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Neuroactive steroids are a group of steroid molecules that are involved in the regulation of functions of the nervous system. The nervous system is not only the site of their action, but their biosynthesis can also occur there. Neuroactive steroid levels depend not only on the physiological state of an individual (person's sex, age, diurnal variation, etc.), but they are also affected by various pathological processes in the nervous system (some neurological and psychiatric diseases or injuries), and new knowledge can be gained by monitoring these processes. The aim of our research was to develop and validate a comprehensive method for the simultaneous determination of selected steroids with neuroactive effects in human serum. The developed method enables high throughput and a sensitive quantitative analysis of nine neuroactive steroid substances (pregnenolone, progesterone, 5α-dihydroprogesterone, allopregnanolone, testosterone, 5α-dihydrotestosterone, androstenedione, dehydroepiandrosterone, and epiandrosterone) in 150 µL of human serum by ultrahigh-performance liquid chromatography with tandem mass spectrometry. The correlation coefficients above 0.999 indicated that the developed analytical procedure was linear in the range of 0.90 nmol/L to 28.46 µmol/L in human serum. The accuracy and precision of the method for all analytes ranged from 83 to 118% and from 0.9 to 14.1%, respectively. This described method could contribute to a deeper understanding of the pathophysiology of various diseases. Similarly, it can also be helpful in the search for new biomarkers and diagnostic options or therapeutic approaches.
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Espectrometria de Massas em Tandem , Humanos , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão/métodos , Neuroesteroides/sangue , Esteroides/sangue , Esteroides/análise , Masculino , Reprodutibilidade dos TestesRESUMO
Some pathological conditions affecting the human body can also disrupt metabolic pathways and thus alter the overall metabolic profile. Knowledge of metabolic disturbances in specific diseases could thus enable the differential diagnosis of otherwise similar conditions. This work therefore aimed to comprehensively characterize changes in tryptophan metabolism in selected neurodegenerative diseases. Levels of 18 tryptophan-related neuroactive substances were determined by high throughput and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry in time-linked blood serum and cerebrospinal fluid samples from 100 age-matched participants belonging to five cohorts: healthy volunteers (n = 21) and patients with Lewy body disease (Parkinson's disease and dementia with Lewy bodies; n = 31), four-repeat tauopathy (progressive supranuclear palsy and corticobasal syndrome; n = 10), multiple system atrophy (n = 13), and Alzheimer's disease (n = 25). Although these conditions have different pathologies and clinical symptoms, the discovery of new biomarkers is still important. The most statistically significant differences (with p-values of ≤0.05 to ≤0.0001) between the study cohorts were observed for three tryptophan metabolites: l-kynurenine in cerebrospinal fluid and 3-hydroxy-l-kynurenine and 5-hydroxy-l-tryptophan in blood serum. This led to the discovery of distinctive correlation patterns between the profiled cerebrospinal fluid and serum metabolites that could provide a basis for the differential diagnosis of neurodegenerative tauopathies and synucleinopathies. However, further large-scale studies are needed to determine the direct involvement of these metabolites in the studied neuropathologies, their response to medication, and their potential therapeutic relevance.
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Doença de Alzheimer , Deficiências na Proteostase , Tauopatias , Humanos , Triptofano , Cinurenina , Soro , Doença de Alzheimer/diagnóstico , BiomarcadoresRESUMO
BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive deterioration of upper and lower motor neurons. A definitive diagnostic test or biomarker for ALS is currently unavailable, leading to a diagnostic delay following the onset of initial symptoms. Our study focused on cerebrospinal fluid (CSF) concentrations of clusterin, tau protein, phosphorylated tau protein, and beta-amyloid1-42 in ALS patients and a control group. METHODS: Our study involved 54 ALS patients and 58 control subjects. Among the ALS patients, 14 presented with bulbar-onset ALS, and 40 with limb-onset ALS. We quantified biomarker levels using enzyme-linked immunosorbent assay (ELISA) and compared the results using the Mann-Whitney U-test. RESULTS: Significant elevations in neurodegenerative markers, including tau protein (p < 0.0001), phosphorylated tau protein (p < 0.0001), and clusterin (p = 0.038), were observed in ALS patients compared to controls. Elevated levels of tau protein and phosphorylated tau protein were also noted in both bulbar and limb-onset ALS patients. However, no significant difference was observed for beta-amyloid1-42. ROC analysis identified tau protein (AUC = 0.767) and p-tau protein (AUC = 0.719) as statistically significant predictors for ALS. CONCLUSION: Our study demonstrates that neurodegenerative marker levels indicate an ongoing neurodegenerative process in ALS. Nonetheless, the progression of ALS cannot be predicted solely based on these markers. The discovery of a specific biomarker could potentially complement existing diagnostic criteria for ALS.
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Esclerose Lateral Amiotrófica , Humanos , Esclerose Lateral Amiotrófica/diagnóstico , Clusterina , Diagnóstico Tardio , Proteínas tau , BiomarcadoresRESUMO
Neurodegenerative diseases are a broad heterogeneous group affecting the nervous system. They are characterized, from a pathophysiological perspective, by the selective involvement of a subpopulation of nerve cells with a consequent clinical picture of a disease. Clinical diagnoses of neurodegenerative diseases are quite challenging and often not completely accurate because of their marked heterogeneity and frequently overlapping clinical pictures. Efforts are being made to define sufficiently specific and sensitive markers for individual neurodegenerative diseases or groups of diseases in order to increase the accuracy and speed of clinical diagnosis. Thus said, this present research aimed to identify biomarkers in the cerebrospinal fluid (CSF) and serum (α-synuclein [α-syn], tau protein [t-tau], phosphorylated tau protein [p-tau], ß-amyloid [Aß], clusterin, chromogranin A [chromogrA], cystatin C [cyst C], neurofilament heavy chains [NFH], phosphorylated form of neurofilament heavy chains [pNF-H], and ratio of tau protein/amyloid beta [Ind tau/Aß]) that could help in the differential diagnosis and differentiation of the defined groups of α-synucleinopathies and four-repeat (4R-) tauopathies characterized by tau protein isoforms with four microtubule-binding domains. In this study, we analyzed a cohort of 229 patients divided into four groups: (1) Parkinson's disease (PD) + dementia with Lewy bodies (DLB) (n = 82), (2) multiple system atrophy (MSA) (n = 25), (3) progressive supranuclear palsy (PSP) + corticobasal syndrome (CBS) (n = 30), and (4) healthy controls (HC) (n = 92). We also focused on analyzing the biomarkers in relation to each other with the intention of determining whether they are useful in distinguishing among individual proteinopathies. Our results indicate that the proposed set of biomarkers, when evaluated in CSF, is likely to be useful for the differential diagnosis of MSA versus 4RT. However, these biomarkers do not seem to provide any useful diagnostic information when assessed in blood serum.
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The term 'endemic parkinsonism' refers to diseases that manifest with a dominant parkinsonian syndrome, which can be typical or atypical, and are present only in a particular geographically defined location or population. Ten phenotypes of endemic parkinsonism are currently known: three in the Western Pacific region; two in the Asian-Oceanic region; one in the Caribbean islands of Guadeloupe and Martinique; and four in Europe. Some of these disease entities seem to be disappearing over time and therefore are probably triggered by unique environmental factors. By contrast, other types persist because they are exclusively genetically determined. Given the geographical clustering and potential overlap in biological and clinical features of these exceptionally interesting diseases, this Review provides a historical reference text and offers current perspectives on each of the 10 phenotypes of endemic parkinsonism. Knowledge obtained from the study of these disease entities supports the hypothesis that both genetic and environmental factors contribute to the development of neurodegenerative diseases, not only in endemic parkinsonism but also in general. At the same time, this understanding suggests useful directions for further research in this area.
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Transtornos Parkinsonianos , Humanos , Transtornos Parkinsonianos/epidemiologia , Transtornos Parkinsonianos/genética , Guadalupe/epidemiologia , Europa (Continente) , Fenótipo , BiologiaRESUMO
BACKGROUND: The pathophysiology of abnormal temperature sensation in Parkinson's disease (PD) remains unclear. Abnormal thermal detection does not seem to depend on the dopaminergic deficit, suggesting that other systems play a role in these changes, probably both central and peripheral. METHODS: We measured thermal detection thresholds (TDT) using quantitative sensory testing (QST) in 28 patients with PD and compared them with 15 healthy controls. RESULTS: Of 28 patients, 21% had increased TDT according to the normative data. TDT were higher on the dominant side. No correlation between TDT and disease duration, severity of motor impairment, and dopaminergic therapy was observed. 50% of the patients had difficulty differentiating between warm and cold stimuli, as TDT were within the normal range in most of these patients. CONCLUSIONS: Twenty-one percent of the patients in our study had increased TDT according to the normative data. Abnormal thermal detection was more pronounced on the dominant side. Abnormal differentiation between the thermal stimuli suggest impaired central processing of thermal information.
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Doença de Parkinson , Humanos , Doença de Parkinson/diagnóstico , Temperatura , Estudos de Casos e Controles , Sensação/fisiologia , Temperatura BaixaRESUMO
The understanding of neurodegenerative diseases, traditionally considered to be well-defined entities with distinguishable clinical phenotypes, has undergone a major shift over the last 20 years. The diagnosis of neurodegenerative diseases primarily requires functional brain imaging techniques or invasive tests such as lumbar puncture to assess cerebrospinal fluid. A new biological approach and research efforts, especially in vivo, have focused on biomarkers indicating underlying proteinopathy in cerebrospinal fluid and blood serum. However, due to the complexity and heterogeneity of neurodegenerative processes within the central nervous system and the large number of overlapping clinical diagnoses, identifying individual proteinopathies is relatively difficult and often not entirely accurate. For this reason, there is an urgent need to develop laboratory methods for identifying specific biomarkers, understand the molecular basis of neurodegenerative disorders and classify the quantifiable and readily available tools that can accelerate efforts to translate the knowledge into disease-modifying therapies that can improve and simplify the areas of differential diagnosis, as well as monitor the disease course with the aim of estimating the prognosis or evaluating the effects of treatment. The aim of this review is to summarize the current knowledge about clinically relevant biomarkers in different neurodegenerative diseases.
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Parkinsonism belongs to the most common neurodegenerative disease. Genetic predisposition could be one of the significant risk factor for disease development. It has been described higher prevalence of parkinsonism in large pedigree from southeastern Moravia region. The study aims were to select accessible subfamily trios from the pedigree suitable for segregation genetic analyses to perform whole exome sequencing (WES) in trio individuals and further to evaluate genetic variants in the each trio. We used IonTorrent platform for WES for five subfamily trios (1-5). Each trio included two affected and one healthy person (as control). Found variants were filtered with respect to MAF < 1% (minor allele frequency), variants effect (based on prediction tools) and disease filter (Parkinsonism responsible genes). Finally, the variants from each trio were assessed with respect to the presence in the patients. There were found no one founder mutation in the subfamilies from the pedigree. Trio 1 shares two variants with trio 2:MC1R:c.322G > A (p.A108T) and MTCL1:c.1445C > T (p.A482V), trio 3 shares two variants with trio 5: DNAJC6:c.1817A > C (p.H606P) and HIVEP3:c.3856C > A (p.R1286W). In trios 4 and 5, there were found two variants in gene CSMD1:c.3335A > G (p.E1112G) and c.4071C > G (p.I1357M) respectively. As the most potentially damaging, we evaluated the non-shared variant SLC18A2:c.583G > A (p.G195S). The variant could affect dopamine transport in dopaminergic neurons. The study of the parkinsonism genetic background in isolated Moravian population suggested that there could be significant accumulation of many risk genetic factors. For verification of the variants influence, it would be appropriate to perform a more extensive population study and suitable functional analysis.
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Parkinson's disease and parkinsonism are relatively common neurodegenerative disorders. This study aimed to assess potential genetic risk factors of haplotypes in genes associated with parkinsonism in a population in which endemic parkinsonism and atypical parkinsonism have recently been found. The genes ADH1C, EIF4G1, FBXO7, GBA, GIGYF2, HTRA2, LRRK2, MAPT, PARK2, PARK7, PINK1 PLA2G6, SNCA, UCHL1, and VPS35 were analyzed in 62 patients (P) and 69 age-matched controls from the researched area (C1). Variants were acquired by high-throughput sequencing using Ion Torrent workflow. As another set of controls, the whole genome sequencing data from 100 healthy non-related individuals from the Czech population were used (C2); the results were also compared with the Genome Project data (C3). We observed shared findings of four intron (rs11564187, rs36220738, rs200829235, and rs3789329) and one exon variant (rs33995883) in the LRRK2 gene in six patients. A comparison of the C1-C3 groups revealed significant differences in haplotype frequencies between ratio of 2.09 for C1, 1.65 for C2, and 6.3 for C3, and odds ratios of 13.15 for C1, 2.58 for C2, and 7.6 for C3 were estimated. The co-occurrence of five variants in the LRRK2 gene (very probably in haplotype) could be an important potential risk factor for the development of parkinsonism, even outside the recently described pedigrees in the researched area where endemic parkinsonism is present.
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The current nosological concept of α-synucleinopathies characterized by the presence of Lewy bodies (LBs) includes Parkinson's disease (PD), Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB), for which the term "Lewy body disease" (LBD) has recently been proposed due to their considerable clinical and pathological overlap. However, even this term does not seem to describe the true nature of this group of diseases. The subsequent discoveries of α-synuclein (αSyn), SNCA gene, and the introduction of new immunohistochemical methods have started intensive research into the molecular-biological aspects of these diseases. In light of today's knowledge, the role of LBs in the pathogenesis and classification of these nosological entities remains somewhat uncertain. An increasingly more important role is attributed to other factors as the presence of various LBs precursors, post-translational αSyn modifications, various αSyn strains, the deposition of other pathological proteins (particularly ß-amyloid), and the discovery of selective vulnerability of specific cells due to anatomical configuration or synaptic dysfunction. Resulting genetic inputs can undoubtedly be considered as the main essence of these factors. Molecular-genetic data indicate that not only in PD but also in DLB, a unique genetic architecture can be ascertained, predisposing to the development of specific disease phenotypes. The presence of LBs thus remains only a kind of link between these disorders, and the term "diseases with Lewy bodies" therefore results somewhat more accurate.
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BACKGROUND: In this study we evaluated the impact of location of deep brain stimulation electrode active contact in different parts of the subthalamic nucleus on improvement of non-motor symptoms in patients with Parkinson's disease. METHODS: The subthalamic nucleus was divided into two (dorsolateral/ventromedial) and three (dorsolateral, medial, ventromedial) parts. 37 deep brain stimulation electrodes were divided according to their active contact location. Correlation between change in non-motor symptoms before and one and four months after deep brain stimulation electrode implantation and the location of active contact was made. RESULTS: In dividing the subthalamic nucleus into three parts, no electrode active contact was placed ventromedially, 28 active contacts were located in the medial part and 9 contacts were placed dorsolaterally. After one and four months, no significant difference was found between medial and dorsolateral positions. In the division of the subthalamic nucleus into two parts, 13 contacts were located in the ventromedial part and 24 contacts were placed in the dorsolateral part. After one month, significantly greater improvement in the Non-motor Symptoms Scale for Parkinson's disease (P=0.045) was found on dorsolateral left-sided stimulation, but no significant differences between the ventromedial and dorsolateral positions were found on the right side. CONCLUSION: This study demonstrated the relationship between improvement of non-motor symptoms and the side (hemisphere, left/right) of the deep brain stimulation electrode active contact, rather than its precise location within specific parts of the subthalamic nucleus in patients treated for advanced Parkinson's disease.
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Estimulação Encefálica Profunda , Doença de Parkinson , Núcleo Subtalâmico , Eletrodos , Humanos , Doença de Parkinson/terapia , Núcleo Subtalâmico/fisiologia , Resultado do TratamentoRESUMO
Corticobasal syndrome (CBS) is clinically characterized by progressive asymmetric rigidity and apraxia together with symptoms suggestive of cortical involvement and basal ganglia dysfunction. The spectrum of neurodegenerative diseases that can manifest with CBS is wide. The associations of CBS with corticobasal degeneration, progressive supranuclear palsy, Alzheimer's disease, frontotemporal lobar degenerations, Creutzfeldt-Jakob disease, or diffuse Lewy body pathology have been reported. We describe the case of a 71-year-old woman with CBS. The histopathological examination of brain tissue revealed concomitant pathology corresponding to the limbic stage of Lewy-related pathology and the intermediate stage of Alzheimer's-type pathology. To date, there have been only a few cases with a similar combination of pathology manifesting with the CBS phenotype that have been described in the literature. The extent and distribution of pathological changes in these cases were somewhat different from ours, and significance for clinical manifestation was attributed to only one of these pathologies. In our case, we assume that both types of pathology contributed to the development of the disease, considering the presumed specific spread of both types of pathological processes according to Braak's staging. Our case expands the spectrum of neurodegenerative pathological processes that may manifest with the typical CBS phenotype. Also, it points out the importance of identifying specific biomarkers that would enable more accurate in vivo differential diagnosis and more accurate determination of the underlying pathological processes of these diseases.
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BACKGROUND: Various cerebrospinal fluid (CSF) biomarkers are studied in Parkinson's disease (PD) and atypical parkinsonian syndromes (APS). Several studies found reduced 5-hydroxyindoleacetic acid (5-HIAA), the main serotonin metabolite, in PD. There is little evidence regarding its levels in APS. METHODS: We measured 5-HIAA in the CSF of 90 PD patients, 16 MSA patients, 26 progressive supranuclear palsy (PSP) patients, 11 corticobasal syndrome (CBS) patients, and 31 controls. We also compared the values in depressed and nondepressed patients. RESULTS: There was a statistically significant difference in CSF 5-HIAA in PD and MSA compared to the control group (median in PD 15.8 µg/L, in MSA 13.6 µg/L vs. 24.3 µg/L in controls; p = 0.0008 in PD, p = 0.006 in MSA). There was no statistically significant difference in CSF 5-HIAA in PSP and CBS compared to the control group (median in PSP 22.7 µg/L, in CBS 18.7 µg/L vs. 24.3 µg/L in controls; p = 1 in both PSP and CBS). CSF 5-HIAA levels were lower in PD patients with depression compared to PD patients without depression (median 8.34 vs. 18.48, p < 0.0001). CONCLUSIONS: CSF 5-HIAA is decreased in PD and MSA. The CSF 5-HIAA levels in PSP and CBS did not differ from those of the control group. There was a tendency toward lower CSF 5-HIAA in MSA than in PD; however, the results did not reach statistical significance. These results may be explained by more severe damage of the serotonergic system in synucleinopathies (PD and MSA) than in tauopathies (PSP and CBS).
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Atrofia de Múltiplos Sistemas , Doença de Parkinson , Transtornos Parkinsonianos , Paralisia Supranuclear Progressiva , Tauopatias , Diagnóstico Diferencial , Humanos , Ácido Hidroxi-Indolacético , Atrofia de Múltiplos Sistemas/diagnóstico , Doença de Parkinson/diagnóstico , Transtornos Parkinsonianos/metabolismoRESUMO
Interactions between prion protein (PrP) and tau protein have long been discussed, especially in relation to the pathogenesis of neurodegenerative diseases. The presence of tauopathy in the genetic forms of Creutzfeldt-Jakob disease (CJD) brains is not uncommon. Molecular interactions between PrP and tau protein have been demonstrated in animal models; the role is attributed to the structural properties of misfolded isoform of the host-encoded prion protein (PrPSc) aggregates, especially amyloid, which contributes to the phosphorylation of tau protein, which is reflected in the frequent occurrence of tau pathology in inherited prion amyloidoses. The question is the relationship between PrPSc and hippocampal tau pathology without amyloid deposits (i.e. PART and ARTAG) in sporadic CJD (sCJD). The co-occurrence of these two proteinopathies in sCJD brains is quite rare. These pathological entities have been described in only a few cases of sCJD, all of them were older than 70 years. There have been speculations about the possibility of accelerating the course of pre-existing tauopathy or the possibility of accelerating the ageing process in the CJD brains. Here we present the clinical course and neuropathological findings of a patient with sCJD in whom the above mentioned tauopathies PART and ARTAG, considered to be typical for older age, were found as early as 58 years of age. According to the available information, this case represents an unusually early occurrence of age-related tauopathies not only in relation to sCJD, but also in general.
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Síndrome de Creutzfeldt-Jakob , Príons , Tauopatias , Idoso , Animais , Encéfalo/metabolismo , Síndrome de Creutzfeldt-Jakob/genética , Humanos , Proteínas Priônicas/genética , Príons/genética , Príons/metabolismoRESUMO
The complex phenomenological understanding of dystonia has transcended from the clinics to genetics, imaging and neurophysiology. One way in which electrophysiology will impact into the clinics are cases wherein a dystonic clinical presentation may not be typical or a "forme fruste" of the disorder. Indeed, the physiological imprints of dystonia are present regardless of its clinical manifestation. Underpinnings in the understanding of dystonia span from the peripheral, segmental and suprasegmental levels to the cortex, and various electrophysiological tests have been applied in the course of time to elucidate the origin of dystonia pathophysiology. While loss of inhibition remains to be the key finding in this regard, intricacies and variabilities exist, thus leading to a notion that perhaps dystonia should best be gleaned as network disorder. Interestingly, the complex process has now spanned towards the understanding in terms of networks related to the cerebellar circuitry and the neuroplasticity. What is evolving towards a better and cohesive view will be neurophysiology attributes combined with structural dynamic imaging. Such a sound approach will significantly lead to better therapeutic modalities in the future.
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Distonia , Distúrbios Distônicos , Cerebelo , Córtex Cerebral , Humanos , NeurofisiologiaRESUMO
Parkinson's disease (PD) is characterized by typical motor symptoms. However, recent studies show several non-motor features that may precede the development of the motor symptoms of PD. The best known premotor symptoms include hyposmia, REM sleep behavior disorder (RBD), constipation, and depression; other symptoms are excessive daytime somnolence, orthostatic hypotension and symptomatic hypotension, erectile or urinary dysfunction, musculoskeletal symptoms, pain, and global cognitive deficit. In this review, we summarize currently available diagnostic methods for these symptoms. We also briefly summarize neuroimaging, polyneuropathy, peripheral markers, and cerebrospinal fluid biomarkers that may be used in the early diagnosis of PD.
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Transtornos Cognitivos , Doença de Parkinson , Transtorno do Comportamento do Sono REM , Constipação Intestinal , Diagnóstico Precoce , Humanos , Doença de Parkinson/diagnóstico , Transtorno do Comportamento do Sono REM/diagnóstico , Transtorno do Comportamento do Sono REM/etiologiaRESUMO
BACKGROUND: Chromogranin A (CgA) and other peptides from the chromogranin-secretogranin family have been recently studied as potential biomarkers of various neurodegenerative diseases, including Parkinson's disease (PD). METHODS: We measured CgA in the cerebrospinal fluid (CSF) of 119 PD patients, 18 multiple system atrophy (MSA) patients, and 31 age-matched controls. We also correlated the values with disease duration and levodopa dose equivalent. RESULTS: In the PD patients, CSF CgA tended to be lower than the control group (median 124.5 vs. 185.2 µg/L; p = 0.057); however, the results did not reach statistical significance. CSF CgA levels in MSA were significantly lower compared to the control group (median 104.4 vs. 185.2; p = 0.014). There was no significant difference in CSF CgA between PD and MSA patients (p = 0.372). There was no association between CSF CgA and disease duration or levodopa dose equivalent in PD or in MSA. CONCLUSIONS: We observed a tendency toward lower CSF CgA levels in both PD and MSA compared to the control group; however, the difference reached statistical significance only in MSA. Based on these results, CgA may have potential as a biomarker in PD and MSA, but further studies on larger numbers of patients are needed to draw conclusions.
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BACKGROUND: Gait disturbance accompanies many neurodegenerative diseases; it is characteristic for Parkinson's disease (PD). Treatment of advanced PD often includes deep brain stimulation (DBS) of the subthalamic nucleus. Regarding gait, previous studies have reported non-significant or conflicting results, possibly related to methodological limitations. OBJECTIVE: The objective of this prospective study was to assess the effects of DBS on biomechanical parameters of gait in patients with PD. METHODS: Twenty-one patients with advanced PD participated in this prospective study. Gait was examined in all patients using the Zebris FDM-T pressure-sensitive treadmill (Isny, Germany) before DBS implantation and after surgery immediately, further immediately after the start of neurostimulation, and 3 months after neurostimulator activation. We assessed spontaneous gait on a moving treadmill at different speeds. Step length, stance phase of both lower limbs, double-stance phase, and cadence were evaluated. RESULTS: In this study, step length increased, allowing the cadence to decrease. Double-stance phase duration, that is, the most sensitive parameter of gait quality and unsteadiness, was reduced, in gait at a speed of 4.5 km/h and in the narrow-based gaits at 1 km/h (tandem gait), which demonstrates improvement. CONCLUSION: This study suggests positive effects of DBS treatment on gait in PD patients. Improvement was observed in several biomechanical parameters of gait.