Assessing the Severity of Cervical Dystonia: Ask the Doctor or Ask the Patient?

Background

Assessing disease severity can be performed using either clinician-rated scales (CRS) or patient-rated outcome (PRO) tools. These two measures frequently demonstrate poor correlations.

Objectives

To determine if the correlation between a CRS and PRO for motor features of cervical dystonia (CD) improves by accounting for non-motor features.

Methods

Subjects with CD (N = 209) were evaluated using a CRS (Toronto Western Spasmodic Torticollis Rating Scale, TWSTRS) and a PRO (Cervical Dystonia Impact Profile, CDIP-58).

Results

Linear regression revealed a weak correlation between the two measures, even when considering only the motor subscales of each. The strength of this relationship improved with a regression model that included non-motor symptoms of pain, depression, and disability.

Conclusions

These results argue that the results of motor assessments in a PRO for CD cannot be fully appreciated without simultaneous assessment of non-motor co-morbidities. This conclusion might apply to other disorders, especially those with frequent non-motor co-morbidities.

Patients with Cognitive Impairment in Parkinson's Disease Benefit from Deep Brain Stimulation: A Case-Control Study

Background

Deep brain stimulation (DBS) for Parkinson's disease (PD) is generally contraindicated in persons with dementia but it is frequently performed in people with mild cognitive impairment or normal cognition, and current clinical guidelines are primarily based on these cohorts.

Objectives

To determine if moderately cognitive impaired individuals including those with mild dementia could meaningfully benefit from DBS in terms of motor and non-motor outcomes.

Methods

In this retrospective case-control study, we identified a cohort of 40 patients with PD who exhibited moderate (two or more standard deviations below normative scores) cognitive impairment (CI) during presurgical workup and compared their 1-year clinical outcomes to a cohort of 40 matched patients with normal cognition (NC). The surgery targeted subthalamus, pallidus or motor thalamus, in a unilateral, bilateral or staged approach.

Results

At preoperative baseline, the CI cohort had higher Unified Parkinson's Disease Rating Scale (UPDRS) subscores, but similar levodopa responsiveness compared to the NC cohort. The NC and CI cohorts demonstrated comparable degrees of postoperative improvement in the OFF-medication motor scores, motor fluctuations, and medication reduction. There was no difference in adverse event rates between the two cohorts. Outcomes in the CI cohort did not depend on the target, surgical staging, or impaired cognitive domain.

Conclusions

Moderately cognitively impaired patients with PD can experience meaningful motor benefit and medication reduction with DBS.

A Multi-center Genome-wide Association Study of Cervical Dystonia

BACKGROUND

Several monogenic causes for isolated dystonia have been identified, but they collectively account for only a small proportion of cases. Two genome-wide association studies have reported a few potential dystonia risk loci; but conclusions have been limited by small sample sizes, partial coverage of genetic variants, or poor reproducibility.

OBJECTIVE

To identify robust genetic variants and loci in a large multicenter cervical dystonia cohort using a genome-wide approach.

METHODS

We performed a genome-wide association study using cervical dystonia samples from the Dystonia Coalition. Logistic and linear regressions, including age, sex, and population structure as covariates, were employed to assess variant- and gene-based genetic associations with disease status and age at onset. We also performed a replication study for an identified genome-wide significant signal.

RESULTS

After quality control, 919 cervical dystonia patients compared with 1491 controls of European ancestry were included in the analyses. We identified one genome-wide significant variant (rs2219975, chromosome 3, upstream of COL8A1, P-value 3.04 × 10^-8 ). The association was not replicated in a newly genotyped sample of 473 cervical dystonia cases and 481 controls. Gene-based analysis identified DENND1A to be significantly associated with cervical dystonia (P-value 1.23 × 10^-6 ). One low-frequency variant was associated with lower age-at-onset (16.4 ± 2.9 years, P-value = 3.07 × 10^-8 , minor allele frequency = 0.01), located within the GABBR2 gene on chromosome 9 (rs147331823).

CONCLUSION

The genetic underpinnings of cervical dystonia are complex and likely consist of multiple distinct variants of small effect sizes. Larger sample sizes may be needed to provide sufficient statistical power to address the presumably multi-genic etiology of cervical dystonia. © 2021 International Parkinson and Movement Disorder Society.

Telemedicine in an Academic Movement Disorders Center during COVID-19

Objective

Telemedicine has rapidly gained momentum in movement disorder neurology during the coronavirus disease (COVID-19) pandemic to preserve clinical care while mitigating the risks of in-person visits. We present data from the rapid implementation of virtual visits in a large, academic, movement disorder practice during the COVID-19 pandemic.

Methods

We describe the strategic shift to virtual visits and retrospectively examine elements that impacted the ability to switch to telemedicine visits using historical prepandemic in-person data as a comparator, including demographics, distance driven, and diagnosis distribution, with an additional focus on patients with deep brain stimulators.

Results

A total of 686 telemedicine visits were performed over a five-week period (60% of those previously scheduled for in-office visits). The average age of participants was 65 years, 45% were female, and 73% were Caucasian. Men were more likely to make the transition (p = 0.02). Telemedicine patients lived farther from the clinic than those seen in person (66.47 km vs. 42.16 km, p < 0.001), age was not associated with making the switch, and patient satisfaction did not change. There was a significant shift in the distribution of movement disorder diagnoses seen by telemedicine compared to prepandemic in-person visits (p < 0.001). Patients with deep brain stimulators were more likely to use telemedicine (11.5% vs. 7%, p < 0.001).

Conclusion

Telemedicine is feasible, viable and relevant in the care of movement disorder patients, although health care disparities appear evident for women and minorities. Patients with deep brain stimulators preferred telemedicine in our study. Further study is warranted to explore these findings.

A metabolomic study of cervical dystonia

INTRODUCTION

Cervical dystonia is the most common of the adult-onset focal dystonias. Most cases are idiopathic. The current view is that cervical dystonia may be caused by some combination of genetic and environmental factors. Genetic contributions have been studied extensively, but there are few studies of other factors. We conducted an exploratory metabolomics analysis of cervical dystonia to identify potentially abnormal metabolites or altered biological pathways.

METHODS

Plasma samples from 100 cases with idiopathic cervical dystonia and 100 controls were compared using liquid chromatography coupled with mass spectrometry-based metabolomics.

RESULTS

A total of 7346 metabolic features remained after quality control, and up to 289 demonstrated significant differences between cases and controls, depending on statistical criteria chosen. Pathway analysis revealed 9 biological processes to be significantly associated at p < 0.05, 5 pathways were related to carbohydrate metabolism, 3 pathways were related to lipid metabolism.

CONCLUSION

This is the first large scale metabolomics study for any type of dystonia. The results may provide potential novel insights into the biology of cervical dystonia.

Soft Nanomembrane Sensors and Flexible Hybrid Bioelectronics for Wireless Quantification of Blepharospasm

Blepharospasm (BL) is characterized by involuntary closures of the eyelids due to spasms of the orbicularis oculi muscle. The gold standard for clinical evaluation of BL involves visual inspection for manual rating scales. This approach is highly subjective and error prone. Unfortunately, there are currently no simple quantitative systems for accurate and objective diagnostics of BL. Here, we introduce a soft, flexible hybrid bioelectronic system that offers highly conformal, gentle lamination on the skin, while enabling wireless, quantitative detection of electrophysiological signals. Computational and experimental studies of soft materials and flexible mechanics provide a set of key fundamental design factors for a low-profile bioelectronic system. The nanomembrane soft electrodes, mounted around the eyes, are capable of accurately measuring clinical symptoms, including the frequency of blinking, the duration of eye closures during spasms, as well as combinations of blinking and spasms. The use of a deep-learning, convolutional neural network, with the bioelectronics offers objective, real-time classification of key pathological features in BL. The wearable bioelectronics outperform the conventional manual clinical rating, as shown by a pilot study with 13 patients. In vivo demonstration of the bioelectronics with these patients indicates the device as an easy-to-use solution for objective quantification of BL.

Dystonia and Tremor: A Cross-Sectional Study of the Dystonia Coalition Cohort

OBJECTIVE

To assess the clinical manifestations and predictors of different types of tremors in individuals with different types of isolated dystonia.

METHODS

Clinical manifestations of tremor were assessed in a multicenter, international cross-sectional, cohort study of 2,362 individuals with all types of isolated dystonia (focal, segmental, multifocal, and generalized) recruited through the Dystonia Coalition.

RESULTS

Methodical and standardized assessments of all participants in this cohort revealed the overall prevalence of any type of tremor was 53.3%. The prevalence of dystonic tremor varied from 36.9% to 48.4%, depending on criteria used to define it. To identify the factors associated with tremors in dystonia, the data were analyzed by generalized linear modeling and cluster analyses. Generalized linear modeling indicated 2 of the strongest factors associated with tremor included body region affected by dystonia and recruitment center. Tremor was also associated with severity of dystonia and duration of dystonia, but not with sex or race. The cluster analysis distinguished 8 subgroups within the whole cohort; defined largely by body region with dystonia, and secondarily by other clinical characteristics.

CONCLUSION

The large number of cases evaluated by an international team of movement disorder experts facilitated the dissection of several important factors that influence the apparent prevalence and phenomenology of tremor in dystonia. These results are valuable for understanding the many differences reported in prior studies, and for guiding future studies of the nosology of tremor and dystonia.

Soft Material-Enabled, Active Wireless, Thin-Film Bioelectronics for Quantitative Diagnostics of Cervical Dystonia

Recent advances in flexible materials, nanomanufacturing, and system integration have provided a great opportunity to develop wearable flexible hybrid electronics for human healthcare, diagnostics, and therapeutics. However, existing medical devices still rely on rigid electronics with many wires and separate components, which hinders wireless, comfortable, continuous monitoring of health-related human motions. Here, we introduce advanced materials and system integration technologies that enable a soft, active wireless, thin-film bioelectronics. The low-modulus, highly flexible wearable electronic system incorporates a nanomembrane wireless circuit and functional chip components, enclosed by a soft elastomeric membrane. The bioelectronic system offers a gentle, seamless mounting on the skin, while offering a comfortable, highly sensitive and accurate detection of head movements. We utilize the wireless wearable hybrid system for quantitative diagnostics of cervical dystonia (CD) that is characterized by involuntary abnormal head postures and repetitive head movements, sometimes with neck muscle pain. A set of analytical and experimental studies shows a soft system packaging, hard-soft materials integration, and quantitative assessment of physiological signals detected by the SKINTRONICS. In vivo demonstration, involving ten human subjects, captures the device feasibility for use in CD measurement.

Lurasidone-Induced Tardive Syndrome

Introduction

Tardive syndrome (TS) is an often irreversible movement disorder caused by dopamine receptor-blocking agents (DRBAs). Although TS are well recognized to occur with typical antipsychotics, less well appreciated is that atypical antipsychotics also carry a risk of TS.

Methods

Case series.

Results

We describe 4 patients who developed tardive dystonia, tardive akathisia, and drug-induced parkinsonism with the use of the atypical antipsychotic, lurasidone, which was U.S. Food and Drug Administration approved in 2013 for use in bipolar disorder and schizophrenia.

Conclusion

Movement disorders are reported as a rare side effect of lurasidone, and, as such, prescribers may perceive a false sense of security regarding this potential complication. Our cases indicate that this relatively new atypical antipsychotic may cause irreversible disabling TS as well as parkinsonism. Caution must be taken when prescribing lurasidone.

Long-term effects of neonatal surgery on adulthood pain behavior

The long-term consequences of neonatal noxious stimulation on adulthood pain behavior were investigated in male and female mice. On the day of birth, mouse pups were exposed to a laparotomy under cold anesthesia followed by an analgesic dose of morphine (10 mg/kg) post-operatively, or a saline control. An additional group of subjects was exposed to the non-noxious aspects of the surgical procedure (cold exposure, separation from the dam, injection) comprising a 'sham' surgery control group, whereas another group of control subjects was administered an injection of saline or morphine, but was otherwise undisturbed. Behavioral observations of the pups immediately following the procedure indicated that the laparotomy produced increased distress vocalizations in the ultrasonic range (40 kHz) compared to both groups of control subjects. During 90 min observations periods following the surgery and 1-week later, maternal care did not vary among treatment conditions. In adulthood, offspring were tested for nociceptive sensitivity on the hot-plate (HP; 53 degrees C), tail-withdrawal (TW; 50 degrees C) and acetic acid abdominal constriction test (AC). On both the TW and the AC tests, neonatal surgery decreased pain behavior relative to both groups of control subjects, an effect that was reversed by post-operative morphine treatment. On the HP test, both groups of subjects exposed to the stressful aspects of neonatal surgery (laparotomy or sham surgery) exhibited decreased pain behavior in adulthood. These findings suggest that early exposure to noxious and/or stressful stimuli may induce long-lasting changes in pain behavior, perhaps mediated by alterations in the stress-axis and antinociceptive circuitry.

Nociception and antinociception during the first week of life in mice: Sex differences and test dependence

This study demonstrates that reliable sex differences in nociceptive and antinociceptive mechanisms are present in even very young subjects. Sex differences were observed in mice tested either on the day of birth or 1 week later on basal tail-flick latency and morphine analgesic magnitude. Female mice had longer tail-withdrawal latencies; male mice demonstrated stronger analgesic responses to morphine. In addition, basal pain behavior and analgesic responsiveness differed between day-old and week-old animals on the hot plate, with day-old mice showing enhanced pain behavior and reduced morphine antinociception compared to week-old subjects. These findings further support the competence of pain processing circuitry in even very young subjects and highlight the early development of nociceptive and antinociceptive mechanisms.

PERSPECTIVE

This study highlights the competence of nociceptive circuitry and the analgesic efficacy of morphine as early as the day of birth in mice, reinforcing the importance of evaluating and treating pain in even the youngest subjects. Sex differences were present, suggesting infant sex as one of several potential factors that predict the experience of procedural or pathological pain and analgesic requirement.