Validation of Polish version of Gastrointestinal Dysfunction Scale for Parkinson's Disease.

AIM OF STUDY: The Gastrointestinal Dysfunction Scale for Parkinson's Disease (GIDS-PD) is a novel, disease-specific self-report questionnaire used to quantitatively assess features of gastrointestinal dysfunction symptoms in patients with Parkinson's Disease. The aim of this paper was to validate the Polish translation of the scale, to summarise its consistency with the English language version, and to assess its clinimetric properties. CLINICAL RATIONALE FOR STUDY: Gastrointestinal dysfunction is a common and often debilitating manifestation of Parkinson's Disease (PD). Gastrointestinal symptoms are also considered to be prodromal features of this disease. To date, there has been no scale in Polish that has precisely assessed gastrointestinal symptoms in patients with PD. MATERIAL AND METHODS: The GIDS-PD was translated into Polish by two investigators (M.K. and J.N.). A back-translation was completed by two separate investigators (M.F. and A.A.) who were not involved in the original translation. Afterwards, 10 Polish PD patients underwent cognitive pre-testing. After the final translation was officially approved by the Movement Disorder Society, it was tested on 64 individuals with PD during field testing. For the purpose of testing scale reliability, 20 of the patients recruited for field testing underwent the GIDS-PD for a second time after 8-12 weeks. RESULTS: The GIDS-PD demonstrated overall good consistency (Cronbach's alpha of 0.74, ICC of 0.74). Regarding the individual domains, the constipation subscore demonstrated good reliability, the bowel irritability subscore demonstrated moderate reliability, and the upper GI subscore demonstrated poor reliability. Upper GI symptoms seem to be less pronounced, and also more varied, in the Polish PD population than in its English language counterpart. CONCLUSIONS AND CLINICAL IMPLICATIONS: This paper provides a validated Polish translation of the GIDS-PD questionnaire. We highly recommend using the GIDS-PD for research purposes, as well as everyday clinical practice in the Polish PD population.

ADCY5-related dyskinesia - case series with literature review.

INTRODUCTION: ADCY5-related dyskinesia is a rare neurological disease caused by mutations in the gene encoding the adenylyl cyclase 5 (ADCY5) isoform, a protein that plays an important role in intracellular transmission. Variants in ADCY5 are associated with a spectrum of neurological disease encompassing dyskinesia, chorea, and dystonia. State of the-art. ADCY5 mutations result in clinically heterogeneous manifestations which comprise a range of core and less to highly variable symptoms. Due to the heterogeneous nature and difficulty in diagnosis of the disorder, available treatments are highly limited. CLINICAL IMPLICATIONS: ADCY5-related dyskinesia was reported in 52 individuals in the literature over a five-year period (January 2017 to January 2022). We have listed all the symptoms and their frequency. The most common symptom reported in these patients was dystonia. Over 50% of patients developed dyskinesia and chorea. We report two cases of familial occurrence of symptomatic ADCY5-related dyskinesia. A 45-year-old patient presented with involuntary movements which had been occurring since childhood. The proband's neurological examination revealed dysarthria, involuntary myoclonic twitches, and choreic movements. The patient's 9-year-old son had developed involuntary movements, mainly chorea and dystonia. FUTURE DIRECTIONS: This paper aims to summarise the recent literature on ADCY5-related neurological disorders and to present a new case of a Polish family with ADCY5 mutation. Genetic diagnostics are important in the context of possible future targeted treatments.

Unilateral gamma knife thalamotomy for tremor safety and efficacy in multimodal assessment: a prospective case-control study with two-year follow-up.

INTRODUCTION: Unilateral gamma knife thalamotomy (GKT) is a treatment option for pharmacoresistant tremor of various aetiologies. There have been to date no randomised controlled trials performed to assess its safety and efficacy. Our aim was to summarise a two-year multimodal observation of patients with tremor caused by Parkinson's Disease (PD) or essential tremor (ET). MATERIAL AND METHODS: 23 patients with PD (n = 12) or ET (n = 11) were included. They underwent assessments before, V0 (n = 23), and 12 months, V12 (n = 23), and 24 months, V24 (n = 15), after unilateral GKT. Patients were assessed with psychological tests and acoustic voice analysis. Tremor assessment was performed with a digitising table using the Fahn-Tolosa-Marin rating scale (FTMRS). The Unified Parkinson's Disease rating scale part III (UPDRS-III) was also used in the PD group. Gait and balance was assessed using clinical tests, stabilometric platform, and treadmill. RESULTS: No side effects were observed in a two-year follow-up. There was no notable deterioration observed in the patients' psychological evaluation, speech, or assessment of gait and balance. The scores were significantly lower (p = 0.01) in parts A and B of FTMRS one year after GKT. In post hoc analysis, the scores did not differ significantly between V0 and V24. In FTMRS part C (activities of daily living), no significant change was observed. There was no significant difference in total UPDRS part III score or in score of UPDRS part III domains 3 and 4 ('tremor at rest' and 'action and postural tremor of hands') between measurements. CONCLUSIONS: UGKT may be a safe treatment modality if performed in an experienced centre. Tremor reduction may diminish over time, and UGKT did not lead to cognitive, gait or speech deterioration in a long-term observation.

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.

Cannabis in Parkinson's Disease - the patient's perspective versus clinical trials: a systematic literature review.

Cannabis and cannabinoids are often considered in the treatment of Parkinson's Disease (PD). The purpose of this paper was to perform a systematic review of the available data on cannabis treatment. We aimed to assess randomised trials as well as surveys among patients. We identified 569 papers on PD and cannabinoid treatment. Of these, there were only seven papers featuring randomised trials on the effects of different cannabinoids on PD. The results of these trials did not support the efficacy of cannabinoids in the treatment of motor signs of PD. Based on the available data, we conclude that there is currently insufficient data to support the administration of cannabinoids to PD patients. Larger, randomised studies of cannabis use in PD should be conducted.

Movement disorders associated with chromosomal aberrations diagnosed in adult patients.

INTRODUCTION: Chromosomal aberrations are rare but important causes of various movement disorders. In cases of movement disorders associated with dysmorphic features, multiorgan involvement and/or intellectual disability, the identification of causative chromosomal aberrations should be considered. AIM OF THE STUDY: The purpose of this article was to summarise clinical findings in six patients with dystonia and two with parkinsonism and identified chromosomal aberrations in a single-centre prospective study. MATERIALS AND METHODS: 15 adult patients with dystonia or parkinsonism were referred to array comparative genomic hybridisation (aCGH) testing from our Department of Neurology between 2014 and 2019. Additionally, one patient had a karyotype examination. Detailed clinical, psychological and radiological diagnostics were performed in each case. RESULTS: Chromosomal aberrations were identified in six patients with dystonia and two with parkinsonism. Two patients were identified with aberrations associated with de Grouchy syndrome. We also reported generalised dystonia in patients with deletion in 3q26.31 and duplication in 3p26.3, as well as dystonia and hypoacusis in a patient with duplication in Xq26.3. One patient was diagnosed with duplication in 21q21.1. Early-onset parkinsonism was a manifestation of deletion in the 2q24.1 region. Late onset parkinsonism was also present in the patient with the most severe aberrations (duplication 1q21.1q44; deletion 10p15.3p15.1; deletion 10q11.21). CONCLUSIONS: Dystonia and parkinsonism are possible manifestations of chromosomal aberrations. Chromosomal aberrations should be excluded in patients with early-onset movement disorders and concomitant dysmorphic features and/or intellectual disability. It is important to include this cause of movement disorders in future classifications. aCGH can be a valuable diagnostic tool in the evaluation of movement disorder aetiology.

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.

In search of Parkinson's disease biomarkers - is the answer in our mouths? A systematic review of the literature on salivary biomarkers of Parkinson's disease.

The identification of reliable biomarkers of Parkinson's disease (PD) is a pivotal step in the introduction of causal therapies. Saliva is a biofluid which may be involved in synuclein pathology in PD. We have reviewed current studies on salivary proteins and compounds in PD patients and healthy controls, and their potential application as biomarkers. A systematic literature search of the Pubmed and Scopus databases was performed. A total of 198 studies were screened, of which 20 were included in our qualitative analysis. We conclude that the oligomeric form of salivary alpha synuclein is higher in PD patients, and that this may serve as a potential biomarker of PD. Salivary DJ-1 concentrations fail to differentiate PD patients from controls. Other enzymes and substances (heme oxygenase-1, nitric oxide, acetylcholinesterase) have been assessed in single studies. Salivary cortisol levels are higher in PD than in healthy subjects. Further validation of these findings is needed. Saliva may be a promising source of biomarkers in PD.

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.

Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) - a case report and review of literature.

CANVAS (cerebellar ataxia with neuropathy and vestibular areflexia syndrome) is a rare neurological syndrome of unknown etiology. The main clinical features include bilateral vestibulopathy, cerebellar ataxia and sensory neuropathy. An abnormal visually enhanced vestibulo-ocular reflex is the hallmark of the disease. We present a case of 58-year-old male patient who has demonstrated gait disturbance, imbalance and paresthesia of feet for 2 years. On examination ataxia of gait, diminished knee and ankle reflexes, absence of plantar reflexes, fasciculations of thigh muscles, gaze-evoked downbeat nystagmus and abnormal visually enhanced vestibulo-ocular reflex were found. Brain magnetic resonance imaging revealed cerebellar atrophy. Vestibular function testing showed severely reduced horizontal nystagmus in response to bithermal caloric stimulation. Nerve conduction study revealed loss of upper and lower limb sensory nerve action potentials. The course of illness was progressive with ataxic gait and unsteadiness as the most disabling symptoms. We report 4-year follow-up of the patient since the beginning of the disease.

Pyruvate dehydrogenase-E1α deficiency presenting as generalized dystonia: A genetic diagnosis with important clinical implications.

Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disease mostly associated with severe lactic acidosis, rapid progression of neurological symptoms and death during childhood. We present a 33-year-old male with PDC deficiency caused by a Val262Leu mutation in PDHA1gene. He demonstrated generalized dystonia affecting trunk and upper extremities and paraparesis as the most significant features, with onset of symptoms at age 8. Brain MRI showed bilaterally increased signal within the globus pallidus, typical of Leigh syndrome. A periodic lactate increase in serum and cerebrospinal fluid was detected. We describe a case of pyruvate dehydrogenase deficiency being diagnosed only 25 years after the onset of symptoms and highlight PDHC deficiency as a possible cause of treatable dystonia in childhood, which may respond well to thiamine and levodopa treatment.

Impact of Physical Exercise on Levodopa Therapy Across Parkinson's Disease Stages.

Background: Levodopa is the gold standard of treatment in Parkinson's disease (PD). Its clinical effect changes as the disease progresses. Wearing off is a frequent first manifestation of motor fluctuations. Some patients with advanced PD report faster wearing off after physical exercise. Objective: The aim was to assess if pharmacokinetics of levodopa is influenced by physical exercise in patients with different disease advancement. Methods: 22 patients with PD (12 untreated with levodopa and 10 with motor fluctuations) and 7 healthy controls (HC) were included. Plasma samples were collected at 9 fixed timepoints following administration of levodopa/benserazide 200/50 mg for two days: rest day and standardized physical exercise day. Clinical assessment with Unified Parkinson Disease Rating Scale part III (UPDRS III) was performed in fixed timepoints. Liquid chromatography-tandem mass spectrometry was used to measure levodopa concentrations. Results: No differences between the HC, levodopa naïve and advanced PD groups were observed regarding selected pharmacokinetic parameters. In advanced PD and HC no differences in pharmacokinetic parameters of levodopa with and without effort were observed. In levodopa naïve PD group higher mean residence time after rest than after exercise (168.9±48.3 min vs. 145.5±50.8 min; p = 0.026) was observed. In advanced PD group higher UPDRS III score (14.45±5.5 versus 20.9±6.1 points, p = 0.04) was observed after exercise. Conclusions: The deterioration of motor status of advanced PD patients after physical effort is not reflected by changes in pharmacokinetics but rather mediated by central mechanisms.

Microbiota Dysbiosis in Parkinson Disease-In Search of a Biomarker.

Numerous studies have highlighted the role of the gastrointestinal system in Parkinson disease pathogenesis. It is likely triggered by proinflammatory markers produced by specific gut bacteria. This review's aim is to identify gut bacterial biomarkers of Parkinson disease. A comprehensive search for original research papers on gut microbiota composition in Parkinson disease was conducted using the PubMed, Embase, and Scopus databases. Research papers on intestinal permeability, nasal and oral microbiomes, and interventional studies were excluded. The yielded results were categorized into four groups: Parkinson disease vs. healthy controls; disease severity; non-motor symptoms; and clinical phenotypes. This review was conducted in accordance with the PRISMA 2020 statement. A total of 51 studies met the eligibility criteria. In the Parkinson disease vs. healthy controls group, 22 bacteria were deemed potentially important. In the disease severity category, two bacteria were distinguished. In the non-motor symptoms and clinical phenotypes categories, no distinct pathogen was identified. The studies in this review report bacteria of varying taxonomic levels, which prevents the authors from reaching a clear conclusion. Future research should follow a unified methodology in order to identify potential biomarkers for Parkinson disease.

Review of the epidemiology and variability of LRRK2 non-p.Gly2019Ser pathogenic mutations in Parkinson's disease.

Parkinson's disease (PD) is a heterogenous neurodegenerative disorder. Genetic factors play a significant role, especially in early onset and familial cases. Mutations are usually found in the LRRK2 gene, but their importance varies. Some mutations, such as p.Arg1441Cys or other alterations in the 1441 codon, show clear correlation with PD, whereas others are risk factors found also in healthy populations or have neglectable consequences. They also exhibit various prevalence among different populations. The aim of this paper is to sum up the current knowledge regarding the epidemiology and pathogenicity of LRRK2 mutations, other than the well-established p.Gly2019Ser. We performed a review of the literature using PubMed database. 103 publications met our inclusion criteria. p.Arg1441Cys, p.Arg1441Gly, p.Arg1441His, p.Arg1441Ser are the most common pathogenic mutations in European populations, especially Hispanic. p.Asn1437His is pathogenic and occurs mostly in the Scandinavians. p.Asn1437Ser and p.Asn1437Asp have been reported in German and Chinese cohorts respectively. p.Ile2020Thr is a rare pathogenic mutation described only in a Japanese cohort. p.Met1869Thr has only been reported in Caucasians. p.Tyr1699Cys, p.Ile1122Val have only been found in one family each. p.Glu1874Ter has been described in just one patient. We found no references concerning mutation p.Gln416Ter. We also report the first case of a Polish PD family whose members carried p.Asn1437His.

Mechanisms of Neurodegeneration in Various Forms of Parkinsonism-Similarities and Differences.

Parkinson's disease (PD), dementia with Lewy body (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA) belong to a group of neurodegenerative diseases called parkinsonian syndromes. They share several clinical, neuropathological and genetic features. Neurodegenerative diseases are characterized by the progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra- and intracellular accumulation of misfolded proteins. The parkinsonian diseases affect distinct areas of the brain. PD and MSA belong to a group of synucleinopathies that are characterized by the presence of fibrillary aggregates of α-synuclein protein in the cytoplasm of selected populations of neurons and glial cells. PSP is a tauopathy associated with the pathological aggregation of the microtubule associated tau protein. Although PD is common in the world's aging population and has been extensively studied, the exact mechanisms of the neurodegeneration are still not fully understood. Growing evidence indicates that parkinsonian disorders to some extent share a genetic background, with two key components identified so far: the microtubule associated tau protein gene (MAPT) and the α-synuclein gene (SNCA). The main pathways of parkinsonian neurodegeneration described in the literature are the protein and mitochondrial pathways. The factors that lead to neurodegeneration are primarily environmental toxins, inflammatory factors, oxidative stress and traumatic brain injury.

Proteomic Profile of Saliva in Parkinson's Disease Patients: A Proof of Concept Study.

Parkinson's disease (PD) is a progressive neurodegenerative disorder. It affects many organs. Lewy bodies-a histopathological "hallmark" of PD-are detected in about 75% of PD submandibular gland samples. We hypothesize that saliva can be a source of biomarkers of PD. The aim of the study was to evaluate and compare the salivary proteome of PD patients and healthy controls (HC). Salivary samples from 39 subjects (24 PD patients, mean age 61.6 ± 8.2; 15 HC, mean age 60.9 ± 6.7) were collected. Saliva was collected using RNA-Pro-Sal kits. Label-free LC-MS/MS mass spectrometry was performed to characterize the proteome of the saliva. IPA analysis of upstream inhibitors was performed. A total of 530 proteins and peptides were identified. We observed lower concentrations of S100-A16, ARP2/3, and VPS4B in PD group when compared to HC. We conclude that the salivary proteome composition of PD patients is different than that of healthy controls. We observed a lower concentration of proteins involved in inflammatory processes, exosome formation, and adipose tissue formation. The variability of expression of proteins between the two groups needs to be considered.

Soluble Urokinase Plasminogen Activator Receptor Levels Correlation with Other Inflammatory Factors in Prognosis of Disability and Death in Patients with Ischemic Stroke.

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker elevated in cardiovascular diseases. The aim of this 3-year follow-up prospective study was to evaluate suPAR levels in patients with a first ischemic stroke in correlation with CRP, PCT, NT-proCNP and endothelin 1-21 and to investigate the impact of suPAR on the outcome. Fifty-one patients (mean age 73.7+ = 11.9 years, 26 female and 25 male) were included. Samples were collected on the first (suPAR 1), third (suPAR 3) and seventh days after stroke onset (suPAR 7). Plasma samples were analyzed using ELISA. A phone interview was conducted to collect follow-up information after 24 and 36 months (modified Rankin Scale, mRS). A positive correlation between suPAR levels and other inflammatory biomarkers (except endothelin 3) was observed. A positive correlation between suPAR 3 and mRS score at 24 months was observed (p = 0.042). The logistic regression model revealed no significant effect of suPAR on death occurrence in the first 24 months: suPAR 1 (p = 0.8794), suPAR 3 (p = 0.2757), and suPAR 7 (p = 0.3652). The suPAR level is a potential inflammatory marker in ischemic stroke, and there is a correlation with other markers. There is no major impact on mortality. However, the suPAR level is associated with a degree of disability or dependence in daily activities 2 years after a stroke.

The matter of significance - Has the p.(Glu121Lys) variant of TOR1A gene a pathogenic role in dystonia or Parkinson disease?

Next Generation Sequencing (NGS), has now become a very powerful tool for decoding variants of genes involved in pathogenesis of number of human disorders. One of the challenges of this method is to decipher the real pathogenic variants from a number of identified, not related to the disorder in analyzed case. Another issue is recognition of new phenotypes previously unrecognized but related to new variants combinations' in known genes. The other aspect is the HGMD or ClinVar mutation databases usage in data interpretation. The aim of this paper is to discuss pathogenicity of p.(Glu121Lys) missense mutation in the TOR1A gene previously described as dystonia causing variant. The patient diagnosed with typical Parkinson disease and positive family history was included into analysis. Also the internal whole exome sequencing (WES) database containing 600 subjects who has performed WES due to different causes was searched. All subjects had WES performed on SureSelect Human All Exon v.6 enrichment, Illumina NovaSeq 6000 platform, (annotations according to internal Institute Mother and Child's pipeline). The TOR1A p.(Glu121Lys) heterozygous mutation was revealed in 1 patient diagnosed with PD and 2 healthy subjects who has no dystonia symptoms. To conclude the TOR1A p.Glu121Lys variant should not be recognized as clearly pathogenic now.

Serum amino acid profile in patients with Parkinson's disease.

Amino acids play numerous roles in the central nervous system, serving as neurotransmitters, neuromodulators and regulators of energy metabolism. The free amino acid profile in serum of Parkinson's disease (PD) patients may be influenced by neurodegeneration, mitochondrial dysfunction, malabsorption in the gastroenteric tract and received treatment. The aim of our study was the evaluation of the profile of amino acid concentrations against disease progression. We assessed the amino acid profile in the serum of 73 patients divided into groups with early PD, late PD with dyskinesia and late PD without dyskinesia. Serum amino acid analysis was performed by high-pressure liquid chromatography with fluorescence detection. We observed some significant differences amongst the groups with respect to concentrations of alanine, arginine, phenylalanine and threonine, although no significant differences were observed between patients with advanced PD with and without dyskinesia. We conclude that this specific amino acid profile could serve as biochemical marker of PD progression.

The Neuromodulatory Impact of Subthalamic Nucleus Deep Brain Stimulation on Gait and Postural Instability in Parkinson's Disease Patients: A Prospective Case Controlled Study.

Background: Subthalamic nucleus deep brain stimulation (STN-DBS) has been an established method in improvement of motor disabilities in Parkinson's disease (PD) patients. It has been also claimed to have an impact on balance and gait disorders in PD patients, but the previous results are conflicting. Objective: The aim of this prospective controlled study was to evaluate the impact of STN-DBS on balance disorders in PD patients in comparison with Best-Medical-Therapy (BMT) and Long-term-Post-Operative (POP) group. Methods: DBS-group consisted of 20 PD patients (8F, 12M) who underwent bilateral STN DBS. POP-group consisted of 14 post-DBS patients (6F, 8M) in median 30 months-time after surgery. Control group (BMT-group) consisted of 20 patients (11F, 9M) who did not undergo surgical intervention. UPDRS III scale and balance tests (Up And Go Test, Dual Task- Timed Up And Go Test, Tandem Walk Test) and posturography parameters were measured during 3 visits in 9 ± 2months periods (V1, V2, V3) 4 phases of treatment (BMT-ON/OFF, DBS-ON/OFF). Results: We have observed the slowdown of gait and postural instability progression in first 9 post-operative months followed by co-existent enhancement of balance disorders in next 9-months evaluation (p < 0.05) in balance tests (Up and Go, TWT) and in posturography examination parameters (p < 0.05). The effect was not observed neither in BMT-group nor POP-group (p > 0.05): these groups revealed constant progression of static and dynamic instability (p > 0.05). Conclusions: STN-DBS can have modulatory effect on static and dynamic instability in PD patients: it can temporarily improve balance disorders. mainly during first 9 post-operative months, but with possible following deterioration of the symptoms in next post-operative months.