveal any coding or structural variant underlying the GWAS signal. However, we identified that this signal mediates PD risk via expression quantitative trait locus (eQTL) mechanisms. While previously identified GBA1 associated disease risk variants are coding mutations, here we suggest a novel functional mechanism consistent with a trend in decreasing glucocerebrosidase activity levels. Given the high population frequency of the underlying signal and the phenotypic characteristics of the homozygous carriers, we hypothesize that this variant may not cause Gaucher disease. Additionally, the prevalence of Gaucher's disease in Africa is low. Interpretation: The present study identifies a novel African-ancestry genetic risk factor in GBA1 as a major mechanistic basis of PD in the African and African admixed populations. This striking result contrasts to previous work in Northern European populations, both in terms of mechanism and attributable risk. This finding highlights the importance of understanding population-specific genetic risk in complex diseases, a particularly crucial point as the field moves toward precision medicine in PD clinical trials and while recognizing the need for equitable inclusion of ancestrally diverse groups in such trials. Given the distinctive genetics of these underrepresented populations, their inclusion represents a valuable step towards insights into novel genetic determinants underlying PD etiology. This opens new avenues towards RNA-based and other therapeutic strategies aimed at reducing lifetime risk. Evidence Before this Study: Our current understanding of Parkinson's disease (PD) is disproportionately based on studying populations of European ancestry, leading to a significant gap in our knowledge about the genetics, clinical characteristics, and pathophysiology in underrepresented populations. This is particularly notable in individuals of African and African admixed ancestries. Over the last two decades, we have witnessed a revolution in the research area of complex genetic diseases. In the PD field, large-scale genome-wide association studies in the European, Asian, and Latin American populations have identified multiple risk loci associated with disease. These include 78 loci and 90 independent signals associated with PD risk in the European population, nine replicated loci and two novel population-specific signals in the Asian population, and a total of 11 novel loci recently nominated through multi-ancestry GWAS efforts.Nevertheless, the African and African admixed populations remain completely unexplored in the context of PD genetics. Added Value of this Study: To address the lack of diversity in our research field, this study aimed to conduct the first genome-wide assessment of PD genetics in the African and African admixed populations. Here, we identified a genetic risk factor linked to PD etiology, dissected African-specific differences in risk and age at onset, characterized known genetic risk factors, and highlighted the utility of the African and African admixed risk haplotype substructure for future fine-mapping efforts. We identified a novel disease mechanism via expression changes consistent with decreased GBA1 activity levels. Future large scale single cell expression studies should investigate the neuronal populations in which expression differences are most prominent. This novel mechanism may hold promise for future efficient RNA-based therapeutic strategies such as antisense oligonucleotides or short interfering RNAs aimed at preventing and decreasing disease risk. We envisage that these data generated under the umbrella of the Global Parkinson's Genetics Program (GP2) will shed light on the molecular mechanisms involved in the disease process and might pave the way for future clinical trials and therapeutic interventions. This work represents a valuable resource in an underserved population, supporting pioneering research within GP2 and beyond. Deciphering causal and genetic risk factors in all these ancestries will help determine whether interventions, potential targets for disease modifying treatment, and prevention strategies that are being studied in the European populations are relevant to the African and African admixed populations. Implications of all the Available Evidence: We nominate a novel signal impacting GBA1 as the major genetic risk factor for PD in the African and African admixed populations. The present study could inform future GBA1 clinical trials, improving patient stratification. In this regard, genetic testing can help to design trials likely to provide meaningful and actionable answers. It is our hope that these findings may ultimately have clinical utility for this underrepresented population.

Anti-PL12 Anti-Synthetase Syndrome and Amyotrophic Lateral Sclerosis: A Case Report of a Rare Comorbidity.

BACKGROUND Anti-PL-12 syndrome is a rare form of myositis. Amyotrophic lateral sclerosis (ALS) is the commonest of the motor neuron disorders. However, the 2 conditions have not been reported to occur together in a single individual. This case report describes a patient who was diagnosed with anti-PL-12 anti-synthetase syndrome and then subsequently was diagnosed with ALS. CASE REPORT A 55-year-old male patient had anti-PL-12 syndrome and ALS occurring together. The patient initially presented with musculoskeletal complaints and was diagnosed with anti-PL-12 syndrome. He later went on to develop shortness of breath. Neurophysiological testing subsequently confirmed ALS as the patient experienced worsening muscle weakness over a 2-year period. A muscle biopsy performed showed neurogenic and myopathic process. The patient eventually lost the ability to ambulate without mobility assistance and suffered cardiac arrest due to complications from ALS, specifically diaphragmatic dysfunction. CONCLUSIONS This case report represents the first documented case of a patient having both anit-PL-12 syndrome and ALS together. It has been suggested that having an autoimmune disease (AID) may increase the subsequent risk of developing ALS. Previous studies did not conduct evaluation to ascertain serological markers for AS antibodies. Lab tests were rechecked and revalidated multiple times in separate facilities for confirmation of results in case of initial lab error. This may suggest a common etiology for both anti-PL-12 syndrome and ALS.

Nonalcoholic Fatty Liver Disease in Patients with Inherited and Sporadic Motor Neuron Degeneration.

We describe evidence of fatty liver disease in patients with forms of motor neuron degeneration with both genetic and sporadic etiology compared to controls. A group of 13 patients with motor neuron disease underwent liver imaging and laboratory analysis. The cohort included five patients with hereditary spastic paraplegia, four with sporadic amyotrophic lateral sclerosis (ALS), three with familial ALS, and one with primary lateral sclerosis. A genetic mutation was reported in nine of the thirteen motor neuron disease (MND) patients. Fatty liver disease was detected in 10 of 13 (77%) MND patients via magnetic resonance spectroscopy, with an average dome intrahepatic triacylglycerol content of 17% (range 2-63%, reference ≤5.5%). Liver ultrasound demonstrated evidence of fatty liver disease in 6 of the 13 (46%) patients, and serum liver function testing revealed significantly elevated alanine aminotransferase levels in MND patients compared to age-matched controls. Fatty liver disease may represent a non-neuronal clinical component of various forms of MND.

Rate of sepsis hospitalizations after misdiagnosis in adult emergency department patients: a look-forward analysis with administrative claims data using Symptom-Disease Pair Analysis of Diagnostic Error (SPADE) methodology in an integrated health system.

OBJECTIVES: Delays in sepsis diagnosis can increase morbidity and mortality. Previously, we performed a Symptom-Disease Pair Analysis of Diagnostic Error (SPADE) "look-back" analysis to identify symptoms at risk for delayed sepsis diagnosis. We found treat-and-release emergency department (ED) encounters for fluid and electrolyte disorders (FED) and altered mental status (AMS) were associated with downstream sepsis hospitalizations. In this "look-forward" analysis, we measure the potential misdiagnosis-related harm rate for sepsis among patients with these symptoms. METHODS: Retrospective cohort study using electronic health record and claims data from Kaiser Permanente Mid-Atlantic States (2013-2018). Patients ≥18 years with ≥1 treat-and-release ED encounter for FED or AMS were included. Observed greater than expected sepsis hospitalizations within 30 days of ED treat-and-release encounters were considered potential misdiagnosis-related harms. Temporal analyses were employed to differentiate case and comparison (superficial injury/contusion ED encounters) cohorts. RESULTS: There were 4,549 treat-and-release ED encounters for FED or AMS, 26 associated with a sepsis hospitalization in the next 30 days. The observed (0.57%) minus expected (0.13%) harm rate was 0.44% (absolute) and 4.5-fold increased over expected (relative). There was a spike in sepsis hospitalizations in the week following FED/AMS ED visits. There were fewer sepsis hospitalizations and no spike in admissions in the week following superficial injury/contusion ED visits. Potentially misdiagnosed patients were older and more medically complex. CONCLUSIONS: Potential misdiagnosis-related harms from sepsis are infrequent but measurable using SPADE. This look-forward analysis validated our previous look-back study, demonstrating the SPADE approach can be used to study infectious disease syndromes.

Prospective Home-use Study on Non-invasive Neuromodulation Therapy for Essential Tremor.

Highlights: This prospective study is one of the largest clinical trials in essential tremor to date. Study findings suggest that individualized non-invasive neuromodulation therapy used repeatedly at home over three months results in safe and effective hand tremor reduction and improves quality of life for many essential tremor patients. Background: Two previous randomized, controlled, single-session trials demonstrated efficacy of non-invasive neuromodulation therapy targeting the median and radial nerves for reducing hand tremor. This current study evaluated efficacy and safety of the therapy over three months of repeated home use. Methods: This was a prospective, open-label, post-clearance, single-arm study with 263 patients enrolled across 26 sites. Patients were instructed to use the therapy twice daily for three months. Pre-specified co-primary endpoints were improvements on clinician-rated Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) and patient-rated Bain & Findley Activities of Daily Living (BF-ADL) dominant hand scores. Other endpoints included improvement in the tremor power detected by an accelerometer on the therapeutic device, Clinical and Patient Global Impression scores (CGI-I, PGI-I), and Quality of Life in Essential Tremor (QUEST) survey. Results: 205 patients completed the study. The co-primary endpoints were met (p≪0.0001), with 62% (TETRAS) and 68% (BF-ADL) of 'severe' or 'moderate' patients improving to 'mild' or 'slight'. Clinicians (CGI-I) reported improvement in 68% of patients, 60% (PGI-I) of patients reported improvement, and QUEST improved (p = 0.0019). Wrist-worn accelerometer recordings before and after 21,806 therapy sessions showed that 92% of patients improved, and 54% of patients experienced ≥50% improvement in tremor power. Device-related adverse events (e.g., wrist discomfort, skin irritation, pain) occurred in 18% of patients. No device-related serious adverse events were reported. Discussion: This study suggests that non-invasive neuromodulation therapy used repeatedly at home over three months results in safe and effective hand tremor reduction in many essential tremor patients.

Botulinum toxin and occupational therapy for Writer's cramp.

BACKGROUND: Writer's cramp (WC) is a form of focal hand dystonia, for which focal botulinum neurotoxin (BoNT) injections are the current best therapy. Past studies have shown that some types of rehabilitative therapy can be useful. We hypothesized that BoNT together with a specific type of occupational therapy would be better than BoNT alone for treating WC patients comparing the effects with a patient-rated subjective scale. METHODS: Twelve WC patients were randomized to two groups. Six received only BoNT therapy and 6 received BoNT & occupational therapy. The occupational therapy involved specific exercises of finger movements in the direction opposite to the dystonic movements during writing. BoNT was injected by movement disorders neurologists in the affected muscles under electromyography-guidance. The primary outcome was the patient-rated subjective scale at 20 weeks. Secondary exploratory outcomes included the writer's cramp rating scale (WCRS), writer's cramp impairment scale (WCIS), the writer's cramp disability scale (WCDS), handgrip strength and kinetic parameters. RESULTS: The patient-rated subjective scale scores at 20 weeks were not significantly different between the two groups. Significant objective improvement was noted in the BoNT & occupational therapy group, as noted by the decrease (28%) in WCIS scores. CONCLUSIONS: Improvement of the primary outcome measure, the patient-rated subjective scale, was not achieved. However, significant improvement was found in the BoNT & occupational therapy group in a secondary measure of impairment. Our hypothesis-driven study results are likely limited by small sample size, and further large-scale studies of occupational therapy methods to improve the efficacy of BoNT seems worthwhile.

The effect of cigarette smoking on the clinical and serological phenotypes of polymyositis and dermatomyositis.

OBJECTIVE: Cigarette smoking is associated with immune-mediated disorders. We explored the contribution of smoking to polymyositis (PM) and dermatomyositis (DM) phenotypes and attempted to determine whether cigarette smoking effects differ by race and genotype. METHODS: Associations of tobacco smoking with disease features, autoantibodies, HLA types, and race were evaluated using multiple logistic regressions in 465 patients. RESULTS: Caucasian ever-smokers (n = 140) were more likely to have PM (adjusted OR = 2.24, 95% CI: 1.41\x963.57), anti-synthetase (adjusted OR = 1.93, 95% CI: 1.12\x963.34) and anti-Jo-1 autoantibodies (adjusted OR = 1.94, 95% CI: 1.08\x963.46) and less likely to have anti-p155/140 autoantibodies (adjusted OR = 0.36, 95% CI: 0.14\x960.92). In Caucasians, ever-smokers had a greater interstitial lung disease (ILD) frequency than never-smokers, while in African-Americans this relationship was inverted, but neither trend reached statistical significance. Pack-years of cigarette smoking showed significant positive associations with PM (adjusted OR = 1.02, 95% CI: 1.002\x961.04) and ILD (adjusted OR = 1.02, 95% CI: 1.001\x961.03) and was inversely associated with anti-p155/140 autoantibodies (adjusted OR = 0.93, 95% CI: 0.87\x960.99) in Caucasians. Caucasian heavy smokers (=20 pack-years) were more likely to have PM (adjusted OR = 2.52, 95% CI: 1.25\x965.09), ILD (adjusted OR = 2.48, 95% CI: 1.23\x965.00) and anti-Jo-1 autoantibodies (adjusted OR = 2.65, 95% CI: 1.16\x966.08) than never-smokers. In Caucasians, compared to never-smokers without HLA-DRB1*03:01 allele, ever-smokers with HLA-DRB1*03:01 allele had the highest odds of PM, ILD, ASA, and anti-Jo-1 autoantibodies. Risks for those with only one of these two factors were intermediate. An inverse pattern was observed regarding anti-p155/140 autoantibodies. CONCLUSION: Tobacco smoking was associated with clinical and autoantibody phenotypes in Caucasians. Our findings also suggest possible interactions among HLA-DRB1*03:01 and smoking on the risk of PM and ILD, as well as, anti-synthetase, anti-Jo-1, and anti-p155/140 autoantibodies in Caucasians.

Can a collaborative healthcare network improve the care of people with epilepsy?

New opportunities are now available to improve care in ways not possible previously. Information contained in electronic medical records can now be shared without identifying patients. With network collaboration, large numbers of medical records can be searched to identify patients most like the one whose complex medical situation challenges the physician. The clinical effectiveness of different treatment strategies can be assessed rapidly to help the clinician decide on the best treatment for this patient. Other capabilities from different components of the network can prompt the recognition of what is the best available option and encourage the sharing of information about programs and electronic tools. Difficulties related to privacy, harmonization, integration, and costs are expected, but these are currently being addressed successfully by groups of organizations led by those who recognize the benefits.

A multicenter, prospective, single arm, open label, observational study of sTMS for migraine prevention (ESPOUSE Study).

Objective To evaluate the efficacy and tolerability of single pulse transcranial magnetic stimulation (sTMS) for the preventive treatment of migraine. Background sTMS was originally developed for the acute treatment of migraine with aura. Open label experience has suggested a preventive benefit. The objective of this trial was to evaluate the efficacy and tolerability of sTMS for migraine prevention. Methods The eNeura SpringTMS Post-Market Observational U.S. Study of Migraine (ESPOUSE) Study was a multicenter, prospective, open label, observational study. From December 2014 to March 2016, patients with migraine (n = 263) were consented to complete a 1-month baseline headache diary followed by 3 months of treatment. The treatment protocol consisted of preventive (four pulses twice daily) and acute (three pulses repeated up to three times for each attack) treatment. Patients reported daily headache status, medication use, and device use with a monthly headache diary. The primary endpoint, mean reduction of headache days compared to baseline, was measured over the 28-day period during weeks 9 to 12. The primary endpoint was compared to a statistically-derived placebo estimate (performance goal). Secondary endpoints included: 50% responder rate, acute headache medication consumption, HIT-6, and mean reduction in total headache days from baseline of any intensity. Results Of a total of 263 consented subjects, 229 completed a baseline diary, and 220 were found to be eligible based on the number of headache days. The device was assigned to 217 subjects (Safety Data Set) and 132 were included in the intention to treat Full Analysis Set. For the primary endpoint, there was a -2.75 ± 0.40 mean reduction of headache days from baseline (9.06 days) compared to the performance goal (-0.63 days) ( p < 0.0001). The 50% responder rate of 46% (95% CI 37%, 56%) was also significantly higher ( p < 0.0001) than the performance goal (20%). There was a reduction of -2.93 (5.24) days of acute medication use, headache impact measured by HIT-6, -3.1 (6.4) ( p < 0.0001), and total headache days of any intensity -3.16 days (5.21) compared to the performance goal (-0.63 days) ( p < 0.0001). The most common adverse events were lightheadedness (3.7%), tingling (3.2%), and tinnitus (3.2%). There were no serious adverse events. Conclusions This open label study suggests that sTMS may be an effective, well-tolerated treatment option for migraine prevention. Trial registration number NCT02357381.

Differences in active range of motion measurements in the upper extremity of patients with writer's cramp compared with healthy controls.

STUDY DESIGN: Exploratory case-control study. INTRODUCTION: Writer's cramp (WC) is a type of focal hand dystonia. The central nervous system plays a role in its pathophysiology, but abnormalities in the affected musculoskeletal components may also be relevant. PURPOSE OF THE STUDY: We compared the active range of motion (ROM) in patients with WC and healthy volunteers (HVs) and correlated the findings with disease duration and severity. METHODS: Affected limb joints were measured with goniometers. Patients were assessed at least 3 months after their last botulinum toxin (botulinum neurotoxin) injection, and strength was clinically normal. t tests were used to compare the ROMs of WC with matched HVs. The Spearman correlation coefficient assessed the relationship of active ROMs to the disease duration and handwriting subscore of the Dystonia Disability Scale. RESULTS: ROMs of D1 metacarpophalangeal (MCP) joint extension as well as D2 and D5 MCP flexion were significantly smaller in WC, and distal interphalangeal joint extension in D3 and D5 was significantly greater compared with HVs. There were negative correlations between D2 MCP flexion and disease duration and with Dystonia Disability Scale. DISCUSSION: Abnormalities in ROMs in WC were found. Severity and disease duration correlated with reduced D2 MCP flexion. This may be related to intrinsic biomechanical abnormalities, co-contraction of muscles, or a combination of subclinical weakness and atrophy from repeated botulinum neurotoxin injections. CONCLUSIONS: Hand biomechanical properties should not be ignored in the pathophysiology of WC. LEVEL OF EVIDENCE: 2c.

Long-term depression-like plasticity of the blink reflex for the treatment of blepharospasm.

Our previous work showed a beneficial therapeutic effect on blepharospasm using slow repetitive transcranial magnetic stimulation, which produces a long-term depression (LTD)-like effect. High-frequency supraorbital electrical stimulation, asynchronous with the R2 component of the blink reflex, can also induce LTD-like effects on the blink reflex circuit in healthy subjects. Patients with blepharospasm have reduced inhibition of their blink recovery curves; therefore, a LTD-like intervention might normalize the blink reflex recovery (BRR) and have a favorable therapeutic effect. This is a randomized, sham-controlled, observer-blinded prospective study. In 14 blepharospasm patients, we evaluated the effects of high-frequency supraorbital stimulation on three separate treatment days. We applied 28 trains of nine stimuli, 400 Hz, either before or after the R2 or used sham stimulation. The primary outcome was the blink rate, number of spasms rated by a blinded physician and patient rating before, immediately after and 1 hour after stimulation while resting, reading, and talking; secondary outcome was the BRR. Stimulation "before" and "after" the R2 both showed a similar improvement as sham stimulation in physician rating, but patients felt significantly better with the before condition. Improvement in recovery of the blink reflex was noted only in the before condition. Clinical symptoms differed in the three baseline conditions (resting, reading, and talking). Stimulation before R2 increased inhibition in trigeminal blink reflex circuits in blepharospasm toward normal values and produced subjective, but not objective, improvement. Inhibition of the blink reflex pathway by itself appeared to be insufficient for a useful therapeutic effect.

Extreme task specificity in writer's cramp.

BACKGROUND: Focal hand dystonia may be task specific, as is the case with writer's cramp. In early stages, task specificity can be so specific that it may be mistaken for a psychogenic movement disorder. METHODS: We describe 4 patients who showed extreme task specificity in writer's cramp. They initially only had problems writing either a single letter or number. Although they were largely thought to be psychogenic, they progressed to typical writer's cramp. CONCLUSIONS: Early recognition of this condition may provide an opportunity for early initiation of treatment.

The sequence effect in de novo Parkinson's disease.

BACKGROUND AND PURPOSE: The sequence effect (SE) in Parkinson's disease (PD) denotes progressive slowness in speed or progressive decrease in amplitude of repetitive movements. It is a well-known feature of bradykinesia and is considered unique in PD. Until now, it was well-documented in advanced PD, but not in drug-naïve PD. The aim of this study is to know whether the SE can also be measured in drug-naïve PD. METHODS: We measured the SE with a computer-based, modified Purdue pegboard in 4 drug-naïve PD patients, which matched our previous study with advanced PD patients. RESULTS: We observed progressive slowness during movement, that is, SE. Statistical analysis showed a strong statistical trend toward the SE with the right hand, but no significance with the left hand. There was no statistical significance of SE with either the more or less affected hands. CONCLUSIONS: These results indicate that the SE can be identified in drug-naïve PD, as well as in advanced PD, with objective measurements and support the idea that the SE is a feature in PD observed during the early stage of the disease without medication.

Characteristics of the sequence effect in Parkinson's disease.

The sequence effect (SE) in Parkinson's disease (PD) is progressive slowing of sequential movements. It is a feature of bradykinesia, but is separate from a general slowness without deterioration over time. It is commonly seen in PD, but its physiology is unclear. We measured general slowness and the SE separately with a computer-based, modified Purdue pegboard in 11 patients with advanced PD. We conducted a placebo-controlled, four-way crossover study to learn whether levodopa and repetitive transcranial magnetic stimulation (rTMS) could improve general slowness or the SE. We also examined the correlation between the SE and clinical fatigue. Levodopa alone and rTMS alone improved general slowness, but rTMS showed no additive effect on levodopa. Levodopa alone, rTMS alone, and their combination did not alleviate the SE. There was no correlation between the SE and fatigue. This study suggests that dopaminergic dysfunction and abnormal motor cortex excitability are not the relevant mechanisms for the SE. Additionally, the SE is not a component of clinical fatigue. Further work is needed to establish the physiology and clinical relevance of the SE. © 2010 Movement Disorder Society.

Tremor and deep brain nuclei hyperintensities in Kabuki syndrome.

Kabuki syndrome is a rare congenital disorder first described in 1981. Case reports indicate multiple congenital abnormalities: skeletal anomalies, cognitive impairment, characteristic facial appearance, and peculiar dermatoglyphic patterns. We describe a patient with Kabuki syndrome who presented with physiologic tremor in her distal upper extremities. Cranial magnetic resonance imaging revealed symmetric T(2)-hyperintense lesions with mildly restricted diffusion in the lentiform nuclei, red nuclei, and dentate nuclei bilaterally. Although multiple abnormalities of the central nervous system were reported previously in Kabuki syndrome, this patient is the first, to the best of our knowledge, with the unique findings that we observed.

Paired associative stimulation induces change in presynaptic inhibition of Ia terminals in wrist flexors in humans.

Enhancements in the strength of corticospinal projections to muscles are induced in conscious humans by paired associative stimulation (PAS) to the motor cortex. Although most of the previous studies support the hypothesis that the increase of the amplitude of motor evoked potentials (MEPs) by PAS involves long-term potentiation (LTP)-like mechanism in cortical synapses, changes in spinal excitability after PAS have been reported, suggestive of parallel modifications in both cortical and spinal excitability. In a first series of experiments (experiment 1), we confirmed that both flexor carpi radialis (FCR) MEPs and FCR H reflex recruitment curves are enhanced by PAS. To elucidate the mechanism responsible for this change in the H reflex amplitude, we tested, using the same subjects, the hypothesis that enhanced H reflexes are caused by a down-regulation of the efficacy of mechanisms controlling Ia afferent discharge, including presynaptic Ia inhibition and postactivation depression. To address this question, amounts of both presynaptic Ia inhibition of FCR Ia terminals (D1 and D2 inhibitions methods; experiment 2) and postactivation depression (experiment 3) were determined before and after PAS. Results showed that PAS induces a significant decrease of presynaptic Ia inhibition of FCR terminals, which was concomitant with the facilitation of the H reflex. Postactivation depression was unaffected by PAS. It is argued that enhancement of segmental excitation by PAS relies on a selective effect of PAS on the interneurons controlling presynaptic inhibition of Ia terminals.