Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

Dystonic Tremor as an Atypical Presentation of Cervical Radiculopathy

Cervical radiculopathy often presents with neck pain, sensory disturbances, or motor weakness. This case report describes an atypical presentation of cervical radiculopathy manifesting as dystonic tremor and brachialgia, which has been documented only once previously. A 46-year-old, right-handed, male delivery worker presented with severe neck pain that gradually evolved into a dystonic tremor and sharp aching pain across his right shoulder. Despite medical intervention, his symptoms persisted, leading him to seek chiropractic care. Physical examination and diagnostic tests revealed degenerative osteophytes, causing bilateral foraminal impingement and narrowing. As orthopedic interventions only provide temporary relief, the patient opted for conservative chiropractic management, which led to a remarkable reduction in pain and complete resolution of the dystonic tremor and brachialgia. This case demonstrates that cervical disc prolapse may manifest with dystonic tremor due to excruciating radiculopathy. Additionally, it emphasizes the potential benefits of chiropractic care in managing such atypical presentations and underscores the need for further research on the mechanisms and management of such cases.

Clinical Features, Neuroimaging, and Levodopa-Responsiveness in Holmes' Tremor: A Video-Based Case-Series with a Review of the Literature

BACKGROUND

Holmes' tremor (HT) is a low-frequency tremor characterized by a combination of rest, posture, and action components. We are reporting the clinical features, neuroimaging findings, and levodopa responsiveness in 12 patients with HT.

CASES

The majority of the patients were male (11/12). Dystonia was observed in 10 patients and the remaining two patients had head tremor, a "forme-fruste" of cervical dystonia. The underlying etiologies were vascular (n = 8), head trauma (n = 2), and tumor resection (n = 2). Neuroimaging showed isolated involvement of the midbrain in four, thalamus in two, and basal ganglia and cerebellum in one patient each. A combination of the lesion (thalamus and cerebellum = 2; cerebellopontine angle = 1, and cortical/subcortical = 1) was present in four patients. Levodopa responsiveness was seen in 75% of patients including one with levodopa-induced dyskinesia.

LITERATURE REVIEW

Of 139 patients from 49 studies, levodopa was tried in 123 patients. Improvement with levodopa was seen in 71 patients (57.72%). No improvement with levodopa was observed in 33 patients (26.82%) and details regarding therapeutic response were unavailable in 19 patients (15.44%).

CONCLUSIONS

Dystonia is an important clinical manifestation of HT. Levodopa responsiveness seen in the majority of the patients is consistent with the hypothesis that nigrostriatal pathway damage is crucial for the pathophysiology of HT.

Tremor Syndromes: An Updated Review

Tremor is the most commonly encountered movement disorder in clinical practice. A wide range of pathologies may manifest with tremor either as a presenting or predominant symptom. Considering the marked etiological and phenomenological heterogeneity, it would be desirable to develop a classification of tremors that reflects their underlying pathophysiology. The tremor task force of the International Parkinson Disease and Movement Disorders Society has worked toward this goal and proposed a new classification system. This system has remained a prime topic of scientific communications on tremor in recent times. The new classification is based on two axes: 1. based on the clinical features, history, and tremor characteristics and 2. based on the etiology of tremor. In this article, we discuss the key aspects of the new classification, review various tremor syndromes, highlight some of the controversies in the field of tremor, and share the potential future perspectives.

[Non-motor conditions in patients with cervical dystonia]

OBJECTIVE

To study non-motor conditions in people with diabetes in comparison with patients with cervicalgia.

MATERIAL AND METHODS

The study included 170 people. The main group consisted of 120 respondents with cervical dystonia (CD) aged 27 to 82 years. The diagnosis of CD was based on the Clinical guidelines for the diagnosis and treatment of dystonia adopted by the European Federation of Neurological Societies, the Society for Movement Disorders and the All-Russian Society of Neurologists. The control group included 50 patients, aged 25 to 82 years, with pain in the cervical spine due to muscle-tonic and myofascial syndromes. A Visual Analogue scale, the Hospital Anxiety and Depression Scale (HADS), the Multidimensional Fatigue Inventory (MFI-20), the Pittsburgh Sleep Quality Index (PSQI) were administered to study the asthenic syndrome in all patients.

RESULTS AND CONCLUSION

Pain, anxiety, depression, asthenic syndrome, insomnia are statistically significant non-motor conditions in patients with CD compared with patients with cervicalgia. CD significantly affects the physical and psychological aspects, worsening the quality of life of these patients. The following gender differences are identified: in women with CD, non-motor disorders (anxiety, depression, general and physical asthenia, insomnia) are significantly more pronounced and the quality of life is significantly reduced compared to men with CD. For the successful treatment of CD, a multimodal approach is needed that provides the treatment of not only motor, but also non-motor disorders. Early detection and treatment of comorbid conditions is an important step in the treatment of CD.

Imepitoin for treatment of idiopathic head tremor syndrome in dogs: A randomized, blinded, placebo-controlled study

Background

Idiopathic head tremor syndrome is a paroxysmal movement disorder of unknown etiology. Spontaneous remission may occur, but owners may request treatment in severely affected dogs with continued episodes. Controlled studies of the disease are not available.

Hypothesis/Objectives

A drug with gamma amino butyric acid‐ergic and anxiolytic effects will decrease head tremor episodes.

Animals

Twenty‐four dogs with severe nonremitting head tremor and presumptive clinical diagnosis of idiopathic head tremor syndrome.

Methods

Prospective, blinded, placebo‐controlled clinical trial to compare imepitoin with placebo in dogs with frequent episodes of idiopathic head tremor. Evaluation of efficacy used the quotient T2/T1 that represented prolongation of the head tremor‐free period compared to a 3‐month baseline. A dog was considered a responder if tremors subsided or if the head tremor‐free period was 3× longer than the longest period during baseline (T2/T1 ≥ 3). Sample size calculations considered a large effect of imepitoin on T2/T1 (Cohen's d = 0.8).

Results

There were no responders in the placebo group (0/12). In the imepitoin group, the responder rate was 17% (2/12; P = .18) with T2/T1 3.8 and 4.0. Mean T2/T1 was 1.0 ± 1.4 in the imepitoin and 0.4 ± 0.4 in the placebo group (P = .37).

Conclusion and Clinical Importance

Imepitoin did not result in a significant overall benefit. Future studies should focus on treatment of subgroups with a common pathophysiology and similar comorbidities.

The Problem of Questionable Dystonia in the Diagnosis of 'Essential Tremor-Plus'

In a recent consensus statement on tremor, the task force of the International Parkinson and Movement Disorder Society proposed a new term, ‘essential tremor-plus (ET-plus)’ which includes patients with the characteristics of essential tremor (ET) and additional soft neurological signs of uncertain significance such as questionable dystonic posturing. The clinical interpretation of questionable dystonia has been left to the investigator. The consensus statement also stated that the ET-plus syndrome does not include other clearly defined syndromes like dystonic tremor. However, the boundary between questionable dystonia and definite dystonia is not distinct leading to diagnostic uncertainty in a clinical setting. A similar case may be classified as ET-plus by one observer and dystonic tremor by another. Following the new definition, many studies have reclassified their ET cohort, and they have highlighted the problem of defining questionable dystonia in the diagnosis of ET plus. ET-plus is likely to be a mixture of patients that actually have dystonia and those that don’t, and clinically all we can do is to be suspicious that there might be dystonia. For example, it is not clear whether we should consider spooning and index finger pointing as a sign of questionable or definite dystonia. There are major research and possible therapeutic implications of questionable dystonia in the diagnosis of ET-plus. The concept of ET-plus is extremely difficult to implement without definite guidelines. The resolution will need a biomarker such as physiology or imaging.

Postural Directionality and Head Tremor in Cervical Dystonia

Background

Although abnormal head and neck postures are defining features of cervical dystonia (CD), head tremor (HT) is also common. However, little is known about the relationship between abnormal postures and HT in CD.

Methods

We analyzed clinical data and video recordings from 185 patients enrolled by the Dystonia Coalition. We calculated the likelihood of their HT and HT type ("regular" vs. "jerky") given directionality of abnormal head postures, disease duration, sex, and age.

Results

Patients with retrocollis were more likely to have HT than patients with anterocollis (X2 (1, N = 121) = 7.98, p = 0.005). There was no difference in HT likelihood given left or right turning in laterocollis and rotation. Patients with HT had longer disease duration (t(183) = 2.27, p = 0.024). There was no difference in age between patients with and without HT. In a logistic regression model, anterocollis/retrocollis direction (X2 (1, N = 121) = 6.04, p = 0.014), disease duration (X2 (1, N = 121) = 7.28, p = 0.007), and the interaction term between age and disease duration (X2 (1, N = 121) = 7.77, p = 0.005) collectively contributed to HT likelihood. None of the postural directionality or demographic variables were associated with differential likelihood of having regular versus jerky HT.

Discussion

We found that HT is more likely for CD patients with a specific directionality in their predominant posture. Our finding that CD patients with longer disease duration have a higher likelihood of HT also raises the question of whether HT becomes more likely over time in individual patients.

Oral propranolol for treatment of the subgroups of essential tremor: a systematic review and meta-analysis protocol

INTRODUCTION

Essential tremor (ET), a tremor disorder, is one of the most common movement disorders. Only oral drugs (propranolol, primidone, topiramate, etc）are still the first-line treatment recommended by the Food and Drug Administration. Propranolol is thought to potentially reduce upper limb action tremor. However, it has a poor effect on axial tremor symptoms, such as essential head tremor and voice tremor. Studies have shown that tremor severity develops over time, possibly producing other clinical tremors and neurological soft signs (such as memory loss, gait abnormalities, balance disorders, etc), which further increases the difficulty of treating tremors. However, some recent studies provide emerging evidence for oral propranolol on subgroups of ET, which is based on the anatomical distribution of ET (lower extremities, head, sound, tongue, etc). This systematic review aims to synthesise these new data to improve the efficacy of propranolol in ET subgroups.

METHODS AND ANALYSIS

We will search for randomised controlled trials from the PubMed, MEDLINE, EMBASE, Cochrane Library, UptoDate and PEDro databases from inception to June 2019. All data will be extracted independently by two reviewers and compared at the end of the review. The two reviewers will screen the study quality, and the Cochrane Collaboration's tool in Review Manager (RevMan) V.5.3.3 will be used to evaluate risk of bias. Our primary outcome will be the functional disability component related to tremors, as measured by the Fahn-Tolosa-Marin Tremor Rating Scale subscales B and C. Secondary outcomes will include severity of tremors and quality of life. Narrative and meta-analytical syntheses are planned.

ETHICS AND DISSEMINATION

Published aggregated data will be used in this review analysis and therefore no ethical approval is required. The results will be published in peer-reviewed journals, and proliferation activities will include diverse social stakeholders, non-academic groups and patients.

PROSPERO REGISTRATION NUMBER

CRD42018112580.

Sustained involuntary muscle activity in cerebral palsy and stroke: same symptom, diverse mechanisms

Individuals with lesions of central motor pathways frequently suffer from sustained involuntary muscle activity. This symptom shares clinical characteristics with dystonia but is observable in individuals classified as spastic. The term spastic dystonia has been introduced, although the underlying mechanisms of involuntary activity are not clarified and vary between individuals depending on the disorder. This study aimed to investigate the nature and pathophysiology of sustained involuntary muscle activity in adults with cerebral palsy and stroke. Seventeen adults with cerebral palsy (Gross Motor Function Classification System I–V), 8 adults with chronic stroke and 14 control individuals participated in the study. All individuals with cerebral palsy or stroke showed increased resistance to passive movement with Modified Ashworth Scale >1. Two-minute surface EMG recordings were obtained from the biceps muscle during attempted rest in three positions of the elbow joint; a maximally flexed position, a 90-degree position and a maximally extended position. Cross-correlation analysis of sustained involuntary muscle activity from individuals with cerebral palsy and stroke, and recordings of voluntary isometric contractions from control individuals were performed to examine common synaptic drive. In total, 13 out of 17 individuals with cerebral palsy and all 8 individuals with stroke contained sustained involuntary muscle activity. In individuals with cerebral palsy, the level of muscle activity was not affected by the joint position. In individuals with stroke, the level of muscle activity significantly (P < 0.05) increased from the flexed position to the 90 degree and extended position. Cumulant density function indicated significant short-term synchronization of motor unit activities in all recordings. All groups exhibited significant coherence in the alpha (6–15 Hz), beta (16–35 Hz) and early gamma band (36–60 Hz). The cerebral palsy group had lower alpha band coherence estimates, but higher gamma band coherence estimates compared with the stroke group. Individuals with increased resistance to passive movement due to cerebral palsy or stroke frequently suffer sustained involuntary muscle activity, which cannot exclusively be described by spasticity. The sustained involuntary muscle activity in both groups originated from a common synaptic input to the motor neuron pool, but the generating mechanisms could differ between groups. In cerebral palsy it seemed to originate more from central mechanisms, whereas peripheral mechanisms likely play a larger role in stroke. The sustained involuntary muscle activity should not be treated simply like the spinal stretch reflex mediated symptom of spasticity and should not either be treated identically in both groups.

[The new tremor classification of the International Parkinson and Movement Disorder Society : Update on frequent tremors]

Tremor is one of the most frequent movement disorders. The recently published new classification of the Movement Disorder Society separates the clinical description of tremor syndromes as so-called axis 1 symptom constellations from the etiologies of tremor (axis 2). The same tremor syndromes can therefore be combined with different causes and vice versa. The terminology used in this classification is precisely defined and thereby also the necessary language for medical communication. Frequent tremor syndromes, such as enhanced physiologic tremor, dystonic and parkinsonian tremor as well as focal tremors and task and position-specific tremors are discussed with respect to the phenomenology, and current therapy.

Head tremor at disease onset: an ataxic phenotype of cervical dystonia

BACKGROUND

Cervical dystonia (CD) can present with head tremor. It is unclear whether ataxic features are differentially associated with this phenotype at onset of CD.

OBJECTIVES

We sought to evaluate: (1) the demographic features of CD patients with (Tr-CD) and without head tremor (nTr-CD) at onset, and (2) the differential ataxic features between these CD subtypes.

METHODS

For the first objective, we compared demographic data in Tr-CD versus nTr-CD subtypes in the entire cohort of CD subjects enrolled in the Dystonia Coalition Natural History and Biorepository studies (n = 1608). For the second objective, we rated the standardized videos from consecutively enrolled Tr-CD subjects (n = 50) and age-, gender-, and disease duration-matched nTr-CD subjects (n = 50) for ataxia severity scoring using the Scale for the Assessment and Rating of Ataxia (SARA) and the International Cooperative Ataxia Rating Scale (ICARS); and for dystonia severity using the Toronto Western Spasmodic Torticollis Rating Scale section-I (TWSTRS) and the Global Dystonia Rating Scale (GDRS).

RESULTS

Of 1,608 subjects, 18.1% (n = 291) were classified as Tr-CD and 81.9% (n = 1317) as nTr-CD. The Tr-CD cohort was older, predominantly female, and had longer disease duration than the nTr-CD cohort (p = 0.01). Compared to nTr-CD, Tr-CD subjects had worse generalized ataxia, speech, and gait and posture scores. High ataxia severity with low dystonia severity distinguished Tr-CD from nTr-CD with high accuracy (area under the curve, 0.91 (95% CI 0.85-0.97).

CONCLUSIONS

Head tremor at disease onset represents a clinically distinguishable subtype of cervical dystonia affecting predominantly older women, with worse ataxia and milder dystonia than the non-tremulous dystonic phenotype.

Defining differences in patient characteristics between spasmodic dysphonia and laryngeal tremor

OBJECTIVE

To compare presenting characteristics of patients with adductor spasmodic dysphonia (ADSD), ADSD with laryngeal tremor (ADSD + LT), and laryngeal tremor without ADSD (LT).

DESIGN

Cross-sectional analysis.

METHODS

Patients treated for laryngeal movement disorders (1990-2016) were included. Analysis of variance and chi square tests measured differences in patient characteristics across the three disease groups. Using ADSD as the referent, multivariable logistic regression models were used to determine whether potential risk factors including patient demographics, family history, presence of potential inciting events prior to disease onset, and coprevalent movement disorders were associated with ADSD + LT or LT.

RESULTS

In all, 652 patients with ADSD (n = 377), ADSD + LT (n = 98), and LT (n = 177) were included. ADSD patients were significantly younger than those with ADSD + LT and LT (52.5 ± 13.4, 63.9 ± 11.3, and 69.3 ± 10.5 years, respectively; P < 0.001). Coprevalent movement disorders were more common in ADSD + LT (38.7%) and LT (57.1%) groups than in the ADSD group (11.5%; P < 0.001). Compared to ADSD, patients with ADSD + LT and LT were more likely to develop an additional movement disorder during follow-up. In multivariable analyses, increasing age, female gender, and having a movement disorder at presentation were associated with significantly greater odds of having ADSD + LT or LT when compared to ADSD.

CONCLUSION

ADSD + LT patients demonstrate intermediate gender composition and age distributions between those with ADSD and LT. These findings suggest that ADSD + LT may be a distinct phenotype in the spectrum of laryngeal movement disorders.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:170-176, 2019.

Consensus Statement on the classification of tremors. from the task force on tremor of the International Parkinson and Movement Disorder Society

BACKGROUND

Consensus criteria for classifying tremor disorders were published by the International Parkinson and Movement Disorder Society in 1998. Subsequent advances with regard to essential tremor, tremor associated with dystonia, and other monosymptomatic and indeterminate tremors make a significant revision necessary.

OBJECTIVES

Convene an international panel of experienced investigators to review the definition and classification of tremor.

METHODS

Computerized MEDLINE searches in January 2013 and 2015 were conducted using a combination of text words and MeSH terms: "tremor", "tremor disorders", "essential tremor", "dystonic tremor", and "classification" limited to human studies. Agreement was obtained using consensus development methodology during four in-person meetings, two teleconferences, and numerous manuscript reviews.

RESULTS

Tremor is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: Axis 1-clinical characteristics, including historical features (age at onset, family history, and temporal evolution), tremor characteristics (body distribution, activation condition), associated signs (systemic, neurological), and laboratory tests (electrophysiology, imaging); and Axis 2-etiology (acquired, genetic, or idiopathic). Tremor syndromes, consisting of either isolated tremor or tremor combined with other clinical features, are defined within Axis 1. This classification scheme retains the currently accepted tremor syndromes, including essential tremor, and provides a framework for defining new syndromes.

CONCLUSIONS

This approach should be particularly useful in elucidating isolated tremor syndromes and syndromes consisting of tremor and other signs of uncertain significance. Consistently defined Axis 1 syndromes are needed to facilitate the elucidation of specific etiologies in Axis 2. © 2017 International Parkinson and Movement Disorder Society.

How Many Dystonias? Clinical Evidence

Literary reports on dystonia date back to post-Medieval times. Medical reports are instead more recent. We review here the early descriptions and the historical establishment of a consensus on the clinical phenomenology and the diagnostic features of dystonia syndromes. Lumping and splitting exercises have characterized this area of knowledge, and it remains largely unclear how many dystonia types we are to count. This review describes the history leading to recognize that focal dystonia syndromes are a coherent clinical set encompassing cranial dystonia (including blepharospasm), oromandibular dystonia, spasmodic torticollis, truncal dystonia, writer's cramp, and other occupational dystonias. Papers describing features of dystonia and diagnostic criteria are critically analyzed and put into historical perspective. Issues and inconsistencies in this lumping effort are discussed, and the currently unmet needs are critically reviewed.