Movement disorders in patients taking anticonvulsants

Neuromuscular Ultrasound Findings of Myokymia in a Young Woman With Generalized Anti-LGI-1 and Anti-Caspr2 Antibodies Negative Isaac Syndrome

ABSTRACT

Isaac syndrome is one of the rare peripheral nerve hyperexcitability (PNH) syndromes, which manifests with gross fasciculations, muscle undulation, twitching, and cramps, with or without autonomic and sensory symptoms. The diagnosis relies on characteristic electromyogram findings and the presence of anti-leucine-rich glial inactivated 1 and anti-contactin-associated protein 2 antibodies in the serum. Here, we report the case of a 21-year-old woman, who presented with extremities and tongue myokymia whose electromyogram findings were compatible with PNH, albeit seronegative for antibodies. Neuromuscular ultrasound was performed showing high-frequency rotatory, to-and-fro, high-amplitude movement of superficial and deep muscle fascicles, more prominent in the proximal than distal muscles. Neuromuscular ultrasound may be a useful adjunct in the diagnosis of PNH.

Gabapentin-Associated Movement Disorders: A Literature Review

BACKGROUND

Gabapentin (GBP)-induced movement disorders (MDs) are under-recognized adverse drug reactions. They are commonly not discussed with patients, and their sudden occurrence can lead to misdiagnosis. This literature review aims to evaluate the clinical-epidemiological profile, pathological mechanisms, and management of GBP-associated MD.

METHODS

Two reviewers identified and assessed relevant reports in six databases without language restriction between 1990 and 2023.

RESULTS

A total of 99 reports of 204 individuals who developed a MD associated with GBP were identified. The MDs encountered were 135 myoclonus, 22 dyskinesias, 7 dystonia, 3 akathisia, 3 stutterings, 1 myokymia, and 1 parkinsonism. The mean and median ages were 54.54 (SD: 17.79) and 57 years (age range: 10-89), respectively. Subjects were predominantly male (53.57%). The mean and median doses of GBP when the MD occurred were 1324.66 (SD: 1117.66) and 1033 mg/daily (GBP dose range: 100-9600), respectively. The mean time from GBP-onset to GBP-associated MD was 4.58 weeks (SD: 8.08). The mean recovery time after MD treatment was 4.17 days (SD: 4.87). The MD management involved GBP discontinuation. A total of 82.5% of the individuals had a full recovery in the follow-up period.

CONCLUSIONS

Myoclonus (GRADE A) and dyskinesia (GRADE C) were the most common movement disorders associated with GBP.

Tiagabine suppresses pentylenetetrazole-induced seizures in mice and improves behavioral and cognitive parameters by modulating BDNF/TrkB expression and neuroinflammatory markers

Tiagabine (Tia), a new-generation antiseizure drug that mimics the GABAergic signaling by inhibiting GABA transporter type-1, is the least studied molecule in chronic epilepsy models with comorbid neurobehavioral and neuroinflammatory parameters. Therefore, the current study investigated the effects of Tia in a real-time manner on electroencephalographic (EEG) activity, behavioral manifestations and mRNA expression in pentylenetetrazole (PTZ)-kindled mice. Male BALB/c mice were treated with tiagabine (0.5, 1 and 2 mg/kg) for 21 days with simultaneous PTZ (40 mg/kg) injection every other day for a total of 11 injections and monitored for seizure progression with synchronized validation through EEG recordings from cortical electrodes. The post-kindling protection from anxiety and memory deficit was verified by a battery of behavioral experiments. Isolated brains were evaluated for oxidative alterations and real-time changes in mRNA expression for BDNF/TrkB, GAT-1 and GAT-3 as well as neuroinflammatory markers. Experimental results revealed that Tia at the dose of 2 mg/kg maximally inhibited the development of full bloom seizure and reduced epileptic spike discharges from the cortex. Furthermore, Tia dose-dependently exerted the anxiolytic effects and protected from PTZ-evoked cognitive impairment. Tia reduced lipid peroxidation and increased superoxide dismutase and glutathione levels in the brain via augmentation of GABAergic modulation. PTZ-induced upregulated BDNF/TrkB signaling and pro-inflammatory cytokines were mitigated by Tia with upregulation of GAT-1 and GAT-3 transporters in whole brains. In conclusion, the observed effects of Tia might have resulted from reduced oxidative stress, BDNF/TrkB modulation and mitigated neuroinflammatory markers expression leading to reduced epileptogenesis and improved epilepsy-related neuropsychiatric effects.

Phenytoin-associated movement disorder: A literature review

Phenytoin (PHT) was first synthesized as a barbiturate derivative and was approved in 1953 by the Food and Drug Administration. This work aimed to review the pathophysiology, epidemiology, clinical presentation, and treatment of PHT-associated movement disorders (MDs). Studies were searched in relevant databases (ScienceDirect, Google Scholar, Excerpta Medica, Latin American and Caribbean Health Sciences Literature, Medline, and Scientific Electronic Library Online) and were selected by two reviewers irrespective of language between 1963 and 2021. Papers of PHT-induced ataxia alone or tremor were excluded. In total, 127 reports with 219 individuals who developed MDs associated with PHT were encountered. MDs found: 126 dyskinesias, 49 myoclonus, 19 dystonia, 14 parkinsonism, 6 tics, 3 stuttering, and 2 restless legs syndrome. The mean age was 35 years (standard deviation [SD]: 23.5) and the predominant sex was male (53.4%). The mean PHT dose when the MD took place was 370.4 mg (SD: 117.5). A serum PHT concentration was reported in 103 cases, ranging from 4 to 110 μg/mL (median: 27.7 μg/mL). No significant relationship was found between PHT dose and age or PHT level. The mean onset time of PHT-associated MD was 23.4 months (SD: 4.4). The mean recovery time after MD management was 3.7 weeks (SD: 1.1). Regarding management, the most common form was PHT withdrawal in 90.4%. 86.3% of the individuals recovered fully. PHT-induced MD was extensively reported in the literature. Only general terms were used in the majority of the reports. The mechanisms underlying the adverse events caused by PHT probably depend on the presence of predisposing factors.

Movement disorders associated with antiseizure medications: A systematic review

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.

Movement Disorders Secondary to Novel Antiseizure Medications in Pediatric Populations: A Systematic Review and Meta-analysis of Risk

Novel antiseizure medications are thought to be safer than their conventional counterparts, though no dedicated analysis of movement disorder risk among pediatric populations using novel antiseizure medications has been completed. We report a systematic review with meta-analysis describing the relationship between novel antiseizure medications and movement disorders in pediatrics.MEDLINE, EMBASE, and the World Health Organization's International Clinical Trials Registry Platform were searched up to October 2020 for randomized controlled trials investigating novel antiseizure medications in pediatric populations. Antiseizure medications included lacosamide, perampanel, eslicarbazepine, rufinamide, fenfluramine, cannabidiol, and brivaracetam. Outcomes were pooled using random effects models; risk difference (RD) and 95% confidence intervals (CIs) were calculated.Twenty-three studies were selected from 1690 nonredundant manuscripts (n = 1912 total). There was a significantly increased risk of movement disorders associated with perampanel (RD 0.07, 95% CI 0.01-0.13; n = 133), though only 1 relevant trial was found. No increased risk of movement disorders was found with other antiseizure medications.Our findings indicate most novel antiseizure medications are safe to use in pediatric populations with respect to movement disorders. However, findings were limited by quality of adverse event reporting.

Differentiating tardive dyskinesia: a video-based review of antipsychotic-induced movement disorders in clinical practice

Accurate diagnosis and appropriate treatment of tardive dyskinesia (TD) are imperative, as its symptoms can be highly disruptive to both patients and their caregivers. Misdiagnosis can lead to incorrect interventions with suboptimal or even deleterious results. To aid in the identification and differentiation of TD in the psychiatric practice setting, we review its clinical features and movement phenomenology, as well as those of other antipsychotic-induced movement disorders, with accompanying links to illustrative videos. Exposure to dopamine receptor blocking agents (DRBAs) such as antipsychotics or antiemetics is associated with a spectrum of movement disorders including TD. The differential diagnosis of TD is based on history of DRBA exposure, recent discontinuation or dose reduction of a DRBA, and movement phenomenology. Common diagnostic challenges are the abnormal behaviors and dyskinesias associated with advanced age or chronic mental illness, and other movement disorders associated with DRBA therapy, such as akathisia, parkinsonian tremor, and tremor related to use of mood stabilizing agents (eg, lithium, divalproex). Duration of exposure may help rule out acute drug-induced syndromes such as acute dystonia or acute/subacute akathisia. Another important consideration is the potential for TD to present together with other drug-induced movement disorders (eg, parkinsonism, parkinsonian tremor, and postural tremor from mood stabilizers) in the same patient, which can complicate both diagnosis and management. After documentation of the phenomenology, severity, and distribution of TD movements, treatment options should be reviewed with the patient and caregivers.

Assessment of Risk Factors and Early Presentations of Parkinson Disease in Primary Care in a Diverse UK Population

IMPORTANCE

Early features of Parkinson disease (PD) have been described through population-based studies that overrepresent White, affluent groups and may not be generalizable.

OBJECTIVE

To investigate the association between risk factors and prediagnostic presentations of PD in an ethnically diverse UK population with high socioeconomic deprivation but universal access to health care.

DESIGN, SETTING, AND PARTICIPANTS

A nested case-control study was conducted using electronic health care records on 1 016 277 individuals from primary care practices in East London to extract clinical information recorded between 1990 and February 6, 2018. The data were analyzed between September 3, 2020, and September 3, 2021. Individuals with a diagnosis of PD were compared with controls without PD or other major neurological conditions.

MAIN OUTCOMES AND MEASURES

A matched analysis (10 controls matched for each patient with PD according to age and sex) and an unmatched analysis (adjusted for age and sex) were undertaken using multivariable logistic regression to determine associations between risk factors and prediagnostic presentations to primary care with subsequent diagnosis of PD. Three time periods (<2, 2-<5, and 5-10 years before diagnosis) were analyzed separately and together.

RESULTS

Of 1 016 277 individuals included in the data set, 5699 were excluded and 1055 patients with PD and 1 009 523 controls were included in the analysis. Patients with PD were older than controls (mean [SD], 72.9 [11.3] vs 40.3 [15.2] years), and more were male (632 [59.9%] vs 516 862 [51.2%]). In the matched analysis (1055 individuals with PD and 10 550 controls), associations were found for tremor (odds ratio [OR], 145.96; 95% CI, 90.55-235.28) and memory symptoms (OR, 8.60; 95% CI, 5.91-12.49) less than 2 years before the PD diagnosis. The associations were also found up to 10 years before PD diagnosis for tremor and 5 years for memory symptoms. Among midlife risk factors, hypertension (OR, 1.36; 95% CI, 1.19-1.55) and type 2 diabetes (OR, 1.39; 95% CI, 1.19-1.62) were associated with subsequent diagnosis of PD. Associations with early nonmotor features, including hypotension (OR, 6.84; 95% CI, 3.38-13.85), constipation (OR, 3.29; 95% CI, 2.32-4.66), and depression (OR, 4.69; 95% CI, 2.88-7.63), were also noted. Associations were found for epilepsy (OR, 2.5; 95% CI, 1.63-3.83) and hearing loss (OR, 1.66; 95% CI, 1.06-2.58), which have not previously been well reported. These findings were replicated using data from the UK Biobank. No association with future PD diagnosis was found for ethnicity or deprivation index level.

CONCLUSIONS AND RELEVANCE

This study provides data suggesting that a range of comorbidities and symptoms are encountered in primary care settings before PD diagnosis in an ethnically diverse and deprived population. Novel temporal associations were observed for epilepsy and hearing loss with subsequent development of PD. The prominence of memory symptoms suggests an excess of cognitive dysfunction in early PD in this population or difficulty in correctly ascertaining symptoms in traditionally underrepresented groups.

Fine motor impairment in children with epilepsy: Relations with seizure severity and lateralizing value

Motor skill deficits are common in epilepsy. The Grooved Pegboard Test (GPT) is the most commonly used fine motor task and is included in the NIH Common Data Elements Battery for the assessment of epilepsy. However, there are limited data on its utility in children and adolescents. The present study investigated the effectiveness of this task in children and adolescents with epilepsy clinically referred for neuropsychological evaluation in a tertiary medical center. Two hundred and two children and adolescents (ages 6-16, 104 males, 98 females) completed the GPT. Base rates of impairment were calculated, correlational analyses determined relations with clinical variables, and ANOVAs and t-tests assessed for differences by seizure type, gender, and lateralized deficits in those with lateralized focal epilepsy. The GPT was sensitive to fine motor impairment in these children and adolescents, with over 60% having impaired performances. Further, performance was significantly correlated with IQ, age of epilepsy onset, number of medications, and seizure frequency. At the group level, those with lateralized focal epilepsy did not show significant differences between left and right hands, though the GPT correctly lateralized 63% of those with large between-hand performance disparities (i.e., one standard deviation or greater). In sum, the GPT is sensitive to fine motor deficits in pediatric epilepsy and is related to known epilepsy severity factors. However, the ability of the task to lateralize epilepsy onset is not robust.

Investigation of the risk of valproic acid-induced tremor: clinical, neuroimaging, and genetic factors

RATIONALE

Investigation of associated risk factors of valproic acid (VPA)-induced tremor helped in increasing tolerance and optimizing treatment scheme individually.

OBJECTIVES

To determine the risk factors of VPA-induced tremor, with particular attention on identifying tremor-susceptible gene mutations.

METHODS

Epileptic patients taking VPA were divided into a tremor and a non-tremor groups. A mutation of rs9652490 in the leucine-rich repeat and immunoglobulin domain-containing Nogo-receptor-interacting protein 1 (LINGO-1) gene was determined by Sanger sequencing. Cerebellar atrophy was assessed, and various cerebellar dimensions were measured on magnetic resonance imaging (MRI) scans.

RESULTS

One hundred and eighty-one of 200 subjects were included. Multivariate regression analysis indicated several VPA-induced tremor-related factors: females (OR = 2.718, p = 0.014), family history of tremor (OR = 7.595, p = 0.003), treatment duration (> 24 months; OR = 3.294, p = 0.002), and daily dosage (> 1,000 mg/d; OR = 19.801, p = 0.008) of VPA. Chi-square tests revealed that treatment with VPA magnesium-ER (p = 0.030) and carbamazepine combination (p = 0.040) reduced the incidence of tremor. One hundred and seventy-six gene sequencing and 86 MRI results excluded any significant difference between the two groups in the mutation of rs9652490 within LINGO-1, the ratio of cerebellar atrophy or the cerebellar-dimension values (p > 0.05). However, mutation of rs9652490 within LINGO-1 was correlated with increased cerebellar atrophy (p = 0.001), reduced cerebellar hemisphere thickness (p = 0.025), and right cerebellar hemisphere longitudinal diameter (p = 0.047).

CONCLUSIONS

Our cohort indicated risk (female, positive family history of tremor, daily dosage > 1000 mg and treatment duration > 24 months of VPA) and protective factors (VPA magnesium-ER and combination with CBZ) of VPA-induced tremor. Mutation of rs9652490 within LINGO-1 correlated with cerebellar atrophy, neither was correlated with VPA-induced tremor.

Valproate-associated Movement Disorder: A Literature Review

Valproate (VPA) was first synthesized in 1882, but it was only in the early 1960s that its anticonvulsant properties were discovered. The aim of this literature review is to evaluate the clinical epidemiological profile, pathological mechanisms, and management of VPA-associated movement disorder (MD). Relevant reports in six databases were identified and assessed by two reviewers without language restriction. A total of 138 reports containing 362 cases of subjects who developed a MD secondary to VPA were reported. The MD identified were parkinsonism (PKN) (252), myoclonus (MCL) (54), dystonia (DTN) (17), dyskinesia (DKN) (16), stutters (4), tics (3), akathisia (AKT) (1). In the not clearly defined group, 15 extrapyramidal symptoms, 3 AKT, 2 DTN, 1 rigidity, 1 unstable gait were assessed. The mean and median age was 55.8 (SD: 16.58) and 61 years (range: 4-87 years). The most common VPA-indication was epilepsy, and 51.36% were males. The mean and median time from the VPA start to the MD onset was 32.75 (SD: 30.05) and 21.15 months (range: 1 day - 20 years). The mean and median time from the VPA withdrawal until the MD recovery was 2.89 (SD: 2.79) and 3 months (1 day - 12 months). The most common management was drug withdrawal. A complete recovery was obtained in 80.61%. VPA-associated MD was extensively reported in the literature. PKN was the most well-described. Future studies need to clearly report the clinical history of the patient, considering the full investigation of other adverse events during their entire life.

Clinical and Kinematic Features of Valproate-Induced Tremor and Differences with Essential Tremor

Tremor is a common movement disorder that can be induced by medications, including valproate, which is used for the treatment of epilepsy. However, the clinical and neurophysiological features of valproate-induced tremor are still under-investigated. We performed a clinical and kinematic assessment of valproate-induced tremor by considering tremor body distribution and activation conditions. We investigated possible correlations between demographic and clinical data and kinematic features. Valproate-induced tremor results were also compared with those collected in a large sample of patients with essential tremor. Sixteen valproate-induced tremor patients and 93 essential tremor patients were enrolled. All participants underwent a standardised neurological examination and video recording. Patients also underwent an objective assessment of postural, kinetic and rest tremor of the upper limbs and head tremor through kinematic analysis. Nonparametric tests were used for statistical comparisons between the two groups. Clinical evaluation showed a higher occurrence of rest tremor as well as head or voice, and lower limb involvement in patients with valproate-induced tremor. Kinematic analysis showed a substantial variability in the tremor features of patients with valproate-induced tremor. Compared to essential tremor, we found a higher occurrence of rest tremor of the upper limbs and the involvement of more body segments in valproate-induced tremor patients. Valproate-induced tremor has distinctive clinical and kinematic features, which may suggest that valproate interferes with the cerebellar functions.

Valproate-induced rest tremor and parkinsonism

Tremor and parkinsonism are recognized side effects of valproate; however, the relationship between rest tremor and other signs of parkinsonism has not been addressed in patients taking valproate. We studied a cohort of 125 consecutive patients treated with valproate due to epilepsy or migraine, evaluated with the Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS). A total of 14 (11.2%) patients had rest tremor (bilateral n = 10, unilateral n = 4). Patients with rest tremor had significant higher scores in the FTM-TRS (P < 0.001), but only one was diagnosed with parkinsonism. Patients may have valproate-induced parkinsonism or exacerbated motor features of Parkinson's disease by valproate. The frequency of parkinsonism was 1.6% in this cohort and of 3% in the pooled data of 717 patients from previous reports. Rest tremor is observed in 11.2% of patients treated with valproate and is related to the burden of valproate-induced tremor, rather than the presence of parkinsonism.

Treatment of tardive dyskinesia: a review and update for dermatologists managing delusions of parasitosis

INTRODUCTION

This article introduces to the dermatology provider two medications for the treatment of tardive dyskinesia (TD), which were the first medications approved by the US FDA specifically for the treatment of TD. In addition to describing these two new medications, this article will also provide a focused review of the pathogenesis of TD, as well as non-FDA-approved treatments, which have been tried prior to the advent of these medications.

METHODS

A PubMed search was conducted and articles were reviewed by the senior authors and included if they were relevant for dermatologists regarding etiology, symptoms, risk, and treatment of TD.

RESULTS

One of the most widely accepted explanations of TD involves the concept of 'dopamine receptor hypersensitivity state.' There are several other less well substantiated proposed pathogenic pathways of TD. The clinical manifestation is characterized by involuntary movements. Prevention includes switching to a 2nd generation agent or using the lowest dose possible for the shortest amount of time. Two new FDA-approved medications for TD are also discussed and reviewed.

CONCLUSION

TD now has FDA-approved medications for treatment. Now, there is even more reason for the dermatologist to have increased confidence when treating delusions of parasitosis (DOP) with antipsychotic agents.

Paroxysmal Genetic Movement Disorders and Epilepsy

Paroxysmal movement disorders include paroxysmal kinesigenic dyskinesia, paroxysmal non-kinesigenic dyskinesia, paroxysmal exercise-induced dyskinesia, and episodic ataxias. In recent years, there has been renewed interest and recognition of these disorders and their intersection with epilepsy, at the molecular and pathophysiological levels. In this review, we discuss how these distinct phenotypes were constructed from a historical perspective and discuss how they are currently coalescing into established genetic etiologies with extensive pleiotropy, emphasizing clinical phenotyping important for diagnosis and for interpreting results from genetic testing. We discuss insights on the pathophysiology of select disorders and describe shared mechanisms that overlap treatment principles in some of these disorders. In the near future, it is likely that a growing number of genes will be described associating movement disorders and epilepsy, in parallel with improved understanding of disease mechanisms leading to more effective treatments.

Risk of Valproic Acid-Related Tremor: A Systematic Review and Meta-Analysis

Purpose: To evaluate the incidence and risk of tremor in patients treated with valproic aid (VPA) monotherapy.

Methods: We searched the PubMed, Embase, and Cochrane Library databases to gather relevant data on tremor in patients taking VPA and other drugs and performed a meta-analysis using Stata15.1 software.

Results: Twenty-nine randomized controlled trials (RCTs) met the inclusion criteria and were included in the meta-analysis. The overall incidence of tremor in patients receiving VPA therapy was 14% [OR = 0.14, 95% CI (0.10–0.17)]. The pooled estimate risk of tremor showed a significant difference between patients treated with VPA and all other drugs [OR = 5.40, 95% CI (3.22–9.08)], other antiepileptic drugs (AEDs) [OR = 5.78, 95% CI (3.18–10.50)], and other non-AEDs [OR = 4.77, 95% CI (1.55–14.72)]. Both a dose of <1,500 mg/d of VPA [included 500 mg/d: OR = 3.57, 95% CI (1.24–10.26), 500–999 mg/d: OR = 3.99, 95% CI (1.95–8.20), 1,000–1,499 mg/d: OR = 8.82, 95% CI (3.25–23.94)] and a VPA treatment duration of <12 m [included ≤ 3 months: OR = 3.06, 95% CI (1.16–8.09), 3–6 months: OR = 16.98, 95% CI (9.14–31.57), and 6–12 months: OR = 4.15, 95% CI (2.74–6.29)] led to a higher risk of tremor than did other drugs, as did higher doses and longer treatment times.

Conclusion: Compared with other drugs, VPA led to a higher risk of tremor, and the level of risk was associated with the dose and duration of treatment.

Prevalence of Extrapyramidal Symptoms in In-Patients With Severe Mental Illnesses: Focus on Parkinsonism

Patients with severe mental illnesses may present extrapyramidal symptoms as part of a concomitant neurological disorder or secondary to medications. Extrapyramidal symptoms are frequently unrecognized, have negative consequences for adherence to treatment, negatively affect quality of life and can induce stigma. We estimated and correlated with demographic and clinical variables prevalence of extrapyramidal symptoms in in-patients with severe mental illnesses. Additionally we evaluated ¹²³I-FP-CIT SPECT binding to striatal dopamine transporter in subjects with clinical manifestations suggestive of Parkinson's Disease and recorded therapeutic management and clinical evolution for 6-months. Extrapyramidal symptoms were present in 144 out of 285 patients (50.5%), mainly tremor (94 patients, 33%). There were 38 patients (13.3%) with parkinsonism and they had older age, more medical comorbidities and medical treatments. In 15/38 patients striatal dopamine transporter binding was abnormal resulting in dose reduction or change of psychotropic drugs as well as combination with antiparkinson therapy. Our study confirmed the clinical and epidemiological relevance of extrapyramidal symptoms among inpatients with severe mental illnesses. A small percentage of patients with extrapyramidal symptoms had features compatible with possible diagnosis of Parkinson's Disease. ¹²³I-FP-CIT SPECT was useful to identify dopaminergic dysfunction and initiate dopamine replacement therapy.

Clinical Spectrum of Drug-Induced Movement Disorders: A Study of 97 Patients

Background:

Drug-induced movement disorders (DIMDs) are commonly encountered, but an often-under-reported subgroup of movement disorders.

Objectives:

We aimed to highlight the spectrum of DIMDs in patients taking different groups of drugs at our movement disorder center.

Methods:

It is a cross-sectional descriptive study including 97 consecutive DIMDs patients diagnosed over the past two years (2017–2019).

Results:

The mean ± standard deviation (SD) age of our study population was 35.89 ± 17.8 years (Range-2–80 years). There were 51 males and 46 females. Different DIMDs observed included tardive dystonia (n = 41; 42.2%), postural tremor (n = 38; 39.2%), parkinsonism (n = 32; 33%), tardive dyskinesia (n = 21; 21.6%), acute dystonia (n = 10; 10.3%), neuroleptic malignant syndrome (NMS) (n = 2; 2.1%), and others [(n = 10; 10.30%) including chorea and stereotypy each in 3; acute dyskinesia in 2; and myoclonic jerks and acute akathisia each in 1 patient]. Of these 97 patients, 49 had more than one type of DIMDs while 48 had a single type of DIMDs. In our study 37 (38%) patients had received non-dopamine receptor blocking agents (non-DRBA), 30 (31%) patients had received dopamine receptor blocking agents (DRBA), and 30 (31%) patients had received both DRBA and non-DRBA.

Conclusions:

Tardive dystonia was the most common DIMDs observed in our study. Our DIMDs patients were younger than other reported studies. We observed a significant number of non-DRBA drugs causing DIMD in our study as compared to previous studies. Drug-induced parkinsonism (DIP) was the most common DIMDs in the DRBA group. Tardive dystonia was the most common DIMDs seen in DRBA + non-DRBA group and the second most common in the DRBA and non-DRBA group. The postural tremor was the most common DIMDs in the non-DRBA group.

Topiramate-Associated Movement Disorder: Case Series and Literature Review

BACKGROUND

Topiramate (TPM) is a fructose derivative, which was originally developed as an antiepileptic. In this context, movement disorders (MDs) are possible adverse events secondary to TPM.

CASE REPORTS

Two patients (cases 1 and 2) developed myoclonus, and the other 2 had restless leg syndrome (RLS, cases 3 and 4). The mean age of the individuals (3 female patients) was 45.75 ± 21.28 years. All the individuals had a negative family history for movement and psychiatry disorders. Topiramate was started at 25 mg with a gradual increase of 25 mg every week. The mean time of onset and recovery of the MD were 1.37 ± 1.10 and 1.02 ± 0.77 months, respectively. The mean TPM dose was 87.5 ± 47.87 mg. Individual 1 presented with upper and lower limb jerks; individual 2 only with upper limb involvement. Individuals 3 and 4 experienced insomnia and nocturnal leg discomfort during inactivity with an urge to move the legs, which they denied having previously; the RLS symptoms occurred within approximately 1 to 3 hours of TPM evening dose. On neurological examination, no tremor or bradykinesia was observed; deep tendon reflexes, sensory examination, and strength were normal and preserved. Laboratory tests, neuroimaging, and electromyography were within normal. Topiramate was discontinued in all of the subjects. Full recovery was obtained in all cases.

CONCLUSIONS

To the authors' knowledge, there are 6 cases of myoclonus, 5 RLS, 2 dystonia, 1 dyskinesia, and 1 periodic limb MD. The best management is probably the discontinuation of TPM, but in RLS patients, the addition of a dopaminergic agonist can be beneficial.

A case of dyskinesia after levetiracetam administration

Background

Antiepileptic drug (AED) induced dyskinesia is an unusual manifestation in the medical field. In the previous case reports describing first generation-AED related involuntary movements, the authors suggested that a plausible cause is pharmacokinetic interactions between two or more AEDs. To date, development of dyskinesia after levetiracetam (LEV) has not been reported.

Case presentation

A 28-year-old woman with a history of brain metastasis from spinal cord glioblastoma presented with several generalized tonic-clonic seizures without restored consciousness. LEV was administered intravenously. Thereafter no more clinical or electroencephalographic seizures were noted on video-EEG monitoring, while chorea movement was observed in her face and bilateral upper limbs.

Discussion and conclusions

To our knowledge, there is no case report of dyskinesia after administration of LEV. Considering the temporal relationship and absence of ictal video-EEG findings, we suggest that development of choreoathetosis was closely associated with the undesirable effects of LEV. We propose that dopaminergic system dysregulation and genetic susceptibility might underlie this unusual phenomenon after LEV treatment.

Neurobiological perspective of 22q11.2 deletion syndrome

22q11.2 deletion syndrome is characterised by a well defined microdeletion that is associated with a high risk of neuropsychiatric disorders, including intellectual disability, schizophrenia, attention-deficit hyperactivity disorder, autism spectrum disorder, anxiety disorders, seizures and epilepsy, and early-onset Parkinson's disease. Preclinical and clinical data reveal substantial variability of the neuropsychiatric phenotype despite the shared underlying deletion in this genetic model. Factors that might explain this variability include genetic background effects, additional rare pathogenic variants, and potential regulatory functions of some genes in the 22q11.2 deletion region. These factors might also be relevant to the pathophysiology of these neuropsychiatric disorders in the general population. We review studies that might provide insight into pathophysiological mechanisms underlying the expression of neuropsychiatric disorders in 22q11.2 deletion syndrome, and potential implications for these common disorders in the general (non-deleted) population. The recurrent hemizygous 22q11.2 deletion, associated with 22q11.2 deletion syndrome, has attracted attention as a genetic model for common neuropsychiatric disorders because of its association with substantially increased risk of such disorders.¹ Studying such a model has many advantages. First, 22q11.2 deletion has been genetically well characterised.² Second, most genes present in the region typically deleted at the 22q11.2 locus are expressed in the brain.^3-5 Third, genetic diagnosis might be made early in life, long before recognisable neuropsychiatric disorders have emerged. Thus, this genetic condition offers a unique opportunity for early intervention, and monitoring individuals with 22q11.2 deletion syndrome throughout life could provide important information on factors contributing to disease risk and protection. Despite the commonly deleted region being shared by about 90% of individuals with 22q11.2 deletion syndrome, neuropsychiatric outcomes are highly variable between individuals and across the lifespan. A clear link remains to be established between genotype and phenotype.^3,5 In this Review, we summarise preclinical and clinical studies investigating biological mechanisms in 22q11.2 deletion syndrome, with a focus on those that might provide insight into mechanisms underlying neuropsychiatric disorders in 22q11.2 deletion syndrome and in the general population.

Medication prescriptions in 322 motor functional neurological disorder patients in a large UK mental health service: A case control study

OBJECTIVE

This study describes medication prescribing patterns in patients with motor functional neurological disorder (mFND) treated in South London and Maudsley NHS Foundation Trust (SLaM), comparing outcomes to a control group of psychiatric patients from the same hospital trust.

METHOD

This is a retrospective case-control study using a psychiatric case register. Cross-sectional data were obtained from 322 mFND patients and 644 psychiatry controls who had had contact with SLaM between 1st January 2006 and 31st December 2016.

RESULTS

A slightly lower proportion of mFND patients received medication compared to controls (76.6% v. 83.4%, OR: 0.59, CI: 0.39-0.89, p < 0.05). Of medication recipients, mFND patients were prescribed a higher number of agents (mean: 4.7 v 2.9, p = 0.001) and had higher prescription rates of antidepressants, anti-epileptics, analgesics, and certain non-psychotropic medications. Higher numbers of prescriptions were associated with co-morbid physical conditions, and previous psychiatric admissions.

CONCLUSIONS

This is the first study to describe medication prescriptions in a large cohort of mFND patients. Patients were prescribed a wide range of psychiatric and physical health medications, with higher rates of polypharmacy than controls. Psychotropic medication prescription is not necessarily the first line treatment for mFND, where physiotherapy and psychotherapy may be offered initially. There is limited, early-phase evidence for pharmacological therapies for mFND, and as such, the benefit-to-risk ratio of prescribing in this complex and poorly understood disorder should be carefully assessed.

The clinical characteristics and related factors of tremor in patients with epilepsy

PURPOSE

Tremor is frequently observed in patients with epilepsy (PWE), which is generally attributed to the side-effect of antiepileptic drugs (AEDs) particularly valproate (VPA) with largely unknown mechanisms. The study aimed to assess the clinical features and related factors of tremor in PWE with tremor.

METHODS

PWE with tremor and a control group of age- and sex-matched PWE without tremor were enrolled. Detailed demographic and clinical information for each individual was recorded. PWE with tremor were evaluated by The Clinical Rating Scale for Tremor (CRST) and Tremor Related Activities of Daily Living (TRADL) questionnaire.

RESULTS

132 individuals were enrolled, which including sixty-six (36 males) PWE with tremor with mean age of 33 years and epilepsy duration of 12.5 years. Tremor was postural in all, with median duration of four and one year from diagnosis and AED treatment to the onset of tremor respectively. The upper limbs were predominantly affected. VPA had been used in 62 (93.9%) PWE with tremor compared to 31 (47.0%) PWE without tremor (P < 0.001). The total CRST score was significantly associated with epilepsy duration and maximum VPA dosage (B = 0.30, p < 0.001; B = 0.32, p = 0.013). Patients with VPA dosage over 17.05 mg/kg/d might be more vulnerable to develop tremor.

CONCLUSIONS

PWE with tremor were more frequently treated with VPA, however, tremor was mild in most without any functional impairment. Epilepsy duration and maximum VPA dosage were important factors of tremor severity, suggesting mechanisms underlying tremor in PWE may be an elaborate interplay of AEDs and disease itself.

Disabling Resting Tremors Induced by the Short-term Infusion of Valproate: A Reversible Phenomenon

Background

Drug-induced tremors after long-term administration of anti-epileptics have been described in the literature. Such tremors are usually postural or action in nature with infrequent resting nature.

Case Report

A 23-year-old female presented in status epilepticus. Past and family histories were negative for seizures. She was managed per protocol with valproate. Within hours, she developed resting tremors. The tremors subsided on changing the anti-epileptic.

Discussion

Resting tremors have mostly been described in the literature as long-term side-effects of valproate. This case illustrates that even short-term infusion of valproate can cause resting tremors.

Tardive Dyskinesia-like Syndrome Due to Drugs that do not Block Dopamine Receptors: Rare or Non-existent: Literature Review

Background

Although tardive dyskinesia (TD) is most commonly defined as a movement disorder caused by chronic exposure to dopamine‐receptor‐blocking drugs (DRBDs), it has also been thought to result from exposure to some non‐DRBDs.

Methods

We critiqued many reviews making the association between non‐DRBDs and a TD‐like syndrome and almost all case reports. We checked whether cases met criteria for the diagnosis of TD‐like syndrome and whether DRBDs had been excluded.

Results

We found that both tricyclic antidepressants and selective serotonin reuptake inhibitor antidepressants may unmask or exacerbate TD after prior exposure to or with concurrent use of DRBDs. We found support for its existence outside of this context to be extremely weak.

Discussion

There is little evidence that drugs other than DRBDs by themselves cause a TD syndrome; most reported cases appear to occur as a result of a “priming” effect induced by a DRBD, which is later unmasked.

Systematic integration of biomedical knowledge prioritizes drugs for repurposing

The ability to computationally predict whether a compound treats a disease would improve the economy and success rate of drug approval. This study describes Project Rephetio to systematically model drug efficacy based on 755 existing treatments. First, we constructed Hetionet (neo4j.het.io), an integrative network encoding knowledge from millions of biomedical studies. Hetionet v1.0 consists of 47,031 nodes of 11 types and 2,250,197 relationships of 24 types. Data were integrated from 29 public resources to connect compounds, diseases, genes, anatomies, pathways, biological processes, molecular functions, cellular components, pharmacologic classes, side effects, and symptoms. Next, we identified network patterns that distinguish treatments from non-treatments. Then, we predicted the probability of treatment for 209,168 compound-disease pairs (het.io/repurpose). Our predictions validated on two external sets of treatment and provided pharmacological insights on epilepsy, suggesting they will help prioritize drug repurposing candidates. This study was entirely open and received realtime feedback from 40 community members.

The clinical features and functional impact of valproate-induced tremor

BACKGROUND

Tremor is a known side-effect of anticonvulsants, particularly of valproate. However, there is a dearth of information regarding detailed clinical features and functional impact of valproate-induced tremor.

METHODS

We studied a cohort of patients treated with anticonvulsants for neurological disorders, through blinded evaluations using the Clinical Rating Scale for Tremor (CRST); we compared the frequency, severity and functional impact of drug-induced tremor between patients treated with valproate and those treated with other anticonvulsants.

RESULTS

From a cohort of 218 consecutive patients, 171 were fully evaluated; 118 patients were taking valproate alone or combined with other anticonvulsants and 53 patients were taking other anticonvulsants. Mean age (±SD) at evaluation of the cohort was 32 ± 13 years, females represented 55.6% of cases. Tremor was more frequently observed in patients taking valproate particularly postural upper limb tremor: 49% vs. 15% (right-side) (P < 0.001) and 48.3% vs. 13.2% (left-side), (P < 0.001); had a higher total CRST score: 12.14 vs. 3.06 (P < 0.001), and required more frequently treatment for drug-induced tremor: 23.7% vs. 5.6% (P=0.005) compared with patients taking other anticonvulsants. Among 118 patients taking valproate, women had a higher total CRST score compared with men: 14.54 ± 14.9 vs. 9.56 ± 9.55 (P=0.034). A weak correlation between the total CRST score, dose per Kg of valproate and serum levels of valproate were observed.

CONCLUSIONS

Tremor is frequently observed in patients taking valproate and is severe enough to require treatment in about 24% of cases.

Neuropsychiatric Complications of Parkinson Disease Treatments: Importance of Multidisciplinary Care

Although Parkinson disease (PD) is defined clinically by its motor symptoms, it is increasingly recognized that much of the disability and worsened quality of life experienced by patients with PD is attributable to psychiatric symptoms. The authors describe a model of multidisciplinary care that enables these symptoms to be effectively managed. They describe neuropsychiatric complications of PD itself and pharmacologic and neurostimulation treatments for parkinsonian motor symptoms and discuss the management of these complications. Specifically, they describe the clinical associations between motor fluctuations and anxiety and depressive symptoms, the compulsive overuse of dopaminergic medications prescribed for motor symptoms (the dopamine dysregulation syndrome), and neuropsychiatric complications of these medications, including impulse control disorders, psychosis, and manic syndromes. Optimal management of these problems requires close collaboration across disciplines because of the potential for interactions among the pathophysiologic process of PD, motor symptoms, dopaminergic drugs, and psychiatric symptoms. The authors emphasize how their model of multidisciplinary care facilitates close collaboration among psychiatrists, other mental health professionals, neurologists, and functional neurosurgeons and how this facilitates effective care for patients who develop the specific neuropsychiatric complications discussed.

A Complex Hyperkinesia Induced by Valproate

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Acute movement disorders in the medical setting

Objective Psychosomatic medicine psychiatrists are often tasked with the evaluation and treatment of complex neuropsychiatric states which may be motoric in phenotype. Little energy has been dedicated to understanding acute movement disorders in the hospital environment. Method Recognizing the importance of frontal-subcortical (corticostriatothalamocortical) circuitry and basal ganglia structures, we present a case series of acute movement disorder phenotypes resulting from underlying medical conditions, commonly-administered medications, or the interaction of both. We organize these scenarios into neurodegenerative disorders, primary psychiatric disorders, neuroinflammation, and polypharmacy, demonstrating a clinical example of each followed by background references on a variety of clinical states and medications contributing to acute movement disorders. In addition, we offer visual illustration of implicated neurocircuitry as well as proposed neurotransmitter imbalances involving glutamate, gamma aminobutyric acid, and dopamine. Furthermore, we review the various clinical syndromes and medications involved in the development of acute movement disorders. Results Acute movement disorder's involve complex interactions between frontal-subcortical circuits and acute events. Given the complexity of interactions, psychopharmacological considerations become critical, as some treatments may alleviate acute movement disorders while others will exacerbate them. Conclusion Integrating underlying medical conditions and acutely administered (or discontinued) pharmacological agents offers an interactional, neuromedical approach to acute movement disorders that is critical to the work of psychosomatic medicine.

Valproate-Associated Parkinsonism: A Critical Review of the Literature

Valproate was first approved as an antiepileptic drug in 1962 and has since also become established as a mood stabiliser and as prophylaxis for migraine. In 1979, Lautin published the first description of a valproate-associated extrapyramidal syndrome. Many cases of valproate-associated parkinsonism have subsequently been published, but uncertainties remain concerning its prevalence, risk factors and prognosis. The aim of this paper is to provide a critical review of the existing literature on valproate-associated parkinsonism and to discuss possible mechanisms. Literature databases were searched systematically: we identified a total of 116 patients with valproate-associated parkinsonism published in case reports, case series and systematic analyses. Prevalence rates ranged widely, between 1.4 and 75 % of patients taking valproate. There was great heterogeneity with regard to clinical presentation, age of onset, valproate dose, concomitant conditions and imaging findings. In all patients apart from three, valproate plasma concentrations were within or even below the recommended reference range when the parkinsonism occurred. Parkinsonism was reversible in the majority of patients, although recovery was often prolonged and sometimes incomplete. A dopaminergic deficit was confirmed in three of six patients investigated with dopamine transporter imaging. Seven of 14 patients who were treated with dopaminergic medication had a good response. The quality of the evidence was assessed and probability of causation was examined using the Naranjo score, which ranged from 0 to 7 (median: 5.0). Several pathophysiological mechanisms, including altered gene expression and neurotransmitter signalling, enhanced neurodegeneration or unmasking subclinical dopaminergic degeneration, could theoretically lead to valproate-associated parkinsonism. Further studies are warranted to elucidate this entity and its underlying pathophysiology.

Lithium Use in Older Adults is Associated with Increased Prescribing of Parkinson Medications

OBJECTIVE

To test the hypothesis of an increased incidence of antiparkinson drug prescribing or Parkinson disease (PD) diagnostic codes after chronic lithium treatment compared with chronic valproic acid or antidepressant treatment among older adults.

METHODS

A retrospective cohort study using healthcare administrative databases in Ontario, Canada included 1,749 lithium users, 1,787 valproic acid users, and 285,154 other antidepressant users ≥ 66 years old having used the drug continuously in monotherapy for at least 1 year. Outcome measures were start of (1) a dopaminergic medication (levodopa or a dopamine agonist), (2) any antiparkinson drug (levodopa, dopamine agonists, anticholinergic medication, amantadine, monoamine oxidase B inhibitors), (3) any antiparkinson drug or a diagnostic code for PD, and (4) any antiparkinson drug in the absence of a diagnostic code for PD.

RESULTS

For patients with no previous antipsychotic use, lithium monotherapy was associated with an increased incidence of dopaminergic drug use (adjusted HR: 1.87; 95% CI: 1.06-3.30) and an increased incidence of antiparkinson drug use or a PD diagnosis (adjusted HR: 1. 68; 95% CI: 1.13-2.48) compared with antidepressant monotherapy.

CONCLUSION

Chronic lithium use is associated with an increased incidence of dopaminergic drug use compared with antidepressants, identifying a prescribing cascade related to lithium use in the elderly. Whether this reflects inappropriate treatment of action tremor or treatment of drug-induced parkinsonism should be addressed by a close examination of prescribing practices.

The long-term safety of antiepileptic drugs

Antiepileptic drugs (AEDs) are used by millions of people worldwide for the treatment of epilepsy, as well as in many other neurological and psychiatric conditions. They are frequently associated with adverse effects (AEs), which have an impact on the tolerability and success of treatment. Half the people who develop intolerable AEs discontinue treatment early on after initiation, while the majority of people will continue to be exposed to their effects for long periods of time. The long-term safety of AEDs reflects their potential for chronic, cumulative dose effects; rare, but potentially serious late idiosyncratic effects; late, dose-related effects; and delayed, teratogenic or neurodevelopmental effects. These AEs can affect every body system and are usually insidious. With the exception of delayed effects, most other late or chronic AEs are reversible. To date, there is no clear evidence of a carcinogenic effect of AEDs in humans. While physicians are aware of the long-term AEs of old AEDs (the traditional liver enzyme-inducing AEDs and valproate), information about AEs of new AEDs (such as lamotrigine, levetiracetam, oxcarbazepine, topiramate or zonisamide), particularly of their teratogenic effects, has emerged over the years. Sporadic publications have raised issues about AEs of the newer AEDs eslicarbazepine, retigabine, rufinamide, lacosamide and perampanel but their long-term safety profiles may take years to be fully appreciated. Physicians should not only be aware of the late and chronic AEs of AEDs but should systematically enquire and screen for these according to the individual AED AE profile. Care should be taken for individuals with comorbid conditions that may render them more susceptible to specific AEs. Prevention and appropriate management of long-term AED AEs is expected to improve adherence to treatment, quality of life and control of epilepsy.

Valproic acid-induced parkinsonism: levodopa responsiveness with dyskinesia

BACKGROUND

Valproic acid is a drug used for the treatment of a variety of psychiatric and neurological disorders. While it is well known to cause postural tremor, hyperammonemia, slowness, and sedation, it has also been described to occasionally cause a reversible form of parkinsonism.

MATERIALS AND METHODS

A series of five cases is reported.

RESULTS

All patients were taking the drug for at least several months before onset of their parkinsonian symptoms. Parkinsonism was defined by the presence of bradykinesia, rigidity, postural instability, and resting tremor, but not postural or action tremor. After discontinuing their valproic acid, improvement was seen by all patients. The course of improvement took days to months after discontinuance. Two of these patients responded to dopaminergic therapy, with drug-induced dyskinesia observed in one. In another patient, valproic acid was thought to unmask underlying Parkinson's Disease; this patient benefited from levodopa as well.

CONCLUSION

Valproic acid-induced parkinsonism can look identical to idiopathic parkinsonism. In all five cases, the relationship between the valproic acid use and parkinsonism was initially unclear because of the delayed and insidious onset. Our finding of levodopa responsiveness and dyskinesia added to the diagnostic confusion. This treatment responsiveness also set it apart from neuroleptic-induced parkinsonism. In all cases improvement of symptoms occurred after discontinuation of the offending medication.

[Not Available]

BACKGROUND/OBJECTIVE

Antipsychotic use in children is increasing. The purpose of the present article is to provide guidance to clinicians on the clinical management of extrapyramidal side effects of second-generation antipsychotics.

METHODS

Published literature, key informant interviews, and discussions with panel members and stakeholder partners were used to identify key clinical areas of guidance and preferences on format for the present recommendations. Draft recommendations were presented to a guideline panel. Members of the guideline panel evaluated the information gathered from the systematic review of the literature and used a nominal group process to reach a consensus on treatment recommendations. A description of the neurological abnormalities commonly seen with antipsychotic medications is provided, as well as recommendations on how to examine and quantify these abnormalities. A stepwise approach to the management of neurological abnormalities is provided.

RESULTS

Several different types of extrapyramidal symptoms can be seen secondary to antipsychotic use in children including neuroleptic-induced acute dystonia, neuroleptic-induced akathisia, neuroleptic-induced parkinsonism, neuroleptic-induced tardive dyskinesia, tardive dystonia and tardive akathisia, and withdrawal dyskinesias. The overwhelming majority of evidence on the treatment of antipsychotic-induced movement disorders is derived from adult patients with schizophrenia. Given the scarcity of paediatric data, recommendations were made with reference to both the adult and paediatric literature. Given the limitations in the generalizability of data from adult subjects to children, these recommendations should be considered on the basis of expert opinion, rather than evidence based.

CONCLUSION

Clinicians must be aware of the potential of second-generation antipsychotics to induce neurological side effects, and should exercise a high degree of vigilance when prescribing these medications.

Tremor: clinical phenomenology and assessment techniques

BACKGROUND

Tremors are among the most common movement disorders. As there can be considerable variability in the manner in which clinicians assess tremor, objective quantitative tools such as electromyography, accelerometry, and computerized, spiral analysis can be very useful in establishing a clinical diagnosis and in research settings.

METHODS

In this review, we discuss the various methods of quantitative tremor analysis and the classification and pathogenesis of tremor. The most common pathologic tremors and an approach to the diagnosis of tremor etiology are described.

CONCLUSIONS

Pathologic tremors are common, and the diagnosis of underlying etiology is not always straightforward. Computerized quantitative tremor analysis is a valuable adjunct to careful clinical evaluation in distinguishing tremulous diseases from physiologic tremors, and can also help shed light on their pathogenesis.