Prominent Tremor Research Articles

A Case Report of Parainfectious Opsoclonus-Myoclonus Syndrome after Powassan Virus Meningitis (P8-10.002)

<h3>Objective:</h3> To report a case of opsoclonus-myoclonus syndrome after Powassan virus meningitis. <h3>Background:</h3> Opsoclonus-myoclonus syndrome is rare in adults and has been associated with viral infection, including West Nile virus (WNV). Powassan virus (PWV) is a tick-borne flavivirus causing a spectrum of disease similar to other flaviviruses such as WNV, which is mosquito-borne. Most human cases in the United States occur in the northeastern and Great Lakes regions from Spring through Fall when ticks are most active. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> A 44-year-old man from Minnesota recovering from a meningitic syndrome characterized by fever, headache, and lymphocytic pleocytosis (860 cells/μL) presented with oscillopsia and gait instability. He reported a history of recent tick exposure. Exam demonstrated opsoclonus most prominent after gaze refixation, myoclonus, prominent tremor and dysmetria of the upper extremities, truncal ataxia, and a wide-based ataxic gait. Magnetic resonance imaging brain was normal. Lyme serology and serum testing for autoimmune/paraneoplastic autoantibodies were unremarkable. Serologic testing detected IgM antibodies against WNV in serum and cerebrospinal fluid. Given history of tick exposure, PWV serology was also performed and demonstrated the presence of IgM antibodies against the virus in both serum and cerebrospinal fluid. Confirmatory plaque reduction neutralization test (PRNT), however, detected neutralizing antibodies against PWV only. He received 5 days of 1g methylprednisolone and 2g/kg intravenous immune globulin, and his symptoms slowly resolved over three months. <h3>Conclusions:</h3> Opsoclonus-myoclonus is uncommon in adults and may be a rare complication of arthropod-borne viral infections, including PWV. Clinicians should consider testing for PWV in patients from endemic regions presenting with opsoclonus-myoclonus and potential tick exposure. <b>Disclosure:</b> Dr. Syc-Mazurek has nothing to disclose. Dr. Santilli has nothing to disclose. Dr. Hass has nothing to disclose. Dr. Skolka has nothing to disclose. Dr. Toledano has nothing to disclose. Dr. Eggers has received intellectual property interests from a discovery or technology relating to health care. Dr. Eggers has received publishing royalties from a publication relating to health care.

Autoimmune glial fibrillary acidic protein astrocytopathy: clinical analysis and review of 15 cases

BackgroundTo review clinical characteristics, auxiliary examination results, treatment effects, and outcomes of patients with autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A).MethodsWe collated and retrospectively analyzed clinical data of 15 patients admitted with clinical characteristics of an autoimmune GFAP-A acute encephalitis or meningitis phenotype.ResultsAll patients were diagnosed with acute-onset meningoencephalitis and meningoencephalomyelitis. Initial presentations included pyrexia and headache at onset; dual symptoms of prominent tremor with urinary and bowel dysfunction; ataxia, psychiatric and behavioral abnormalities, and impaired consciousness; neck resistance; reduced extremity muscle strength; blurred vision; epileptic seizures; and reduced basic blood pressure. Cerebrospinal fluid (CSF) examination showed that the degree of protein elevation was significantly higher than the degree of increase in white blood cells. Moreover, in the absence of obvious low chloride and glucose levels, CSF chloride levels decreased in 13 patients, accompanied by a CSF glucose level decrease in four. Brain abnormalities were found in magnetic resonance imaging of ten patients, with a linear radial perivascular enhancement present in the lateral ventricles of two patients and symmetric abnormalities in the splenium of the corpus callosum in three patients.ConclusionsAutoimmune GFAP-A may be a spectrum disorder, with acute- or subacute-onset meningitis, encephalitis, and myelitis being the main phenotypes. When used for acute stage treatment, combined hormone and immunoglobulin therapy was superior to hormone pulse therapy or immunoglobulin pulse therapy alone. However, hormone pulse therapy alone without immunoglobulin pulse therapy was associated with a greater number of remaining neurological deficits.

Clinical and Preclinical Neuroimaging Changes in Spinocerebellar Ataxia Type 12: A Study of Three Chinese Pedigrees

Background: Spinocerebellar ataxia type 12 (SCA12) is a rare SCA subtype with unclear clinical and imaging features. Also, the radiological changes in prodromal and early stages remain unknown. Methods: Ten symptomatic and two pre­symptomatic cases from three Chinese pedigrees received clinical assessments and imaging studies including routine magnetic resonance imaging (MRI), diffusion kurtosis imaging (DKI), and positron emission tomography (PET) using ¹⁸F-flurodeoxyglucose (FDG) to investigate glucose metabolism in brain and ¹⁸F-vesicle monoamine transporter 2 (VMAT2) to inspect the integrity of the dopaminergic neuron. Seventy-two healthy individuals were recruited as controls in the quantitative FDG-PET analysis. Imaging parameters were compared between symptomatic and presymptomatic cases with different disease durations. Results: Patients displayed prominent action tremor, moderate ataxia, and subtle parkinsonism with poor levodopa-response. MRI showed extensive but heterogeneous cerebral atrophy, which was most evident in the frontoparietal lobes. Cerebellar atrophy was apparent in later stages. DKI detected impaired fibers in the cerebellar peduncles. In both symptomatic and pre­symptomatic cases, PET-CT showed an earlier FDG decline than atrophic changes in multiple regions, and the frontoparietal lobes were the earliest and most severe. However, the VMAT2 density were normal in the putamen and caudate nucleus of most cases (7/8). Conclusions: We first found that hypometabolism in the cerebral cortex, but not cerebellum, is an early and prominent change in SCA12. The integrity of presynaptic dopaminergic neurons remains largely spared during the whole disease process.

Serum Neurofilament Light Chain and Contactin-1 Levels Are Not Potential Serum Biomarkers in Anti-MAG IgM Paraprotein Related Peripheral Neuropathy

IntroductionPeripheral neuropathies (PN) caused by immunoglobulin M (IgM) paraproteinemia are rare disorders that require close collaboration between hematologists and neurologists for adequate diagnosis and management. The IgM paraproteinemia is caused by an underlying B-cell clone that can often be classified as IgM monoclonal gammopathy (IgM monoclonal gammopathy of undetermined significance (MGUS) or Waldenström macroglobulinaemia (WM)). Anti-myelin-associated glycoprotein (MAG) IgM paraprotein related PN (anti-MAG PNP) is the most frequent variety and accounts for approximately 50% of cases. Treatment targeted at the B-cell clone i.e. rituximab +/- chemotherapy, is only indicated in severe and/or progressive cases. However, establishing disease severity and tracking progression over time is difficult since the most prominent symptoms, i.e. imbalance, gait ataxia, sensory disturbances and tremor, are difficult to capture reliably. Anti-MAG titers and paraprotein levels do not correlate well with disease activity and are thus not suitable as biomarkers for disease severity, activity and/or response. The lack of reliable biomarkers also impacts successful execution of clinical trials and therefore hampers introduction of novel targeted non-cytotoxic therapies such as BTK inhibition in this patient population. Therefore, biomarkers for disease severity, activity and response to treatment represent a great unmet need in anti-MAG PN.Nerve damage proteins are increasingly used as disease-overarching response biomarkers in neuropathies, and have been introduced not only in the research setting but also in routine clinical care. Neurofilament light chain (NfL) is used as response biomarker by detecting axonal damage regardless of the underlying disorder, and, recently, contactin-1 (CNTN-1) has been identified as a potential biomarker for damage to the paranode (a nerve region in between the node of Ranvier and compact myelin) where the MAG protein is also present. We therefore aimed to assess whether serum NfL, and CNTN-1 levels may function as nerve damage biomarkers in anti-MAG PN.MethodsWe included treatment-naïve patients with anti-MAG PN (PN) who fulfilled the following criteria: IgM paraproteinemia in the serum, presence of an IgM MAG-antibody in the serum, a clinical diagnosis of anti-MAG PN by a neurologist with expertise in peripheral nerve disorders confirmed by nerve conduction studies. As controls, treatment-naïve patients with IgM MGUS or WM without signs of neuropathy were included (non-PN). NfL levels were measured in serum using a Simoa assay. Abnormal sNfL levels were defined as at or above the 95th percentile of age-specific cut-off values in healthy controls (HCs). CNTN-1 levels were measured using the Human Magnetic Luminex Assay. Abnormal sCNTN1 levels were defined as below the 5th percentile of values in HCs. Differences between PN and non-PN groups were assessed with the Mann-Whitney U test.ResultsA total of 24 PN and 10 non-PN patients were included (Table 1). In the PN cohort, all patients had anti-MAG antibodies, with a titer of >10.000 in 22 (92%) patients. Data from 222 HCs (mean age 46 years; SD 14; range 19-98 years) were used to establish reference values. Median sNfL levels were similar between PN and non-PN patients (Table 2). Abnormal sNfL levels were present in 4 (17%) PN patients (range sNfL: 29.7-42.8 pg/mL) and in 1 (10%; 59.2pg/mL) non-PN patient (Figure 1A). Median sCNTN1 levels were also similar between PN and non-PN patients (Table 2). One (4%) patient in the PN cohort and 1 (10%) patient in the non-PN cohort had abnormal CNTN-1 levels (Figure 1B).ConclusionOur results do not support further studies on NfL and/or CNTN-1 in serum as potential biomarkers in anti-MAG PN, since the majority of anti-MAG PN and non-PN patients had normal levels of sNfL and sCNTN-1. In case sNfL was abnormal, levels were only modestly increased above cutoff and substantially lower compared to the high levels seen in other neuropathies. [Display omitted] DisclosuresMinnema: Alnylam: Consultancy; Celgene: Other: Travel expenses; BMS: Consultancy; Cilag: Consultancy; Janssen: Consultancy; Kite/Gilead: Consultancy. Kersten: Celgene: Research Funding; Novartis: Consultancy, Honoraria, Other: Travel support; Miltenyi Biotec: Consultancy, Honoraria, Other: Travel support; Roche: Consultancy, Honoraria, Other: Travel support, Research Funding; BMS/Celgene: Consultancy, Honoraria; Takeda: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding. Vos: Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: Other: Travel reimbursement.

Machine learning discriminates voice tremor in essential tremor and dysphonia

Patients with essential tremor and adductor-type spasmodic dysphonia may manifest a prominent voice tremor. The diagnosis of voice tremor is currently based on perceptual and qualitative analysis. We have recently demonstrated in two independent studies that advanced voice analysis with machine learning objectively discriminates normal voices from those recorded from patients with essential tremor and dysphonia. The aim of this study is to achieve a direct and objective discrimination between voice samples recoded from patients with essential tremor and dysphonia both manifesting voice tremor.

Pathophysiology of motor symptoms in Parkinson's disease: Role of primary motor cortex

Parkinson's disease, the most common movement disorder, is a progressive neurodegenerative disease clinically characterized by prominent motor symptoms, e.g., bradykinesia, rigidity, and tremor in addition to postural and gait disorders and, in some cases, levodopa-induced dyskinesia (LID). From a pathophysiological point of view, the motor symptoms of Parkinson's disease are traditionally considered to reflect dopaminergic denervation of the basal ganglia, with only a few exceptions. Changes in neuronal activity, abnormal oscillations, and altered plasticity, and sensorimotor integration mechanisms have been described at the level of basal ganglia.

Impact of DaTscan Imaging on Clinical Decision Making in Clinically Uncertain Parkinson's Disease.

Background:The diagnosis of Parkinson’s disease (PD) is primarily clinical, but in cases of diagnostic uncertainty, evaluation of nigrostriatal dopaminergic degeneration (NSDD) by imaging of the dopamine transporter using DaTscan with single-photon emission computed tomography (SPECT) brain imaging may be helpful.Objective/Methods:In the current paper, we describe clinical scenarios for which DaTscan imaging was used in a prospective case series of 201 consecutive patients in whom a movement disorder specialist ordered DaTscan imaging to clarify NSDD. We describe the impact of DaTscan results on changing or confirming pre-DaTscan clinical diagnosis and on post-DaTscan treatment changes.Results/Conclusion:DaTscan imaging can be useful in several clinical scenarios to determine if NSDD is present. These include in patients with early subtle symptoms, suboptimal response to levodopa, prominent action tremor, drug-induced parkinsonism, and in patients with lower extremity or other less common parkinsonism clinical presentations. We also found DaTscan imaging to be useful to determine underlying NSDD in patients with PD diagnosis for 3-5 years but without apparent clinical progression or development of motor fluctuations. Overall, in 201 consecutive patients with clinically questionable NSDD, DaTscan was abnormal in 58.7% of patients, normal in 37.8%, and inconclusive in 3.5%. DaTscan imaging changed clinical diagnosis in 39.8% of patients and led to medication therapy changes in 70.1% of patients.

Study of variability in tremor in Parkinson's Disease population

Objective: Tremor predominant Parkinson's Disease is often characterized by prominent tremor in at least one limb with relatively less significant rigidity and bradykinesia. Tremor is an involuntary oscillation of the body and as such is very disabling. The first line medication is very effective in controlling the tremor. The objective of the study is to measure the improvement in tremor after giving the medication.

Acute effects of adaptive Deep Brain Stimulation in Parkinson’s disease

BackgroundBeta-based adaptive Deep Brain Stimulation (aDBS) is effective in Parkinson’s disease (PD), when assessed in the immediate post-implantation phase. However, the potential benefits of aDBS in patients with electrodes chronically implanted, in whom changes due to the microlesion effect have disappeared, are yet to be assessed. MethodsTo determine the acute effectiveness and side-effect profile of aDBS in PD compared to conventional continuous DBS (cDBS) and no stimulation (NoStim), years after DBS implantation, 13 PD patients undergoing battery replacement were pseudo-randomised in a crossover fashion, into three conditions (NoStim, aDBS or cDBS), with a 2-min interval between them. Patient videos were blindly evaluated using a short version of the Unified Parkinson’s Disease Rating Scale (subUPDRS), and the Speech Intelligibility Test (SIT). ResultsMean disease duration was 16 years, and the mean time since DBS-implantation was 6.9 years. subUPDRS scores (11 patients tested) were significantly lower both in aDBS (p=<.001), and cDBS (p = .001), when compared to NoStim. Bradykinesia subscores were significantly lower in aDBS (p = .002), and did not achieve significance during cDBS (p = .08), when compared to NoStim. Two patients demonstrated re-emerging tremor during aDBS. SIT scores of patients who presented stimulation-induced dysarthria significantly worsened in cDBS (p = .009), but not in aDBS (p = .407), when compared to NoStim. Overall, stimulation was applied 48.8% of the time during aDBS. ConclusionBeta-based aDBS is effective in PD patients with bradykinetic phenotypes, delivers less stimulation than cDBS, and potentially has a more favourable speech side-effect profile. Patients with prominent tremor may require a modified adaptive strategy.

Annals for Educators - 5 May 2020.

Annals for Educators - 5 May 2020.

079 Glial fibrillary acidic protein (GFAP) astrocytopathy associated with cerebral micro-infarction and poor therapeutic response

IntroductionGlial fibrillary acidic protein (GFAP) astrocytopathy is a lesser recognised immune-mediated meningo-encephalomyelitis, which is steroid responsive in the majority of cases. Neuroimaging is unique with a distinctive symmetric white matter perivascular linear and punctate enhancement pattern. We present a case with classical phenotype but delayed clinical response, and highlight the importance of early recognition and treatment.CaseA 59-year-old Caucasian female presented with a two month history of headache, gait disturbance, insomnia, agitation, disorientation and reduced oral intake. Examination revealed a high frequency upper limb tremor, hypertonicity and pathologically brisk reflexes with impaired cognitive function. MRI brain and spinal cord demonstrated high T2 signal and striking perivascular and punctate enhancement in supratentorial white matter, cervical and upper thoracic cord. CSF examination revealed lymphocytic pleocytosis and elevated protein. Brain biopsy demonstrated reduced GFAP expression, perivascular T-lymphocytic infiltrate, and recent white matter microinfarction. CSF and serum GFAP antibodies were positive.Motor deterioration accompanied progression to a stuporous state. High dose corticosteroids were commenced, followed by intravenous immunoglobulin and mycophenolate. While there was marked improvement of perivascular contrast enhancement on imaging, the patient continued to demonstrate prominent tremor, gait disturbance and behavioural issues 9 months following symptom onset.ConclusionsThe persistence of disability in this case is likely the result of axonal loss from the initial insult, reflected by the biopsy evidence of microinfarction. Awareness of the unique pattern on MRI and the clinical phenotype will aid in early recognition and prompt treatment of this condition, thus preventing the potential long term morbidity.

Topiramate Responsive Prominent Head Tremor as an Atypical Presentation of Guillain-Barré Syndrome

Neuropathic tremors are often encountered in both hereditary as well as acquired inflammatory demyelinating neuropathies, such as IgM paraproteinemic neuropathy and chronic inflammatory demyelinating polyradiculoneuropathy and occasionally during the recovery phase of Guillain-Barre syndrome (GBS). Acute motor axonal neuropathy (AMAN) accounts for up to 30–65% the patients with GBS in East Asia and is rarely associated with a neuropathic tremor. We report a patient with AMAN, who presented with pure motor quadriplegia with bulbar symptoms and a prominent atypical resting head tremor during the acute phase of illness, which showed an excellent response to topiramate therapy.

Initial phases of explosion earthquakes accompanying Vulcanian eruptions at Lokon-Empung volcano, Indonesia

We examine the initial phases of explosion earthquakes accompanying Vulcanian eruptions at Lokon-Empung volcano in Indonesia to reveal the triggering process of explosive eruptions. In 2012–2013, 56 Vulcanian eruptions at Lokon-Empung were observed by our temporary observation network being comprised of four broadband seismometers and two infrasound microphones at 1.6–6.8km from the active vent. The seismic records of each explosion earthquake share almost the same waveform characteristics of initial phases, consisting of a small compressional onset (P phase) and a subsequent large dilatational phase (D phase). Particle orbits of both phases show straight motion from beneath the active vent, which suggests that these phases are composed of a longitudinal body wave. For each explosion, the origin times of the P phase precedes 0.8–2.5s before the occurrence of an explosion at the vent that are detected by infrasound data. Since the signal-to-noise ratio of the P phase is insufficient for a quantitative analysis, we analyze the D phase dominating the initial phases. Our analysis for the signals of 0.2–1.0Hz shows the D phase are well explained by a cylindrical contraction source with a half-cosine shaped time function located at 1.0–1.3km depth beneath the active vent. We also recognize that some explosions are followed by a prominent tremor that coincides with continuous ash emission (ET). The seismic amplitudes and intensity of the D phase of events in ET are larger than the explosions without accompanying tremor (EX). The frequency distribution of the time interval from the previous eruption is also different in the events in ET and EX. The implosion source in the initial phases of explosion earthquakes at several km beneath the active vent has been reported at Sakurajima volcano. Since our result shows considerable agreement with the previous works at Sakurajima, both Lokon-Empung and Sakurajima may share similar initial processes of Vulcanian eruptions.

Benign tremulous Parkinsonism: a unique entity or another facet of Parkinson's disease?

Benign tremulous parkinsonism (BTP) is characterized by a prominent tremor that occurs both at rest and with action in conjunction with other mild features of parkinsonism. The progression of symptoms is typically slow and there is often a positive family history. Although BTP is included within the phenotypic spectrum of Parkinsonism its exact relationship with idiopathic Parkinson’s disease remains unclear. Treatment of BTP is challenging especially considering the poor response to levodopa, therefore surgical therapies such as deep brain stimulation surgery are sought for treatment of these tremors. In this review, we will summarize the clinical features, diagnosis, neuropathology and treatment for BTP.

Novel GNAL mutation with intra-familial clinical heterogeneity: Expanding the phenotype

IntroductionMutations in GNAL have been associated with adult-onset cranio-cervical dystonia, but a limited number of cases have been reported so far and the clinical spectrum associated with this gene still needs to be fully characterized. MethodsWe identified an Italian family with adult-onset, dominantly-inherited dystonia whose members presented with different combinations of dystonia affecting the cervical, oro-mandibular and laryngeal regions associated with prominent tremor in some cases. Pure asymmetric upper limb dystonic tremor was present in one of the members and jerky cervical dystonia was also observed. A dedicate dystonia gene panel (Illumina) was used to screen for dystonia-associated genes and Sanger sequencing was performed to confirm results obtained and to perform segregation analysis. ResultsA novel single-base mutation in GNAL exon 9 (c.628G>A; p.Asp210Asn) leading to an aminoacidic substitution was identified and confirmed by Sanger sequencing. In silico prediction programmes as well as segregation analysis confirmed its pathogenicity. Clinically, no generalization of dystonia was observed after onset and DBS lead to an excellent motor outcome in two cases. ConclusionWe report a novel GNAL mutation and expand the clinical spectrum associated with mutations in this gene to comprise pure asymmetric dystonic tremor and a jerky cervical phenotype partially mimicking DYT11 positive cases.

Dopamine transporter scanning in the evaluation of patients with suspected Parkinsonism: a case-based user’s guide

Given the wide range of manifestations of parkinsonism and its mimics, the diagnosis may remain elusive or be misattributed in some patients. Dopamine transporter (DAT) single photon emission computed tomography (SPECT) (DaTscan), an imaging technique that probes the integrity of the presynaptic nigrostriatal system, can be useful in the evaluation of clinically complex parkinsonian disorders in the appropriate context and when adequately interpreted. Pearls and pitfalls in the use of DaTscan for the differential diagnosis of parkinsonisms are reviewed using a case-based format. While the DaTscan is no replacement for a careful neurological examination in ascertaining the likelihood of Parkinson disease or other parkinsonisms in most clinical scenarios, it can be useful in the assessment of disorders where an abducting resting tremor, a prominent postural tremor, or incongruent features are not sufficiently clear on exam to distinguish neurodegenerative parkinsonism from dystonia, drug-induced parkinsonism and functional (psychogenic) parkinsonism, respectively.

The phenotypic spectrum of DYT24 due to ANO3 mutations

Genes causing primary dystonia are rare. Recently, pathogenic mutations in the anoctamin 3 gene (ANO3) have been identified to cause autosomal dominant craniocervical dystonia and have been assigned to the dystonia locus dystonia-24 (DYT24). Here, we expand on the phenotypic spectrum of DYT24 and provide demonstrative videos. Moreover, tremor recordings were performed, and back-averaged electroencephalography, sensory evoked potentials, and C-reflex studies were carried out in two individuals who carried two different mutations in ANO3. Ten patients from three families are described. The age at onset ranged from early childhood to the forties. Cervical dystonia was the most common site of onset followed by laryngeal dystonia. The characteristic feature in all affected individuals was the presence of tremor, which contrasts DYT24 from the typical DYT6 phenotype. Tremor was the sole initial manifestation in some individuals with ANO3 mutations, leading to misdiagnosis as essential tremor. Electrophysiology in two patients with two different mutations showed co-contraction of antagonist muscles, confirming dystonia, and a 6-Hz arm tremor at rest, which increased in amplitude during action. In one of the studied patients, clinically superimposed myoclonus was observed. The duration of the myoclonus was in the range of 250 msec at about 3 Hz, which is more consistent with subcortical myoclonus. In summary, ANO3 causes a varied phenotype of young-onset or adult-onset craniocervical dystonia with tremor and/or myoclonic jerks. Patients with familial cervical dystonia who also have myoclonus-dystonia as well as patients with prominent tremor and mild dystonia should be tested for ANO3 mutations. © 2014 The Authors. Movement Disorders published by International Parkinson and Movement Disorder Society

Cardiac Arrest Following Foreign-Body Aspiration

<b>Background: </b> Patients with Parkinson disease (PD) may be akinetic/rigid, be tremor dominant, or have comparable severity of these motor symptoms (classic). The pathophysiologic basis of different PD phenotypes is unknown. This study assessed pallidal and striatal dopamine level patterns in different motor subgroups of PD and normal control brains. <b>Methods: </b> Globus pallidus and striatum dopamine (DA) levels were measured with high performance liquid chromatography in eight autopsy confirmed PD and five control frozen brains. <b>Results: </b> DA levels in the external globus pallidus (GPe) of normal brains were nearly six times greater than in the internal pallidum (GPi). In PD, the mean loss of DA was marked (−82%) in GPe and moderate (−51%) in GPi. DA loss of variable degree was seen in different subdivisions of GPe and GPi in PD; however, DA levels were near normal in the ventral (rostral and caudal) GPi of PD cases with prominent tremor. There was marked loss of DA (−89%) in the caudate and severe loss (−98.4%) in the putamen in PD. The pattern of pallidal DA loss did not match the putaminal DA loss. <b>Conclusion: </b> There is sufficient loss of dopamine (DA) in external globus pallidus and the internal globus pallidum (GPi) as may contribute to the motor manifestations of Parkinson disease (PD). The possible functional disequilibrium between GABAergic and DAergic influences in favor of DA in the caudoventral parts of the GPi may contribute to resting tremor in tremor dominant and classic PD cases. <b>GLOSSARY: </b><b>CN</b> = caudate nucleus; <b>DA</b> = dopamine; <b>GPe</b> = external globus pallidus; <b>GPi</b> = internal globus pallidum; <b>LB</b> = Lewy body; <b>MDCS</b> = Movement Disorder Clinic in Saskatoon; <b>PD</b> = Parkinson disease; <b>PUT</b> = putamen; <b>VTA</b> = ventral tegmental area.

Spinocerebellar ataxia type 15: diagnostic assessment, frequency, and phenotypic features

BackgroundTo guide time- and cost-efficient analyses of the increasing number of autosomal-dominant spinocerebellar ataxia genes (SCAs), more information about frequency distributions, phenotypic characteristics and optimal diagnostic strategies is warranted.ObjectiveTo assess...

Deep Brain Stimulation for Parkinson's Disease: Where Do We Stand?

Deep Brain Stimulation for Parkinson's Disease: Where Do We Stand?