Persistence of Basal Ganglia Oscillatory Activity During Tremor Attenuation by Movement in Parkinson's Disease Patients

BACKGROUND

One of the characteristics of parkinsonian tremor is that its amplitude decreases with movement. Current models suggest an interaction between basal ganglia (BG) and cerebello-thalamo-cortical circuits in parkinsonian tremor pathophysiology.

OBJECTIVE

We aimed to correlate central oscillation in the BG with electromyographic activity during re-emergent tremor in order to detect changes in BG oscillatory activity when tremor is attenuated by movement.

METHODS

We performed a prospective, observational study on consecutive parkinsonian patients who underwent deep brain stimulation surgery and presented re-emergent tremor. Coherence analysis between subthalamic nucleus/globus pallidus internus (STN/GPi) tremorous activity measured by microrecording (MER) and electromyogram (EMG) from flexor and extensor wrist muscles during rest, posture, and re-emergent tremor pause was performed during surgery. The statistical significance level of the MER-EMG coherence was determined using surrogate data analysis, and the directionality of information transfer between BG and muscle was performed using entropy transfer analysis.

RESULTS

We analyzed 148 MERs with tremor-like activity from 6 patients which were evaluated against the simultaneous EMGs, resulting in 296 correlations. Of these, 26 presented a significant level of coherence at tremor frequency, throughout rest and posture, with a complete EMG stop in between. During the pause, all recordings showed sustained MER peaks at tremor frequency (±1.5 Hz). Information flows preferentially from BG to muscle during rest and posture, with a loss of directionality during the pause.

CONCLUSIONS

Our results suggest that oscillatory activity in STN/GPi functionally linked to tremor sustains firing frequency during re-emergent tremor pause, thus suggesting no direct role of the BG circuit on tremor attenuation due to voluntary movements. © 2024 International Parkinson and Movement Disorder Society.

Predictors and Pathophysiology of Axial Postural Abnormalities in Parkinsonism: A Scoping Review

Background

Postural abnormalities involving the trunk are referred to as axial postural abnormalities and can be observed in over 20% of patients with Parkinson's disease (PD) and in atypical parkinsonism. These symptoms are highly disabling and frequently associated with back pain and a worse quality of life in PD. Despite their frequency, little is known about the pathophysiology of these symptoms and scant data are reported about their clinical predictors, making it difficult to prompt prevention strategies.

Objectives

We conducted a scoping literature review of clinical predictors and pathophysiology of axial postural abnormalities in patients with parkinsonism to identify key concepts, theories and evidence on this topic.

Methods

We applied a systematic approach to identify studies, appraise quality of evidence, summarize main findings, and highlight knowledge gaps.

Results

Ninety-two articles were reviewed: 25% reported on clinical predictors and 75% on pathophysiology. Most studies identified advanced disease stage and greater motor symptoms severity as independent clinical predictors in both PD and multiple system atrophy. Discrepant pathophysiology data suggested different potential central and peripheral pathogenic mechanisms.

Conclusions

The recognition of clinical predictors and pathophysiology of axial postural abnormalities in parkinsonism is far from being elucidated due to literature bias, encompassing different inclusion criteria and measurement tools and heterogeneity of patient samples. Most studies identified advanced disease stage and higher burden of motor symptoms as possible clinical predictors. Pathophysiology data point toward many different (possibly non-mutually exclusive) mechanisms, including dystonia, rigidity, proprioceptive and vestibular impairment, and higher cognitive deficits.

Establishing an online resource to facilitate global collaboration and inclusion of underrepresented populations: Experience from the MJFF Global Genetic Parkinson's Disease Project

Parkinson's disease (PD) is the fastest-growing neurodegenerative disorder, currently affecting ~7 million people worldwide. PD is clinically and genetically heterogeneous, with at least 10% of all cases explained by a monogenic cause or strong genetic risk factor. However, the vast majority of our present data on monogenic PD is based on the investigation of patients of European White ancestry, leaving a large knowledge gap on monogenic PD in underrepresented populations. Gene-targeted therapies are being developed at a fast pace and have started entering clinical trials. In light of these developments, building a global network of centers working on monogenic PD, fostering collaborative research, and establishing a clinical trial-ready cohort is imperative. Based on a systematic review of the English literature on monogenic PD and a successful team science approach, we have built up a network of 59 sites worldwide and have collected information on the availability of data, biomaterials, and facilities. To enable access to this resource and to foster collaboration across centers, as well as between academia and industry, we have developed an interactive map and online tool allowing for a quick overview of available resources, along with an option to filter for specific items of interest. This initiative is currently being merged with the Global Parkinson's Genetics Program (GP2), which will attract additional centers with a focus on underrepresented sites. This growing resource and tool will facilitate collaborative research and impact the development and testing of new therapies for monogenic and potentially for idiopathic PD patients.

International Genetic Testing and Counseling Practices for Parkinson's Disease

BACKGROUND

There is growing clinical and research utilization of genetic testing in Parkinson's disease (PD), including direct-to-consumer testing.

OBJECTIVES

The aim is to determine the international landscape of genetic testing in PD to inform future worldwide recommendations.

METHODS

A web-based survey assessing current practices, concerns, and barriers to genetic testing and counseling was administered to the International Parkinson and Movement Disorders Society membership.

RESULTS

Common hurdles across sites included cost and access to genetic testing, and counseling, as well as education on genetic counseling. Region-dependent differences in access to and availability of testing and counseling were most notable in Africa. High-income countries also demonstrated heterogeneity, with European nations more likely to have genetic testing covered through insurance than Pan-American and Asian countries.

CONCLUSIONS

This survey highlights not only diversity of barriers in different regions but also the shared and highly actionable needs for improved education and access to genetic counseling and testing for PD worldwide. © 2023 International Parkinson and Movement Disorder Society.

Genetic Testing in Parkinson's Disease

Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Clinical correlates of Fear of Falling in Progressive Supranuclear Palsy and Multiple System Atrophy

BACKGROUND

Clinical correlates of fear of falling (FoF) are scarcely studied in patients with Progressive Supranuclear Palsy (PSP) and Multiple System Atrophy (MSA).

OBJECTIVE

To evaluate the clinical correlates of FoF in PSP and MSA.

METHODS

A cross-sectional study with motor , cognitive and psychiatric assessment and longitudinal evaluation of falls and FoF at 6-month follow-up.

RESULTS

Twenty-one patients with PSP-P, 22 with MSA (13 MSA-P and 9 MSA-C) and 22 healthy controls were evaluated. 76.2% of patients with PSP and 86.4%of patients with MSA had FoF regardless of falls. Berg Balance Scale (p<0.001), Tinetti Mobility Test (p<0.01), Beck Anxiety Inventory (p=0.001) and Beck Depression Inventory-II (p=0.01) correlated with FoF in patients with PSP and MSA, whereas Timed up and Go test (p=0.01) and Starkstein's Apathy Scale only in MSA (p=0.04).

CONCLUSION

Mobility, balance and gait performance as well as anxiety and depression in PSP and MSA, and apathy in MSA were determinants of FoF. These findings underline the importance of a multidisciplinary approach to FoF in neurodegenerative atypical parkinsonism.

Motor assessment of patients with multiple system atrophy: underuse of the Unified Multiple System Atrophy Rating Scale (UMSARS)

PURPOSE

Despite the availability of the Unified Multiple System Atrophy (MSA) Rating Scale (UMSARS) for almost two decades, studies still use scales developed for Parkinson's disease (PD) or ataxia (ATX). Our aim was to evaluate the use of UMSARS (part II, motor) compared to other motor rating scales in patients with MSA.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant literature search was conducted concerning studies of patients with MSA, reporting motor assessment with clinical rating scales, and focusing on the frequency of UMSARS use.

RESULTS

We included 261 articles, of which 42.9% did not use UMSARS, but rather scales for PD (59.8%), ATX (24.1%), or both (14.3%). Although UMSARS use increased with time, misuse of PD and ATX scales persists, with no evidence of a decremental trend.

CONCLUSIONS

Although higher in observational studies, the misuse of PD and ATX-related scales in MSA patients persists in prospective (planned) trials. Reasons for that must be addressed.

Life events and the onset of motor symptoms in Parkinson's disease

BACKGROUND

Whether there may be any relationship between stressful or traumatic life events (LE) and the subsequent motor symptoms onset in Parkinson's disease (PD) is still controversial.

OBJECTIVES

To explore whether a subjectively perceived as stressful or traumatic LE were more frequently present in a group of recent motor onset parkinsonian patients (Recent Onset Parkinsonism - ROP) compared with healthy controls (HC) and a group of patients already diagnosed as PD.

METHODS

A consecutive series of 139 ROP patients, 138 matched PD patients and 138 HC were pooled through a validated LE exposure questionnaire evaluating the number of patients affected by LE and the amount of LE per group occurred in the last year, segregating by subjective severity in total and severe LE.

RESULTS

There was no significant difference in the percentage of patients affected by total (p = 0.134) nor by severe (p = 0.133) LE within the 3 groups. No significant difference was observed in the number of total LE between ROP and HC (p = 0.063), ROP and PD (p = 0.688), nor in severe LE (ROP vs. HC, p = 0.637. ROP vs. PD, p = 0.500).

CONCLUSIONS

During the year of parkinsonian motor symptoms onset, the number of ROP patients exposed to total or severe LE or the amount of total or severe LE suffered by ROP were not significantly different to the group of PD patients or HC. A casual relationship between LE and the onset of motor symptoms in parkinsonian patients may be suggested.

Intermittent Apomorphine Use for off Period Rescue in Parkinson's Disease: A Pragmatic Review of over Three Decades of Clinical Experience

Background

Although proven very efficacious as treatment for Parkinson's disease by Schwab as far back as the 1950s, and later confirmed by Cotzias and colleagues in the early 1970s, use of intermittent subcutaneous injections of the dopamine agonist apomorphine remains limited worldwide.

Objectives

To review evidence regarding use of intermittent, on-demand apomorphine as a treatment for off-period disability in Parkinson's disease.

Methods

A PRISMA-compliant structured literature search was carried out with a focus on clinical effect (motor improvement, daily off time decrease; latency, duration), antiemetic prophylaxis, and adverse events.

Results

Fifty-eight studies were evaluated. Apomorphine administration route was subcutaneous in 29 (50%), sublingual in 14 (24.1%), intranasal in 6 (10.3%), inhaled in 5 (8.6%), rectal in 3 (5.2%) and transdermal in 1 (1.7%). Irrespective of the route, motor disability improved 19% to 74% and daily off time decreased 3% to 68%, with subcutaneous having the fastest onset of action ranging from 6 to 24 minutes and lasting 28 to 96 minutes. Antiemetic prophylaxis was used in almost all studies. Systemic side effects like nausea and yawning were mild and well tolerated, but sedation led to discontinuation of subcutaneous apomorphine in 5.5%. Local side effects to subcutaneous administration did not result in discontinuation. Stomatitis with the early sublingual formulations led to discontinuation in nearly half of patients and was reduced to 16.7% with novel film strips.

Conclusions

Intermittent subcutaneous injections remain the most reliable and safest route of apomorphine administration, with an efficacy for off period treatment supported by nearly four decades of clinical experience.

Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

BACKGROUND

As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited.

OBJECTIVE

The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD.

METHODS

We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed.

RESULTS

We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published.

CONCLUSIONS

Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Early motor response to dopamine replacement therapy in Parkinson's disease patients carrying GBA variants

BACKGROUND

Mutations in the glucocerebrosidase (GBA) gene represent the most common genetic risk factor for Parkinson's Disease (PD) and are associated with a more aggressive motor phenotype at late stages. However, the motor response at early stages of disease remains understudied.

METHODS

Retrospective study of PD patients that underwent next-generation sequencing panel tests for PD-related genes. We extracted demographic data and the MDS-UPDRS III response to an acute levodopa challenge (LDC), the best ON score, and the levodopa equivalent daily dose (LEDD) during the first six months after the LDC and initiation of DRT. We compared the response of GBA-PD patients to that of patients without pathogenic variants or rearrangements in other PD related genes (sporadic PD).

RESULTS

13 GBA-PD and 48 sporadic PD patients were identified. Baseline MDS-UPDRS III score (24.6 ± 9.6 vs. 21.8 ± 9.3. p = 0.4), response to LDC (39.2% ± 7.9% vs. 32.7% ± 13.4%; p = 0.1), best ON score (36.9% ± 39.5% vs. 41.6% ± 20.8%; p = 0.6) and LEDD (188 mg ± 100 mg vs. 261.8 mg ± 164.8 mg; p = 0.2) during the first six months after initiation of DRT were not different between GBA-PD and sporadic PD patients.

CONCLUSIONS

At early disease stages of GBA-PD, the motor response to acute levodopa challenge test and the initial response to DRT are similar to that of patients with sporadic PD. Although limited by small sample size, these preliminary findings should be confirmed by future prospective larger studies.

P145 A DUAL CARDIAC COMPLICATION FOR … COMBINATION CHEMOTHERAPY FOR KIDNEY CANCER

We present the case of a 66–year–old patient suffering from metastatic kidney cancer who came to the emergency room complaining of dyspnea. 10 days prior to the event, the patient had received the last administration of chemotherapy which consisted of the combination of pembrolizumab (a monoclonal antibody) and axitinib (a tyrosine kinase inhibitor). The cardiological checks carried out up to that moment had not shown changes in the heart. In the emergency room ECG showed the presence of a sinus rhythm with a complete block of the right branch and no signs of ischemia were evident; blood chemistry tests showed an increase in troponin and BNP values. Echocardiography showed moderate left ventricular dysfunction. Therapy with diuretics, beta–blockers and Ras inhibitors was initiated which allowed for rapid resolution of symptoms. At a follow–up five days later the patient presented asymptomatic but with diffuse inversion of the T waves, a new elevation of troponin and more surprisingly the echo showed, in the presence of moderate left ventricular dysfunction, a mobile formation at the level of the apex of the left ventricle. Unfractionated heparin therapy was initiated since, on the basis of echocardiographic characteristics, the diagnosis appeared to be that of thrombosis and chemotherapy was suspended. In the following days the echo did not reveal any modification of the neoformation therefore in consideration of the characteristics (size and high degree of mobility) and of the oncological prognosis of more than one year we decided to initiate the patient to cardiac surgery for the removal operation. The histological analysis of the neoformation confirmed the thrombotic nature. Repeated echocardiography 15 days after surgery showed an almost complete recovery of the ejection fraction. To our knowledge, tyrosine kinase inhibitors can cause ventricular dysfunction (apoptosis) but, in general, it is not an acute event. Pembrolizumab has caused cases of acute myocarditis requiring discontinuation of therapy. As for the origin of the thrombosis the causes are not clear, it could be an effect of left ventricular dysfunction for myocarditis but it cannot be excluded that it is secondary to the use of one or both chemotherapy drugs.

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Task force consensus on nosology and Cut‐Off values for axial postural abnormalities in parkinsonism

Background

There is no consensus with regard to the nosology and cut‐off values for postural abnormalities in parkinsonism.

Objective

To reach a consensus regarding the nosology and cut‐off values.

Methods

Using a modified Delphi panel method, multiple rounds of questionnaires were conducted by movement disorder experts to define nosology and cut‐offs of postural abnormalities.

Results

After separating axial from appendicular postural deformities, a full agreement was found for the following terms and cut‐offs: camptocormia, with thoracic fulcrum (>45°) or lumbar fulcrum (>30°), Pisa syndrome (>10°), and antecollis (>45°). “Anterior trunk flexion,” with thoracic (≥25° to ≤45°) or lumbar fulcrum (>15° to ≤30°), “lateral trunk flexion” (≥5° to ≤10°), and “anterior neck flexion” (>35° to ≤45°) were chosen for milder postural abnormalities.

Conclusions

For axial postural abnormalities, we recommend the use of proposed cut‐offs and six unique terms, namely camptocormia, Pisa syndrome, antecollis, anterior trunk flexion, lateral trunk flexion, anterior neck flexion, to harmonize clinical practice and future research.

Validation of an events exposure questionnaire for individuals living in major cities of Argentina

Most of the validated 'events exposure' questionnaires are focused on lifetime burden and are hardly applicable to Argentina owing to its sociocultural and natural conditions, where corruption and economic crises have been hitting middle-class people's lives in a cyclic manner. This prompted us to develop a new questionnaire, validated in Argentina, to assess the occurrence of exposure to events and their severity over a limited period. Deductive (bibliographic search) and inductive (by a Delphi group) selection was used to create an initial group of 24 questions, which were condensed into a final 14-item questionnaire. After administration to 512 inhabitants of the metropolitan area of Buenos Aires and other major cities in Argentina, the questionnaire was shown to have an intraclass correlation coefficient of 0.996 and an internal consistency, measured by the omega coefficient, of 0.86. Because this study was conducted during the coronavirus disease 2019 (COVID-19) pandemic, an additional question on how this situation affected individuals was included. The time span used to measure event exposure was 1 year prior to the study. In the case of an affirmative event exposure, the responder selected the severity of the stress perception generated on a Likert-like scale, ranging from 0 (nothing) to 5 (severe). Fifty-eight per cent of the responders were women, and the mean age was 47.14 years (SD: 13.97). The average annual event incidence per person was 2.5 events (SD: 1.88). Thirty-two per cent (164/512) reported at least one 5-point event on the severity scale. Ten per cent (51/512) responded that the COVID-19 pandemic affected them in a different manner than events related to personal or family disease, or the death of a close family member or friend.

How much time is needed in clinical practice to reach a diagnosis of clinically established Parkinson's disease?

INTRODUCTION

The implementation of accepted clinical diagnostic criteria has improved the accuracy of a clinical diagnosis of Parkinson's disease (PD). Time frames of 3-10 years have been empirically proposed to reach a diagnosis of clinically established PD.

METHODS

We explored the time to a Final Clinical Diagnosis (FCD) and the factors that predict faster diagnoses in patients presenting with parkinsonism and/or tremor between 2009 and 2015 at our tertiary center. All patients underwent a standardized workout process to reach a FCD, which included an acute levodopa challenge (LDC) after the first visit.

RESULTS

Among the 326 patients included, 215 (66%) received a FCD within the first six months after the LDC. A FCD was reached in 95% and 100% of patients in 33 and 108 months, respectively. PD was the FCD in 196 patients (60.1%). The FCD was reached faster in patients with a positive response to levodopa and when the FCD was PD.

CONCLUSION

The time needed to reach a final diagnosis in the clinical setting was 2.75 years in 95% of patients presenting initially with parkinsonism and/or tremor. Patients with positive responses to levodopa at the LDC, benefited from shorter delays until the FCD.

Correlation between 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET in patients with Parkinson's disease: a pilot study

Objective

To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (^99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (¹⁸F-FDOPA PET) in the setting of a movement disorders clinic.

Materials and Methods

In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson’s disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to ^99mTc-TRODAT-1 SPECT and ¹⁸F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed.

Results

The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when ^99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between ¹⁸F-FDOPA PET and ^99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01).

Conclusion

It appears that ^99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.

Cardiac Involvement in Movement Disorders

Background

Several conditions represented mainly by movement disorders are associated with cardiac disease, which can be overlooked in clinical practice in the context of a prominent primary neurological disorder.

Objectives

To review neurological conditions that combine movement disorders and primary cardiac involvement.

Methods

A comprehensive and structured literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was conducted to identify disorders combining movement disorders and cardiac disease.

Results

Some movement disorders are commonly or prominently associated with cardiac disease. Neurological and cardiac symptoms may share underlying physiopathological mechanisms in diseases, such as Friedreich's ataxia and Wilson's disease, and in certain metabolic disorders, including Refsum disease, Gaucher disease, a congenital disorder of glycosylation, or cerebrotendinous xanthomatosis. In certain conditions, such as Sydenham's chorea or dilated cardiomyopathy with ataxia syndrome (ATX-DNAJC19), heart involvement can present early in the course of disease, whereas in others such as Friedreich's ataxia or Refsum disease, cardiac symptoms tend to present in later stages. In another 68 acquired or inherited conditions, cardiac involvement or movement disorders are seldom reported.

Conclusions

As cardiac disease is part of the phenotypic spectrum of several movement disorders, heart involvement should be carefully investigated and increased awareness of this association encouraged as it may represent a leading cause of morbidity and mortality.

Involuntary moaning in a Hispanic family with eight affected members

Involuntary moaning has been reported in sporadic cases of neurodegenerative diseases. A five-generation Hispanic family with eight members exhibiting involuntary moaning, most of whom with isolated moaning in the absence of any additional neurological disorder carried a missense variant in the NEFH gene segregating in the family.

Limitations of the Unified Multiple System Atrophy Rating Scale as outcome measure for clinical trials and a roadmap for improvement

PURPOSE

The unified multiple system atrophy (MSA) rating scale (UMSARS) was developed almost 20 years ago as a clinical rating scale to capture multiple aspects of the disease. With its widespread use, the shortcomings of the UMSARS as a clinical outcome assessment (COA) have become increasingly apparent. We here summarize the shortcomings of the scale, confirm some of its limitations with data from the Natural History Study of the Synucleinopathies (NHSS), and suggest a framework to develop and validate an improved COA to be used in future clinical trials of disease-modifying drugs in patients with MSA.

METHODS

Expert consensus assessment of the limitations of the UMSARS and recommendations for the development and validation of a novel COA for MSA. We used UMSARS data from the ongoing NHSS (ClinicalTrials.gov: NCT01799915) to showcase some of these limitations.

RESULTS

The UMSARS in general, and specific items in particular, have limitations to detect change resulting in a ceiling effect. Some items have specific limitations including unclear anchoring descriptions, lack of correlation with disease severity, susceptibility to improve with symptomatic therapies (e.g., orthostatic hypotension, constipation, and bladder dysfunction), and redundancy, among others.

CONCLUSIONS

Because of the limitations of the UMSARS, developing and validating an improved COA is a priority. The time is right for academic MSA clinicians together with industry, professional societies, and patient advocacy groups to develop and validate a new COA.

Myoclonus-Ataxia Syndromes: A Diagnostic Approach

Background

A myriad of disorders combine myoclonus and ataxia. Most causes are genetic and an increasing number of genes are being associated with myoclonus-ataxia syndromes (MAS), due to recent advances in genetic techniques. A proper etiologic diagnosis of MAS is clinically relevant, given the consequences for genetic counseling, treatment, and prognosis.

Objectives

To review the causes of MAS and to propose a diagnostic algorithm.

Methods

A comprehensive and structured literature search following PRISMA criteria was conducted to identify those disorders that may combine myoclonus with ataxia.

Results

A total of 135 causes of combined myoclonus and ataxia were identified, of which 30 were charted as the main causes of MAS. These include four acquired entities: opsoclonus-myoclonus-ataxia syndrome, celiac disease, multiple system atrophy, and sporadic prion diseases. The distinction between progressive myoclonus epilepsy and progressive myoclonus ataxia poses one of the main diagnostic dilemmas.

Conclusions

Diagnostic algorithms for pediatric and adult patients, based on clinical manifestations including epilepsy, are proposed to guide the differential diagnosis and corresponding work-up of the most important and frequent causes of MAS. A list of genes associated with MAS to guide genetic testing strategies is provided. Priority should be given to diagnose or exclude acquired or treatable disorders.

Management of Advanced Therapies in Parkinson's Disease Patients in Times of Humanitarian Crisis: The COVID-19 Experience

Background

Although the COVID-19 pandemic is affecting a relatively small proportion of the global population, its effects have already reached everyone. The pandemic has the potential to differentially disadvantage chronically ill patients, including those with Parkinson's disease (PD). The first health care reaction has been to limit access to clinics and neurology wards to preserve fragile patients with PD from being infected. In some regions, the shortage of medical staff has also forced movement disorders neurologists to provide care for patients with COVID-19.

Objective

To share the experience of various movement disorder neurologists operating in different world regions and provide a common approach to patients with PD, with a focus on those already on advanced therapies, which may serve as guidance in the current pandemic and for emergency situations that we may face in the future.

Conclusion

Most of us were unprepared to deal with this condition given that in many health care systems, telemedicine has been only marginally available or only limited to email or telephone contacts. In addition, to ensure sufficient access to intensive care unit beds, most elective procedures (including deep brain stimulation or the initiation of infusion therapies) have been postponed. We all hope there will soon be a time when we will return to more regular hospital schedules. However, we should consider this crisis as an opportunity to change our approach and encourage our hospitals and health care systems to facilitate the remote management of chronic neurological patients, including those with advanced PD.

Heart rate variability and falls in Huntington's disease

PURPOSE

Persons with Huntington's disease (HD) have a high incidence of falls. Autonomic nervous system dysfunction has been reported even in early stages of this disease. To date, there has been no analysis of the relationship between heart rate variability (HRV) and falls in this patient population. The aim of the study reported here was to evaluate the relationship between HRV and falls in persons with HD.

METHODS

Huntington's disease patients enrolled in a prospective study on fear of falling and falls were assessed using short-term HRV analyses and blood pressure measures in both the resting and standing states. Time-frequency domains and nonlinear parameters were calculated. Data on falls, the risk of falling (RoF) and disease-specific scales were collected at baseline and at the end of the 6-month follow-up.

RESULTS

Of the 24 HD patients who were invited to participate in the study, 20 completed the baseline analysis and 18 completed the 6-month follow-up. At baseline, seven (35%) HD patients reported at least one fall (single fallers) and 13 (65%) reported ≥ 2 falls (recurrent fallers) in the previous 12 months. At baseline, recurrent fallers had lower RMSSD (root mean square of successive RR interval differences) in the resting state (RMSSD-resting), higher LF/HF (low/high frequency) ratio in both states and higher DFA-α1 parameter (detrended fluctuation analyses over the short term) in both states. This association was similar at the 6-month follow-up for recurrent fallers, who showed lower RMSSD-resting and higher LF/HF ratio in the standing state (LF/HF-standing) than single fallers. Significant correlations were found between the number of falls, RMSSD-resting and LF/HF-standing. No differences were found between recurrent and single fallers for any blood pressure measures.

CONCLUSIONS

The observed HRV pattern is consistent with a higher sympathetic prevalence associated with a higher RoF. Reduced parasympathetic HRV values in this patient population predict being a recurrent faller at 6 months of follow-up, independently of orthostatic phenomena.

Nosology and Phenomenology of Psychosis in Movement Disorders

Background

Psychotic symptoms, such as delusions and hallucinations, are part of the clinical picture of several conditions presenting movement disorders. Phenomenology and epidemiology of psychosis in Parkinson's disease have received wide attention; however, the presence of psychosis in other movement disorders is, comparatively, less well known.

Objectives

To review psychotic symptoms present in different movement disorders.

Methods

A comprehensive and structured literature search was performed to identify and analyze data on patients with movement disorders and comorbid psychosis.

Results

In monogenic parkinsonisms, such as PARK-GBA, PARK-LRRK2, and PARK-SNCA, visual hallucinations related to dopamine replacement therapy are frequent as well as are delusions in PARK-LRRK2 and PARK-SNCA, but not in PARK-GBA. Different types of delusions and hallucinations are found in Huntington's disease and other choreic disorders. In Tourette's syndrome, paranoid delusions as well as visual, olfactory, and auditory hallucinations have been described, which usually develop after an average of 10 years of disease. Delusions in ataxias are more frequent in ATX-TBP, ATX-ATN1, and ATX-ATXN3, whereas it is rare in Friedreich's ataxia. Psychosis is also a prominent and frequent clinical feature in Fahr's disease, Wilson's disease, neurodegeneration with brain iron accumulation, and some lysosomal storage disorders, whereas it is uncommon in atypical parkinsonisms and dystonia. Psychosis usually occurs at late disease stages, but may appear as onset symptoms of the disease, especially in Wilson's disease, Huntington's disease, late-onset Tays-Sachs, and Niemann-Pick.

Conclusion

Psychosis is a frequent comorbidity in most hyper- and hypokinetic movement disorders. Appropriate recognition is relevant both in the early and late disease stages.

Re-emergent tremor provocation

INTRODUCTION

Rest and re-emergent tremor (RET) in Parkinson's disease (PD) are known to be markedly variable. The aim of this study is to evaluate the effect of tremor provocation on RET latency and variability.

METHODS

We performed a prospective observational study in 21 PD patients with RET. Evaluations were conducted by accelerometric analysis of hand movements with and without provocation by counting out loud backwards from 100, in the OFF state. Differences in RET pause duration, tremor power at peak frequency, root mean square (RMS) and slope of return of the tremor after the pause was measured. Inter- and intra-subject variability were also calculated.

RESULTS

RET pause duration showed a 75% decrease after provocation (p < 0.001), which led to zero in 52% of cases, as compared to 9% in unprovoked measurements (p < 0.001). Provocation also led to a 2.57 time increase in tremor power (p < 0.001), 1.37 time increase in RMS (p < 0.001) and 2.47 time increase in slope (p < 0.001). A significant decrease in inter-subject variability was also observed (p = 0.001).

CONCLUSION

Tremor provocation led to RET amplitude increase, pause shortening, and variability decrease. Therefore, while provocation can be recommended for the evaluation of rest tremor in clinical practice, it might well annul its value for identifying the pause prior to re-emergent tremor.

Design and validation of a new instrument to assess fear of falling in Parkinson's disease

BACKGROUND

Fear of falling may be significantly associated with falls in Parkinson's disease (PD) and may have a negative impact on quality of life. Nevertheless, there are no valid and reliable tools to examine this condition in PD. The objective of this study was to design and determine the psychometric attributes of an instrument to assess fear of falling in PD.

METHODS

A prospective 1-year, 2-phase study was conducted to validate the Fear of Falling Scale, a self-assessed instrument for assessing fear of falling in PD. During phase 1, we designed a scale to measure the severity of fear of falling and determine its baseline psychometric characteristics, whereas phase 2 was a 1-year follow-up study to assess the frequency of falls and other clinical factors linked to fear of falling. Convergent and discriminant validity were assessed against the Fear of Falling Measure and the Starkstein Apathy Scale, respectively.

RESULTS

The Fear of Falling Scale showed high internal consistency, test-retest reliability, and strong convergent and discriminant validity. There was a significant association between fear of falling score and the presence of both generalized anxiety disorder and major depression, poor balance-related motor ability, increased nonmotor symptoms of PD, more severe impairments in activities of daily living, and increased motor fluctuations. Finally, generalized anxiety disorder was a significant predictor of number of falls during a 12-month follow-up period.

CONCLUSIONS

The Fear of Falling Scale is a valid and reliable instrument to assess fear of falling in PD. Fear of falling in PD is associated with specific psychiatric and motor disorders and is significantly related to the performance of balance-related motor functions. © 2019 International Parkinson and Movement Disorder Society.

Animals in the Brain

Background

Pareidolic associations are commonly used in medical education to enhance perception of radiological abnormalities. A number of animal-inspired neuroradiological pareidolias have been defined which should alert clinicians to specific movement disorder diagnoses.

Methods

A review of the published literature detailing neuroradiological abnormalities in movement disorder syndromes was conducted, looking specifically for established animal-inspired pareidolic associations.

Results

A number of animal-inspired neuroradiological patterns with specific movement disorder associations have been defined. These include eye of the tiger sign, face of the panda sign, swallow tail sign, hummingbird sign, Mickey Mouse sign, ears of the lynx sign, dragonfly cerebellum, tadpole sign, tigroid/leopard skin sign, and bat wing sign.

Conclusion

Pareidolias represent a quick and easy way of enhancing perception, thereby improving the efficiency and accuracy of image analysis. Movement disorder physicians should keep in mind these associations, given that they will likely facilitate scan analysis.

Latency of re-emergent tremor in Parkinson's disease is influenced by levodopa

INTRODUCTION

Re-emergent tremor (RET) is a common form of postural tremor observed in Parkinson's disease (PD) patients. Recent studies have shown that administration of levodopa decreases RET amplitude. However, drug effects on tremor pause duration are less clear.

METHODS

We performed a prospective observational study in PD patients with RET, subjected to acute levodopa challenge. Tremor activity was measured during OFF and ON states both clinically, as well as by using accelerometers taped to the back of both hands. Correlation between RET amplitude and pause duration, as well with MDS-UPDRS scores were investigated. The slope of gradual increase of postural tremor after the pause was also measured in the OFF and ON states.

RESULTS

Significant inverse correlation between tremor amplitude and RET pause duration was observed in OFF (rs = -0.474, p = 0.030) and ON (rs = -0.569, p = 0.006) states. Levodopa reduced tremor amplitude (26%, p = 0.004) dampening slope gradient (22%, p = 0.029). Tremor pause duration also showed inverse correlation with postural tremor amplitude measured by MDS-UPDRS in OFF (rs = -0.311, p = 0.048) and ON (rs = -0.503, p = 0.020) states, as well as with total MDS-UPDRS Part III score (rs = -0.295, p = 0.009). Finally, accelerometric analysis proved to be more sensitive than visual inspection for detecting tremor pauses.

CONCLUSION

Our results suggest RET pause duration is amplitude related, since levodopa-induced amplitude decrease led to pause prolongation, associated with decreased tremor intensity and slope gradient dampening.

Genetic Dystonia-ataxia Syndromes: Clinical Spectrum, Diagnostic Approach, and Treatment Options

BACKGROUND

Dystonia and ataxia are manifestations of numerous disorders, and indeed, an ever-expanding spectrum of genes causing diseases that encompass dystonia and ataxia are discovered with the advances of genetic techniques. In recent years, a pathophysiological link between both clinical features and the role of the cerebellum in the genesis of dystonia, in some cases, has been proposed. In clinical practice, the genetic diagnosis of dystonia-ataxia syndromes is a major issue for genetic counseling, prognosis and, occasionally, specific treatment.

METHODS

For this pragmatic and educational review, we conducted a comprehensive and structured literature search in Pubmed, OMIM, and GeneReviews using the key words "dystonia" and "ataxia" to identify those genetic diseases that may combine dystonia with ataxia.

RESULTS

There are a plethora of genetic diseases causing dystonia and ataxia. We propose a series of clinico-radiological algorithms to guide their differential diagnosis depending on the age of onset, additional neurological or systemic features, and imaging findings. We suggest a sequential diagnostic approach to dystonia-ataxia syndromes. We briefly highlight the pathophysiological links between dystonia and ataxia and conclude with a review of specific treatment implications.

CONCLUSIONS

The clinical approach presented in this review is intended to improve the diagnostic success of clinicians when faced with patients with dystonia-ataxia syndromes.