Essential tremor.
Ontology highlight
ABSTRACT:
SUBMITTER: Clark LN
PROVIDER: S-EPMC5898616 | biostudies-literature | 2018
REPOSITORIES: biostudies-literature
Publications
Essential tremor (ET) is one of the most common neurologic disorders, and genetic factors are thought to contribute significantly to disease etiology. There has been a relative lack of progress in understanding the genetic etiology of ET. This could reflect a number of factors, including the presence of substantial phenotypic and genotypic heterogeneity. Thus, a meticulous approach to phenotyping is important for genetic research. A lack of standardized phenotyping across studies and patient cen ...[more]
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Project description:Essential tremor (ET) is among the most common neurological diseases and it often runs in families. How knowledgeable ET patients and their families are about their disease has been the subject of surprisingly little scholarship.To fill this gap in knowledge, we administered a comprehensive 32-item survey (i.e., questions about etiology, pathophysiology, symptoms and signs, natural history, and treatments) to 427 participants, including 76 ET probands, 74 affected relatives (AFRs), 238 unaffected relatives, and 39 spouses of unaffected relatives, all of whom were participating in two ET family studies. We hypothesized that there would be gaps in knowledge about ET and furthermore, that probands and AFRs would be the most knowledgeable, followed by unaffected relatives and then spouses of unaffected relatives, who would be the least knowledgeable.Overall, ET patients lacked knowledge about their disease. Nearly one-third of probands answered "yes" or "do not know" to the question, "is ET the same or different from the type of tremor that many normal people can get when they become old and frail?" A similar proportion did not know whether children could get ET or they responded "no." Nearly one-fourth of affecteds (i.e., probands and AFRs) did not know whether or to what degree (e.g., very well, moderately well, not well) the symptoms of ET could be medically controlled, and 38.0% either reported that there was no brain surgery for ET or reported that they did not know. Nearly 17% of affecteds did not endorse genes as a cause for ET, which was surprising given the fact that this was a family study of ET. Probands and AFRs were the most knowledgeable, followed by unaffected relatives. Spouses of unaffected relatives were the least knowledgeable.We targeted a large group of ET patients and their families, as this group is perhaps most likely to be informed about the disease. ET patients and their AFRs were more knowledgeable about the features of ET than their family members without ET. Overall, however, knowledge of ET was very limited and this lack of knowledge encompassed all aspects of the disease including its underlying causes, the nature of the symptoms and signs, its natural history and its treatment. Further ET awareness education and programs targeting both families of ET patients and the public would help alleviate this gap in knowledge.
| S-EPMC5790790 | biostudies-literature
Project description:The neuronal physiological correlates of clinical heterogeneity in human essential tremor are unknown. We now test the hypothesis that thalamic neuronal and EMG activities during intention essential tremor are similar to those of the intention tremor which is characteristic of cerebellar lesions. Thalamic neuronal firing was studied in a cerebellar relay nucleus (ventral intermediate, Vim) and in a pallidal relay nucleus (ventral oral posterior, Vop) during stereotactic surgery for the treatment of tremor. Nine patients with essential tremor were divided clinically into two categories: one with a substantial component of tremor with intention (termed intention ET) and the other without (postural ET). These types of essential tremor were compared with patients having intention tremor plus other clinical signs of cerebellar disease (cerebellar tremor). Neurons in patients with either intention ET or cerebellar tremor had lower firing rates and lower spike×EMG coherence than those in patients with postural ET. Patients with intention ET had a lower spike×EMG phase lead than those with postural ET. Overall, thalamic activity measures of intention ET were different from postural ET but not apparently different from those of cerebellar tremor. One patient with the intention ET (number 4) had a good response to a left thalamotomy and then suffered a right cerebellar hemispheric infarct five years later. After the stroke the intention ET recurred, which is consistent with our hypothesis that intention ET is similar to that of the intention tremor which is characteristic of cerebellar lesions.
| S-EPMC3889719 | biostudies-literature
Project description:Essential tremor is one of the most common tremor syndromes. According to the recent tremor classification, tremor as a symptom is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: axis 1-defining syndromes based on the clinical features such as historical features, tremor characteristics, associated signs, and laboratory tests; and axis 2-classifying the etiology (Bhatia et al., Mov Disord 33:75-87, 2018). The management of this condition has two major approaches. The first is to exclude treatable etiologies, as particularly during the onset of this condition the presentation of a variety of etiologies can be with monosymptomatic tremor. Once the few etiologies with causal treatments are excluded, all further treatment is symptomatic. Shared decision-making with enabling the patient to knowledgeably choose treatment options is needed to customize the management. Mild to moderate tremor severity can sometimes be controlled with occupational treatment, speech therapy of psychotherapy, or adaptation of coping strategy. First-line pharmacological treatments include symptomatic treatment with propranolol, primidone, and topiramate. Botulinum toxin is for selected cases. Invasive treatments for essential tremor should be considered for severe tremors. They are generally accepted as the most powerful interventions and provide not only improvement of tremor but also a significant improvement of life quality. The current standard is deep brain stimulation (DBS) of the thalamic and subthalamic region. Focused ultrasound thalamotomy is a new therapy attracting increasing interest. Radiofrequency lesioning is only rarely done if DBS or focused ultrasound is not possible. Radiosurgery is not well established. We present our treatment algorithm.
| S-EPMC7851235 | biostudies-literature
Project description: Not available
| S-EPMC2987372 | biostudies-literature
Project description:Introduction: The diagnosis of essential tremor (ET) remains a clinical one, and diagnostic errors are common. We aimed to (1) determine precisely how frequently ET diagnoses are misapplied (i.e., what percentage of patients who have been assigned an "ET" diagnosis actually have another movement disorder), (2) determine which other movement disorders are most often misclassified as "ET," and (3) examine the clinical features that were most associated with diagnostic errors. Methods: One hundred four consecutive patients were included who met the following criteria: (1) initial outpatient evaluation by one of the authors (EDL) between January 2015 and December 2019 and (2) pre-evaluation diagnosis of ET. Data on an extensive number of clinical features were extracted from the electronic medical record. Results: Forty-seven (45.2%) patients received a post-evaluation diagnosis of ET, 29 (27.9%) of dystonia, and 28 (26.9%) of other diagnoses including Parkinson's disease (PD) [6 (5.8%)]. Factors associated with an alternative post-evaluation diagnosis other than ET were pre-evaluation diagnosis made by a non-neurologist, shorter tremor duration, irregular tremor, abnormal limb postures, among others. Discussion: Diagnosing ET remains a challenge, with the diagnosis being over-applied and being used as a "waste basket." More than one-half of the patients who were referred to our clinic with an intake diagnosis of ET were given an alternative post-evaluation diagnosis. While PD was reported to be the most frequently missed diagnosis in a past study, dystonia was most commonly missed in our study. Several clinical features can help to differentiate ET from other tremor disorders.
| S-EPMC7109309 | biostudies-literature
Project description:Forehead tremor has only been reported in two patients with essential tremor, one with rhythmic tremor and the other with dystonic tremor. We report 4 new patients with essential tremor who present a 4-6?Hz frontal tremor registered by electromyography and unusual features like frontal tremor preceding limb tremor or unilateral involvement. Frontal tremor is present in some patients with essential tremor, sometimes preceding limb tremor. Treatment with botulinum toxin may be useful.
| S-EPMC3420609 | biostudies-literature
Project description:BackgroundIsolated tremor in the elderly is commonly diagnosed as essential tremor (ET). The prevalence of tremor increases steeply with increasing age, whereas hereditary tremor is becoming less common. Moreover, late-manifesting tremor seems to be associated with dementia and earlier mortality. We hypothesize that different entities underlie tremor in the elderly.MethodsTwo thousand four hundred forty-eight subjects from the Longitudinal Study of Aging Danish Twins older than 70 y answered screening questions for ET in 2001. Two thousand fifty-six (84%) participants drew Archimedes spirals to measure their tremor severity, and classical aging phenotypes were assessed. A subgroup of 276 individuals fulfilling either screening criteria for ET or being controls were personally assessed. Medications and mortality data are available.ResultsThe spiral score increased with age. The spiral score correlated with tremor severity. For the whole cohort, mortality was significantly correlated with the spiral score, and higher spiral scores were associated with lower physical and cognitive functioning. Multivariate analysis identified higher spiral scores as an independent risk factor for mortality. In contrast, the ET patients did not show an increased but rather a lower mortality rate although it was not statistically significant. Consistent with a slower than normal aging, they were also physically and cognitively better functioning than controls.ConclusionsBecause incident tremors beyond 70 y of age show worse aging parameters and mortality than controls and ET, we propose to label it 'aging-related tremor' (ART). This tremor starts later in life and is accompanied by subtle signs of aging both cognitively and physically. More detailed clinical features and pathogenesis warrant further assessment.
| S-EPMC4779797 | biostudies-literature
Project description:BackgroundThere is a growing interest in nonpharmacological approaches for essential tremor (ET), including tremor cancelation devices. However, the true efficacy of such devices in ET remains unclear.MethodsA systematic literature review was conducted using standardized criteria regarding efficacy and comfortability. Devices focused on design or experimental testing in which tremor was simulated in a robot were excluded.ResultsOut of 324 articles initially identified, 12 articles were included. Orthoses using biomechanical loading and neuromodulation with electrical stimulation, and external tremor cancelation devices, were the main interventions used to suppress tremor. All devices were designed to control tremor of the upper limbs at different anatomical locations. Overall, an average tremor attenuation of 50–98% was reported (level of evidence III). Interference with voluntary movements and portability was described as the main drawback.DiscussionIn conclusion, this review highlights the growing interest in emerging tremor control devices and the importance of assessing comfort without affecting voluntary movements. However, the level of evidence regarding the efficacy of these tremor control devices remains low. An integrated multidisciplinary combination approach of engineering, robotics, physiology, physiotherapy, and clinical assessment is needed to improve the quality of non-pharmacological interventions for ET.
| S-EPMC6898897 | biostudies-literature
Project description:ImportanceEssential vocal tremor (EVT) is a neurologic voice disorder characterized by periodic fluctuations in pitch and loudness that can hinder intelligibility. Defining the normative range of vocal tremor frequency may assist in diagnosis and provide insight into disease mechanisms.ObjectiveTo characterize the normative voice tremor frequency in EVT (in hertz).Design, setting, and participantsCross-sectional observational study of 160 patients with EVT. The setting was a tertiary voice center. Participants were identified from a database of consecutive patients diagnosed as having laryngeal movement disorders between January 1, 1990, and April 1, 2017.Main outcomes and measuresThe following 3 methods measured the frequency of tremor experienced by patients with EVT: perceptual method, computerized peak detection method, and laryngeal electromyography method. Within-person and population-level tremor frequencies were compared across modalities to assess measurement reliability and consistency and to characterize the normal distribution of tremor frequencies in this population.ResultsAmong 160 participants (median age, 70 years; interquartile range [IQR], 64-77 years; 90.6% female [n = 145]), the median frequency of EVT was consistently between 4 and 5 Hz across all 3 methods (perceptual, 4.8 Hz [IQR, 4.4-5.5 Hz]; computerized peak detection, 4.6 Hz [IQR, 4.2-5.0 Hz]; and laryngeal electromyography, 4.3 Hz [IQR, 3.8-5.0 Hz]). The mean in-person differences between each measurement method were not clinically meaningful (range, 0.1-0.5 Hz). Including all interquartile ranges across measurement modalities, the normative tremor frequency range for EVT was 3.8 to 5.5 Hz.Conclusions and relevanceTo our knowledge, this is the largest study to date to characterize the normal frequency of tremor in patients with EVT. The normative frequency of EVT (range, 3.8-5.5 Hz) falls within a much narrower range than previously reported. Those whose frequency is outside this range may still have EVT but should be carefully evaluated for potential other causes of vocal tremor. Defining characteristics of EVT may aid appropriate diagnosis and improve understanding of this disease.
| S-EPMC6583089 | biostudies-literature
Project description:The field of essential tremor (ET) genetics remains extremely challenging. The relative lack of progress in understanding the genetic etiology of ET, however, does not reflect the lack of a genetic contribution, but rather, the presence of substantial phenotypic and genotypic heterogeneity. A meticulous approach to phenotyping is important for genetic research in ET. The only tool for phenotyping is the clinical history and examination. There is currently no ET-specific serum or imaging biomarker or defining neuropathological feature (e.g., a protein aggregate specific to ET) that can be used for phenotyping, and there is considerable clinical overlap with other disorders such as Parkinson's disease (PD) and dystonia. These issues greatly complicate phenotyping; thus, in some studies, as many as 30-50% of cases labeled as "ET" have later been found to carry other diagnoses (e.g., dystonia, PD) rather than ET. A cursory approach to phenotyping (e.g., merely defining ET as an "action tremor") is likely a major issue in some family studies of ET, and this as well as lack of standardized phenotyping across studies and patient centers is likely to be a major contributor to the relative lack of success of genome wide association studies (GWAS). To dissect the genetic architecture of ET, whole genome sequencing (WGS) in carefully characterized and well-phenotyped discovery and replication datasets of large case-control and familial cohorts will likely be of value. This will allow specific hypotheses about the mode of inheritance and genetic architecture to be tested. There are a number of approaches that still remain unexplored in ET genetics, including the contribution of copy number variants (CNVs), 'uncommon' moderate effect alleles, 'rare' variant large effect alleles (including Mendelian and complex/polygenic modes of inheritance), de novo and gonadal mosaicism, epigenetic changes and non-coding variation. Using these approaches is likely to yield new ET genes.
| S-EPMC4863985 | biostudies-literature