Cognitive functions, fatigue, depression, anxiety, and sleep disturbances: assessment of nonmotor features in young patients with essential tremor

Sleep and circadian rhythm dysfunctions in movement disorders beyond Parkinson's disease and atypical parkinsonisms

PURPOSE OF REVIEW

This review aimed to comprehensively outline sleep and circadian rhythm abnormalities in hyperkinetic movement disorders beyond Parkinson's disease and atypical parkinsonisms, including tremor, dystonia, choreiform movements, tics, and ataxia disorders.

RECENT FINDINGS

Insomnia, poor sleep quality, and excessive daytime sleepiness (EDS) are commonly reported in essential tremor, Wilson's disease, tics or Tourette's syndrome, and spinocerebellar ataxia (SCA). REM sleep behavior disorder (RBD) have been observed in Wilson's disease and SCA. A combination of REM and non-REM parasomnias, along with nocturnal stridor with the initiation of sleep and re-entering after awakening, are characterized by undifferentiated Non-REM and poorly structured N2 in anti-IgLON5 disease. Restless legs syndrome (RLS) has been reported commonly in SCAs. Sleep-related dyskinesia has been reported in ADCY5-related disease and GNAO1-related movement disorder.

SUMMARY

Sleep problems can manifest as a result of movement disorders, either through direct motor disturbances or secondary nonmotor symptoms. Medication effects must be considered, as certain medications for movement disorders can exacerbate or alleviate sleep disturbances. Distinguishing sleep problems in some diseases might involve pathognomonic symptoms and signs, aiding in the diagnosis of movement disorders.

Functional Neurological Disorders Among Patients With Tremor

OBJECTIVE

Functional neurological disorders (FNDs) are increasingly recognized in the general population and neurology clinics, and there is evidence that patients with neurological disorders are more likely to have a FND. This study was designed to identify the clinical features of FNDs among patients with movement disorders when the two disorders coexist.

METHODS

The clinical histories and video recordings of 150 consecutive patients with tremors were examined: the types of tremor included essential tremor; essential tremor plus; dystonic tremor; tremor associated with dystonia; and drug-induced, myoclonic, orthostatic, task-specific, parkinsonian, Holmes, and unclassified tremor. Using criteria for "possible" and "probable" coexistent FND, clinical features that helped differentiate between functional and other neurological tremors were identified.

RESULTS

There were 27 (18%) patients with functional manifestations, and 17 (11% of full sample) of these patients had signs suggestive of comorbid functional tremor. Patients with comorbid functional manifestations were younger at presentation, and these patients had greater severity of tremor, particularly upper limb postural tremor. Functional manifestations were not more commonly observed among patients with any particular type of tremor, except for patients with Holmes tremor, who were more likely to have comorbid functional neurological manifestations.

CONCLUSIONS

About 18% of patients with diverse types of tremors also had comorbid functional neurological manifestations. Of the coexistent FNDs, functional tremor was the most common. Patients with co-occurring functional and other neurological tremors presented for evaluation at a younger age and had greater severity of arm tremor than those without comorbid functional neurological manifestations.

Exploring serum α‑synuclein and its autoantibodies in essential tremor: implications for diagnosis and symptom correlations

There is no definite biomarker for confirming the diagnosis of essential tremor (ET) or differentiating it from other diseases, particularly Parkinson's disease. The present study aimed to investigate the serum levels of the α-synuclein protein (α-syn) and its autoantibodies in patients with ET compared with healthy controls and its relation to motor and non-motor symptoms in patients with ET. Serum α-syn and its autoantibodies were measured in 32 patients with ET and 32 age- and sex-matched controls. Both groups were assessed using the non-motor symptoms scale, MoCA, Beck Depression Inventory, Hamilton Anxiety Rating Scale, and the Short Form 36 Health Survey Questionnaire. Tremor was assessed using the Fahn-Tolosa-Marin Tremor Rating Scale. The serum α-syn concentration in patients with ET was significantly lower than that in healthy controls (P<0.001), with a positive predictive value of 0.81 and a negative predictive value of 0.75, while the serum anti-a-syn autoantibody concentration was not significantly different between the two groups. There were no correlations between serum α-syn or its autoantibodies and patients' clinical characteristics. Furthermore, patients with ET had worse cognitive impairment, depression, anxiety, non-motor symptoms and quality of life. The serum α-syn concentration was lower in patients with ET than in controls, with favorable predictive values, suggesting that it could serve as a biomarker for ET diagnosis.

Subjective Sleep Disturbance and Lewy Pathology: Data from a Cohort of Essential Tremor Brain Donors

INTRODUCTION

Sleep disturbances have been associated with essential tremor (ET). However, their pathophysiological underpinnings remain unknown. In this exploratory study, we examined the association between subjective sleep disturbances and the presence of Lewy pathology (LP) on postmortem brain examination in ET cases.

METHODS

Fifty-two ET cases enrolled in a prospective, longitudinal study were assessed over an average period of 42 months. Cases completed the Pittsburgh Sleep Quality Index (PSQI), which yields seven component scores (e.g., sleep quality, sleep latency). For each component score, we calculated the difference between the last score and the baseline score. Brains were harvested at death. Each had a complete neuropathological assessment, including extensive α-synuclein immunostaining. We examined the associations between baseline PSQI scores and the change in PSQI scores (last - first), and LP on postmortem brain examination.

RESULTS

ET cases had a mean baseline age of 87.1 ± 4.8 years. LP was observed in 12 (23.1%) of 52 cases; in 7 of these 12, LP was observed in the locus coeruleus (LC). Change in time needed to fall asleep (last - first sleep latency component score) was associated with presence of LP on postmortem brain examination - greater increase in sleep latency was associated with higher odds of LP (odds ratio = 2.98, p = 0.02). The greatest increase in sleep latency was observed in cases with LP in the LC (p = 0.04).

CONCLUSION

In ET cases, increases in sleep latency over time could be a marker of underlying LP, especially in the LC.

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.

Executive dysfunction accompanying essential tremor

Essential tremor (ET) is one of the most common neurological diseases. New evidence suggest that ET is associated with cognitive disorders other than motor symptoms. We aimed to investigate executive dysfunctions, which are comorbid cognitive deficiencies that may accompany ET. The study was conducted as an observational, case-control study in the Neurology Department of Ankara City Hospital in a 3-month period. The "Fahn-Tolosa-Marin Tremor Evaluation Scale" was used to rate tremor severity. Both patients and control group were subjected to the Mini Mental Test, followed by the Stroop TBAG test (TBAG is composed of the first letters of "TUBİTAK Temel Bilimler Araştırma Grubu," which means Scientific and Technological Research Council of Turkey Basic Sciences Research Group), word fluency (category fluency), phonemic fluency (K), and abstract thinking (binary similarities, proverb interpretation) tests. Both the patient and the control group consisted of 20 women and 20 men, with age, gender, and educational background compatible. Mean age of the patient group was 34.80 ± 13.23 years, while it was 34.95 ± 10.21 years in control group. In the ET group, statistically significant impairment was detected in the Stroop Test section 5 duration and error + correction number, category fluency, binary similarity, and phonemic fluency tests compared to the control group. There was a correlation between the severity of tremor and especially Stroop, category fluency, and binary similarity tests such that, as the severity of tremor increased, these test scores deteriorated. In ET patients, an impairment, accompanying tremor, may be present in executive functions that are a part of frontal lobe functions even in younger patients. This finding may suggest that impairment in the cerebellum-thalamus-frontal lobe connection may play a role in ET pathology.

Associations between cognitive function and a range of significant life events in an elderly essential tremor cohort study

BACKGROUND

Although essential tremor (ET) is associated with cognitive decline, we know little about how specific cognitive changes predict significant events in patients' lives. We examined the relations of attention, executive function, language, memory, and visuospatial performance to the occurrence of near falls, falls, walking aid use, home health aide use, non-independent living and hospitalizations within a prospective, longitudinal study of ET cases. We expected executive function and memory to be most strongly associated with these events.

METHODS

131 ET cases (mean age at baseline = 76.4 ± 9.4 years; 109 normal cognition; 17 mild cognitive impairment, 5 demented) completed questionnaires (clinical history and occurrence of life events) and a battery of neuropsychological tests at baseline and at 18, 36, and 54 months. We assessed associations between cognitive functioning and outcomes via regression equations.

RESULTS

Cases with lower baseline levels of executive function reported more near falls, p < 0.006, and were more likely to use a walking aid, p < 0.03, odds ratio (OR) = 2.89 during the follow-up period, than were other cases. Decline in executive function was associated with home health aide use during follow-up, p < 0.04, OR = 3.34. Baseline visuospatial performance also bore a marginally significant association with non-independent living arrangements during follow-up, p < 0.06, OR = 2.13. These effects were independent of age and tremor severity.

CONCLUSION

These data establish the important role that cognitive decline, and executive function specifically, play in the experiences of ET patients. Moreover, these associations are of sufficient magnitude to have significant clinical implications.

Association between cognitive diagnosis and a range of significant life events in an elderly essential tremor cohort: a longitudinal, prospective analysis

Background

Although essential tremor (ET) patients have greater odds of mild cognitive impairment (MCI) and dementia than age-matched controls, the functional consequences of these enhanced odds are unknown. We examined associations between cognitive diagnosis and the occurrence of near falls, falls, use of a walking aid or a home health aide, non-independent living, or hospitalizations within a prospective, longitudinal study of ET patients.

Methods

A total of 131 ET patients (mean baseline age = 76.4 ± 9.4 years) completed a battery of neuropsychological tests and questions about life events and were assigned diagnoses of normal cognition (NC), MCI, or dementia at the baseline and at 18-, 36-, and 54-month follow-ups. Kruskall-Wallis, chi-square, and Mantel-Haenszel tests assessed whether the diagnosis was associated with the occurrence of these life events.

Results

Patients with final diagnoses of dementia were more often reported as living non-independently than NC or MCI patients and more often used walking aids than NC patients, with a p-value of <0.05. Patients with a final MCI or dementia diagnosis more often employed a home health aide than NC patients, with a p-value of <0.05. Moreover, Mantel-Haenzsel tests revealed linear associations between the occurrence of these outcomes and the level of cognitive impairment, with a p-value of <0.001 (i.e., dementia > MCI > NC).

Conclusion

Cognitive diagnosis was associated with reported life events of ET patients, including the use of a mobility aid, employment of a home health aide, and removal from an independent living situation. These data provide rare insights into the important role cognitive decline plays in the experiences of ET patients.

Odds of Medical Comorbidities in Essential Tremor: Retrospective Analysis of a Large Claims Database in the United States

INTRODUCTION

Essential tremor (ET) is the most common tremor disorder, estimated to affect 7 million individuals in the USA. There is little empirical evidence on comorbidities among this population beyond higher prevalence of brain-related and stress-related disorders. This study aims to examine differences in the prevalence of the 31 Elixhauser comorbidities among ET patients compared to statistically similar control patients.

METHODS

An extract from Optum's de-identified Clinformatics® Data Mart Database (CDM) from 2018 to 2019 of adults aged 40-80 years with at least one claim with an ET diagnosis was propensity score matched to controls. Logistic regression was used to generate doubly robust adjusted odds ratios for each of the 31 Elixhauser comorbidities.

RESULTS

In these analyses, ET patients had significantly greater adjusted odds of depression, alcohol abuse, and other neurological disorders, as well as chronic pulmonary disease, renal failure, hyperthyroidism, and cardiac arrhythmias relative to controls. They also had lower odds of uncomplicated diabetes, congestive heart failure, metastatic cancer, paralysis, peripheral vascular disease, and fluid and electrolyte disorders.

CONCLUSION

A number of recent studies, including our own, suggest that psychiatric, neurologic, and stress-related disorders may be more prevalent among ET patients than controls. Additional differences in the prevalence of a range of medical comorbidities have also been variably reported across studies, suggesting that some combination of these might be more prevalent. Further studies would be of value in sorting through these associations.

Differential contributions of depression, apathy, and anxiety to neuropsychological performance in Parkinson's disease versus essential tremor

INTRODUCTION

Mood symptoms are common features of Parkinson's disease (PD) and essential tremor (ET) and have been linked to worse cognition. The goals of the present study were to compare the severity of anxiety, apathy, and depressive symptoms in PD, ET, and healthy controls (HC) and to examine differential relationships between mood and cognition.

METHOD

Older adults with idiopathic PD (N = 448), ET (N = 128), or HC (N = 136) completed a multi-domain neuropsychological assessment consisting of memory, executive function, and attention/working memory domains. Participants also completed self-reported mood measures. Between-group differences in mood and cognition were assessed, and hierarchical regression models were conducted to examine relationships between mood and cognition in each group.

RESULTS

Relative to the HC group, the PD and ET groups reported more mood symptoms and scored lower across all cognitive measures. There were no differences between the two movement disorder groups. Mood variables explained 3.9-13.7% of the total variance in cognitive domains, varying by disease group. For PD, apathy was the only unique predictor of executive function (β = -.114, p = .05), and trait anxiety was the only unique predictor of attention/working memory (β = -.188, p < .05). For ET, there were no unique predictors, though the overall models significantly predicted performance in the executive function and attention/working memory domains.

CONCLUSIONS

In a large cohort of ET and PD, we observed that the two groups had similar self-reported mood symptoms. Mood symptoms were differentially associated with cognition in PD versus ET. In PD, increased apathy was associated with worse executive function and higher trait anxiety predicted worse attention/working memory. For ET, there were no unique predictors, though the overall mood symptom severity was related to cognition. Our study highlights the importance of considering the relationship between mood and neuropsychological performance in individuals with movement disorders.

Essential tremor patients experience significant burden beyond tremor: A systematic literature review

Background

Essential tremor (ET) is among the most common movement disorders in adults. While ET is diagnosed and primarily characterized by the presence of tremor, it also can impact cognition, sleep, mood, and motor functioning more broadly. The manifestations of ET can have various consequences, including difficulty with activities of daily living (ADL), embarrassment, and overall decline in health-related quality of life, which have not been fully explored in prior studies.

Objective

We performed a systematic literature review to comprehensively characterize the burden experienced by patients with ET from the clinical and humanistic perspectives, focusing on outcomes beyond tremor.

Methods

This systematic literature review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches in PubMed, Embase, and Cochrane Library identified original, observational studies of the clinical and humanistic burden in adult patients with ET published in English between 2010 and 2020. Studies assessing epidemiology, treatment patterns, or disease management were excluded. Search results were screened according to pre-determined eligibility criteria. Data from included studies were collected, independently verified, and qualitatively synthesized.

Results

Following the screening of 2,303 records and 145 full-text articles, 39 studies were identified. There was significant heterogeneity in study designs, statistical approaches, and patient cohorts across the included studies. Patients with ET in these studies exhibited more severe disabilities and reduced independence compared to healthy individuals, and they often struggled to perform ADL and relied on caregivers for physical and emotional support. Patients also experienced various issues with movement and balance, increased risk of falls, depression, anxiety, poor sleep quality, and psychosocial consequences including embarrassment, apathy, and enfeeblement.

Conclusion

A systematic literature review of non-tremor manifestations and/or consequences of ET identified far-reaching negative impacts on patients' ability to function independently and revealed accompanying psychosocial effects, including social fear and embarrassment. The reduced function and psychosocial deficits observed in patients with ET result in significant clinical and humanistic burdens, decreasing quality of life. Future studies should evaluate this condition beyond the tremor itself to provide an improved understanding of the multi-dimensional burden of the disease, thereby highlighting the need to diagnose and appropriately manage patients with ET.

Does essential tremor increase risk of cognitive impairment and dementia? Yes

Essential Tremor (ET), by definition, is a disorder of movement. Yet over the years, epidemiologic, clinical, pathologic, and neuroimaging studies have converged to reveal a cognitive side of ET. The cognitive symptoms in ET are heterogeneous and are likely to reflect heterogeneous underlying mechanisms. In this chapter, we review and synthesize a diverse set of studies from both population-based settings to cohorts with more detailed investigations into cognition to consider the various mechanisms by which cognitive symptoms may emerge in a subset of individuals with ET. As part of our analysis, we consider questions surrounding ET diagnosis and the possibility of comorbid disease as potential factors that, upon closer examination, appear to strengthen the argument in favor of ET as a risk factor for dementia. Importantly, we also consider the clinical relevance of cognitive impairment in ET. While ET is not universally characterized by significant cognitive deficits, the data from epidemiological, cognitive, neuroimaging, and postmortem neuropathologic studies converge to reveal an increased risk for cognitive impairment and dementia among individuals with ET. We conclude by offering directions for future research, and a neurocognitive framework with which to consider existing findings and to use in the design of novel studies dedicated to clarifying the basis, nature, and course of cognitive impairments in ET.

Depressive symptoms predict memory decline in Essential Tremor

INTRODUCTION

Essential tremor (ET), a common movement disorder, is characterized by motor, cognitive and psychiatric symptoms. Depressed mood, a symptom of ET, has historically been viewed as a psychological response to disability. However, depressive symptoms are emerging as a predictor of cognitive decline across several clinical populations. We examined if depressive symptoms predict decline in global cognition, memory, and executive functioning among older adults with ET.

METHODS

125 cognitively normal participants with ET completed three in-person assessments of cognition, mood, and motor symptoms at baseline, 18 months, and 36 months; baseline data were collected from July 2014-July 2016. Depressive symptoms were measured with the Geriatric Depression Scale. Cognitive functioning was measured via a 3-4 hour neuropsychological evaluation. Generalized linear regression models examined depressive symptoms as a predictor of decline in global cognition, executive functioning (EF), and memory.

RESULTS

Participants were grouped according to a median split (GDS <5 versus ≥ 5) due to the bimodal distribution of the data. In unadjusted models, depressive symptoms did not predict change in global cognition (b = -0.002, p = .502) or EF (b = 0.000, p = .931), however individuals with GDS ≥ 5 demonstrated faster memory decline in unadjusted (b = -0.008, p = .039) and adjusted models (b = -0.009, p = .019).

CONCLUSION

The presence of 5 or more depressive symptoms predicted mildly faster memory decline in cognitively normal older adults with ET over 36 months. We discuss potential mechanisms and clinical implications.

Does essential tremor increase the risk of dementia? No

Essential tremor (ET) is the most common neurological cause of tremor affecting adult humans affecting about 6% of those over age 65 years. In the United States, dementia has a prevalence of 15% in those age 68 and older. Overlap of the two conditions is therefore not surprising. Several studies report mild subclinical cognitive dysfunction in non-demented people with ET, likely related to overactivity of fronto-cerebellar circuitry involved in tremor pathophysiology. Frontal/executive dysfunction is often though not exclusively noted, and some studies have even shown areas of cognitive strengths. Mild cognitive impairment (MCI) is impairment which a person is aware of but does not interfere significantly with daily activities. While MCI has been considered to presage dementia this is not necessarily the case, as some persons with MCI revert to normal cognition in follow-up. Dementia is a clinical syndrome with cognitive impairment interfering with daily activities. Population-based and clinic-based studies have shown mixed results regarding rates of MCI in ET. A handful of studies have looked at development of dementia in ET with differing results. Brain pathology studies in ET and dementia or investigating Alzheimer-type pathology have thus far been unrevealing. There is evidence by some investigators supporting a greater risk of dementia for those having older onset tremor, while those having ET at a younger age faring at least as well as controls regarding risk of cognitive impairment and dementia. At present the evidence is inconclusive that ET as a group are at a greater risk of developing dementia.

Association of Essential Tremor With Dementia and Affective Disorders: A Meta-Analysis

Background

The dementia and affective disorders are common non-motor features in patients with essential tremor (ET). However, the relationship of ET with cognitive impairments and affective disorders remains controversial. This meta-analysis aimed to analyze the association of ET with dementia and affective disorders.

Methods

Original studies published from January 1999 to October 2019 were systematically searched from the database of Medline (OvidSP), EMBASE (OvidSP), and the Cochrane Central Register of Controlled Trials. Pooled standard mean difference (SMD, random effect model), odds ratios (ORs), relative risk (RR), and 95% CI were calculated.

Results

Compared with the Non-ET group, patients with ET had significantly lower Mini-Mental State Examination (MMSE) score (SMD, −1.16; 95% CI, −1.75 to −0.58; p = 0.0001) and had significantly higher depressive and anxiety symptoms scale score (SMD, 0.55; 95% CI, 0.22–0.87; p = 0.0009). The OR for dementia and affective disorders in individuals with ET compared with individuals without ET was 2.49 (95% CI, 2.17–2.85, p &lt; 0.00001). While there was no significant difference in Montreal Cognitive Assessment (MoCA) score between ET and Non-ET groups (SMD, −0.52; 95% CI, −0.16 to 0.13; p = 0.23), there was a significant difference in the risk of mortality between ET and Non-ET groups (RR = 4.69, 95% CI, 2.18–10.07).

Conclusion

The non-motor symptoms should not be neglected among patients with ET. However, the causal relationship between ET and dementia, depression, and anxiety is unclear.

Disrupted Brain Functional Network Topology in Essential Tremor Patients With Poor Sleep Quality

Sleep disturbances, especially poor quality of sleep (QoS), are common among essential tremor (ET) patients and may have adverse effects on their quality of life, but the etiology driving the poor QoS in these individuals remains inadequately understood. Few data are available on the neuroimaging alterations of ET with poor QoS. Thirty-eight ET patients with poor QoS (SleET), 48 ET patients with normal QoS (NorET), and 80 healthy controls (HCs) participated in this study. All subjects underwent a 3.0-T magnetic resonance imaging (MRI) scan for resting-state functional MRI data collection. Then, the whole-brain functional connectome was constructed by thresholding the partial correlation matrices of 116 brain regions. Graph theory and network-based statistical analyses were performed. We used a non-parametric permutation test for group comparisons of topological metrics. Partial correlation analyses between the topographical features and clinical characteristics were conducted. The SleET and NorET groups exhibited decreased clustering coefficients, global efficiency, and local efficiency and increased the characteristic path length. Both of these groups also showed reduced nodal degree and nodal efficiency in the left superior dorsolateral frontal gyrus, superior frontal medial gyrus (SFGmed), posterior cingulate gyrus (PCG), lingual gyrus, superior occipital gyrus, right middle occipital gyrus, and right fusiform gyrus. The SleET group additionally presented reduced nodal degrees and nodal efficiency in the right SFGmed relative to the NorET and HC groups, and nodal efficiency in the right SFGmed was negatively correlated with the Pittsburgh Sleep Quality Index score. The observed impaired topographical organizations of functional brain networks within the central executive network (CEN), default mode network (DMN), and visual network serve to further our knowledge of the complex interactions between tremor and sleep, adding to our understanding of the underlying neural mechanisms of ET with poor QoS.

The Hidden Burden of Disease and Treatment Experiences of Patients with Essential Tremor: A Retrospective Claims Data Analysis

INTRODUCTION

Essential tremor (ET) affects approximately 7 million people in the USA, yet public recognition of the disease and its impact remain low.

METHODS

A retrospective observational study examined US claims data from 2015 to 2019 using the Compile database. ET diagnoses were captured using longitudinal data from 2015 to 2019 and for the year 2019, with diagnosis estimates extrapolated to the general US population. Confirmed ET was identified by an ET diagnosis code with at least two relevant prescriptions or by two diagnosis codes for ET and unspecified tremor at least 90 days apart. Comorbidity and treatment use data were extracted, and medication compliance and 2-year treatment persistence were assessed as measures of treatment adherence.

RESULTS

A total of 1,336,183 patients with ET diagnoses codes were identified from 2015 through 2019, corresponding to 2,226,971 projected US diagnoses. In 2019, 128,263 patients had a confirmed ET diagnosis, corresponding to 213,772 projected US confirmed diagnoses. Of these, 96% had at least one comorbidity, and 64% received at least one pharmacologic treatment. Propranolol (24%) and primidone (20%) comprised the most common ET prescriptions. Two-year medication discontinuation rates were approximately 40%.

CONCLUSION

Our findings revealed that 1 million people were diagnosed and sought treatment for ET in the USA from 2015 to 2019. Projected population estimates of approximately 2 million people diagnosed suggest a further 1 million remain untreated. Our findings highlight the complexity of patient care in ET, complicated by delayed diagnoses, multiple comorbidities, and lack of effective and tolerable therapies that can mitigate treatment adherence limitations.

Primidone Intolerance in Essential tremor: Is it More than Just Age?

Background:

There are few medications for the treatment of essential tremor (ET). One of these, primidone, which is one of only two front-line agents, is associated with considerable adverse drug reactions (ADRs). It is unclear why some primidone-treated ET patients develop ADRs whereas others do not, and why these ADRs seem to be more prevalent in ET patients than primidone-treated patients with epilepsy.

Objective:

To review several possible explanations underlying the above-referenced differences.

Methods:

A literature search was conducted in PubMed in October 2021. Studies reporting the ADRs of primidone in different neurological conditions were comprehensively reviewed.

Discussion:

Although there were no head-to-head data, a review of the previous studies on ET and epilepsy patients indicates that the former is relatively more intolerant to primidone. Moreover, not all ET patients develop ADR of similar nature or severity. We discuss several potential mechanisms for this variability in the intolerance to primidone. These include: (i) older age (ET vs. epilepsy patients), (ii) cross-tolerance to primidone in patients with epilepsy, (iii) neurobiological (GABA-related) abnormalities associated with ET.

Conclusion:

We speculate that there are several possible explanations for primidone intolerance in ET. These possibilities should be tested in future studies, and we propose the roadmap for designing these studies. It is of value to obtain detailed insight into these complex issues because primidone remains one of the few frontline anti-tremor medications in ET. Answers to issues we have raised in this article could facilitate more customized formulation of primidone in ET patients.

Mild cognitive impairment, dementia and risk of mortality in essential tremor: A longitudinal prospective study of elders

BACKGROUND

There is evidence that the risk of mortality is increased in patients with essential tremor (ET), however, there are few longitudinal, prospective data on the predictors of mortality in ET. There is also evidence that ET is associated with cognitive impairment; yet, it is unknown whether this is associated with elevated risk of mortality.

METHODS

In a longitudinal, prospective study of 194 elders with ET, an extensive neuropsychological test battery was performed at three time points: baseline, 18 months, and 36 months, and cognitive diagnoses (normal, mild cognitive impairment [MCI], and dementia) were assigned during consensus conferences. We used Cox proportional hazards models to estimate hazard ratios (HR) for death.

RESULTS

The mean baseline age was 79.1 ± 9.7 years. During follow-up, 52 (26.8%) died. In initial univariate models, a variety of baseline factors were associated with increased risk of mortality, including demographic variables (i.e., older age), cognitive variables and gait and balance variables. In the final multivariate Cox model, baseline dementia (HR = 2.66, p = 0.006), older baseline age (HR = 1.18, p < 0.001), and more reported falls at baseline (HR = 1.10, p < 0.001) were independently associated with increased risk of mortality. Amnestic MCI was marginally associated with increased risk of mortality (HR = 1.93, p = 0.08) in primary analyses and significantly (p < 0.05) in several sensitivity analyses.

CONCLUSIONS

In this longitudinal, prospective study, baseline dementia resulted in a 2- to 3-times increase in risk of mortality in ET, further highlighting the clinical significance of cognitive impairment, specifically dementia, in this population.

Genomic Markers for Essential Tremor

There are many reports suggesting an important role of genetic factors in the etiopathogenesis of essential tremor (ET), encouraging continuing the research for possible genetic markers. Linkage studies in families with ET have identified 4 genes/loci for familial ET, although the responsible gene(s) have not been identified. Genome-wide association studies (GWAS) described several variants in LINGO1, SLC1A2, STK32B, PPARGC1A, and CTNNA3, related with ET, but none of them have been confirmed in replication studies. In addition, the case-control association studies performed for candidate variants have not convincingly linked any gene with the risk for ET. Exome studies described the association of several genes with familial ET (FUS, HTRA2, TENM4, SORT1, SCN11A, NOTCH2NLC, NOS3, KCNS2, HAPLN4, USP46, CACNA1G, SLIT3, CCDC183, MMP10, and GPR151), but they were found only in singular families and, again, not found in other families or other populations, suggesting that some can be private polymorphisms. The search for responsible genes for ET is still ongoing.

Sleep disorders in essential tremor: systematic review and meta-analysis

Sleep disorders are frequent in patients diagnosed with essential tremor (ET). The present review focuses on sleep disorders and the results of polysomnographic studies performed in patients with ET. For this purpose we performed a systematic review crossing the search term "essential tremor" with "sleep," "sleep disorders," "sleep disturbances" and "polysomnography," and with specific sleep disorders, according to the International Classification of the Sleep Disorders-Third Edition, using the PubMed, EMBASE, MEDLINE, and Web of Science Databases. The most frequent sleep problems reported by patients with ET were the bad quality of sleep and excessive daytime somnolence (the latter could be related to drugs commonly used for the treatment of ET). Probable rapid eye movement sleep behavior disorder, coexistent restless legs syndrome, insomnia, and nocturia were not infrequent complaints, while the presence of other sleep disorders in patients with ET was restricted to anecdotal reports or not described. Meta-analyses of previous reports showed that patients with ET (according to the PRISMA and MOOSE guidelines) showed higher scores in the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale than controls and lower scores than those of patients diagnosed with Parkinson's disease. Studies using polysomnography in patients with ET are scarce and do not permit to establish valid conclusions regarding polysomnographic features in this disorder.

Fatigue in hypokinetic, hyperkinetic, and functional movement disorders

The emerging science of fatigue has soundly endorsed the need for its unified definition, shared terminology and increased recognition in neurological illnesses. Nevertheless, the real impact of fatigue remains under-recognized. Fatigue describes a sense of tiredness, lack of energy or need for increased effort often perceived as overwhelming, pervasive, and disabling. It is a common feature of chronic medical conditions and neurological diseases, including Parkinson's disease (PD) and other hypokinetic, hyperkinetic, and functional movement disorders (FMD). While there is solid evidence for the burden of fatigue in PD, knowledge of fatigue in other movement disorders (MDS) is still limited. Lack of consensus definition, rigorous measures and the high prevalence of potential confounders such as apathy, depression and sleepiness are the main obstacles in studying fatigue in MDS. This review of the prevalence, impact, and clinical correlates of fatigue in common MDS summarizes current hypotheses for the pathophysiological mechanisms underlying fatigue and gives a brief overview of treatment options. Fatigue is a prevalent, disabling, primary non-motor symptom (NMS) in MDS, including atypical and secondary parkinsonisms, dystonia, essential tremor (ET) and a hallmark feature of FMD. We report the hypothesis that fatigue is a perceptual disorder of the sensorimotor system. Given the relevance of this burdensome symptom, fatigue deserves greater clinical and research attention to better understand its manifestation and pathophysiology and to improve diagnosis and treatment.

Phenotypic Features of Isolated Essential Tremor, Essential Tremor Plus, and Essential Tremor-Parkinson's Disease in a Movement Disorders Clinic

Background:

Patients with essential tremor were initially considered to have isolated tremor, but additional motor and non-motor features have been increasingly recognized. The term “essential tremor plus” was adopted by the Task Force on Tremor of the International Parkinson and Movement Disorder Society to describe essential tremor patients with additional neurologic signs.

Objectives:

To characterize essential tremor patients and their phenotypes in a movement disorders clinic population in the context of the new tremor classification.

Methods:

Demographic, clinical, historical, treatment, and diagnostic data were retrospectively collected on 300 patients diagnosed by movement disorder experts with essential tremor. Patients were classified as having essential tremor, essential tremor plus, or essential tremor-Parkinson’s disease combination, and features between these groups were compared.

Results:

Of the 300 patients, 20.7% were classified as isolated essential tremor, 53.3% as essential tremor plus, and 26.0% as essential tremor-Parkinson’s disease. There was no significant difference in the duration of tremor symptoms. Essential tremor plus patients were more likely to have dystonia, tandem gait abnormalities, head tremor and greater tremor severity. Essential tremor-Parkinson’s disease patients were more likely to have RBD symptoms. There was no significant difference in cognitive impairment between essential tremor plus and essential tremor-Parkinson’s disease patients.

Conclusions:

Additional motor and non-motor features, including parkinsonism, are common in patients with essential tremor. Further studies are needed to clarify essential tremor phenotypes and to provide insights into possible subtypes.

Highlights:

300 patients with essential tremor from a movement disorders clinic were re-classified based on the Movement Disorder Society Consensus Statement on the Classification of Tremors. Additional motor and non-motor features, including parkinsonism, were common, and only 20.7% of patients remained classified as isolated essential tremor.

The Essential Tremors: Evolving Concepts of a Family of Diseases

The past 10 years has seen a remarkable advance in our understanding of the disease traditionally referred to as “essential tremor” (ET). First, the clinical phenotype of ET has been expanded from that of a bland, unidimensional, and monosymptomatic entity to one with a host of heterogeneous features. These features include a broader and more nuanced collection of tremors, non-tremor motor features (e.g., gait abnormalities) and a range of non-motor features, including cognitive, psychiatric, sleep, and other abnormalities. The natural history of these features, as well as their relationships with one another and with disease duration and severity, are better appreciated than they were previously. Studies of disease etiology have identified a number of candidate genes as well as explored several environmental determinants of disease. In addition, the decade has seen the beginnings and expansion of rigorous postmortem studies that have identified and described the postmortem changes in the brains of patients with ET. This emerging science has given rise to a new notion that the disease, in many cases, is one of cerebellar system degeneration. Across all of these studies (clinical, etiological, and pathophysiological) is the observation that there is heterogeneity across patients and that “essential tremor” is likely not a single disease but, rather, a family of diseases. The time has come to use the more appropriate terminology, “the essential tremors,” to fully describe and encapsulate what is now apparent. In this paper, the author will review the clinical, etiological, and pathophysiological findings, referred to above, and make the argument that the terminology should evolve to reflect advances in science and that “the essential tremors” is a more scientifically appropriate term.

Sleep Disorders in Patients with Essential Tremor

PURPOSE OF THE REVIEW

Patients diagnosed with essential tremor (ET) report frequent sleep complaints. This review focuses on the main findings of studies addressing sleep features in patients diagnosed with ET, updating previously reported information. Bad quality of sleep and excessive daytime somnolence are very frequent in patients with ET, although the effects of the drugs used for the therapy of ET could contribute to these complaints. REM sleep behavior disorder, restless legs, insomnia, and nocturia are frequent complaints as well. There is a lack of studies addressing polysomnographic features of ET.

Disrupted Brain Network Topology in Drug-naïve Essential Tremor Patients with and Without Depression : A Resting State Functional Magnetic Resonance Imaging Study

PURPOSE

This study was carried out to investigate brain functional connectome and its potential relationships with the disease severity and emotion function in patients with essential tremor with and without depressive symptoms by using resting-state functional magnetic resonance imaging and graph theory approaches.

METHODS

In this study 33 essential tremor patients with depression, 45 essential tremor patients without depression and 79 age and gender-matched healthy controls were recruited to undergo a 3.0‑T imaging scan. The whole brain functional connectome was constructed by thresholding the partial correlation matrices of 116 brain regions, and the topologic properties were analyzed by using graph theory approaches and network-based statistic approaches. Nonparametric permutation test was also used for group comparisons of topological metrics. Correlation analyses between topographic features and the clinical characteristics were performed.

RESULTS

The functional connectome in both essential tremor patients with and without depression showed abnormalities at the global level (decrease in clustering coefficient, global efficiency, and local efficiency but increase in characteristic path length) and at the nodal level (decrease nodal centralities in the cerebellum, motor cortex, prefrontal-limbic regions, default mode network) (p < 0.05, false discovery rate corrected). Moreover, essential tremor patients with depression showed higher node efficiency in superior frontal gyrus and posterior cingulate gyrus compared to essential tremor without depression.

CONCLUSION

Our results may provide insights into the underlying pathophysiology of essential tremor patients with and without depression and aid the development of some potential biomarkers of the depressive symptoms in patients with essential tremor.

The spiral axis: A comparison of unaffected first-degree relatives of essential tremor cases vs. controls

We previously observed that during a spiral drawing task, in essential tremor (ET) cases, the tremor wave forms align along a single predominant axis. This interesting clinical feature can distinguish ET from dystonia cases. We now investigate whether the unaffected relatives of ET cases also express this trait, albeit perhaps in a milder form. To address our aim, we assessed the spiral axis in 237 unaffected first-degree relatives of ET cases (FD-ET), comparing them to 105 controls (Co). A movement disorder neurologist assessed four hand drawn spirals for the presence of a single identifiable tremor orientation axis. A spiral axis score (range = 0-4 [a single axis on 4 spirals]) was assigned to each enrollee. FD-ET had higher spiral axis scores than Co. In a contingency table, the distribution of spiral axis scores differed in the two groups: FD-ET (highest) and Co (lowest) (ordinal chi-square test p = 0.014). Furthermore, when spiral axis scores were examined as a continuous measure, the groups differed (Mann-Whitney test p = 0.03) - with the means being 0.51 (FD-ET) and 0.26 (Co). These data have scientific implications. They (1) show that such axes are more common in relatives of ET cases than controls, and (2) raise the possibility that the spiral axis may be an early subclinical feature of ET.

Mood and emotional disorders associated with parkinsonism, Huntington disease, and other movement disorders

This chapter provides a review of mood, emotional disorders, and emotion processing deficits associated with diseases that cause movement disorders, including Parkinson's disease, Lewy body dementia, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, frontotemporal dementia with parkinsonism, Huntington's disease, essential tremor, dystonia, and tardive dyskinesia. For each disorder, a clinical description of the common signs and symptoms, disease progression, and epidemiology is provided. Then the mood and emotional disorders associated with each of these diseases are described and discussed in terms of clinical presentation, incidence, prevalence, and alterations in quality of life. Alterations of emotion communication, such as affective speech prosody and facial emotional expression, associated with these disorders are also discussed. In addition, if applicable, deficits in gestural and lexical/verbal emotion are reviewed. Throughout the chapter, the relationships among mood and emotional disorders, alterations of emotional experiences, social communication, and quality of life, as well as treatment, are emphasized.

Prospective Longitudinal Study of Gait and Balance in a Cohort of Elderly Essential Tremor Patients

Background: Essential tremor (ET) encompasses a variety of features, including tremor, cognitive dysfunction, and gait and balance impairments. Gait and balance impairments in ET are often mild, but they can be severe and are, in some cases, associated with functional sequelae in terms of increased fall risk and reduced balance confidence. Previous research on gait and balance in ET has been limited to cross-sectional comparisons. There have been no longitudinal studies or prospective studies. As such, our understanding of natural history and possible predictors of declines in ET-related gait and balance impairments is incomplete. Objectives: We (1) present natural history data on the change in gait and balance measures over time, (2) provide estimates of annual rate of change in each gait and balance metric, and (3) examine the relationship between baseline clinical predictors and changes in gait and balance over time. Methods: 149 ET participants (mean age 78.7 years), enrolled in a prospective, longitudinal, clinical-pathological study, underwent an extensive evaluation of cognition, tremor, and gait and balance at three distinct intervals performed every 18 months. Gait and balance measures included a combination of performance-based tests (e.g., tandem gait, tandem stance) and self-reported assessments (e.g., number of falls, use of a walking aid). Results: Between the baseline and final assessments, numerous balance and gait measures showed evidence of decline and annual rates of change were quantified for each. We examined the predictive utility of clinical variables at baseline for five gait and balance outcomes, with global cognition and executive function standing out as the most consistent predictors. Conclusions: We present a much-needed look into the course of disease for elderly patients with ET, focusing on changes observed in gait and balance and the predictors of these changes. These results also add another dimension to the relevance of cognitive impairment observed in ET; such impairment can now be viewed as predictive of poorer gait and balance over time in ET. These findings are a useful tool for clinicians, patients, and their families to better understand and plan for changing disease-features over time.

Brain microstructural changes and cognitive function in non-demented essential tremor patients: a diffusion tensor imaging study

BACKGROUND

Essential tremor (ET) is disease with both motor and non-motor features. Notable among the non-motor features is cognitive impairment. While this impairment has been attributed to cortico-thalamo-cerebellar pathway pathology, it is likely that a more complicated involvement of brain structures underlies cognitive function in ET.

OBJECTIVE

To evaluate the brain microstructural changes of both white matter and grey matter in ET using region of interest based diffusion tensor imaging (DTI), and to correlate these changes with cognitive function assessed during detailed neuropsychological testing.

METHOD

Thirty-five non-demented ET patients with a range of cognitive function (Clinical Dementia Rating = 0-0.5, mean age = 57.5 ± 16.7 years, age range = 23-76 years) underwent a comprehensive neuropsychological evaluation and brain magnetic resonance imaging, including DTI. DTI findings were reported as fractional anisotropy, average diffusion coefficient, these values were evaluated for 32 ROIs. Cognitive domains included attention, visuospatial functions, executive function, verbal memory, visual memory, and language. Domain Z-scores were calculated each cognitive domain and compared for each brain region.

RESULTS

Microstructural changes in prefrontal cortical areas (dorsolateral, ventrolateral), paralimbic and limbic structures (posterior cingulate cortex, precuneus, hippocampus), basal ganglia (substantia nigra, putamen, caudate nucleus) and white matter bundles (corpus callosum, anterior thalamic radiation, longitudinal fasciculus, frontooccipital fasciculus, etc.) correlated with specific domains of cognitive function in ET patients.

CONCLUSION

These data suggest that not only the cerebello thalamocortical pathway, but numerous other brain structures are related to level of cognitive performance and possibly underlie cognitive dysfunction in ET.

Alexithymia is a non motor symptom of essential tremor regardless of the presence of depression and anxiety

OBJECTIVE

Essential tremor (ET) is one of the most common movement disorders. Aside from tremor, patients may exhibit other motor features as well as non-motor features, including neuropsychiatric symptoms. The cerebellum and cerebellar connections are thought to play a key role in the pathophysiology of ET. Cognitive and affective disturbances can occur in the context of cerebellar disease. Our aim was to study the prevalence and clinical correlates of alexithymia and its relationship to depression and anxiety in ET patients and control subjects (CS).

METHOD

We enrolled 100 ET patients and 100 age- and gender-matched CS. The Toronto Alexithymia Scale-20 (TAS-20), the Beck depression inventory-II and the Beck anxiety inventory were administered.

RESULTS

Alexithymia levels were significantly higher in ET patients than CS (respective mean TAS-20 scores = 50.63 ± 9.79 vs. 44.05 ± 12.51, p < 0.001).  There were robust associations between alexithymia, depressive symptoms, and anxiety but, after excluding the ET patients and the CS who had moderate or severe depression or who had moderate or severe anxiety, the total alexithymia score remained significantly higher in the ET than the CS group (46.78 ± 9.19 vs. 41.18 ± 11.79, p ≤ 0.01).

CONCLUSION

This study suggests that prevalence of alexithymia is significantly higher in ET patients. Alexithymia might be another non-motor neuropsychiatric symptom of the disease.  Further studies are needed to confirm and expand upon our findings.

Cognitive and brain micro-structural correlates of alexithymia in essential tremor patients

Essential tremor (ET) is the most common movement disorder which has both motor and non-motor findings such as neuropsychiatic symptoms. Alexithymia is defined as inability to identify and describe emotions experienced by one's self or others. In our study, we aimed to evaluate the neurocognitive and brain micro-structural correlates of alexithymia in ET. 40 ET patients (mean age = 53.05 ± 19.74 years), were included. Fahn-Tolosa-Marin Tremor Rating Scale, Toronto Alexithymia Scale (TAS), Beck Depression Inventory, Beck Anxiety Inventory and detailed neurocognitive evaluation were applied to all patients. The patients were divided into three groups based on their TAS scores: no alexithymia, probable alexithymia, definite alexithymia. Diffusion Tensor Imaging (DTI) was performed in all patients. The mean TAS score was 50.05 ± 10.06. Depressive symptoms and anxiety levels were higher in definite alexithymia (p < 0.001, p < 0.01). Partial correlation controlling for age, gender and educational level between alexithymia scores and each cognitive test showed significant association between similarities (p < 0.001) and phonemic verbal fluency (p = 0.04). Left orbitofrontal cortex average diffusion coefficient (ADC) value (p = 0.05), left anterior cingulate cortex fractional anisotropy (FA) value (p = 0.04), right cuneus FA value (p = 0.04), left amygdala ADC value (p = 0.01) and left insula ADC value (p = 0.02) were differed between groups. TAS and DTImetrics were not found to be independently associated with the level of anxiety (p < 0.001) and depressive symptoms (p < 0.01). As a conclusion, impairments in executive function and complex attention were correlated with higher levels of alexithymia in ET. Many micro-structural alterations were determined to be correlated with alexithymia levels.

Can Resistance Training Improve Upper Limb Postural Tremor, Force Steadiness and Dexterity in Older Adults? A Systematic Review

BACKGROUND

The ageing process and several health conditions may increase tremor and reduce force steadiness and dexterity, which can severely impact on function and quality of life. Resistance training can evoke a range of neuromuscular adaptions that may significantly reduce tremor and/or increase force steadiness and/or dexterity in older adults, irrespective of their health condition.

OBJECTIVES

The objective of this study was to systematically review the literature to determine if a minimum of 4 weeks' resistance training can reduce postural tremor and improve force steadiness and/or dexterity in older adults, defined as aged 65 years and over.

METHODS

An electronic search using Ovid, CINAHL, SPORTDiscus and EMBASE was performed. Risk of bias was assessed using the Cochrane Risk of Bias Tool.

RESULTS

Fourteen studies met the eligibility criteria, including six randomised controlled trials and two quasi-randomised controlled trials. All eight studies that recruited healthy older adults reported significant reductions in postural tremor and/or improvements in force steadiness and dexterity. Five out of seven studies that examined older adults with a particular health condition reported some improvements in force steadiness and/or dexterity. Specifically, significant benefits were observed for older adults with chronic obstructive pulmonary disease and essential tremor; however, small or no changes were observed for individuals with osteoarthritis or stroke.

CONCLUSIONS

Resistance training is a non-pharmacological treatment that can reduce tremor and improve force steadiness and dexterity in a variety of older adult populations. Future research should employ randomised controlled trials with larger sample sizes, better describe training programme methods, and align exercise prescription to current recommendations for older adults.

REM sleep behaviour disorder in essential tremor: A polysomnographic study

Our objectives were to assess the prevalence of REM sleep behaviour disorder in patients with Essential Tremor, using video-polysomnography and to compare REM sleep behaviour disorder features in essential tremor with those of patients with alpha-synucleinopathies. Forty-nine patients with essential tremor were screened with the REM Sleep Behaviour Disorder Screening Questionnaire. Patients scoring positive and those with spontaneous complaints of REM sleep behaviour disorder (n = 6) underwent video-polysomnography. The clinical features of essential tremor were compared between patients with and without REM sleep behaviour disorder. Video-polysomnography data were compared between patients who had essential tremor and Parkinson's disease with REM sleep behaviour disorder and those with idiopathic REM sleep behaviour disorder. Fourteen patients (23.5%) screened positive for REM sleep behaviour disorder, confirmed by video-polysomnography in five (11.6%). All patients with essential tremor and REM sleep behaviour disorder had rest tremor, compared with 13 (34.2%) in the group with essential tremor but without REM sleep behaviour disorder (p = .009). In video-polysomnography, patients with essential tremor and REM sleep behaviour disorder were similar to patients with Parkinson's disease with REM sleep behaviour disorder and presented worse sleep dysfunction and lower severity of REM sleep behaviour disorder compared to those with idiopathic REM sleep behaviour disorder. We found a high prevalence of REM sleep behaviour disorder in patients with essential tremor, associated with a predominance of rest tremor. Polysomnography data from patients with essential tremor and REM sleep behaviour disorder were similar to those in patients with Parkinson's disease. This suggests a relation between this subgroup of patients with essential tremor and the alpha-synucleinopathies.

Essential tremor-plus: a controversial new concept

In addition to redefining essential tremor (ET), the 2018 consensus statement of the Movement Disorder Society on tremor coined a new term: essential tremor-plus (ET-plus). This term is uncertainly defined as tremor with the characteristics of ET, with additional neurological signs of uncertain clinical significance. If ET-plus had been defined on the basis of a difference in underlying pathology or an appreciable difference in prognosis, it would have a valid, scientific rationale, as does the term Parkinson-plus. However, there is no such evidence, so the basis for the term is questionable. In fact, ET-plus might only represent a state condition (ie, patients with ET might develop these additional clinical features when the disease is at a more advanced stage). We caution against coining new terms that are not supported by a firm scientific basis and encourage research into the creation of essential tremor subsets that are defined with respect to differences in underlying causes or pathophysiology.

Profiles of Normal Cognition in Essential Tremor

OBJECTIVES

Patients with essential tremor exhibit heterogeneous cognitive functioning. Although the majority of patients fall under the broad classification of cognitively "normal," essential tremor is associated with increased risk for mild cognitive impairment and dementia. It is possible that patterns of cognitive performance within the wide range of normal functioning have predictive utility for mild cognitive impairment or dementia. These cross-sectional analyses sought to determine whether cognitive patterns, or "clusters," could be identified among individuals with essential tremor diagnosed as cognitively normal. We also determined whether such clusters, if identified, were associated with demographic or clinical characteristics of patients.

METHODS

Elderly subjects with essential tremor (age >55 years) underwent comprehensive neuropsychological testing. Domain means (memory, executive function, attention, visuospatial abilities, and language) from 148 individuals diagnosed as cognitively normal were partitioned using k-means cluster analysis. Individuals in each cluster were compared according to cognitive functioning (domain means and test scores), demographic factors, and clinical variables.

RESULTS

There were three clusters. Cluster 1 (n = 64) was characterized by comparatively low memory scores (p < .001), Cluster 2 (n = 39) had relatively low attention and visuospatial scores (p < .001), and Cluster 3 (n = 45) exhibited consistently high performance across all domains. Cluster 1 had lower Montreal Cognitive Assessment scores and reported more prescription medication use and lower balance confidence.

CONCLUSIONS

Three patterns of cognitive functioning within the normal range were evident and tracked with certain clinical features. Future work will examine the extent to which such patterns predict conversion to mild cognitive impairment and/or dementia.

Demoralization in essential tremor: prevalence, clinical correlates, and dissociation from tremor severity

OBJECTIVE

Essential tremor (ET) is associated with psychological difficulties, including anxiety and depression. Demoralization (feelings of helplessness, hopelessness, inability to cope), another manifestation of psychological distress, has yet to be investigated in ET. Our objectives are to (1) estimate the prevalence of demoralization in ET, (2) assess its clinical correlates, and (3) determine whether demoralization correlates with tremor severity.

METHODS

We administered the Kissane Demoralization Scale (KDS-II) and several psychosocial evaluations (ie, scales assessing subjective incompetence, resilience, and depression [eg, Geriatric Depression Scale]) to 60 ET subjects. Tremor was assessed with a disability score and total tremor score. KDS-II >8 indicated demoralization.

RESULTS

Among 60 ET subjects (mean age = 70.2 ± 6.8 years), the prevalence of demoralization was 13.3%, 95% confidence interval = 6.9-24.2%. Although there was overlap between demoralization and depression (10% of the sample meeting criteria for both), 54% of depressed subjects were not demoralized, and 25% of demoralized subjects were not depressed. Demoralization correlated with psychological factors, but demoralized subjects did not have significantly higher total tremor scores, tremor disability scores, or years with tremor.

CONCLUSIONS

Demoralization has a prevalence of 13.3% in ET, similar to that in other chronic or terminal illnesses (eg, cancer 13-18%, Parkinson's disease 18.1%, coronary heart disease 20%). Demoralization was not a function of increased tremor severity, suggesting that it is a separable construct, which could dictate how a patient copes with his/her disease. These data further our understanding of the psychological and psychosocial correlates of ET.

Evaluation of depression, anxiety and quality of life in patients with non-obstructive azoospermia

OBJECTIVE

The aim of this study was to determine the levels of depression, anxiety and quality of life in non-obstructive azoospermia (NOA) patients who attended our clinic.

MATERIALS AND METHODS

A total of 40 male patients were included in the study troubled with non-obstructive azoospermia. An etiological classification was made according to the hormone levels of the patients. The semen specimen was obtained by masturbation from the patients. Three questionnaires, the Beck Depression Inventory, the Beck Anxiety Inventory, and the Short Form of the World Health Organization Quality of Life Questionnaire, were utilized in the study.

RESULTS

The mean age of the patients in the study was 32.75±5.22 years. The patients were classified as follows: 26 (65%) patients were idiopathic, 11 (27.5%) patients were hyper-hypo and 3 (7.5%) patients could not be reached. In this cohort, 62.5% of patients had minimal depression, 27.5% of patients had mild depression and 10% of patients had moderate depression. In addition, 97.5% of patients had minimal anxiety and 2.5% of the patients had mild anxiety. Quality of life scores of the patients were 58.75% for general health status, 70.98% for physical health status, 72.92% for psychological status, 65% for social relations and 66.25% for environmental status.

CONCLUSION

NOA particularly affects men in terms of biological, psychological and social aspects. In order to evaluate the quality of life and psychiatric conditions patients with azoospermia, various questionnaires may be applied before infertility treatment. Thus, patients who need psychiatric support can be identified.

Clinical Profile of Non-Motor Symptoms in Patients with Essential Tremor: Impact on Quality of Life and Age-Related Differences

Background

Identifying the clinical phenotypes of non-motor symptoms (NMSs) of essential tremor (ET) among different populations is necessary due to their impact on the quality of life (QoL). This study aimed to investigate the clinical phenotype and impact of NMSs on QoL in Egyptian patients with ET.

Methods

Thirty ET patients were compared to 30 matched controls. Subjects were evaluated by the Fahn-Tolosa-Marin Tremor Rating Scale, Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment, Hamilton Anxiety Rating Scale, Beck Depression Inventory, Pittsburgh Sleep quality Index, and the Short Form 36 Health Survey Questionnaire. Both groups were divided into two subgroups of younger (<45 years, 14 patients) and older age (>45 years, 16 patients) groups, to investigate age-related differences.

Results

ET patients showed significantly worse cognition, depression, anxiety, sleep and NMSS domains (p < 0.001), compared to controls, that negatively affected and predicted QoL. Older patients had more cognitive impairment (p = 0.003) and worse sleep/fatigue (p = 0.032) and sexual functions (p = 0.006), compared to younger group.

Discussion

The study supports that NMSs are integral part of ET, negatively affect QoL, and similarly affect younger and older patients. Therefore, NMSs should be explored for proper care of ET patients.

Prevalence and Risk Factors of Depression and Anxiety in Essential Tremor Patients: A Cross-Sectional Study in Southwest China

Background: Essential tremor (ET) is one of the most common movement disorders, and it has been associated with anxiety and depression, but risk factors for these mental symptoms are unclear. This study aimed to evaluate the prevalence and potential risk factors of depression and anxiety in ET patients in China. Methods: This cross-sectional study involved 245 Han Chinese patients with ET. Depression was assessed using the Hamilton Depression Rating Scale-24 Items, and anxiety was assessed using the Hamilton Anxiety Rating Scale. Clinico-demographic characteristics were compared between patients with or without depression or anxiety. Results: We revealed that 63.3% of patients had at least mild anxiety and 54.3% had at least mild depression. Severity of anxiety or depression was correlated with lower Mini-Mental State Exam score (P = 0.028 and P = 0.002, respectively), higher self-report functional disability score (P = 0.027 and P = 0.003, respectively), as well as the presence of tremor in the neck (both P < 0.001), face (P = 0.025 and P < 0.001, respectively), or voice (both P < 0.001). Binary logistic regression identified female sex, presence with cranial tremor, and greater functional disability score as risk factors of anxiety; the last two factors were also the determinants of depression. Neither anxiety nor depression correlated with physician-assessed severity of arm or leg tremor. Conclusion: Chinese ET patients show high prevalence of depression and anxiety. ET patients should be screened for these mental symptoms, especially women and those with cranial tremor and self-reported functional disability.

Therapeutic Approaches for the Management of Sleep Disorders in Geriatric Population

OBJECTIVE

Aging is a natural biological phenomenon that occurs in human beings. With increasing of age, there is an appearance of deleterious changes related to progression onto pathological conditions, including hypertension, heart disease, diabetes, hearing and vision impairments, as well as sleep disorders. It is important to recognize that some sleep disturbances reported by aged subjects include insomnia, obstructive sleep apnea, restless legs syndrome, among others. Moreover, accumulating evidence indicates that coexistence of medical issues with sleep disorders constitutes clinical challenges for treatment of comorbidities in elderly. Here, we have attempted to review and summarize the available literature that assesses the sleep disturbances in aging. In addition, we highlight the management of sleep disorders associated with aging. Due to the particular health condition of aged adults, the development of effective pharmacological interventions for sleep disorders treatment in aging is warranted.

METHODS

Review of studies retrieved from the PubMed.

RESULTS

The sleep-wake cycle includes abnormalities classified as sleep disorders. Comorbidity between sleep disturbances and aging-related health issues will represent a public health challenge to be addressed in the near future. Moreover, this scenario will suggest an area that requires further drug investigation and design of new pharmacological and pharmaceutical strategies to treat sleep disorders in the elderly population.

CONCLUSION

The review highlights the sleep disturbances in aging. We focus on current knowledge in medicinal chemistry and further design of new treatments tools for managing sleep disturbances in the aged population.

Enfeeblement in Elders with Essential Tremor: Characterizing the Phenomenon and Its Role in Caregiver Burden

Background

Individuals with essential tremor (ET), a common movement disorder, experience functional impairment, which contributes to burden experienced by their loved ones and caregivers. Some burdened caregivers report their loved ones as seeming debilitated or prematurely old, a concept that we have called enfeeblement. Using the Essential Tremor Enfeeblement Survey (ETES), we seek to characterize enfeeblement in elders with ET and assess its contribution to caregiver burden.

Methods

We administered the ETES (range = 8–40, higher scores indicating more enfeeblement) and other scales to 98 caregivers of individuals with ET. Individuals with ET were also queried regarding tremors, cognitive abilities, and overall health. We then identified demographic and clinical correlates of ETES and modeled the contribution of ETES to caregiver burden (assessed using the Zarit 12-item Burden Interview [ZBI-12]).

Results

Mean ETES score was 14.2 ± 6.2 (median = 12.0, range = 8.0–32.0); 26.5% of respondents endorsed at least one of the eight ETES items. Older age, greater tremor severity and disability, more functional and gait disability, more cognitive difficulty, and more depressive symptoms were associated with higher ETES scores. ETES was the strongest contributor to caregiver burden (ZBI-12) and substantially increased the variance explained in models of caregiver burden.

Discussion

Enfeeblement seems to describe a previously unexplained component of caregiver burden in elders with ET. The presence of enfeeblement may contribute to greater burden and should be factored into assessments of patient and caregiver needs.

Essential tremor: diagnosis and management

Essential tremor is one of the most common movement disorders in adults and can affect both children and adults. An updated consensus statement in 2018 redefined essential tremor as an isolated action tremor present in bilateral upper extremities for at least three years. Tremor may also be present in other locations, commonly the neck or the vocal cords. Patients with additional neurologic symptoms are now categorized as "essential tremor plus." Additional clinical features associated with the condition include but are not limited to cognitive impairment, psychiatric disorders, and hearing loss. When treatment is needed, propranolol and primidone are considered first line treatments. Patients who are severely affected are often offered deep brain stimulation. Although the ventral intermediate nucleus of the thalamus is the traditional surgical target, the caudal zona incerta is also being studied as a possible superior alternative. Magnetic resonance imaging guided high intensity focused ultrasound is a newer surgical alternative that may be ideal for patients with substantial medical comorbidities. Current research explores novel oral treatments, chemodenervation, and noninvasive neuromodulation for treatment of essential tremor.

Graph theory analysis of resting-state functional magnetic resonance imaging in essential tremor

Essential tremor (ET) is a neurological disease with both motor and nonmotor manifestations; however, little is known about its underlying brain basis. Furthermore, the overall organization of the brain network in ET remains largely unexplored. We investigated the topological properties of brain functional network, derived from resting-state functional magnetic resonance imaging (MRI) data, in 23 ET patients versus 23 healthy controls. Graph theory analysis was used to assess the functional network organization. At the global level, the functional network of ET patients was characterized by lower small-worldness values than healthy controls-less clustered functionality of the brain. At the regional level, compared with the healthy controls, ET patients showed significantly higher values of global efficiency, cost and degree, and a shorter average path length in the left inferior frontal gyrus (pars opercularis), right inferior temporal gyrus (posterior division and temporo-occipital part), right inferior lateral occipital cortex, left paracingulate, bilateral precuneus bilaterally, left lingual gyrus, right hippocampus, left amygdala, nucleus accumbens bilaterally, and left middle temporal gyrus (posterior part). In addition, ET patients showed significant higher local efficiency and clustering coefficient values in frontal medial cortex bilaterally, subcallosal cortex, posterior cingulate cortex, parahippocampal gyri bilaterally (posterior division), right lingual gyrus, right cerebellar flocculus, right postcentral gyrus, right inferior semilunar lobule of cerebellum and culmen of vermis. Finally, the right intracalcarine cortex and the left orbitofrontal cortex showed a shorter average path length in ET patients, while the left frontal operculum and the right planum polare showed a higher betweenness centrality in ET patients. In conclusion, the efficiency of the overall brain functional network in ET is disrupted. Further, our results support the concept that ET is a disorder that disrupts widespread brain regions, including those outside of the brain regions responsible for tremor.

Neuroimaging depression and anxiety in essential tremor: A diffusion tensor imaging study

OBJECTIVE

Patients with essential tremor (ET) may exhibit non-motor features, including those that are neuropsychiatric. Depression and anxiety are the most common among these. This study aims to investigate the possible relationship between microstructural brain changes and symptoms of depression and anxiety in ET.

METHODS

We assessed 62 ET patients (40 women and 22 men, mean age 46.0 ± 20.4) for symptoms of depression and anxiety using the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). Thirty-two patients had severe or moderate symptoms of anxiety, and 15 patients had severe or moderate depressive symptoms. Microstructural brain changes were evaluated using diffusion tensor imaging (DTI), which was reported using fractional anisotropy (FA), mean diffusivity (MD), apparent diffusion coefficient (ADC), radial diffusivity (RD), and axial diffusivity (AD) values calculated for 17 regions of interest including the prefrontal cortex, paralimbic and limbic structures and cerebellar peduncles. We evaluated the relationship between observed changes in brain regions and symptoms of depression and anxiety.

RESULTS

Decreased left amygdala FA (p = 0.003) and increased left amygdala RD (p = 0.04) were detected in depressed vs. non-depressed ET patients. Left ventrolateral prefrontal cortex (VLPFC) FA (p = 0.02) and left precuneus FA (p = 0.02) values differed between anxious patients vs. non-anxious ET patients. BDI scores were correlated with left amygdala FA and left RD, while BAI scores were correlated with left VLPFC FA and left precuneus FA.

DISCUSSION

Our results provide evidence that symptoms of depression and anxiety could be based in structural brain changes observed in patients with ET.

Mind the gaps: What we don't know about cognitive impairment in essential tremor

INTRODUCTION

Although the hallmark feature of essential tremor (ET) is tremor, there is growing appreciation that cognitive impairment also occurs, including increased prevalence of mild cognitive impairment (MCI) and increased prevalence and incidence of dementia. With emerging knowledge of ET-cognitive impairment, come fundamental questions regarding its course, bases, predictors and clinical outcomes. Studies in the general population and in Parkinson's disease (PD), a related movement disorder, offer a starting point from which to begin filling these clinically important knowledge gaps.

METHODS

A PubMed search (June 2018) identified articles for this review.

RESULTS

Much of our knowledge of cognitive impairment in ET is of the static condition (e.g., prevalence of cognitive impairment in ET), with nearly no information on its bases, predictors and dynamics (i.e., course, and clinical outcomes). In PD, where such data have been published, rates of cognitive decline and conversion to MCI/dementia are higher than in the general population. Predictors of cognitive change in PD and the general population have also been identified, yet they only partially overlap one another.

CONCLUSION

The predictors and dynamics of cognitive impairment have been investigated fairly extensively in the general population, to a somewhat lesser extent in PD, and are emerging only now in ET. We suggest that longitudinal studies specific to ET are needed, and we outline variables to be considered in these investigations. Increased knowledge of ET-cognitive impairment will facilitate meaningful counseling of patients and their families.

What Predicts Mortality in Essential Tremor? A Prospective, Longitudinal Study of Elders

Objective: Essential tremor (ET) is among the most common neurologic diseases. Although in the past it was considered a benign condition, recent research has demonstrated increased risk of mortality. To date, however, no studies have examined predictors of mortality in ET.

Methods: In a longitudinal, prospective study of 141 elders with ET, we used Cox proportional-hazards models to estimate hazard ratios (HRs) for death.

Results: The mean baseline age was 81.1 ± 8.8 years. During the follow-up interval, 27 (19.1%) died. Average time from baseline to death was 12.3 ± 8.7 months (range = 0.3–31.2). In univariate Cox regression models, older age (HR = 1.16, p < 0.001), lower Montreal Cognitive Assessment score (HR = 0.88, p = 0.004), higher Clinical Dementia Rating (CDR) score (HR = 4.53, p < 0.001), higher score on the Geriatric Depression scale (GDS) (HR = 1.07, p = 0.048), less balance confidence (HR = 0.98, p = 0.006), more falls (HR = 1.11, p = 0.003), and more tandem mis-steps (HR = 1.53, p = 0.004) were associated with increased risk of mortality. In the final multivariate Cox model, older age (HR = 1.14, p = 0.005), higher CDR score (HR = 3.80, p = 0.002) and higher GDS (HR = 1.11, p = 0.01) were independently associated with increased risk of mortality.

Conclusions: This study highlights several independent predictors of mortality in elderly ET; clinicians should consider screening for depressive symptoms, assessing cognition and tracking CDR scores, and assessing balance while evaluating patients with ET.