Reflexive and voluntary saccadic eye movements as biomarker of Huntington's Disease.

INTRODUCTION: Subtle abnormalities in the preclinical stage of Huntington's Disease (HD) can be detected using saccadic eye movement assessment reflecting disease progression. This study was aimed to evaluate abnormalities in saccade parameters in asymptomatic carriers and symptomatic HD patients at various stages of HD. MATERIAL AND METHODS: The study enrolled 104 participants, including 14 asymptomatic carriers of HTT mutations, 44 symptomatic HD patients, and 46 control subjects. HD severity was measured using the Unified Huntington's Disease Rating Scale Total Motor Score (UHDRS-TMS) and Total Functional Capacity Scale (TFC). The evaluation of rapid eye movements (reflexive saccades, anti-saccades, memory-guided saccades) was carried out using 'Saccadometer Research'. RESULTS: Measures of reflexive and volitional saccades did not differ between the asymptomatic carriers and controls. Significant latency prolongation and increased physiological variability of latency times, as well as higher error rates among HD patients, were found in all saccade tasks (p < 0.001) compared to the controls. Abnormalities in saccade parameters were more pronounced in the advanced stages of the disease. Latency of saccades and error rate of volitional saccades correlated with the UHDRS-TMS and TFC scores. CONCLUSIONS: The saccade parameters in asymptomatic HD carriers with a long time to disease development were similar to those in the control group. Saccade abnormalities appeared in symptomatic patients at the beginning of the disease, and correlated with HD severity.

Characteristics of transitional locomotor tasks performed by patients with dementia.

Elderly individuals may be at increased risk of falls than their peers. Early identification of balance disorders and their appropriate intervention are crucial for patients with dementia. The aim of this study was to identify postural instability in patients from mild to moderate dementia while performing transitional locomotor tasks under different conditions. Fifty-four patients with dementia and 30 healthy controls voluntarily participated in the study. The transitional locomotor task was performed on two force platforms under four conditions: unimpeded transition, obstacle clearance, step-up and step-down trials. The recording of center of foot pressure displacements was divided into three distinct phases: 1st phase-quiet standing before the transitional locomotor task, 2nd phase-forward stepping, 3rd phase-quiet standing after the transitional locomotor task. Patients with dementia were characterized by a longer transitional locomotor task time than the control group under all conditions (P < 0.03). Significant differences in quiet standing before the transitional locomotor task were observed between patients with dementia and the control group, but only in unimpeded transition and obstacle clearance trials (P < 0.02). No significant differences in quiet standing after step transition were observed between patients with dementia and the control group (P > 0.05). Postural control research in patients with dementia should focus on the functional motor task rather than on a simple motor task (quiet standing). Because even patients with mild dementia have impaired dynamic balance, the assessment of transitional locomotor tasks performed by patients with dementia might provide an indicator of an early diagnosis of dementia and might lead to better individualized physiotherapy.

Cathepsin B p.Gly284Val Variant in Parkinson's Disease Pathogenesis.

Parkinson's disease (PD) is generally considered a sporadic disorder, but a strong genetic background is often found. The aim of this study was to identify the underlying genetic cause of PD in two affected siblings and to subsequently assess the role of mutations in Cathepsin B (CTSB) in susceptibility to PD. A typical PD family was identified and whole-exome sequencing was performed in two affected siblings. Variants of interest were validated using Sanger sequencing. CTSB p.Gly284Val was genotyped in 2077 PD patients and 615 unrelated healthy controls from the Czech Republic, Ireland, Poland, Ukraine, and the USA. The gene burden analysis was conducted for the CTSB gene in an additional 769 PD probands from Mayo Clinic Florida familial PD cohort. CTSB expression and activity in patient-derived fibroblasts and controls were evaluated by qRT-PCR, western blot, immunocytochemistry, and enzymatic assay. The CTSB p.Gly284Val candidate variant was only identified in affected family members. Functional analysis of CTSB patient-derived fibroblasts under basal conditions did not reveal overt changes in endogenous expression, subcellular localization, or enzymatic activity in the heterozygous carrier of the CTSB variant. The identification of the CTSB p.Gly284Val may support the hypothesis that the CTSB locus harbors variants with differing penetrance that can determine the disease risk.

Is deep brain stimulation effective in Huntington's Disease? - a systematic literature review.

INTRODUCTION: Huntington's Disease (HD) is an autosomal dominant neurodegenerative disorder. Substantial for a diagnosis of the disease are motor disorders, with chorea as a hallmark symptom. Other disease manifestations include cognitive dysfunction and psychiatric disorders. Currently, pharmacological treatment plays the most important role in the therapy of HD patients. However, deep brain stimulation (DBS) is considered a potential therapeutic option. AIM OF THE STUDY: Systematic review of current literature on DBS efficacy and safety in the management of motor, behavioural and cognitive functions in patients with HD. MATERIAL AND METHODS: A systematic review was conducted with the use of the Scopus database and the following search criteria: TITLE (huntington*) AND TITLE-ABS-KEY ('deep brain stimulation' OR 'neuromodulation'). Our search criteria included original studies with at least five patients, reporting any motor, cognitive and/or behavioural, and functional assessment data with at least a 6-month follow-up. Finally, four selected publications were analysed. RESULTS: In all analysed publications, we found a statistically significant improvement of Unified Huntington's Disease Rating Scale (UHDRS) chorea subscore by an average of 40, to over 60% after DBS implantation. Heterogeneous results were obtained for UHDRS total motor score. DBS did not improve functional capacity of HD patients in the analysed studies. We found no systematic assessment concerning the effect of DBS in HD on behaviour, cognition or speech. CONCLUSIONS: DBS implantation could be considered as a therapeutic option for patients with severe, drug-resistant chorea. However, the evidence for this is limited. To date, no high-quality data based on randomised controlled trials supports the long-term safety and efficacy of DBS in HD. This treatment option should therefore currently be considered as investigational.

Botulinum toxin type-A preparations are not the same medications - basic science (Part 1).

Botulinum neurotoxin type A (BoNT/A) formulations are widely used in clinical practice. Although they share a common mechanism of action resulting in presynaptic block in acetylocholine release, their structure and pharmacological properties demonstrate some similarities and many differences. Bioequivalence has been discussed since the onset of the clinical use of BoNT/A. In this review, we provide an update on the studies and compare the molecular structure, mechanisms of action, diffusion and spread, as well as immunogenicity and dose equivalence of onabotulinumtoxinA, abobotulinumtoxinA and incobotulinumtoxinA.

Validation of the Polish version of the Unified Dyskinesia Rating Scale (UDysRS).

BACKGROUND: In 2008, the Movement Disorders Society published the Unified Dyskinesia Rating Scale (UDysRS). This has become the established tool for assessing the severity and disability associated with dyskinesia in patients with Parkinson's Disease (PD). We translated and validated the Polish version of the UDysRS, explored its dimensionality, and compared it to the Spanish version, which is the Reference Standard for UDysRS translations. MATERIAL AND METHODS: The UDysRS was translated into Polish by a team led by JS and GO. The back-translation, completed by colleagues fluent in both Polish and English who were not involved in the original translation, was reviewed and approved by the Executive Committee of the MDS Rating Scales Programme. Then the translated version of the UDysRS underwent cognitive pretesting, and the translation was modified based on the results. The approved version was considered to be the Official Working Document of the Polish UDysRS and was tested on 250 Polish PD patients recruited at movement disorder centres. Data was compared to the Reference Standard used for validating UDysRS translations. RESULTS: The overall factor structure of the Polish version was consistent with that of the Reference Standard version, as evidenced by the high Confirmatory Fit Index score (CFI = 0.98). The Polish UDysRS was thus confirmed to share a common factor structure with the Reference Standard. CONCLUSIONS: The Official Polish UDysRS translation is recommended for use in clinical and research settings. Worldwide use of uniform rating measures offers a common ground to study similarities and differences in disease manifestations and progression across cultures.

Clinical phenotype heterogeneity in a family with ε-sarcoglycan gene mutation.

AIM OF THE STUDY: This paper describes six cases of patients with myoclonus-dystonia syndrome who are members of a family in which an SGCE gene mutation has been confirmed. CLINICAL RATIONALE FOR THE STUDY: Myoclonus-dystonia syndrome is a very rare disease, with an incidence in Europe of about 2 in every million. Due to the fact that only a few case reports of this illness are accessible in the literature, the material we collected seems to be valuable for clinical practice. MATERIALS AND METHODS: A history was taken, and physical and genetic examinations of the patients were performed. Furthermore, the clinical examination of three patients was video-recorded. RESULTS: The clinical picture of the disease varied significantly between the described individuals, from a healthy carrier of the SGCE mutation to patients presenting mild to moderate symptoms. The differences concerned the age at onset of the disease, the initial symptoms, the intensity of involuntary movements, and the predominant symptoms. In addition to the typical movement disorders which are myoclonus and dystonia, in the described family there was also the coexistence of epilepsy, obsessive-compulsive behaviour, dyslexia, dysgraphia, non-harmonious development of cognitive processes, as well as mild phenotypic features of muscular dystrophy. The mutation (NM_001099401.2:c.806-809delACTG) found in the presented family has not been described elsewhere. CONCLUSIONS AND CLINICAL IMPLICATIONS: Our description of six cases of patients demonstrates the heterogeneity of the natural course of the disease, even in patients with the same mutation. It seems reasonable to regularly examine relatives of patients with myoclonus-dystonia syndrome, who should be observed for involuntary movements as well as non-motor symptoms.

Validation of the Polish version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS).

BACKGROUND: In 2008, the Movement Disorders Society (MDS) published a new Unified Parkinson's Disease Rating Scale (MDS-UPDRS) as the official benchmark scale for Parkinson's Disease (PD). We have translated and validated the Polish version of the MDS-UPDRS, explored its dimensionality, and compared it to the original English one. METHODS: The MDS-UPDRS was translated into Polish by a team of Polish investigators led by JS and GO. The back-translation was completed by colleagues fluent in both languages (Polish and English) who were not involved in the original translation, and was reviewed by members of the MDS Rating Scales Programme. Then the translated version of the MDS-UPDRS underwent cognitive pretesting, and the translation was modified based on the results. The final translation was approved as the Official Working Document of the MDS-UPDRS Polish version, and was tested on 355 Polish PD patients recruited at movement disorders centres all over Poland (at Katowice, Gdansk, Lódz, Warsaw, Wroclaw, and Kraków). Confirmatory and explanatory factor analyses were applied to determine whether the factor structure of the English version could be confirmed in the Polish version. RESULTS: The Polish version of the MDS-UPDRS showed satisfactory clinimetric properties. The internal consistency of the Polish version was satisfactory. In the confirmatory factor analysis, all four parts had greater than 0.90 comparative fit index (CFI) compared to the original English MDS-UPDRS. Explanatory factor analysis suggested that the Polish version differed from the English version only within an acceptable range. CONCLUSIONS AND CLINICAL IMPLICATIONS: The Polish version of the MDS-UPDRS meets the requirements to be designated as the Official Polish Version of the MDS-UPDRS, and is available on the MDS web page. We strongly recommend using the MDS-UPDRS instead of the UPDRS for research purposes and in everyday clinical practice.

A study in a Polish ataxia cohort indicates genetic heterogeneity and points to MTCL1 as a novel candidate gene.

Inherited ataxias are a group of highly heterogeneous, complex neurological disorders representing a significant diagnostic challenge in clinical practice. We performed a next-generation sequencing (NGS) analysis in 10 index cases with unexplained progressive cerebellar ataxia of suspected autosomal recessive inheritance. A definite molecular diagnosis was obtained in 5/10 families and included the following diseases: autosomal recessive spastic ataxia of Charlevoix-Saguenay, POLR3B-related hypomyelinating leukodystrophy, primary coenzyme Q10 deficiency type 4, Niemann-Pick disease type C1 and SYNE1-related ataxia. In addition, we found a novel homozygous MTCL1 loss of function variant p.(Lys407fs) in a 23-year-old patient with slowly progressive cerebellar ataxia, mild intellectual disability, seizures in childhood and episodic pain in the lower limbs. The identified variant is predicted to truncate the protein after first 444 of 1586 amino acids. MTCL1 encodes a microtubule-associated protein highly expressed in cerebellar Purkinje cells; its knockout in a mouse model causes ataxia. We propose MTCL1 as a candidate gene for autosomal recessive cerebellar ataxia in humans. In addition, our study confirms the high diagnostic yield of NGS in early-onset cerebellar ataxias, with at least 50% detection rate in our ataxia cohort.

Posterior Subthalamic Area Deep Brain Stimulation for Treatment of Refractory Holmes Tremor.

Three right-handed patients diagnosed with Holmes tremor (HT), who suffered from pharmacotherapy-refractory tremor, were eligible for unilateral posterior subthalamic area deep brain stimulation (PSA-DBS). All patients were evaluated with the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) and Clinical Global Impression scale (CGI) before DBS, 6, and 12 months after the PSA-DBS as well as at the last follow-up. In all patients, we observed a significant improvement of tremor control as demonstrated by changes in the FTMTRS and the CGI scales. Mean improvement of tremor in all patients was 56% for the FTMRTS with a corresponding change in the CGI scale. Our study demonstrates that PSA-DBS is efficacious in the treatment of HT. Indeed, PSA is a promising target for DBS for intractable proximal and distal tremor, even in cases of previous, suboptimal functional neurosurgery. The beneficial effect lasts over a long-term follow-up. PSA-DBS may be considered as an alternative target of DBS in tremor treatment.

[Sleep disorders in Parkinson's disease].

Sleep disorder are common non-motor symptoms in Parkinson`s disease (PD). They can be found in different sleep stages or appear during the daytime. They correlate with faster progression of motor problems and lower quality of a patient's life. Sleep physiology, different sleep dysfunction such as: RBD-REM sleep behavior disorder, EDS - excessive daytime sleepiness, insomnia, OSAS-obstructive sleep apnea syndrome, and their clinical manifestation have been presented in this review. Diagnostic and therapy possibilities have been summarized as well. Particular attention has also been paid to the coexistence of various non-motor symptoms such as pain, depression or nocturia, and their correlations with sleeping problems.

Effects of repeated abobotulinumtoxinA injections in upper limb spasticity.

INTRODUCTION: The efficacy of single injections of abobotulinumtoxinA (Dysport) is established in adults with upper limb spasticity. In this study we assessed the effects of repeated injections of abobotulinumtoxinA over 1 year. METHODS: Patients (n = 258, safety population) received 500 U, 1,000 U, or 1,500 U (1,500-U dose included 500-U shoulder injections) for up to 4 or 5 treatment cycles. Assessments included treatment-emergent adverse events (TEAEs), muscle tone, passive and active range of motion (XV1, XA ), angle of catch (XV3 ), Disability Assessment Scale (DAS) score, Modified Frenchay Scale (MFS) score, and Physician Global Assessment (PGA) score. RESULTS: The incidence of TEAEs decreased across cycles. Muscle tone reduction and XV1 remained stable across cycles, whereas XV3 and XA continued to improve at the finger, wrist, and elbow flexors. DAS and PGA improved across cycles. MFS improved best with 1,500 U. DISCUSSION: A favorable safety profile and continuous improvements in active movements and perceived and active function were associated with repeated abobotulinumtoxinA injections in upper limb muscles. Muscle Nerve 57: 245-254, 2018.

Heterozygous PINK1 p.G411S increases risk of Parkinson's disease via a dominant-negative mechanism.

SEE GANDHI AND PLUN-FAVREAU DOI101093/AWW320 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: It has been postulated that heterozygous mutations in recessive Parkinson's genes may increase the risk of developing the disease. In particular, the PTEN-induced putative kinase 1 (PINK1) p.G411S (c.1231G>A, rs45478900) mutation has been reported in families with dominant inheritance patterns of Parkinson's disease, suggesting that it might confer a sizeable disease risk when present on only one allele. We examined families with PINK1 p.G411S and conducted a genetic association study with 2560 patients with Parkinson's disease and 2145 control subjects. Heterozygous PINK1 p.G411S mutations markedly increased Parkinson's disease risk (odds ratio = 2.92, P = 0.032); significance remained when supplementing with results from previous studies on 4437 additional subjects (odds ratio = 2.89, P = 0.027). We analysed primary human skin fibroblasts and induced neurons from heterozygous PINK1 p.G411S carriers compared to PINK1 p.Q456X heterozygotes and PINK1 wild-type controls under endogenous conditions. While cells from PINK1 p.Q456X heterozygotes showed reduced levels of PINK1 protein and decreased initial kinase activity upon mitochondrial damage, stress-response was largely unaffected over time, as expected for a recessive loss-of-function mutation. By contrast, PINK1 p.G411S heterozygotes showed no decrease of PINK1 protein levels but a sustained, significant reduction in kinase activity. Molecular modelling and dynamics simulations as well as multiple functional assays revealed that the p.G411S mutation interferes with ubiquitin phosphorylation by wild-type PINK1 in a heterodimeric complex. This impairs the protective functions of the PINK1/parkin-mediated mitochondrial quality control. Based on genetic and clinical evaluation as well as functional and structural characterization, we established p.G411S as a rare genetic risk factor with a relatively large effect size conferred by a partial dominant-negative function phenotype.

The relation between plasma α-synuclein level and clinical symptoms or signs of Parkinson's disease.

INTRODUCTION: Parkinson disease (PD) is the common neurodegenerative disease. α-Synuclein (ASN), main aggregating protein in neural cells of CNS in PD, was found in peripheral fluids. Testing ASN in plasma is potential test for diagnose PD, but previous studies are controversial. The aim of this study was to investigate if plasma ASN level may be a valuable biomarker, is the level of plasma ASN concentration different in various motor subtypes of diseases, is there a relation between the level of plasma ASN and the severity of motor symptoms. METHODS: Patients with PD hospitalized in Neurology Department, Medical College were performed sequencing the 8th and 9th exon of GBA gene. Next plasma ASN level was tested in 58 patients with sequenced GBA gene and in 38 healthy volunteers (HV), matched by the age (respectively 68.43 vs. 64.57 years of age) and sex (female %, respectively: 43.10 vs.44.74). Patients were assessed with the scales: UPDRS (II, III, IV), Hoehn-Yahr (HY) and qualified to PIGD or TD subtype. For homogeneity of the group patients with GBA mutation were excluded from the analysis. RESULTS: The ASN level did not differ between patients and HV (respectively: 4.53 vs. 3.73ng/ml) and between patients with different subtypes. There was inverse correlation between ASN and HY in PIGD subtype. CONCLUSIONS: Plasma ASN level is not valuable marker of the disease. It does not differ in subtypes of the disease. There is relation between plasma ASN level and the severity of the disease in PIGD subtype.

Eye movements in essential tremor patients with parkinsonian and cerebellar signs.

Apart from intention tremor essential tremor (ET) patients may display other cerebellar signs, like dysmetria or tandem gait disturbances as well as parkinsonian signs like resting tremor, cogwheel sign, subtle bradykinesia. Previous reports claimed the occurrence of the eye movement abnormalities characteristic for dysfunction of cerebellar dorsal vermis in ET patients with concomitant cerebellar signs. There are no previous reports evaluating the eye movement abnormalities in ET patients with concomitant parkinsonian signs. The objective of this study was to determine the relationship between the occurrence of parkinsonian and cerebellar signs and the oculomotor abnormalities in ET patients. METHOD: Fifty ET patients including 6 (12.0%) patients with concomitant parkinsonian signs (ET-P), 20 (40.0%) patients with cerebellar signs (ET-C), 7 (14.0%) with mixed parkinsonian and cerebellar signs (ET-M), 17 (34.0%) patients with the only tremor (ET-T) together with 42 healthy controls were included to the study. Reflexive, pace-induced and cued saccades were recorded using Saccadometer Advanced. Smooth pursuit and fixation were tested using EOG. RESULTS: Latency of pace-induced saccades was significantly longer in ET-C and ET-M patients compared to ET-T and ET-P patients. Latency of cued saccades was significantly longer in ET-M patients compared to ET-T. There were no significant differences of the eye movement parameters between ET-P patients compared to ET-T patients. CONCLUSION: In ET patient with concomitant cerebellar signs prolonged volitional saccades latency was detected. There are no particular differences in the eye movements in ET patients with concomitant parkinsonian signs compared to ET patients without concomitant signs.

Cognitive impairment and BDNF serum levels.

BACKGROUND/AIMS: To investigate the alterations of brain-derived neurotrophic factor (BNDF) serum levels in subjects with different intensity of cognitive impairment and different neurodegenerative processes. MATERIAL AND METHODS: Serum BDNF levels were analyzed by ELISA kit in 378 subjects: 134 Alzheimer's disease (AD) patients, 115 amnestic mild cognitive impairment (MCI) patients, and 129 controls divided into two groups: neurodegenerative control group (ND), consisting of 49 Parkinson's disease patients without any cognitive complaints, and cognitively normal control group (CN), consisting of 80 subjects without any neurological disorders. RESULTS: AD patients had significantly lower (p<0.001) BDNF serum levels compared to MCI, CN and ND controls. Age and education had significant influence on BDNF serum levels regardless the diagnosis or group assignment. We have found no influence of depression on BDNF serum levels either in our group as a whole, or in each group assessed separately. We found significant correlation between BDNF serum levels and cognitive impairments. After multiple comparisons between the groups, we found that, after adjustment for confounding factors (age, gender, education, depression, cognitive impairment), BDNF serum levels were the lowest in AD group (p=0.05). CONCLUSIONS: Advanced age and low educational level are associated with decreased BDNF serum levels. Decreased BDNF serum levels correspond to the severity of cognitive impairment. There is no correlation between BDNF serum levels and depressive symptoms.

[Gait disturbances and falls in various types of dementias].

Dementia is a group of symptoms of damage of higher cortical functions. The causes of dementia include brain diseases, most often chronic and progressive, leading to cognitive impairment typical of these disorders. Apart from progressive cognitive deficits, dementias may coexist with mental disorders, sleep disorders, epileptic seizures, parkinsonism and other motor disorders. Motor disorders, including gait disturbances and falls, represent a serious challenge to the health of older adults and contribute to loss of mobility and independence. Analysis of motor disturbances in the population of healthy older adults and those with progressive cognitive impairment is likely to support effective planning of pharmacological therapies and rehabilitation for this group of patients.

The Role of Single Nucleotide Polymorphisms of Monoamine Oxidase B, Dopamine D2 Receptor, and DOPA Decarboxylase Receptors Among Patients Treated for Parkinson's Disease.

This study aimed to investigate the association between selected variants of genes related to dopamine metabolism pathways and the risk of and progression of Parkinson's disease (PD). This prospective cohort study was conducted in one academic teaching hospital. The study was conducted on 126 patients diagnosed with idiopathic Parkinson's disease. Blood samples were collected to conduct a genotyping of MAOB, DRD1, DRD2, and DDC genes. Genotype and allele frequencies of MAOB (rs1799836) variants were not associated with the course of PD. Genotype and allele frequencies of DRD2 (rs2283265) variants were associated with risk of dementia (p = 0.001) and resulted in parts II and III of the UPDRS scale (p = 0.001). Genotype and allele frequencies of DRD2 (rs1076560) variants were associated with risk of dementia (p = 0.001) and resulted in parts II and III of the UPDRS scale (p = 0.001). Genotype and allele frequencies of DDC (rs921451) variants were not associated with the course of PD.