Association between male gender and pediatric essential tremor

Clinical and Electrophysiological Characterization of Essential Tremor in 18 Children and Adolescents

Background

Essential tremor (ET) is considered the most frequent abnormal movement in the general population, with childhood onset in 5 to 30% of the patients.

Methods

A multicenter, descriptive cross-sectional study enrolled patients ⩽18 years with a definite diagnosis of ET according to the International Parkinson and Movement Disorders Society criteria. Demographic data, clinical and electrophysiological characteristics of the tremor, neurological examination and impact on quality of life were collected.

Results

9 males and 9 females were included (mean age of 13.9 years). Tremor was characterized by : upper limb onset at a mean age of 6.5 years; at enrollment, upper limbs localization, and involvement of an additional body region in 28% of the patients; kinetic tremor in all of the patients combined with postural tremor in 17 and rest tremor in 3; tremor mean frequency of 7.6 Hz, mean burst duration of 82.7 ms; identification of mild myoclonic jerks on the polymyographic recordings in 7 patients; altered quality of life with worse emotional outcomes in girls and when a disease duration >5 years was suggested.

Discussion

Childhood-onset ET is associated with delayed diagnosis and remarkable functional impact. Electromyographic identification of additional mild myoclonus is a new finding whose significance is discussed.

Highlights

ET onset involved upper limbs and at inclusion, 28% of the patients exhibited involvement of an additional body region.ET impacted quality of life for all patients.Girls and patients affected for >5 years reported worse emotional outcomes.Mild myoclonic jerks were identified on 7/17 polymyographic recordings.

Effect of exercise devised to reduce arm tremor in the sighting phase of archery

BACKGROUND

In archery training, side bridges are performed in a posture similar to archery shooting for training the muscles around the shoulder joint and the shoulder girdle of the pusher.

AIM

The purpose of this study was to determine whether a low-tremor side-bridge exercise for 4 weeks improves bow tremor during archery movements.

METHODS

Participants were 20 male college students. First, we measured the tremor during side bridges performed with trunk inclinations of 25°, 40°, 55°, and 70° using an accelerometer attached to the elbow joint and identified low-tremor side bridges. The participants were then randomly divided into intervention and non-intervention groups, and the low-tremor side bridges were performed for 4 weeks.

RESULTS

The effect of the intervention was determined by measuring the total tremor value using an accelerometer attached to the bow and changes in the median power frequency (MdPF) of the middle deltoid, upper trapezius, and lower trapezius. This intervention reduced the bow tremor and the median power frequency of the middle deltoid (p < 0.05).

CONCLUSIONS

The findings suggested that the tremor during the archery sighting phase could be reduced by performing side bridges with a specific trunk angle for a certain period of time. This intervention was also shown to reduce the intermediate frequency of the middle deltoid. The reduced tremor can shorten the sighting phase, which can facilitate injury prevention.

Essential tremor

Essential tremor (ET) is a chronic and progressive neurologic disease. Its central and defining clinical feature is a 4-12Hz kinetic tremor, that is, tremor that occurs during voluntary movements such as drinking from a cup or writing. Patients may also exhibit a range of other tremors-postural, rest, intention, additional motor features (e.g., mild gait ataxia, mild dystonia), as well as nonmotor features. The disease itself seems to be a risk factor for other degenerative diseases such as Alzheimer's disease and Parkinson's disease. Both genetic and toxic environmental factors have been explored as etiologic factors. In addition to a growing appreciation of the presence of clinical, etiologic, and pathologic heterogeneity, there is some support for the notion that ET itself may not be a single disease, but may be a family of diseases whose central defining feature is kinetic tremor of the arms, and which might more accurately be referred to as "the essential tremors." Recent research has increasingly placed the seat of the disease in the cerebellum and cerebellar system and identified a host of neurodegenerative changes within the cerebellum, indicating that this progressive disorder is likely degenerative.

Sex and gender differences in movement disorders: Parkinson's disease, essential tremor, dystonia and chorea

Sex and gender-based differences in epidemiology, clinical features and therapeutical responses are emerging in several movement disorders, even though they are still not widely recognized. In this chapter, we summarize the most relevant evidence concerning these differences in Parkinson's disease, essential tremor, dystonia and chorea. Indeed, both sex-related biological (hormonal levels fluctuations) and gender-related variables (socio-cultural and environmental factors) may differently impact symptoms manifestation and severity, phenotype and disease progression of movement disorders on men and women. Moreover, sex differences in treatment responses should be taken into account in any therapeutical planning. Physicians need to be aware of these major differences between men and women that will eventually have a major impact on better tailoring prevention, treatment, or even delaying progression of the most common movement disorders.

Clinical and laboratory features of children with tremor: a single-center experience

AIM

Tremor is an involuntary, rhythmic, oscillatory movement of body parts around a central point or plane which arises from contraction of antagonist muscles. Evaluation of pediatric patients with tremor can be challenging due to limited population-based studies in children. The aim of this study is to evaluate the demographic, clinical and laboratory features of childhood tremor, retrospectively.

MATERIALS AND METHODS

Patients under the age of 18 years presenting with tremor (n = 111) to the Pediatric Neurology Unit of Kecioren Research and Training Hospital between January 2014 and December 2019 were included in the study. Patients with neuromuscular disease, vertebral pathology or incomplete data in hospital records were not included. Also, benign tremor causes (jitteriness, shuddering attack, etc.) seen in the neonatal and infancy period were excluded from the study as the number of patients was insufficient. Demographic data, type and duration of tremor, accompanying symptoms, chronic diseases and medications, family history, physical and neurological examination, laboratory findings, neuroimaging findings were retrospectively analyzed and recorded.

RESULTS

A total of 111 children (59 girls and 52 boys) were included in our study and the female to male ratio was 1.1. The mean age at tremor onset and age at admission to hospital were 13.2 ± 2.8 years (range 4-17 years), and 14.8 ± 2.0 years (range 6-17 years), respectively. The most common type of tremor was essential tremor (62.2%), followed by enhanced physiologic (18.9%). None of the patients had acute metabolic disorder. Diagnostic tests revealed the etiology in 12 patients. These were vitamin B12 deficiency in 11 patients and multiple sclerosis in one patient. Drug-induced and task-specific tremors were determined in 4 patients each. It was determined that in patients with a positive family history, tremor appeared or was noticed at a younger age.

CONCLUSIONS

Most of the cases with tremor can be diagnosed accurately by a detailed medical history, physical and neurological examination. Essential tremor is the most common type of tremor in children. Laboratory tests and imaging methods have limited additional yield in elucidating the etiology. Early recognition of tremor and related signs and symptoms in childhood is important for the detection and treatment of the possible underlying cause.

How Common is Essential Tremor? Update on the Worldwide Prevalence of Essential Tremor

Background

Essential tremor (ET) is among the most prevalent movement disorders. Comprehensive reviews of disease prevalence were published in 1998 and 2010 but not since then. We reviewed the prevalence of ET in population-based epidemiological studies, derived a precise summary estimate of prevalence from these studies, and examined differences in prevalence across studies. We used two methods: a descriptive-analytical approach and a meta-analysis.

Methods

A PUBMED search yielded 14 published papers since the 2010 review.

Results

There were 42 population-based prevalence studies (23 countries and 6 continents). In a meta-analysis, pooled prevalence (all ages) = 1.33%, with statistically significant heterogeneity across studies (I2 = 99.3%, p < 0.0001). In additional descriptive analyses, median crude prevalence (all ages) = 0.4% and mean = 0.67%. Prevalence increased markedly with age, and especially with advanced age. In the meta-analysis, prevalence (age ≥ 65 years) = 5.79%, and in descriptive analyses, median crude prevalence (age ≥ 60-65) = 5.9% and mean = 8.0%. In the oldest age groups, median prevalence = 9.3%, with several studies reporting values >20%. The prevalence increased by 74% for every decade increase in age (p < 0.0001). Gender did not impact the prevalence of ET (p = 0.90).

Discussion

Precise prevalence estimates are important because they form the numerical basis for public health initiatives and offer clues about underlying biological factors of mechanistic importance. The prevalence of ET among those age ≥ 65 is similar to that reported for Alzheimer's disease in elders, suggesting that ET may be the most common neurodegenerative disease.

The global prevalence of essential tremor, with emphasis on age and sex: A meta-analysis

Background

Essential tremor (ET) is one of the most common neurological disorders that impairs quality of life and leads to disability and social handicap. It was estimated that approximate 0.9% of people worldwide were affected by ET. The last decade has seen new investigations on the epidemiology of ET, enabling us to provide an up-to-date estimation of ET prevalence, with emphasis on age and sex.

Methods

We searched PubMed, Medline, Embase and Global Health for studies that reported the prevalence of ET in the general population. Potential sources of heterogeneity were examined by age-adjusted meta-regression. The age- and sex-specific prevalence of ET was constructed with a multilevel mixed-effects meta-regression.

Results

A total of 29 articles were included in our systematic review and meta-analysis. The prevalence of ET increased dramatically with advancing age, where the prevalence estimate in people aged under 20 years was 0.04% (95% confidence interval [CI] = 0.00-0.29) and that in elderly aged 80 years and above was 2.87% (95% CI = 1.07-7.49). ET was consistently more common in males than in females. In 2020, the overall prevalence of ET in the general population was 0.32% (95% CI = 0.12-0.91), and the prevalence was higher in males (0.36%, 95% CI = 0.14-1.03) than in females (0.28%, 95% CI = 0.11-0.79). In 2020, the number of people affected by ET was 24.91million (95% CI = 9.51-70.92), among whom 56% were males.

Conclusions

This study provides an up-to-date estimation of ET prevalence in the general population throughout the whole life span, with emphasis on age and sex. The adoption of an internationally acknowledged diagnostic strategy is prompted in future epidemiological investigations.

Protocol registration

PROSPERO (CRD42020203979)

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.

A Series of 211 Children with Probable Essential Tremor

Background

The objective of this study was to characterize the clinical features, course, and treatment of essential tremor (ET) in children.

Methods

A retrospective chart review was conducted over 25 years (1984-2011). Inclusion criteria were age <21 years and satisfying the core diagnostic criteria for ET. Primary exclusion criteria included other neurological findings, tremorogenic medications, sudden onset/stepwise progression, primary orthostatic tremor, and isolated task specificity; and secondary exclusion criteria were abnormal neuroimaging or metabolic/thyroid studies. Cases were reviewed for age, sex, family history, tremor characteristics, functional impairment, treatment, and follow-up.

Results

In total, 211 children had ET, including 130 males and 81 females. The mean ± standard deviation age was at diagnosis was 14.09 ± 5.0 years, the age of onset was 9.71 ± 5.62 years, and the age of onset was birth in 7 children. One hundred ninety-nine children had bilateral hand tremor, 34 had asymmetry, 9 had unilateral onset but later became bilateral. Twelve children had voice tremors, 13 had leg tremors, 5 had head tremors, and 7 had trunk tremors. Tremor at rest was present in 20 children. Thirty-five percent of the children had a family history of ET, including in a father (n = 21), mother (n = 13), brother (n = 6), sister (n = 3), and other family member (n = 28). Fifty-five percent of patients had functional disabilities, including writing (n = 66), eating (n = 28) drinking from a cup (n = 13), typing (n = 4), playing instruments (n = 6), buttoning (n = 6), and playing (n = 3). For treatment, 33 patients received propranolol, 1 received atenolol, 13 received primidone, 3 received metoprolol, and 1 received nadolol. In total, 99 patients were followed for a mean ± standard deviation of 1.82 ± 2.21 years.If left untreated, tremor remained unchanged in 33 patients, and 7 had an apparent short-term improvement. On propranolol, 15 of 20 patients significantly improved.

Conclusions

This is the largest series to date of ET in children. The current findings indicate that onset at birth is possible, family history is less common in children than in adults, and tremor at rest is possible. Functional disability was noted in 55% of children, and 29.4% required medication.

Familial versus Sporadic Essential Tremor: What Patterns Can One Decipher in Age of Onset?

BACKGROUND

Essential tremor (ET) is a very prevalent neurological disease. Although familial and sporadic ET cases are assumed to have different age at onset distributions, no detailed study of this question has been carried out.

METHODS

Using a carefully characterized sample of 376 ET cases (232 (61.7%) familial) enrolled in a clinical-epidemiological study, we contrasted the age of onset distributions in familial versus sporadic ET.

RESULTS

Familial ET had a lower age at onset distribution, regardless of the current age. The majority (71 (86.6%) of 82) of ET cases that appeared during childhood were familial rather than sporadic. Additionally, the onset of ET occurred after age 40 in a majority of cases (125 (53.9%) of 232 with familial ET and 118 (81.9%) of 144 with sporadic ET), and in approximately one-quarter to one-half of cases, after age 60.

CONCLUSIONS

The age of onset of ET differs between familial and sporadic ET and furthermore, is variable within each of these groups. The onset of ET during childhood is usually familial, and the small number of identified exceptions could be due to de novo mutations. Understanding the heterogeneity in onset age will provide insights into the nature of underlying etiological and patho-biological processes about which little is presently known.

When do essential tremor patients develop head tremor? Influences of age and duration and evidence of a biological clock

BACKGROUND

Essential tremor (ET) is a chronic, progressive neurological disease. Head (neck) tremor may eventually develop in as many as 30-60% of patients, yet it is unclear why. Is its appearance merely a function of advancing disease duration? Alternatively, is patient age a primary factor? The latter would argue for the presence of a biological clock that is important for the expression of this clinical feature of ET.

METHODS

A total of 363 ET patients were enrolled in a cross-sectional, clinical-epidemiological study. Each ET patient underwent a 20-min videotaped neurological examination which included an assessment of the presence/absence of head tremor.

RESULTS

Head tremor was present on examination in 140 (38.6%) patients. Young patients, even with longer-duration tremor, rarely had head tremor: 2/27 (7.4%) patients<40 years old with tremor duration≥10 years had head tremor versus 121/283 (42.8%) older patients (>60 years old) with tremor duration≥10 years (p<0.001). In a multivariate logistic regression analysis, while head tremor was associated with age (p<0.001) it was not independently associated with tremor duration (p=0.26); interestingly, it was associated with gender in that model (p<0.001). With the exception of 1 patient, head tremor did not begin before the age of 36.

CONCLUSIONS

Data suggest that the appearance of head tremor in ET depends on a biological factor that is intrinsic to the patient (i.e. age) and is not a clear consequence of advancing disease duration.

Essential tremor

Essential tremor (ET) is among the most common neurological disorders. This chapter reviews the epidemiology, clinical features, and pathophysiology of ET. The defining feature is a kinetic tremor of the arms. Patients often have a postural tremor as well. Other body regions may also be involved (especially the head). The severity of tremor may range from mild cases in population settings to more severe cases in treatment settings. Motor features aside from tremor have been described in ET, including tandem gait difficulty. Mild cognitive changes (especially executive dysfunction) have been documented in many studies as well. Despite being regarded as one of the most common hyperkinetic movement disorders, establishing a precise prevalence has been difficult, yet the prevalence among persons aged 40 and older seems to be 4% or higher. There are numerous examples of families in which the disease appears to be inherited yet genetic studies have not progressed to the point where ET genes have been identified. There is also a growing understanding that environmental factors are likely to contribute to the etiology of ET. More recent postmortem studies have helped localize the possible source of ET to structural alterations in the cerebellum and its connecting pathways.

Essential tremor: evolving clinicopathological concepts in an era of intensive post-mortem enquiry

Essential tremor (ET) is one of the most common neurological disorders. In recent years, as a result of systematic post-mortem examinations, our knowledge of the pathophysiology of this disease has grown substantially. Clearly identifiable structural changes (ie, Purkinje cell loss, Lewy bodies) have been observed in the brains of individuals with ET. These changes are not uniform and seem to follow several patterns, localising to the cerebellum itself or to a collection of brainstem neurons that synapse directly with Purkinje cells. Furthermore, these changes are similar to those seen in degenerative diseases. A wealth of clinical, epidemiological, and now post-mortem data indicate that this disease, or perhaps this family of diseases, is likely to be neurodegenerative. The molecular mechanisms that underlie these structural changes in ET are unknown. However, with more controlled, tissue-based studies being done, it is hoped that these mechanisms will be elucidated, thereby laying the foundation for the development of more targeted, effective pharmacotherapeutic interventions.

Aqueductal stenosis presenting as isolated tremor: case report and review of the literature

Essential tremor is rare in children, particularly in the absence of a significant family history. We report the case of a child with compensated hydrocephalus secondary to aqueductal stenosis whose sole presenting symptom was tremor. An otherwise healthy 6-year-old male developed a fine hand tremor, which over the course of 4 years both increased in intensity and spread to involve the lower limbs and head. After an MRI had confirmed hydrocephalus due to aqueductal stenosis, the patient underwent an endoscopic third ventriculostomy. His tremor improved markedly, but did not completely resolve. Occult hydrocephalus should be considered in the differential diagnosis of new-onset tremor. Progression of the tremor should halt with treatment of the hydrocephalus, and clinical improvement may be seen.

Epidemiology and management of essential tremor in children

Essential tremor (ET) is a common, often familial, movement disorder characterized by tremor of the limbs, head, and voice. Epidemiological surveys indicate that up to 5% of the adult population has ET, and 5-30% of adults with ET report symptom onset during childhood. There is, however, little published regarding ET in the pediatric population, and no prospective studies targeted specifically to children. Retrospective studies from subspecialty movement disorder clinics indicate that childhood-onset ET is usually hereditary, begins at a mean age of 6 years, and affects boys three times as often as girls. While ET occasionally results in disability during childhood, only one-quarter of children seeing a neurologist for ET require pharmacotherapy. Small case series suggest that propranolol is effective in approximately 50% of children with ET, but controlled treatment trials are lacking.

Environmental epidemiology of essential tremor

BACKGROUND

Essential tremor (ET) is one of the most common neurological disorders. Despite this, the disease mechanisms and etiology are not well understood. While susceptibility genotypes undoubtedly underlie many ET cases, no ET genes have been identified thus far. As with many other progressive, degenerative neurological disorders, it is likely that environmental factors contribute to the etiology of ET. Environmental epidemiology is the study in specific populations or communities of the effect on human health of physical, biologic and chemical factors in the external environment. The purpose of this article is to review current knowledge with regards to the environmental epidemiology of ET.

RESULTS

As will be discussed, a series of preliminary case-control studies in recent years has begun to explore several candidate toxins/exposures, including harmane (1-methyl-9H-pyrido[3,4-b]indole), lead and agricultural exposures/pesticides.

CONCLUSIONS

While several initial results are promising, as will be discussed, additional studies are needed to more definitively establish whether these exposures are associated with ET and if they are of etiological importance.

A population-based study of mortality in essential tremor

BACKGROUND

Although data are sparse, people with essential tremor (ET) are usually assumed to have mortality rates similar to those in the general population. Because ET is common, particularly among older adults, an influence of ET on the life span would have important public health implications. The authors compared the risks of mortality in patients with ET and control subjects without ET.

METHODS

A prospective, population-based design was used to compare the risk of mortality in participants with ET vs controls in three communities in central Spain. Participants were evaluated at baseline (1994 to 1995) and at follow-up 3 years later (1997 to 1998). The relative risk (RR) of mortality (ET vs controls) was estimated using Cox proportional hazards models that excluded participants with Parkinson disease or dementia.

RESULTS

Mean baseline age was 73.5 +/- 6.4 years. There were 33 (16.4%) deaths among 201 ET cases and 465 (13.9%) among 3,337 controls. In an unadjusted Cox model, risk of mortality was increased in ET (RR = 1.59, 95% CI = 1.11 to 2.27, p = 0.01). In a Cox model that adjusted for baseline age, gender, educational category, current ethanol drinking, use of antidepressant medication, and community, RR = 1.45, 95% CI = 1.01 to 2.08, p = 0.04. In an adjusted Cox model restricted to persons with longer (>3 years) follow-up, RR = 4.69 (95% CI = 2.18 to 10.07, p = 0.001).

CONCLUSIONS

In this longitudinal, prospective study, the risk of mortality was increased in essential tremor. Additional studies of incident cases are needed to confirm these results.

Clinical features of childhood onset essential tremor

Childhood onset essential tremor (ET) is uncommon. It is not clear as to whether ethnicity-specific differences may influence the phenotypic features. To determine the frequency and clinical characteristics of childhood ET in a tertiary referral center. In a prospective evaluation of 120 consecutive ET patients in a movement disorders clinic, we found a 15.5% (19) frequency of childhood onset ET patients. The mean age of onset and mean age was 10.8 +/- 4.1 (6-16) years and 25.7 +/- 15.0 (16-73) years consisting of 73.6% (14/19) men and 26.4% (5/19) women. A positive family history of ET was present in 11 of 19 (52.6%). Presence of a head tremor was observed in 2/19 (10.5%). We highlighted a relatively high frequency (15,5%) of childhood ET in our Asian cohort. In addition, we drew attention to the male preponderance and the low frequency of head tremor in childhood ET corroborating study findings in white ET patients. These observations appear to transcend ethnic and cultural differences and lend further support that gender difference may play a role in the pathogenesis and expression of ET.