Rest tremor in Parkinson's disease: Body distribution and time of appearance

Motor Features of Parkinson's Disease

The most characteristic motor feature of Parkinson's disease is bradykinesia. Other cardinal motor features of Parkinson's disease include tremor (particularly rest tremor), rigidity, and postural instability/gait changes. Additional motor features common to the disease include dystonia, postural abnormalities, speech and swallowing dysfunction, and levodopa-related dyskinesias. The pathophysiology of many of these motor features remains poorly understood. During the natural course of the disease, nonmotor features (discussed elsewhere) often precede the onset of motor features and meaningfully contribute to motor disability and the gradual decline in the quality of life.

Lip and Jaw Tremor in Parkinson's Disease

Background

Parkinson's disease (PD) is characterized clinically by the presence of bradykinesia, rigidity, and tremor. Although upper limb rest tremor is the most common form of tremor in PD, lip/jaw tremor is identified in a proportion of these patients.

Methods

We aimed to assess the frequency, features, and correlates of lip/jaw tremor in PD.

Results

We studied 229 consecutive patients with PD. There were 39 (17%) patients with lip/jaw tremor, 22 of them (56.4%) were males. Slight lip/jaw tremor was identified in n = 10 (25.6%), mild in n = 15 (38.5%), moderate in n = 13 (33.3%) and severe in n = 1 (2.6%) case. Patients with lip/jaw tremor had a positive association with older age, greater limb rest tremor scores (P = 0.009), and higher total MDS-UPDRS-III scores (P < 0.001) in the multivariate regression analysis. There were 6 patients with isolated lip/jaw tremor (i.e. without limb rest tremor). These patients were all male (P = 0.038), tended to be older (75.7 vs. 67.7 years, P = 0.078) and had greater cognitive impairment (P = 0.034) than the rest of the cohort, but there was no association with other body tremors or total motor score.

Conclusions

Lip/jaw tremor was identified in 17% of cases; it was associated with greater motor severity and limb rest tremor, suggesting shared pathophysiology with limb rest tremor. A subgroup with isolated lip/jaw tremor showed reduced cognitive performance, but no association with other body tremors.

Head tremor in Parkinson´s Disease, clinical Associations and response to therapy

Background

Tremor is frequently observed in patients with Parkinsońs disease (PD). Tremor most commonly affects the upper limbs but may also affect the axial muscles in PD. Head tremor (HT) is usually identified in patients with essential tremor (ET) and cervical dystonia (CD), but rarely reported in PD.

Objectives Methods

We aimed to assess the frequency, clinical features, correlates, and underlying mechanisms of HT in PD.

Results

Among 229 patients with PD, we identified 19 (8.3 %) of patients with HT. There were 11 males and 8 females with a median age at evaluation of 62.0 years. Five patients had slight, ten had mild and four had moderately severe HT. Yes-yes HT was the most common type. HT was associated with PD in 13 patients, eight of them had severe tremor-dominant presentation. In 3 patients there were signs suggesting underlying ET, while 3 patients had CD. Complete resolution of HT was observed with levodopa and/or deep brain stimulation (DBS) in patients with PD only, but inconsistent improvement was observed with comorbid ET or CD. Longer evolution time since PD onset (P = 0.024), rest tremor (P = 0.001) and CD (P = 0.003) were independently associated with HT in the multivariate analysis.

Conclusions

HT was identified in 8.3% of patients with PD. It associated with longer evolution since PD onset, the severity of rest tremor and presence of CD. HT is observed in the context of PD only, particularly in those with severe tremor-dominant presentation, comorbid ET or CD. Most patients improve with dopaminergic therapy or DBS.

The Effect of Oropharyngeal Resting Tremor on Swallowing Function in a Clinical Cohort of People with Parkinson's Disease

Parkinson's Disease (PD) is a progressive neurodegenerative disease, with hallmark symptomology typically consisting of tremor, bradykinesia, and rigidity. Though the classic "pill-rolling" rest tremor in the hand or upper limb are often the most salient, it can occur throughout the body including the lower limbs, jaw, face, or tongue. There have been investigations into other motor related phenomena potentially affecting swallow function in PwPD previously. However, there have been no investigations of how oropharyngeal resting tremor in structures such as the tongue or larynx explicitly affects swallowing physiology. A retrospective analysis of previously conducted VFSS on 34 patients diagnosed with idiopathic PD (IPD) was performed to examine how individuals that displayed resting tremor during VFSS (Tremor +) and those who did not (Tremor-) differ in swallowing function. Measures of swallowing function including timing intervals of key swallow events, post-swallow residue, and penetration-aspiration scale (PAS) scores were recorded, and key demographic information including time since diagnosis and medication status were extracted from the medical records available. Multivariate models were used to identify differences between tremor groups for timing intervals and post-swallow residue, and chi-squares were computed for differences in PAS score distribution by group and bolus. Sixty-eight percent (23/34) of this sample displayed oropharyngeal resting tremor in at least one structure during VFSS. There were no instances of other tremor types observed in this sample. All participants were taking medication to manage PD symptomology. Significant effects of tremor group were observed for swallow timing intervals related to airway closure (p < 0.001), post-swallow residue (p < 0.05), and swallow safety at the bolus level in the Tremor + group (p < 0.001). These results suggest that PwPD who present with resting tremor in oropharyngeal structures may manifest with different variations in swallowing physiology, including altered timings of swallow events, increased pharyngeal residue, and greater associations of airway invasion with thinner and larger volume boluses. This study highlights the need for substantially more research into how motor fluctuations and phenotypes of PwPD contribute to alterations in swallowing function.

Updates in essential tremor

Essential tremor (ET) is one of the most common tremor disorders and can be disabling in its affect on daily activities. There have been major breakthroughs in the treatment of tremor and ET is the subject of important ongoing research. This review will present recent advancements in the epidemiology, genetics, pathophysiology, diagnosis, comorbidities, and imaging of ET. Current and future treatment options in the management of ET will also be reviewed. The need for continued innovation and scientific inquiry to address the unmet needs of persons of ET will be highlighted.

Refining the clinical diagnosis of Parkinson's disease

Our ability to define, understand, and classify Parkinson's disease (PD) has undergone significant changes since the disorder was first described in 1817. Clinical features and neuropathologic signatures can now be supplemented by in-vivo interrogation of genetic and biological substrates of disease, offering great opportunity for further refining the diagnosis of PD. In this mini-review, we discuss the historical perspectives which shaped our thinking surrounding the definition and diagnosis of PD. We highlight the clinical, genetic, pathologic and biologic diversity which underpins the condition, and proceed to discuss how recent developments in our ability to define biologic and pathologic substrates of disease might impact PD definition, diagnosis, individualised prognostication, and personalised clinical care. We argue that Parkinson's 'disease', as currently diagnosed in the clinic, is actually a syndrome. It is the outward manifestation of any array of potential dysfunctional biologic processes, neuropathological changes, and disease aetiologies, which culminate in common outward clinical features which we term PD; each person has their own unique disease, which we can now define with increasing precision. This is an exciting time in PD research and clinical care. Our ability to refine the clinical diagnosis of PD, incorporating in-vivo assessments of disease biology, neuropathology, and neurogenetics may well herald the era of biologically-based, precision medicine approaches PD management. With this however comes a number of challenges, including how to integrate these technologies into clinical practice in a way which is acceptable to patients, promotes meaningful changes to care, and minimises health economic impact.

Bedside clinical assessment of patients with common upper limb tremor and algorithmic approach

The diagnostic approach for patients with tremor is challenging due to the complex and overlapping phenotypes among tremor syndromes. The first step in the evaluation of tremor is to identify the tremulous movement and exclude the tremor mimics. The second step is to classify the tremor syndrome based on the characteristics of tremor from historical clues and focused examination (Axis 1). Comprehensive tremor examinations involve the assessment of tremor in different conditions (rest, action or mixed, position or task-specific), distribution of tremor (upper limb, lower limb, head, jaw), positive signs for functional tremor (FT) if suspected (distractibility, entrainment, co-contraction), and associated neurological signs including parkinsonism, dystonic posture, cerebellar/brainstem signs, neuropathy, and cognitive impairment. A pivotal feature in this step is to determine any distinct feature of a specific isolated or combined tremor syndrome. In this review, we propose an algorithm to assess upper limb tremors. Ancillary testing should be performed if clinical evaluation is unclear. The choice of investigation depends on the types of tremors considered to narrow down the spectrum of etiology (Axis 2). Laboratory blood tests are considered for acute onset and acute worsening of tremors, while structural neuroimaging is indicated in unilateral tremors with acute onset, nonclassical presentations, and a combination of neurological symptoms. Neurophysiological study is an important tool that aids in distinguishing between tremor and myoclonus, etiology of tremor and document specific signs of FT. Treatment is mainly symptomatic based depending on the etiology of the tremor and the patient's disabilities.

Parkinson's Disease Patient Monitoring: A Real-Time Tracking and Tremor Detection System Based on Magnetic Measurements

Reliable diagnosis of early-stage Parkinson’s disease is an important task, since it permits the administration of a timely treatment, slowing the progression of the disease. Together with non-motor symptoms, other important signs of disease can be retrieved from the measurement of the movement trajectory and from tremor appearances. To measure these signs, the paper proposes a magnetic tracking system able to collect information about translational and vibrational movements in a spatial cubic domain, using a low-cost, low-power and highly accurate solution. These features allow the usage of the proposed technology to realize a portable monitoring system, that may be operated at home or in general practices, enabling telemedicine and preventing saturation of large neurological centers. Validation is based on three tests: movement trajectory tracking, a rest tremor test and a finger tapping test. These tests are considered in the Unified Parkinson’s Disease Rating Scale and are provided as case studies to prove the system’s capabilities to track and detect tremor frequencies. In the case of the tapping test, a preliminary classification scheme is also proposed to discriminate between healthy and ill patients. No human patients are involved in the tests, and most cases are emulated by means of a robotic arm, suitably driven to perform required tasks. Tapping test results show a classification accuracy of about 93% using a k-NN classification algorithm, while imposed tremor frequencies have been correctly detected by the system in the other two tests.

Classification of vocal tremor using updated consensus-based tremor classification criteria

OBJECTIVES

This study characterized the clinical phenotypes of individuals with vocal tremor (VT) using tremor classification criteria published by the International Parkinson and Movement Disorder Society (IPMDS) including laryngeal features from the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS).

METHODS

VT phenotypic descriptors were extracted from participant medical records from 2017 to 2019. Clinical phenotype descriptors included the: (a) chief complaint and discipline for the first appointment, (b) demographics, (c) tremor body distribution, condition, frequency, and progression, (d) exacerbating/alleviating factors, (e) treatment approaches, and (g) neurologic comorbidities. Descriptive statistics were conducted.

RESULTS

Of 179 meeting inclusion criteria, 2/3 were female; tremor onset affected voice (43%) or extremity (32%) and 2/3 were documented with tremor duration of 3 years or more. Those with primary VT first saw otolaryngology or speech language pathology (59%), whereas those with primary extremity/head tremor first saw neurology (36%). Documentation commonly omitted tremor clinical features such as (a) observed conditions of tremor (64%), (b) laryngeal features (64%), and (c) tremor frequency (92%). Thus, VT classification was based on comorbidity in 49% of patients (ie, essential tremor (48%), dystonia (72%), and Parkinson's disease (100%)) and 32% had inadequate documentation to classify.

CONCLUSION

The majority of individuals with VT were unable to be classified based on documented clinical features highlighting the need for consistent multidisciplinary assessment of tremor affecting speech structures. The primary site of tremor determined the first discipline seen. Most commonly classified VT categories included essential tremor (47%), dystonia (28%), Parkinsonism (7%), and isolated VT (19%).

LEVEL OF EVIDENCE

4.

Facial tremor in patients with Parkinson's disease: prevalence, determinants and impacts on disease progression

BACKGROUND

Facial (lip and jaw) tremor (FT) is associated with Parkinson's disease (PD) but few studies have been conducted to explore its clinical profile. We performed this study to investigate the prevalence and clinical correlates of FT in PD, and further to evaluate its effect on disease progression.

METHODS

A retrospective, cross-sectional (n = 2224) and longitudinal (n = 674) study was conducted. The presence of FT was based on a ≥ 1 score in the United PD Rating Scale (UPDRS) item 20A. Group comparisons were conducted, followed by a forward binary logistic regression analysis. Inverse probability of treatment weighting (IPTW) based on the propensity score and weighted or unweighted Cox regression models were used to explore the impact of FT on five clinical milestones including death, UPDRS III 11-point increase, Hoehn and Yahr (H&Y) stage reaching 3, dyskinesia development, and Montreal Cognitive Assessment 3-point decrease.

RESULTS

FT was presented in 403 patients (18.1%), which showed increasing trends with disease duration and H&Y score. Age (P < 0.001), female (P < 0.001), disease duration (P = 0.001), speech (P = 0.011), rigidity (P = 0.026), rest tremor on limbs (P < 0.001), kinetic tremor on hands (P < 0.001), and axial symptoms (P = 0.013) were independent factors associated with FT. Both unweighted and weighted Cox regression models indicated that baseline FT and FT as the initial symptom were not associated with the five outcomes.

CONCLUSIONS

Our study suggested that FT was not uncommon and provided a deeper insight into the characteristics of FT in PD. The predict value of FT on long-term progronis of PD may need future longer follwe-up study.

The influence of posture duration on hand tremor during tasks with attention-distraction in persons with Parkinson's disease

BACKGROUND

Tremor is one of the hallmarks and most bothersome symptoms in Parkinson's disease (PD). The classical PD tremor is present at rest, but postural tremor also occurs. PD tremor can be continuous or intermittently present and can have a re-emergent nature. The tremor intensity is affected by attention and stress level. Observations of PD tremor have indicated increased tremor intensity with time during 30-s tremor assessments. This phenomenon has not previously been studied systematically. Thus, in order to contribute to our understanding of the mechanisms associated with PD tremor, our aim was to investigate the influence of time during a posture holding and a resting task on hand tremor characteristics in persons with PD compared to healthy peers.

METHOD

Fifty persons with PD and at least one tremoring hand (tremor intensity exceeding mean + 2SD of a healthy reference group (REF), N = 40) were included from a clinical trial population. Hand accelerations in a rest and postural condition were measured in 30-s assessments while the participants performed a self-paced simple subtraction task with eyes closed to standardize attention without inducing stress. Tremor intensity, maximal power, frequency of maximal power and tremor onset time was calculated for three consecutive 10-s time intervals.

RESULTS

Tremor intensity and maximal power increased significantly during the 30-s recording in the PD-group in both conditions (1st-3rd time-interval, tremor intensity: rest + 65% p < 0.0001, postural + 55% p < 0.0001; maximal power: rest + 93% p < 0.0001, postural + 82% p < 0.001). No effect of time was found on frequency of maximal power in the PD-group or on any effect measure in the REF-group.

CONCLUSION

Tremor intensity and maximal power increased with time in the PD-group during 30-s tasks, while no change with time was found in the REF-group. In contrast, frequency of maximal power remained unchanged, which may suggest that the same neural circuits were responsible for the tremor generation throughout the tasks. The increase in tremor intensity and maximal power could not solely be explained by re-emergence of tremor. This suggests an increasing or gradually more synchronized cortico-spinal drive throughout the tasks. However, this requires further studies to determine.

The effect of 8 weeks of treatment with transcranial pulsed electromagnetic fields on hand tremor and inter-hand coherence in persons with Parkinson's disease

BACKGROUND

Parkinson's disease (PD) tremor comprises asymmetric rest and postural tremor with unilateral onset. Tremor intensity can be amplified by stress and reduced by attention, and the medical treatment is complex. Mirror movements and unintentional synchronization of bimanual movements, possibly caused by insufficient inhibition of inter-hemispheric crosstalk, have been reported in PD, indicating a lag of lateralization. Potential neuroprotective effects of pulsed electromagnetic fields (PEMF) have been reported in-vitro and in rodents, as have influences of PEMF on human tremor. The aim was to investigate the effect of 8 weeks daily transcranial PEMF treatment (T-PEMF) of persons with PD on rest and postural hand tremor characteristics and on inter-hand coherence.

METHODS

Hand accelerations of 50 PD participants with uni- or bilateral tremor participating in a clinical trial were analysed. A rest and postural tremor task performed during serial subtraction was assessed before and after 8 weeks of T-PEMF (30 min/day, 50 Hz, ±50 V, 3 ms squared pulses) or placebo treatment (sham stimulation 30 min/day). Forty matched healthy persons (no treatment) were included as reference. Intensity and inter-hand coherence related measures were extracted.

RESULTS

The T-PEMF treatment decreased the inter-hand coherence in the PD group with unilateral postural tremor. The PD group with unilateral postural tremor was less clinically affected by the disease than the PD group with bilateral postural tremor. However, no differences between T-PEMF and placebo treatment on either intensity related or coherence related measures were found when all persons with PD were included in the analyses. The peak power decreased and the tremor intensity tended to decrease in both treatment groups.

CONCLUSIONS

Eight weeks of T-PEMF treatment decreased inter-hand coherence in the PD group with unilateral postural tremor, while no effects of T-PEMF treatment were found for the entire PD group. The unilateral postural tremor group was less clinically affected than the bilateral postural tremor group, suggesting that early treatment initiation may be beneficial. In theory, a reduced inter-hand coherence could result from a neuronal treatment response increasing inter-hemispheric inhibition. However, this requires further studies to determine. Studies of even longer treatment periods would be of interest.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02125032. Registered 29 April 2014, https://clinicaltrials.gov/ct2/show/NCT02125032?term=NCT02125032&rank=1.

Exploring bedside clinical features of parkinsonism: A focus on differential diagnosis

The proper diagnosis of parkinsonian disorders usually involves three steps: identifying core features of parkinsonism; excluding other causes; and collating supportive evidence based on clinical signs or investigations. While the recognition of cardinal parkinsonian features is usually straightforward, the appreciation of clinical features suggestive of specific parkinsonian disorders can be challenging, and often requires greater experience and skills. In this review, we outline the clinical features that are relevant to the differential diagnosis of common neurodegenerative parkinsonian disorders, including Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration. We aim to make this process relatable to clinicians-in-practice, therefore, have categorised the list of clinical features into groups according to the typical sequence on how clinicians would elicit them during the examination, starting with observation of facial expression and clinical signs of the face, spotting eye movement abnormalities, examination of tremors and jerky limb movements, and finally, examination of posture and gait dysfunction. This review is not intended to be comprehensive. Rather, we have focused on the most common clinical signs that are potentially key to making the correct diagnosis and those that do not require special skills or training for interpretation. Evidence is also provided, where available, such as diagnostic criteria, consensus statements, clinicopathological studies or large multi-centre registries. Pitfalls are also discussed when relevant to the diagnosis. While no clinical signs are pathognomonic for certain parkinsonian disorders, certain clinical clues may assist in narrowing a differential diagnosis and tailoring focused investigations for the individual patient.