Patient selection and injection techniques for botulinum neurotoxin in oromandibular dystonia.

Oromandibular dystonia (OMD) is a form of focal dystonia that involves the masticatory, lower facial, labial, and lingual musculature. It is a disabling disorder which had limited treatment options until the recent introduction of botulinum toxin (BoNT) as the recommended first-line therapy by most experts and evidence-based literature. Owing to the complex relationship between the muscles of mastication and surrounding muscles, there is a wide variety of dynamic clinical presentations, making clinical recognition and the corresponding approach to BoNT injection therapy difficult. In this review, the authors provide a framework for practical clinical approaches, beginning with the recognition of clinical subtypes of OMD (jaw-opening, jaw-closing, jaw-deviating, lingual, peri-oral, and/or pharyngeal dystonias), followed by patient selection and clinical evaluation to determine function interferences, with injection techniques illustrated for each subtype. Careful stepwise planning is recommended to identify the muscles that are primarily responsible and employ a conservative approach to dosing titration. Treating physicians should be diligent in checking for adverse events, especially for the first few injection cycles, as muscles involved in OMD are small, delicate, and situated in close proximity. It is recommended that future studies should aim to establish the clinical efficacy of each subtype, incorporating muscle targeting techniques and patient-centred outcome measures that are related to disturbed daily functions.

Medications used to treat tremors.

Tremor is one of the most common movement disorders, though it can arise in the context of several unrelated neurological disorders whose pharmacology and anatomical origins differ greatly. Treatment of tremors can take advantage of several medications and neurosurgical treatments. Medications useful for treating tremor are discussed in this review, including those for action tremor as seen in essential tremor, the resting tremor of Parkinson's disease, orthostatic tremor, cerebellar tremor, Holmes tremor, dystonic tremor, and drug-induced tremors. A medication that is useful for most types of tremors is the beta-blocker propranolol, though even in essential tremor it can fail to be effective at tremor control. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.

Parkinsonism in viral, paraneoplastic, and autoimmune diseases.

Secondary parkinsonism, namely parkinsonism due to causes other than idiopathic neurodegeneration, may have multiple etiologies. Common secondary etiologies of parkinsonism such as drug-induced or vascular etiologies are well documented. Other secondary causes of parkinsonism such as infectious (mainly viral and prion-like diseases), autoimmune (systemic/drug-induced) and paraneoplastic etiologies are rare but are a topic of increasing interest. Older examples from the existing literature demonstrate the intricacies of viral infection from the last pandemic of the 20th century on the development of hypokinetic symptoms experienced in post-encephalitic patients. Viral and prion-like infections are only part of a complex interplay between the body's immune response and aberrant cell cycle perturbations leading to malignancy. In addition to the classic systemic autoimmune diseases (mainly systemic lupus erythematosus - SLE, and Sjögren syndrome), there have been new developments in the context of the current COVID-19 pandemic as well as more prominent use of immunotherapies such as immune checkpoint inhibitors in the treatment of solid tumors. Both of these developments have deepened our understanding of the underlying pathophysiologic process. Increased awareness and understanding of these rarer etiologies of parkinsonism is crucial to the modern diagnostic evaluation of a patient with parkinsonian symptoms as the potential treatment options may differ from the conventional levodopa-based therapeutic regimen of idiopathic Parkinson's disease. This review article aims to give an up-to-date review of the current literature on parkinsonian symptoms, their pathogenesis, diagnostic methods, and available treatment options. Many potential future directions in the field of parkinsonian conditions remain to be explored. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Expanding phenomenologic heterogeneity of tardive syndromes: Time for an updated assessment tool.

Tardive syndromes (TDS) are a group of hyperkinetic and hypokinetic movement disorders that occurs after exposure to dopamine receptor blocking agents such as antipsychotic and antiemetic drugs. The Abnormal Involuntary Movement Scale (AIMS) is a widely used instrument that has become the standard for assessment of tardive dyskinesia (TDD), the most common form of TDS. However, the AIMS has a number of clinimetric limitations and was designed primarily to assess the anatomic distribution and severity of involuntary movements without regard to phenomenology. To build on recent advances in understanding and treatment of TDS, re-evaluation and revision of the AIMS that could aid both clinical practice and research may be worthwhile. Challenges, such as retaining the efficiency of the current AIMS, incorporating evaluation of impairment in daily activities, and re-training clinicians for a revised examination procedure and rating instrument, are very likely surmountable.

Orally inhaled levodopa (CVT-301) for early morning OFF periods in Parkinson's disease.

BACKGROUND: CVT-301 (Inbrija) is a self-administered orally inhaled levodopa approved for the intermittent treatment of OFF episodes in patients with Parkinson's disease (PD) treated with carbidopa/levodopa. Prior studies only evaluated CVT-301 after the first ON of the day. OBJECTIVE AND METHODS: The objective of this study was to evaluate the safety and tolerability of CVT-301 for early morning OFF. Using a randomized, double-blind, 2-way crossover design, eligible patients in the morning OFF state (having not received PD medication overnight) received a single dose of CVT-301 84 mg or placebo on 2 dosing days, immediately after their first morning oral carbidopa/levodopa dose. Safety assessments included treatment-emergent adverse events, vital signs, and patient- and examiner-reported dyskinesia. An exploratory efficacy assessment was examiner-rated time-to-ON with carbidopa/levodopa + CVT-301 vs carbidopa/levodopa + placebo. RESULTS: Of the 36 patients (mean age 62.9 years) who enrolled and completed the study, 9 (25.0%) reported treatment-emergent adverse events following CVT-301 administration; 4 (11.1%) reported treatment-emergent adverse events following placebo. The most common adverse event was cough (4 [11.1%] for CVT-301 vs 1 [2.8%] for placebo), which was typically mild and transient. Incidence of asymptomatic orthostatic hypotension (CVT-301, 6; placebo, 7) and examiner-rated dyskinesia were similar for both (36-39% mild, 3-6% moderate, and 0% severe). Median time-to-ON was 25.0 min following carbidopa/levodopa + CVT-301 and 35.5 min following carbidopa/levodopa + placebo (P = 0.26). At 30 min, more patients had turned ON following carbidopa/levodopa + CVT-301 administration (66.7%), compared with carbidopa/levodopa + placebo (44.5%) (P = 0.040). CONCLUSION: Single doses of CVT-301 84 mg administered with oral carbidopa/levodopa for early morning OFF symptoms were well-tolerated, with no notable safety concerns.

Setting the record straight: The nosology of tardive syndromes.

We propose the use of the term tardive dyskinesia to refer to the original description of repetitive and complex oral-buccal-lingual (OBL) movements and the analogous repetitive movements of the limbs, trunk, or pelvis. The term tardive syndrome is an umbrella term to be used to refer to the spectrum of all persistent hyperkinetic, hypokinetic, and sensory phenomenologies resulting from chronic dopamine receptor blocking agent (DRBA) exposure. TD is a type of TS. The term tardive dystonia (TDyst) should be used when dystonia is the main feature of TS. Retrocollis and oromandibular dystonia appear to be the most common form of Tdyst. Tardive akathisia refers to the inability to remain still with an urge to move, giving the appearance of restlessness. In tardive tourettism, the patient has complex motor and phonic tics associated with premonitory urge and relief of tension after performing the tic behavior, thus resembling Tourette's syndrome. Tardive tremor is composed of mainly postural and kinetic tremors. It differs from the resting tremor seen in drug-induced parkinsonism. Tardive pain occurs in association with chronic use of DRBAs and involves the mouth, tongue, and genital region with no physical findings. In tardive parkinsonism, the patient has persistent parkinsonism even after discontinuation of the DRBA although this diagnosis is in question and may represent DRBA-uncovered idiopathic Parkinson's disease or coincident development of Parkinson's disease while taking DRBAs.

Levodopa-induced dyskinesia: clinical features, incidence, and risk factors.

Symptoms of Parkinson's disease have been controlled with levodopa for many years; however, motor complications consisting of wearing off of medication effect and dyskinesias tend to occur within a few years of starting levodopa. Motor complications can begin a few months after taking levodopa, with the average time to onset estimated to be 6.5 years. Dyskinesias can be troublesome and require intervention. Levodopa-induced dyskinesia can be composed of a variety of movement disorders including chorea, dystonia, ballism, myoclonus, and akathisia. Based on the clinical pattern, the most common dyskinesia is chorea and choreoathetosis. The clinical manifestations can be divided into three main categories based on their clinical movement patterns and the temporal correlation between the occurrence of dyskinesia and the levodopa dosing: on or peak-dose dyskinesias, biphasic dyskinesias, and Off dyskinesias. Severe cases of dyskinesia have been reported, with the extreme being dyskinesia-hyperpyrexia syndrome. The prevalence of LID has been reported in many studies, but the reported incidence varies. The rate of LID development is from 3 to 94%. The prevalence of LID mainly depends on age at onset, disease duration, and severity, and duration of levodopa therapy. Some of the risk factors for the development of dyskinesia are modifiable. Modifiable risk factors include levodopa dose and body weight. Non-modifiable risk factors include age, gender, duration of disease, clinical subtype, disease progression, disease severity, and genetic factors.

Author Correction to: Pooled Analyses of Phase III Studies of ADS-5102 (Amantadine) Extended-Release Capsules for Dyskinesia in Parkinson's Disease.

An Online First version of this article was made available online at http://link.springer.com/journal/40263/onlineFirst/page/1 on 12 March 2018. An error was subsequently identified in the article, and the following correction should be noted.

Pooled Analyses of Phase III Studies of ADS-5102 (Amantadine) Extended-Release Capsules for Dyskinesia in Parkinson's Disease.

BACKGROUND: Although levodopa is considered the most effective pharmacotherapy for motor symptoms of Parkinson's disease (PD), chronic use is associated with motor complications, including fluctuating response and unpredictable, involuntary movements called dyskinesia. ADS-5102 (amantadine) extended-release (ER) capsules (GOCOVRITM) is a recent US FDA-approved treatment for dyskinesia in PD patients. ADS-5102 is a high-dose, ER formulation of amantadine, administered orally once daily at bedtime, that achieves high plasma drug concentrations throughout the day. OBJECTIVE: In this study, we present pooled results from two randomized, double-blind, placebo-controlled, phase III ADS-5102 trials. PATIENTS AND METHODS: The two studies in PD patients with dyskinesia shared design and eligibility criteria, differing only in treatment duration. Results from common assessment time points were pooled. RESULTS: At 12 weeks, the least squares (LS) mean change in total score on the Unified Dyskinesia Rating Scale among 100 patients randomized to ADS-5102 and 96 patients randomized to placebo was - 17.7 (standard error [SE] 1.3) vs. - 7.6 (1.3) points, respectively (- 10.1 points, 95% confidence interval [CI] - 13.8, - 6.5; p < 0.0001). The relative treatment difference between groups was 27.3% (p < 0.0001). At 12 weeks, the LS mean change in OFF time was - 0.59 (0.21) vs. +0.41 (0.20) h/day, a difference of - 1.00 h/day (95% CI - 1.57, - 0.44; p = 0.0006). For both efficacy measures, a significant difference from placebo was attained by two weeks, the first post-baseline assessment, and was maintained throughout 12 weeks. In the pooled ADS-5102 group, the most common adverse events were hallucination, dizziness, dry mouth, peripheral edema, constipation, falls, and orthostatic hypotension. CONCLUSIONS: These analyses provide further evidence supporting ADS-5102 as an adjunct to levodopa for treating both dyskinesia and OFF time in PD patients with dyskinesia. Clinicaltrials.gov identifier: NCT02136914 and NCT02274766.

The nosology of tardive syndromes.

Since the original description of side effects of neuroleptics, different terminologies and definitions for tardive dyskinesia (TD) and tardive syndrome (TS) have been used by different authors, and often these two terms have been used interchangeably. This paper proposes a nosology designed to define and clarify various terms and phenomenologies within the TS spectrum. We propose to use the term tardive dyskinesia to refer to the original description of repetitive and complex oral-buccal-lingual (OBL) movements, as well as to the analogous repetitive movements that can appear in the limbs, trunk, or pelvis. The repetitive, relatively rhythmic nature of the movements is the common denominator of this phenomenologic category. The term tardive syndrome refers to the spectrum of all persistent hyperkinetic, hypokinetic and sensory phenomenologies resulting from chronic dopamine receptor blocking agents (DRBA) exposure. Thus, TS is an umbrella term. When dystonia is the main feature of TS it is considered to be tardive dystonia (TDyst). Retrocollis appears to be the predominant form of cervical dystonia in this condition. Cranial dystonias, particularly oromandibular dystonia, are also common forms of TDyst. Tardive akathisia refers to the inability to remain still with an urge to move, giving the appearance of restlessness. It is a sensory phenomenon and a common and disabling form of TS. Unlike acute akathisia, tardive akathisia tends to occur late and persists after the drug is withdrawn. In tardive tourettism, the patient exhibits the features of Tourette syndrome with complex motor and phonic tics associated with premonitory urge and relief of tension after performing the tic behavior. Tardive tremor differs from the resting tremor seen in drug-induced parkinsonism in that it is mainly a postural and kinetic greater than resting tremor. Tardive pain has been reported in association with chronic use of DRBA's. The pain involved the mouth, tongue and the genital region. The patients tended to obsess over the pain and usually had some other form of motor tardive syndrome, either tardive dyskinesia, tardive akathisia or tardive dystonia. The term tardive parkinsonism has been proposed for those drug induced parkinsonism patients who have persistent symptoms following discontinuation of the DRBA. However, there is a strong possibility that the DRBA may have simply unmasked subclinical parkinsonism or that there is coincident Parkinson disease developing during the period the patient is taking the DRBA.

ADS-5102 (Amantadine) Extended-Release Capsules for Levodopa-Induced Dyskinesia in Parkinson Disease (EASE LID Study): A Randomized Clinical Trial.

Importance: Medical treatment of levodopa-induced dyskinesia (LID) in Parkinson disease (PD) is an unmet need. Objective: To evaluate the efficacy and safety of ADS-5102 (amantadine) extended-release 274-mg capsules for treatment of LID in patients with PD. Design, Setting, and Participants: A randomized, double-blind, placebo-controlled clinical trial was conducted between May 7, 2014, and July 22, 2015, at 44 North American sites among patients with PD treated with levodopa who experienced at least 1 hour of troublesome dyskinesia per day with at least mild functional impact. Interventions: Patients were randomized to receive placebo or 274 mg of ADS-5102 administered orally at bedtime for up to 25 weeks. Main Outcomes and Measures: The primary efficacy analysis was the change from baseline to week 12 in the Unified Dyskinesia Rating Scale total score for ADS-5102 vs placebo in the modified intent-to-treat population. OFF time (amount of time the PD medication is not controlling motor symptoms) was a key secondary end point. Safety analyses included all patients who received the study drug (ADS-5102 or placebo). Results: A total of 189 patients were screened, and 126 were randomized; the modified intent-to-treat population included 121 patients (51 women and 70 men; mean [SD] age, 64.7 [9.1] years). At week 12, the least-squares mean (SE) change in the Unified Dyskinesia Rating Scale score was -15.9 (1.6) for ADS-5102 (n = 63) and -8.0 (1.6) for placebo (n = 58) (treatment difference, -7.9; 95% CI, -12.5 to -3.3; P < .001). OFF time decreased by a mean (SE) of 0.6 (0.3) hours for ADS-5102 and increased by 0.3 (0.3) hours for placebo (treatment difference, -0.9 hours; 95% CI, -1.6 to -0.2; P = .02). Common adverse events for ADS-5102 vs placebo included visual hallucinations (15 [23.8%] vs 1 [1.7%]), peripheral edema (15 [23.8%] vs 0), and dizziness (14 [22.2%] vs 0). Adverse events led to treatment discontinuation for 13 patients receiving ADS-5102 (20.6%) vs 4 patients receiving placebo (6.9%). Conclusions and Relevance: ADS-5102, 274 mg at bedtime, may be an effective treatment for LID. An additional benefit is reduced OFF time. To our knowledge, this is the first demonstration of an oral treatment reducing both LID and OFF time in patients with PD with dyskinesia. Trial Registration: clinicaltrials.gov Identifier: NCT02136914.

The sleeping brain in Parkinson's disease: A focus on REM sleep behaviour disorder and related parasomnias for practicing neurologists.

Sleep disorders are identified as common non-motor symptoms of Parkinson's disease (PD) and recently this recognition has been expanded to include parasomnias, encompassing not only REM sleep behaviour disorder (RBD), but also other non-REM forms. RBD, a prototypical parasomnia in PD, exists even in the prodromal stage of the disease, and is characterized by the presence of dream enactment behaviours occurring alongside a loss of normal skeletal muscle atonia during REM sleep. In contrast, non-REM parasomnias are more frequently observed in the late stage PD. However, the development of these disorders often overlaps and it is not uncommon for PD patients to meet the criteria for more than one type of parasomnias, thus making a clinical distinction challenging for practicing neurologists who are not sleep specialists. Indeed, clinical recognition of the predominant form of parasomnia does not just depend on video-polysomnography, but also on an individual physician's clinical acumen in delineating pertinent clinical history to determine the most likely diagnosis and proceed accordingly. In this review article, we highlight the various forms of parasomnias that have been reported in PD, including, but not limited to, RBD, with a focus on clinical symptomatology and implications for clinical practice. In addition, we review the differences in PD-related parasomnias compared to those seen in general populations. With advances in sleep research and better technology for ambulatory home monitoring, it is likely that many unanswered questions on PD-related parasomnias will soon be resolved resulting in better management of this nocturnal challenge in PD.

Hallucinations and the spectrum of psychosis in Parkinson's disease.

Hallucinations and psychosis can be a part of Parkinson's disease and are considered to be a nonmotor symptom or a neuropsychiatric complication of the disease. Hallucinations of different modalities and delusions can occur beyond the common visual hallucinations. The various types of hallucinations and psychotic symptoms comprising the spectrum of Parkinson's disease psychosis is the subject of this review article.

Treatment of myoclonus-dystonia syndrome with tetrabenazine.

BACKGROUND: Many cases of myoclonus-dystonia (M-D) are due to mutations in SGCE (DYT11). For the majority of patients, myoclonus is relatively more severe than dystonia and can lead to significant functional disability. Deep brain stimulation has been chosen as a treatment option in some patients given that M-D often responds poorly to oral pharmacotherapy. METHODS: Two siblings with M-D due to the same SGCE deletion mutation were evaluated with the Global Dystonia Rating Scale (GDRS), Fahn-Marsden Rating Scale (FM) and Unified Myoclonus Rating Scale (UMRS) on and off tetrabenazine. RESULTS: Both subjects showed marked improvement in myoclonus and mild-to-moderate improvement in dystonia with tetrabenazine. In addition, the response to tetrabenazine has been sustained for years. CONCLUSIONS: A therapeutic trial of tetrabenazine should be considered in patients with M-D, especially before consideration of deep brain stimulation. An adequately powered multi-center, double-blind study of tetrabenazine will be required to determine the relative contributions of tetrabenazine therapy to myoclonus, dystonia, quality of life, and activities of daily living in patients with M-D.

A rare sequence variant in intron 1 of THAP1 is associated with primary dystonia.

Although coding variants in THAP1 have been causally associated with primary dystonia, the contribution of noncoding variants remains uncertain. Herein, we examine a previously identified Intron 1 variant (c.71+9C>A, rs200209986). Among 1672 subjects with mainly adult-onset primary dystonia, 12 harbored the variant in contrast to 1/1574 controls (P < 0.01). Dystonia classification included cervical dystonia (N = 3), laryngeal dystonia (adductor subtype, N = 3), jaw-opening oromandibular dystonia (N = 1), blepharospasm (N = 2), and unclassified (N = 3). Age of dystonia onset ranged from 25 to 69 years (mean = 54 years). In comparison to controls with no identified THAP1 sequence variants, the c.71+9C>A variant was associated with an elevated ratio of Isoform 1 (NM_018105) to Isoform 2 (NM_199003) in leukocytes. In silico and minigene analyses indicated that c.71+9C>A alters THAP1 splicing. Lymphoblastoid cells harboring the c.71+9C>A variant showed extensive apoptosis with relatively fewer cells in the G2 phase of the cell cycle. Differentially expressed genes from lymphoblastoid cells revealed that the c.71+9C>A variant exerts effects on DNA synthesis, cell growth and proliferation, cell survival, and cytotoxicity. In aggregate, these data indicate that THAP1 c.71+9C>A is a risk factor for adult-onset primary dystonia.

Amiloride but not memantine reduces neurodegeneration, seizures and myoclonic jerks in rats with cardiac arrest-induced global cerebral hypoxia and reperfusion.

It has been reported that both activation of N-methyl-D-aspartate receptors and acid-sensing ion channels during cerebral ischemic insult contributed to brain injury. But which of these two molecular targets plays a more pivotal role in hypoxia-induced brain injury during ischemia is not known. In this study, the neuroprotective effects of an acid-sensing cation channel blocker and an N-methyl-D-aspartate receptor blocker were evaluated in a rat model of cardiac arrest-induced cerebral hypoxia. We found that intracisternal injection of amiloride, an acid-sensing ion channel blocker, dose-dependently reduced cerebral hypoxia-induced neurodegeneration, seizures, and audiogenic myoclonic jerks. In contrast, intracisternal injection of memantine, a selective uncompetitive N-methyl-D-aspartate receptor blocker, had no significant effect on cerebral hypoxia-induced neurodegeneration, seizure and audiogenic myoclonic jerks. Intracisternal injection of zoniporide, a specific sodium-hydrogen exchanger inhibitor, before cardiac arrest-induced cerebral hypoxia, also did not reduce cerebral hypoxia-induced neurodegeneration, seizures and myoclonic jerks. These results suggest that acid-sensing ion channels play a more pivotal role than N-methyl-D-aspartate receptors in mediating cerebral hypoxia-induced brain injury during ischemic insult.

Efficacy and Safety of IncobotulinumtoxinA in Subjects Previously Treated with Botulinum Toxin Versus Toxin-Naïve Subjects with Cervical Dystonia.

BACKGROUND: To determine whether botulinum toxin treatment history affected the outcomes of a study comparing the safety and efficacy of incobotulinumtoxinA with placebo in subjects with cervical dystonia (CD). METHODS: This was a prospective, double-blind, randomized, placebo-controlled, multicenter trial in botulinum toxin-treated or toxin-naïve CD subjects. Subjects received a fixed dose of either 120 U or 240 U of incobotulinumtoxinA or placebo. The primary outcome measure was change from baseline to Week 4 in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score. Treatment-emergent adverse events (TEAEs) were also evaluated. This report represents a subgroup analysis of botulinum toxin-treated or toxin-naïve subjects. RESULTS: Participants (N = 233; 38.6% toxin-naïve) had a mean age of 52.8 years. IncobotulinumtoxinA significantly improved TWSTRS total scores from baseline to Week 4 in both dose groups versus placebo, and the improvement persisted through the end of the study (≤20 weeks). Both the previously toxin-treated and toxin-naïve subjects demonstrated significant improvements in TWSTRS total scores at Week 4 compared to baseline. The most frequent TEAEs in the incobotulinumtoxinA groups were dysphagia, neck pain, and muscular weakness, which were generally mild. TEAEs were more common in the 240 U group and toxin-naïve subjects. DISCUSSION: Overall, incobotulinumtoxinA was safe and effective in CD, regardless of toxin therapy history. A lower starting dose may be better tolerated among toxin-naïve subjects without sacrificing efficacy.