Does this patient have Parkinson disease?

Potential Binding Sites of Pharmacological Chaperone NCGC00241607 on Mutant β-Glucocerebrosidase and Its Efficacy on Patient-Derived Cell Cultures in Gaucher and Parkinson's Disease

Mutations in the GBA1 gene, encoding the lysosomal enzyme glucocerebrosidase (GCase), cause Gaucher disease (GD) and are the most common genetic risk factor for Parkinson's disease (PD). Pharmacological chaperones (PCs) are being developed as an alternative treatment approach for GD and PD. To date, NCGC00241607 (NCGC607) is one of the most promising PCs. Using molecular docking and molecular dynamics simulation we identified and characterized six allosteric binding sites on the GCase surface suitable for PCs. Two sites were energetically more preferable for NCGC607 and located nearby to the active site of the enzyme. We evaluated the effects of NCGC607 treatment on GCase activity and protein levels, glycolipids concentration in cultured macrophages from GD (n = 9) and GBA-PD (n = 5) patients as well as in induced human pluripotent stem cells (iPSC)-derived dopaminergic (DA) neurons from GBA-PD patient. The results showed that NCGC607 treatment increased GCase activity (by 1.3-fold) and protein levels (by 1.5-fold), decreased glycolipids concentration (by 4.0-fold) in cultured macrophages derived from GD patients and also enhanced GCase activity (by 1.5-fold) in cultured macrophages derived from GBA-PD patients with N370S mutation (p < 0.05). In iPSC-derived DA neurons from GBA-PD patients with N370S mutation NCGC607 treatment increased GCase activity and protein levels by 1.1-fold and 1.7-fold (p < 0.05). Thus, our results showed that NCGC607 could bind to allosteric sites on the GCase surface and confirmed its efficacy on cultured macrophages from GD and GBA-PD patients as well as on iPSC-derived DA neurons from GBA-PD patients.

Genetics, molecular control and clinical relevance of habituation learning

Habituation is the most fundamental form of learning. As a firewall that protects our brain from sensory overload, it is indispensable for cognitive processes. Studies in humans and animal models provide increasing evidence that habituation is affected in autism and related monogenic neurodevelopmental disorders (NDDs). An integrated application of habituation assessment in NDDs and their animal models has unexploited potential for neuroscience and medical care. With the aim to gain mechanistic insights, we systematically retrieved genes that have been demonstrated in the literature to underlie habituation. We identified 258 evolutionarily conserved genes across species, describe the biological processes they converge on, and highlight regulatory pathways and drugs that may alleviate habituation deficits. We also summarize current habituation paradigms and extract the most decisive arguments that support the crucial role of habituation for cognition in health and disease. We conclude that habituation is a conserved, quantitative, cognition- and disease-relevant process that can connect preclinical and clinical work, and hence is a powerful tool to advance research, diagnostics, and treatment of NDDs.

Psychological Factors Associated With Fear of Falling Avoidance Behavior in Parkinson's Disease: The Role of Depression, Anxiety, and Catastrophizing

PURPOSE

The purpose of this study was to examine the relationship between psychological factors (depression, anxiety, and catastrophizing) and fear of falling avoidance behavior (FFAB) among individuals with Parkinson's disease (PD).

METHODS

A secondary analysis of cross-sectional data from 59 individuals with PD using hierarchical multiple regression.

RESULTS

Disease severity (Movement Disorder Society - Unified PD Rating Scale) and catastrophizing (Consequences of Falling Questionnaire (CoF)) explained approximately 48.2% of the variance in the FFAB Questionnaire scores (P < .001). Catastrophizing was the only significant psychological variable (P < .001). The damage to identity subscale of the CoF was significant in the final model (P < .001).

CONCLUSIONS

Catastrophizing about the consequences of falls explained the largest portion of variability in FFAB after controlling for disease severity. Catastrophizing about the immediate consequences of falling may play a prominent role in FFAB and may be a potential treatment target for mitigating FFAB.

A Possible Role for HMG-CoA Reductase Inhibitors and Its Association with HMGCR Genetic Variation in Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disease characterised by both motor- and non-motor symptoms, including cognitive impairment. The aetiopathogenesis of PD, as well as its protective and susceptibility factors, are still elusive. Neuroprotective effects of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors—statins—via both cholesterol-dependent and independent mechanisms have been shown in animal and cell culture models. However, the available data provide conflicting results on the role of statin treatment in PD patients. Moreover, cholesterol is a vital component for brain functions and may be considered as protective against PD. We present possible statin effects on PD under the hypothesis that they may depend on the HMG-CoA reductase gene (HMGCR) variability, such as haplotype 7, which was shown to affect cholesterol synthesis and statin treatment outcome, diminishing possible neuroprotection associated with HMG-CoA reductase inhibitors administration. Statins are among the most prescribed groups of drugs. Thus, it seems important to review the available data in the context of their possible neuroprotective effects in PD, and the HMG-CoA reductase gene’s genetic variability.

Exploring Test-Retest Reliability and Longitudinal Stability of Digital Biomarkers for Parkinson Disease in the m-Power Data Set: Cohort Study

Background

Digital biomarkers (DB), as captured using sensors embedded in modern smart devices, are a promising technology for home-based sign and symptom monitoring in Parkinson disease (PD).

Objective

Despite extensive application in recent studies, test-retest reliability and longitudinal stability of DB have not been well addressed in this context. We utilized the large-scale m-Power data set to establish the test-retest reliability and longitudinal stability of gait, balance, voice, and tapping tasks in an unsupervised and self-administered daily life setting in patients with PD and healthy controls (HC).

Methods

Intraclass correlation coefficients were computed to estimate the test-retest reliability of features that also differentiate between patients with PD and healthy volunteers. In addition, we tested for longitudinal stability of DB measures in PD and HC, as well as for their sensitivity to PD medication effects.

Results

Among the features differing between PD and HC, only a few tapping and voice features had good to excellent test-retest reliabilities and medium to large effect sizes. All other features performed poorly in this respect. Only a few features were sensitive to medication effects. The longitudinal analyses revealed significant alterations over time across a variety of features and in particular for the tapping task.

Conclusions

These results indicate the need for further development of more standardized, sensitive, and reliable DB for application in self-administered remote studies in patients with PD. Motivational, learning, and other confounders may cause variations in performance that need to be considered in DB longitudinal applications.

Diagnostic accuracy of glabellar tap sign for Parkinson's disease

Glabellar tap or reflex (GR) is an old bedside clinical test used in the diagnostics of Parkinson’s disease (PD), but its diagnostic value is unclear. This study examines the diagnostic validity and reliability of GR in PD in relation to brain dopaminergic activity. GR was performed on 161 patients with PD, 47 patients with essential tremor (ET) and 40 healthy controls immediately prior to dopamine transporter (DAT) [¹²³I]FP-CIT SPECT scanning. The binding ratios were investigated with consideration of the GR result (normal/abnormal). In addition, the consistency of the GR was investigated with 89 patients after a mean follow-up of 2.2 years. PD and ET patients had higher GR scores than healthy controls (p < 0.001), but there was no difference in GR between PD and ET patients (p = 0.09). There were no differences in the ratio of abnormal to normal GRs between the PD and ET groups (73% vs. 64% abnormal, respectively, p = 0.13) or in DAT binding between PD patients with abnormal and normal GRs (p > 0.36). Over follow-up, the GR changed from abnormal to normal in 20% of PD patients despite the presence of clinically typical disease. The sensitivity and specificity of GR for differentiating PD from ET were 78.3% and 36.2%, respectively. Although GR has been used by clinicians in the diagnostics of PD, it does not separate PD from ET. It also shows considerable inconsistency over time, and abnormal GR has no relationship with dopamine loss. Its usefulness should be tested for other clinical diagnostic purposes.

Fear-of-falling activity-avoidance behavior in people with Parkinson's disease: a scoping review protocol

OBJECTIVE

The objective of this review is to explore existing literature related to fear of falling activity avoidance behavior and identify what is known about this phenomenon in people with Parkinson's disease.

INTRODUCTION

Falling and fear of falling are significant concerns for persons with Parkinson's disease. Fear of falling is a significant problem over and above falling itself and can lead to activity avoidance. Activity-avoidance behavior is a risk factor for increased falls and can lead to further functional decline. A better understanding of the fear of falling and the associated avoidance behavior can inform screening, evaluation, and interventions to decrease fall risk and improve activity engagement and quality of life for persons with Parkinson's disease.

INCLUSION CRITERIA

This review will consider studies published in English that include individuals diagnosed with Parkinson's disease experiencing fear of falling that impacts activity engagement with no limit on participant age or time of publication.

METHODS

JBI methodology will be used to conduct this scoping review. A three-step search strategy will be utilized. The databases to be searched include MEDLINE (PubMed), Embase (Elsevier), Scopus (Elsevier), APA PsycINFO (EBSCO), CINAHL (EBSCO), Papers First (OCLC), and ProQuest Dissertations and Theses (ProQuest). Two independent reviewers will screen the titles, abstracts, and full text of the selected studies. Data collection will be performed with a tool developed by the researchers based on the standardized tool from JBI SUMARI. Data will be presented in a comprehensive narrative summary.

Ambroxol increases glucocerebrosidase (GCase) activity and restores GCase translocation in primary patient-derived macrophages in Gaucher disease and Parkinsonism

Mutations in the glucocerebrosidase gene (GBA) encoding the lysosomal enzyme glucocerebrosidase (GCase) cause Gaucher disease (GD) and are the most commonly known genetic risk factor for Parkinson disease (PD). Ambroxol is one of the most effective pharmacological chaperones of GCase. Fourteen GD patients, six PD patients with mutations in the GBA gene (GBA-PD), and thirty controls were enrolled. GCase activity and hexosylsphingosine (HexSph) concentration were measured in dried blood and macrophage spots using liquid chromatography coupled with tandem mass spectrometry. The effect of ambroxol on GCase translocation to lysosomes was assessed using confocal microscopy. The results showed that ambroxol treatment significantly increased GCase activity in cultured macrophages derived from patient blood monocytic cell (PBMC) of GD (by 3.3-fold) and GBA-PD patients (by 3.5-fold) compared to untreated cells (p < 0.0001 and p < 0.0001, respectively) four days after cultivation. Ambroxol treatment significantly reduced HexSph concentration in GD (by 2.1-fold) and GBA-PD patients (by 1.6-fold) (p < 0.0001 and p < 0.0001, respectively). GD macrophage treatment resulted in increased GCase level and increased enzyme colocalization with the lysosomal marker LAMP2. The possible binding modes of ambroxol to mutant GCase carrying N370S amino acid substitution at pH 4.7 were examined using molecular docking and molecular dynamics simulations. The ambroxol position characterized by minimal binding free energy was observed in close vicinity to the residue, at position 370. Taken together, these data showed that PBMC-derived macrophages could be used for assessing ambroxol therapy response for GD patients and also for GBA-PD patients.

Nanotechnology-based Targeting of Neurodegenerative Disorders: A Promising Tool for Efficient Delivery of Neuromedicines

Traditional drug delivery approaches remained ineffective in offering better treatment to various neurodegenerative disorders (NDs). In this context, diverse types of nanocarriers have shown their great potential to cross the blood-brain barrier (BBB) and have emerged as a prominent carrier system in drug delivery. Moreover, nanotechnology-based methods usually involve numerous nanosized carrier platforms, which potentiate the effect of the therapeutic agents in the therapy of NDs especially in diagnosis and drug delivery with negligible side effects. In addition, nanotechnology-based techniques have offered several strategies to cross BBB to intensify the bioavailability of drug moieties in the brain. In the last few years, diverse kinds of nanoparticles (NPs) have been developed by incorporating various biocompatible components (e.g., polysaccharide-based NPs, polymeric NPs, selenium NPs, AuNPs, protein-based NPs, gadolinium NPs, etc.), that showed great therapeutic benefits against NDs. Eventually, this review provides deep insights to explore recent applications of some innovative nanocarriers enclosing active molecules for the efficient treatment of NDs.

Lipid and Lipid Raft Alteration in Aging and Neurodegenerative Diseases: A Window for the Development of New Biomarkers

Lipids in the brain are major components playing structural functions as well as physiological roles in nerve cells, such as neural communication, neurogenesis, synaptic transmission, signal transduction, membrane compartmentalization, and regulation of gene expression. Determination of brain lipid composition may provide not only essential information about normal brain functioning, but also about changes with aging and diseases. Indeed, deregulations of specific lipid classes and lipid homeostasis have been demonstrated in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). Furthermore, recent studies have shown that membrane microdomains, named lipid rafts, may change their composition in correlation with neuronal impairment. Lipid rafts are key factors for signaling processes for cellular responses. Lipid alteration in these signaling platforms may correlate with abnormal protein distribution and aggregation, toxic cell signaling, and other neuropathological events related with these diseases. This review highlights the manner lipid changes in lipid rafts may participate in the modulation of neuropathological events related to AD and PD. Understanding and characterizing these changes may contribute to the development of novel and specific diagnostic and prognostic biomarkers in routinely clinical practice.

Mutation analysis of Parkinson's disease genes in a Russian data set

Common variants and risk factors related to familial and sporadic cases of Parkinson's disease (PD) in diverse populations have been identified at numerous genomic loci. In this study, genetic analysis was performed through a screening of LRRK2 G2019S, GBA mutations (L444P, N370S), and common variants (E326K, T369M) in 762 PD patients and in 400 controls. Next-generation sequencing analysis of 22 PD-related genes in 28 early-onset PD cases from North-Western region of Russia was performed. The frequency of LRRK2 G2019S mutation was 5.8% in familial and 0.5% in sporadic PD cases. The frequency of GBA mutations (L444P, N370S) in PD patients was higher compared to controls (odds ratio [OR] = 6.9, 95% confidence interval [CI], 0.9-53.13, p = 0.031), particularly in patients with early-onset compared to late-onset PD (OR = 3.90 [95% CI, 1.2-13.2], p = 0.009). The frequency of E326K and T369M was twice higher among PD patients than in controls (OR = 2.24, 95% CI 1.05-4.79, p = 0.033). However, the screening of 22 PD-related genes using our novel panel of gene resequencing in our series of 28 early-onset PD failed to identify any mutations. LRRK2 and GBA mutations were found to be common risk factors for PD in North-Western region of Russia.

Habituation is altered in neuropsychiatric disorders-A comprehensive review with recommendations for experimental design and analysis

Abnormalities in the simplest form of learning, habituation, have been reported in a variety of neuropsychiatric disorders as etiologically diverse as Autism Spectrum Disorder, Fragile X syndrome, Schizophrenia, Parkinson's Disease, Huntington's Disease, Attention Deficit Hyperactivity Disorder, Tourette's Syndrome, and Migraine. Here we provide the first comprehensive review of what is known about alterations in this form of non-associative learning in each disorder. Across several disorders, abnormal habituation is predictive of symptom severity, highlighting the clinical significance of habituation and its importance to normal cognitive function. Abnormal habituation is discussed within the greater framework of learning theory and how it may relate to disease phenotype either as a cause, symptom, or therapy. Important considerations for the design and interpretation of habituation experiments are outlined with the hope that these will aid both clinicians and basic researchers investigating how this simple form of learning is altered in disease.

Oligomeric α-synuclein and glucocerebrosidase activity levels in GBA-associated Parkinson's disease

Alpha-synuclein oligomerization plays a key role in the development of Parkinson's disease (PD). Being the most common genetic contributor to PD, glucocerebrosidase 1 (GBA) mutations have been associated with decreased GBA enzymatic activity in PD patients with mutations in the GBA gene (GBA-PD). However, it is unknown whether the activities of other lysosomal hydrolases are being altered in GBA-PD patients and are accompanied by an increase in alpha-synuclein oligomerization. The aim of our study was to estimate GBA enzymatic activity as well as the activities of five other lysosomal hydrolases (galactocerebrosidase, alpha-glucosidase, alpha-galactosidase, sphingomyelinase, alpha-iduronidase) in dried blood spots with assessing plasma oligomeric alpha-synuclein levels in sporadic PD (sPD) patients, in GBA-PD patients and in controls. GBA enzymatic activity and plasma oligomeric alpha-synuclein levels were assessed in sPD patients (N=84), in GBA-PD patients (N=21) and controls (N=62) by LC-MS/MS and ELISA methods accordingly. GBA-PD patients showed lower GBA enzymatic activity compared to controls (p=0.001) and to sPD (p=0.0001). We also found the reduction of GLA enzymatic activity (but not of other lysosomal hydrolases) in GBA-PD (p=0.001). At the same time plasma oligomeric alpha-synuclein levels were increased in GBA-PD group compared to sPD and controls (p=0.002 and p<0.0001, respectively). Our results suggest that the decrease in enzymatic activity of lysosomal hydrolases in GBA mutation carriers may contribute to PD pathogenesis by increasing the level of neurotoxic oligomeric alpha-synuclein species.

Deficits in the Mimicry of Facial Expressions in Parkinson's Disease

Background: Humans spontaneously mimic the facial expressions of others, facilitating social interaction. This mimicking behavior may be impaired in individuals with Parkinson's disease, for whom the loss of facial movements is a clinical feature.

Objective: To assess the presence of facial mimicry in patients with Parkinson's disease.

Method: Twenty-seven non-depressed patients with idiopathic Parkinson's disease and 28 age-matched controls had their facial muscles recorded with electromyography while they observed presentations of calm, happy, sad, angry, and fearful emotions.

Results: Patients exhibited reduced amplitude and delayed onset in the zygomaticus major muscle region (smiling response) following happy presentations (patients M = 0.02, 95% confidence interval [CI] −0.15 to 0.18, controls M = 0.26, CI 0.14 to 0.37, ANOVA, effect size [ES] = 0.18, p < 0.001). Although patients exhibited activation of the corrugator supercilii and medial frontalis (frowning response) following sad and fearful presentations, the frontalis response to sad presentations was attenuated relative to controls (patients M = 0.05, CI −0.08 to 0.18, controls M = 0.21, CI 0.09 to 0.34, ANOVA, ES = 0.07, p = 0.017). The amplitude of patients' zygomaticus activity in response to positive emotions was found to be negatively correlated with response times for ratings of emotional identification, suggesting a motor-behavioral link (r = –0.45, p = 0.02, two-tailed).

Conclusions: Patients showed decreased mimicry overall, mimicking other peoples' frowns to some extent, but presenting with profoundly weakened and delayed smiles. These findings open a new avenue of inquiry into the “masked face” syndrome of PD.

Anticipatory and Compensatory Postural Adjustments in Response to External Lateral Shoulder Perturbations in Subjects with Parkinson's Disease

The purpose of this study was to investigate the anticipatory (APA) and compensatory (CPA) postural adjustments in individuals with Parkinson’s disease (PD) during lateral instability of posture. Twenty-six subjects (13 individuals with PD and 13 healthy matched controls) were exposed to predictable lateral postural perturbations. The electromyographic (EMG) activity of the lateral muscles and the displacement of the center of pressure (COP) were recorded during four time intervals that are typical for postural adjustments, i.e., immediately before (APA1, APA2) and after (CPA1 and CPA2) the postural disturbances. The magnitude of the activity of the lateral muscles in the group with PD was lower only during the CPA time intervals and not during the anticipatory adjustments (APAs). Despite this finding, subjects with PD exhibit smaller COP excursions before and after the disturbance, probably due to lack of flexibility and proprioceptive impairments. The results of this study suggest that postural instability in subjects with PD can be partially explained by decreased postural sway, before and after perturbations, and reduced muscular activity after body disturbances. Our findings can motivate new studies to investigate therapeutic interventions that optimize the use of postural adjustment strategies in subjects with PD.

Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

BACKGROUND

Dystonia and tremor share many commonalities. Isolated tremor is part of the phenomenological spectrum of isolated dystonia and of essential tremor. The occurrence of subtle features of dystonia may allow one to differentiate dystonic tremor from essential tremor. Diagnostic uncertainty is enhanced when no features of dystonia are found in patients with a tremor syndrome, raising the question whether the observed phenomenology is an incomplete form of dystonia.

METHODS

Known forms of syndromes with isolated tremor are reviewed. Diagnostic uncertainties between tremor and dystonia are put into perspective.

RESULTS

The following isolated tremor syndromes are reviewed: essential tremor, head tremor, voice tremor, jaw tremor, and upper-limb tremor. Their varied phenomenology is analyzed and appraised in the light of a possible relationship with dystonia.

DISCUSSION

Clinicians making a diagnosis of isolated tremor should remain vigilant for the detection of features of dystonia. This is in keeping with the recent view that isolated tremor may be an incomplete phenomenology of dystonia.

Risk of developing Parkinson's disease among patients with asthma: a nationwide longitudinal study

BACKGROUND

A cross-sectional retrospective study suggested a link between allergic diseases and Parkinson's disease. However, the temporal association between asthma and Parkinson's disease remains unknown.

METHODS

From the Taiwan National Health Insurance Research Database, 10 455 patients who were diagnosed with asthma between 1998 and 2008 and aged ≥45 years and 41 820 age- and sex-matched controls were selected for our study and observed until the end of 2011. Those who developed Parkinson's disease during the follow-up period were identified. We also examined the asthma severity, as indicated by the frequency of admission (times per year) for asthma exacerbation, and the risk of subsequent Parkinson's disease.

RESULTS

Patients with asthma had an increased risk of developing Parkinson's disease (hazard ratio [HR]: 3.10, 95% confidence interval [CI]: 2.20-4.36) after we adjusted for demographic data, health system use, medical comorbidities, and medication use. Sensitivity tests yielded consistent findings after we excluded observations on the first year (HR: 2.90, 95% CI: 2.04-4.13) and first 3 years (HR: 2.46, 95% CI: 1.64-3.69). Patients with asthma who had more frequent admissions (times per year) during the follow-up period exhibited a greater risk of subsequent Parkinson's disease (>2: HR: 16.42, 95% CI: 5.88-45.91; 1-2: 12.69, 95% CI: 5.03-31.71; 0-1: HR: 2.92, 95% CI: 1.91-4.49).

CONCLUSION

Patients with asthma had an elevated risk of developing Parkinson's disease later in life, and we observed a dose-dependent relationship between greater asthma severity and a higher risk of subsequent Parkinson's disease.

TOTAL HIP ARTHROPLASTY IN PATIENTS WITH PARKINSON'S DISEASE

The aim of this study is to evaluate the results of total hip arthroplasty in patients with Parkinson’s disease during a period of five years, focusing on the assessment of the risks and benefits of surgery. During this period we performed total hip arthroplasty in 14 patients (15 hips) with Parkinson’s disease. Patients were evaluated by subjective symptoms and objective findings, with a focus on the use of support while walking and walking distance, severity of Parkinson’s disease before surgery and at the time of the last follow-up. During the postoperative period, the following parameters were assessed: length of ICU stay, mobilization, complications, the total duration of hospitalization and follow-up care after discharge.

Of the 11 patients (12 hips) followed-up 1–5 years with an average of 3 years after operation 8 cases showed progression of neurological disability. 5 patients (6 hips) showed an increased dependence on the use of support when walking and reduced distance that the patient was able to walk. Subjectively, 10 hip joints were completely painless and 2 patients complained of only occasional mild pain in the operated hip. Complications that were encountered were urinary tract infection (5 patients), cognitive impairment (3 patients) and pressure ulcer (2 patients). We did not observe any infection or dislocation of the prosthesis. Three patients fell and fractured the femur and 3 patients in our cohort died during follow up.

Implantation of total replacement is possible with judicious indication after careful evaluation of neurological finding in patients with minimal or mild functional impairment of the locomotor system. Prerequisite for a good result is precise surgical technique and optimal implant position with balanced tension of the muscles and other soft tissues around the hip.

The glabellar reflex is a poor measure of Parkinson motor severity

BACKGROUND

The glabellar reflex (GR) is often interpreted as a clinical measure of parkinsonism, although data to support this are weak. It is one of ten items used in the Simpson Angus Scale, a popular measure of parkinsonism in psychiatric studies of neuroleptic drugs. We hypothesized that the GR might be a measure of hypomimia.

METHODS

This was a chart review of 99 consecutive patients with idiopathic Parkinson's disease (PD) seen in a movement disorders center. All patients had standard Unified Parkinson's Disease Rating Scale (UPDRS) motor scale assessments in addition to a standardized assessment of the glabellar reflex (GR). We compared the number of blinks to the hypomimia score (item 2 on UPDRS motor scale) and other measures of PD severity.

RESULTS

We found that there was a statistically significant but weak correlation between the GR blink number and hypomimia as well as the total score on the UPDRS motor section. We also found that the blink number was widely discrepant for an individual hypomimia score.

CONCLUSION

The GR is not a useful measure of hypomimia or motor severity in PD.

How to tackle tremor - systematic review of the literature and diagnostic work-up

Background: Tremor is the most prevalent movement disorder in clinical practice. It is defined as involuntary, rhythmic, oscillatory movements. The diagnostic process of patients with tremor can be laborious and challenging, and a clear, systematic overview of available diagnostic techniques is lacking. Tremor can be a symptom of many diseases, but can also represent a distinct disease entity. Objective: The objective of this review is to give a clear, systematic and step-wise overview of the diagnostic work-up of a patient with tremor. The clinical relevance and value of available laboratory tests in patients with tremor will be explored. Methods: We systematically searched through EMBASE. The retrieved articles were supplemented by articles containing relevant data or provided important background information. Studies that were included investigated the value and/or usability of diagnostic tests for tremor. Results: In most patients, history and clinical examination by an experienced movement disorders neurologist are sufficient to establish a correct diagnosis, and further ancillary examinations will not be needed. Ancillary investigation should always be guided by tremor type(s) present and other associated signs and symptoms. The main ancillary examination techniques currently are electromyography and SPECT imaging. Unfortunately, many techniques have not been studied in large prospective, diagnostic studies to be able to determine important variables like sensitivity and specificity. Conclusion: When encountering a patient with tremor, history, and careful clinical examination should guide the diagnostic process. Adherence to the diagnostic work-up provided in this review will help the diagnostic process of these patients.

Review of MR elastography applications and recent developments

The technique of MR elastography (MRE) has emerged as a useful modality for quantitatively imaging the mechanical properties of soft tissues in vivo. Recently, MRE has been introduced as a clinical tool for evaluating chronic liver disease, but many other potential applications are being explored. These applications include measuring tissue changes associated with diseases of the liver, breast, brain, heart, and skeletal muscle including both focal lesions (e.g., hepatic, breast, and brain tumors) and diffuse diseases (e.g., fibrosis and multiple sclerosis). The purpose of this review article is to summarize some of the recent developments of MRE and to highlight some emerging applications.

The diagnostic challenge of primary dystonia: evidence from misdiagnosis

Although the understanding of dystonia has improved in recent years, primary dystonia is still insufficiently recognized and patients may not receive the correct diagnosis, leading to transient or permanent misclassification of their symptoms. We reviewed cases of primary dystonia who were at first misdiagnosed and analyzed the reasons why the correct diagnosis was first missed and later retained. Primary dystonia is misdiagnosed mainly, but not exclusively, in favor of other movement disorders: Parkinson's disease (PD), essential tremor, myoclonus, tics, psychogenic movement disorder (PMD), and even headache or scoliosis. Accounts are more numerous for PD and PMD, where diagnostic tests, such as DAT scan and psychological assessment, support clinical orientation. The correct diagnosis was achieved in all cases following the recognition of inconsistencies in the first judgment and of distinctive clinical features of dystonia. These clues have been collected here and assembled into a diagnostic epitome.

Metabolic profiling of Parkinson's disease: evidence of biomarker from gene expression analysis and rapid neural network detection

Background

Parkinson's disease (PD) is a neurodegenerative disorder. The diagnosis of Parkinsonism is challenging because currently none of the clinical tests have been proven to help in diagnosis. PD may produce characteristic perturbations in the metabolome and such variations can be used as the marker for detection of disease. To test this hypothesis, we used proton NMR and multivariate analysis followed by neural network pattern detection.

Methods & Results

¹H nuclear magnetic resonance spectroscopy analysis was carried out on plasma samples of 37 healthy controls and 43 drug-naive patients with PD. Focus on 22 targeted metabolites, 17 were decreased and 5 were elevated in PD patients (p < 0.05). Partial least squares discriminant analysis (PLS-DA) showed that pyruvate is the key metabolite, which contributes to the separation of PD from control samples. Furthermore, gene expression analysis shows significant (p < 0.05) change in expression of PDHB and NPFF genes leading to increased pyruvate concentration in blood plasma. Moreover, the implementation of ¹H- NMR spectral pattern in neural network algorithm shows 97.14% accuracy in the detection of disease progression.

Conclusion

The results increase the prospect of a robust molecular definition in detection of PD through the early symptomatic phase of the disease. This is an ultimate opening for therapeutic intervention. If validated in a genuinely prospective fashion in larger samples, the biomarker trajectories described here will go a long way to facilitate the development of useful therapies. Moreover, implementation of neural network will be a breakthrough in clinical screening and rapid detection of PD.

Parkinson's disease and the orthopaedic patient

Parkinson's disease is a progressive neurologic disorder that affects the musculoskeletal system in multiple ways. As medication and surgical management of this disorder have improved, the life spans and quality of life of patients affected by it also have improved. With age, the risk of fracture, osteoarthritis, and osteopenia increase in patients with Parkinson's disease compared with the general population. The symptoms of Parkinson's disease predispose patients to gait abnormalities and loss of bone mass, which commonly result in falls and fracture. Although preventive measures such as medication, lifestyle changes, and vitamin replacement may help, surgical intervention is often indicated. Surgical treatment and postoperative management of both elective and emergent surgery are complicated and controversial.

Prevalence of movement disorders in an elderly nursing home population

We studied the prevalence of movement disorders in a large nursing home population (397 patients, mean age 86 years) in New York City. Patients were first evaluated by specially trained research coordinators and final clinical diagnoses were confirmed by a movement disorder specialist. A movement disorder was identified in 21% of patients (83/397). The most frequent movement disorders were essential tremor (ET) (8.8%) and parkinsonism (7.1%). Only half of those admitted with a diagnosis of parkinsonism were confirmed in their diagnosis by the movement disorder specialists. Three percent of patients exhibited drug-induced tremor, 1.3% had dystonia, 0.5% had myoclonus and 0.3% had generalized dyskinesias. Overall, our findings underline the high frequency of movement disorders in a nursing home population. The discrepancy between our findings and the prevalence rates for parkinsonism reported on the initial transfer diagnosis emphasizes the difficulty of accurate diagnosis of movement disorders and in particular parkinsonism.

Overview of Parkinson's disease

This overview of Parkinson's disease is designed to serve as a background to the discussion elsewhere in this supplement on the pharmacotherapy used in its management. Parkinson's disease is a common progressive neurodegenerative condition associated with significant disability and negative impact on quality of life. Although the cause of Parkinson's disease is unknown, the pathologic manifestation involves the loss or dysfunction of dopaminergic neurons in the substantia nigra pars compacta. Characteristic clinical manifestations include difficulty with coordinated movement such as asymmetric resting tremor, rigidity, and bradykinesia. These symptoms and their response to levodopa constitute the basis for a clinical diagnosis of Parkinson's disease. Postural instability and gait abnormalities occur in more advanced disease. Although there is no cure for Parkinson's disease, a number of pharmacologic treatments are available for managing the motor and nonmotor symptoms. Research is under way to assess the disease-modifying ability of both standard and newer treatments.

Gait and posture impairment, parkinsonism and cognitive decline in older people

Our objective was to examine the frequency of gait and posture impairment and parkinsonism in 3 waves of the Canadians Study of Health and Aging (CSHA) and to determine their relationship to the development of cognitive impairment-not dementia (CIND) and dementia. A secondary analysis of a Canadian population-based cohort study was performed. People 65 years of age and older without cognitive impairment or dementia underwent examination for the presence of gait or posture impairment (GPI) or parkinsonism (based on the presence of 2/3 signs among resting tremor, rigidity or bradykinesia), both defined by a clinical examination. Risk for development of cognitive impairment or dementia was examined at 5 and 10 year follow up in pre-specified logistic regression models adjusted for age, sex, education and in separate models, frailty. The frequency of GPI ranged from 25 to 30% in cognitively unimpaired to 46-53% in CIND and demented subjects. Parkinsonism was more common with increasing cognitive impairment at each wave of the CSHA. Both GPI and parkinsonism predicted cognitive decline. Frailty reduced, but did not eliminate the impact of these motor measures and was itself a significant predictor of cognitive decline. In conclusion, motor impairment and frailty are common in older people and are associated with an increased risk of cognitive decline and dementia. GPI is common in CIND, while GPI and parkinsonism are both common in dementia.

PAM: passive marker-based analyzer to test patients with neural diseases

Neurologists observed specific changes in the movement coordination of their patients - compared to healthy control subjects - a long time ago. In the early, preclinical phase the subtle changes cannot be detected by visual inspection. Similarly, variations in the performance of a patient resulting from minor changes in the stage of the disease remain undetected for the human observer. Evaluation of well-defined movement patterns aids the diagnosis even early diagnosis and assessment of the actual state of patients with neural diseases. Passive marker-based motion analysis is especially suitable for testing human movements. The markers are lightweight (1...10 grams), and no wires are needed between the markers and the analyzer. The markers and the analysis cause absolutely no discomfort to the persons. The performance of commercially available motion analyzers by far exceeds the requirements needed to record and evaluate the movement patterns of patients with neural diseases. As a consequence, these devices are too expensive for this purpose. A simple device has been developed that is affordable for routine clinical use. In harmony with the practice of neurologists, parameters have been defined that characterize both the speed and the regularity of movements. These parameters help in staging patients.

Test-retest Reliability of the Physical Performance Test for Persons with Parkinson Disease

BACKGROUND AND PURPOSE

Reliable measures are needed to document functional status and disease progression for people with Parkinson disease (PD). We, therefore, evaluated the reliability of the Physical Performance Test (PPT) for people with PD.

METHODS

Fourteen community-dwelling subjects with PD participated: 8 males, 6 females; modified Hoehn and Yahr Stages 2 and 2.5; mean age 62.4 years (+6.3). The test was administered twice, 1 week apart. The 7-item and 9-item summary scores of the PPT were each compared between sessions using repeated measures analysis of variance (ANOVA). The intraclass correlation coefficient (ICC) and method error (ME) were calculated to further assess reliability.

RESULTS

Between sessions, 7- and 9-item summed scores were not statistically different. The range of summed scores fell in the midst of the available score range for both the 7- and 9-item tests suggesting resistance to floor and ceiling effects. The ICCs showed good agreement (7-item = 0.818; 9-item = 0.895) indicating test reliability for this population. Based on the ME, an examiner can expect a 6% variation for the 7-item summary score and a 4% variation for the 9-item score summary between testing sessions.

CONCLUSIONS

The 7- and 9-item PPTs were demonstrated to be reliable objective measures in individuals with PD. Simple props and brief administration time (10-15 minutes) make the test practical to use.

Opioids and motor complications in Parkinson's disease

The long-term treatment of Parkinson's disease with L-dopa is often associated with the appearance of involuntary movements called L-dopa-induced dyskinesias. These debilitating side-effects are thought to result from an aberrant form of plasticity triggered by a combination of factors related to dopamine denervation and repeated L-dopa administration. In animal models of Parkinson's disease, dopamine denervation and repeated L-dopa administration are associated with an enhancement of opioid transmission in the basal ganglia. The exact role of this increased opioid activity is still under debate. It has been proposed that some of the changes in opioid transmission are directly involved in the genesis of L-dopa-induced dyskinesias. In this article, we suggest that changes in opioid transmission in the basal ganglia in response to denervation and repeated L-dopa therapy are, instead, part of compensatory mechanisms to prevent motor complications. Initially, these compensatory mechanisms might be sufficient to attenuate the parkinsonian syndrome and delay the appearance of involuntary movements. But with the progression of the disease and repeated exposure to L-dopa, these mechanisms eventually fail. These new insights could contribute to better understanding of the motor complications in Parkinson's disease and lead to the development or improvement of pharmacological strategies to prevent or reduce L-dopa-induced dyskinesias.

G2019S LRRK2 mutation in familial and sporadic Parkinson's disease in Russia

Among mutations associated with autosomal dominant and sporadic Parkinson's disease (PD) the G2019S substitution in the leucine-rich repeat kinase 2 (LRRK2) gene is the most frequently identified. To estimate its frequency in Russia, we analyzed 208 patients with PD from the Northwestern region of Russia. Of these, 51 patients were probands from families with PD compatible with autosomal dominant inheritance. The control group represented 161 subjects without neurological disorders settled in the same region. The frequency of the G2019S mutation was greater in familial PD (2 [3.9%] of 51) than in sporadic PD (1 [0.6%] of 157). In addition, this mutation was found in the proband's father, who also had PD, in 1 PD family, and in 1 carrier without signs of PD at age 40 in another PD family. All carriers were heterozygous for the G2019S mutation and reported the Ashkenazi Jewish origin. The mutation was not found in the control group.

Evaluation of movement speed and reaction time as predictors of all-cause mortality in men

Muscle power is associated with mortality independent of strength, suggesting that movement speed and coordination convey health-related information. We hypothesized that movement speed is a marker of longevity. Our participants included 1196 men who performed a tapping and/or auditory simple (respond to a sound) and disjunctive (respond to a higher pitched sound) reaction-time tasks while participating in the Baltimore Longitudinal Study of Aging. Mortality was assessed over 40 years. Tapping time was associated with mortality (relative risk [RR] = 1.34 per minute, 95% confidence interval [CI], 1.05-1.70) adjusted for age, and persisted with adjustments for arm strength and power. Simple (RR = 1.17 per 100 ms, 95% CI, 1.03-1.32) and disjunctive (RR = 1.14 per 100 ms, 95% CI, 1.03-1.27) reaction times but not their difference (RR = 1.04 per 100 ms, 95% CI, 0.92-1.19) were associated with mortality after adjustments for age, neurological/psychiatric and neck/arm pain histories. Age-associated impairments in motor control systems but not the decision to move affects longevity.

Rhythmic and dysrhythmic thalamocortical dynamics: GABA systems and the edge effect

Brain function is fundamentally related in the most general sense to the richness of thalamocortical interconnectivity, and in particular to the rhythmic oscillatory properties of thalamocortical loops. Such rhythmicity is involved in the genesis of cognition, in the sleep-wake cycle, and in several neurological and psychiatric disorders. The role of GABA-mediated transmission in regulating these functional states is addressed here. At the cortical level, inhibition determines the spread of cortical activation by sculpting the precise activity patterns that underlie the details of cognition and motor control. At the thalamic level, GABA-mediated inhibition modulates and resets distribution of the ongoing thalamocortical rhythmic oscillations that bind multisensory inputs into a single cognitive experience and regulate arousal levels.

Analysis of finger-tapping movement

The piano-playing-like finger-tapping movement has been analyzed with a precision image-based motion analyzer (PRIMAS). 32 healthy subjects (148 recordings) and 10 Parkinsonian patients (25 recordings) were tested. The tracking of fingers during the whole movement increased the level of information obtained from the finger-tapping test compared to visual observation or to measurement with simple contact sensors. Different feature extraction methods have been developed to evaluate the movement and thus the actual performance of the tested person. The reliability of a novel parameter, the finger-tapping test score (FTTS), that takes into account both the speed and the regularity (periodicity) of finger-tapping, was assessed in six control subjects, with four subjects tested at least 14 times. FTTS helps in staging of Parkinsonian patients. A simple and cheap device (passive marker-based analyser of movement, PAM) has been developed that is affordable for routine clinical use.

Glabellar and palmomental reflexes in parkinsonian disorders

The authors examined the glabellar reflex and the palmomental reflex in 100 subjects, including patients with Parkinson disease (n = 41), patients with progressive supranuclear palsy (n = 12), patients with multiple system atrophy (n = 7), and healthy, age-matched, controls (n = 40). The study provides evidence that these reflexes, particularly glabellar reflex, are relatively sensitive signs of parkinsonian disorders, but they lack specificity as they do not differentiate among the three most common parkinsonian disorders.

Genetics of parkin-linked disease

Research into Parkinson's disease (PD), once considered the archetypical non-genetic neurodegenerative disorder, has been revolutionized by the identification of a number of genes, mutations of which underlie various familial forms of the disease. Whereas such mutations appear to exist in a relatively small number of individuals from a few families, the study of the function of these genes promises to reveal the fundamental disease pathogenesis, not only of familial forms of the disease, but also of the much more common sporadic PD. The observation that mutations in the second identified PD locus (parkin) are common in juvenile- and early-onset PD and increasing evidence supporting a direct role for parkin in late-onset disease make this gene a particularly compelling candidate for intensified investigation. The determination of the frequency and effect of parkin mutations in various subsets of PD will be crucial for understanding the way in which parkin is related to neurodegenerative mechanisms, and whether these subsets might be effectively identified and treated. In addition, many aspects of parkin-linked disease, originally thought to be well defined, have now been obscured both by genetic studies that preclude a simple model of disease transmission and by clinical and pathological studies that demonstrate broad variability in cases with parkin mutations. Future studies that address the issues in question should have a far-reaching impact in downstream biochemical studies and our understanding of parkin's role in PD.

Parkinson's disease and exposure to infectious agents and pesticides and the occurrence of brain injuries: role of neuroinflammation

Idiopathic Parkinson's disease (PD) is a devastating movement disorder characterized by selective degeneration of the nigrostriatal dopaminergic pathway. Neurodegeneration usually starts in the fifth decade of life and progresses over 5-10 years before reaching the fully symptomatic disease state. Despite decades of intense research, the etiology of sporadic PD and the mechanism underlying the selective neuronal loss remain unknown. However, the late onset and slow-progressing nature of the disease has prompted the consideration of environmental exposure to agrochemicals, including pesticides, as a risk factor. Moreover, increasing evidence suggests that early-life occurrence of inflammation in the brain, as a consequence of either brain injury or exposure to infectious agents, may play a role in the pathogenesis of PD. Most important, there may be a self-propelling cycle of inflammatory process involving brain immune cells (microglia and astrocytes) that drives the slow yet progressive neurodegenerative process. Deciphering the molecular and cellular mechanisms governing those intricate interactions would significantly advance our understanding of the etiology and pathogenesis of PD and aid the development of therapeutic strategies for the treatment of the disease.