Crosschecking the subjective everyday Parkinson's experience among patients and their caregiving spouses: French versions of the Belastungsfragebogen Parkinson Kurzversion (Bela-P-k and Bela-A-k).

BACKGROUND: Parkinson's disease (PD) affects all dimensions of the patient's and the caregiver's daily life. There are two questionnaires in German, Bela-A-k (for caregivers) and Bela-P-k (for PD patients), that can be used to assess the PD-related psychosocial burden in a dyad. The patient's and the caregiver's perspective of living with PD can be crosschecked. Four dimensions are explored: physical performance, emotional load, social relationships, and couple/family life. OBJECTIVES: The purpose of the study was to translate these questionnaires into French and to test them among patients and caregivers. METHODS: The questionnaires were translated from German into French by forward and backward translation, followed by a cultural crosscheck. Participants were invited to test the consensual French version in its online administered version created via Lime Survey® software. Participants filled out the questionnaires twice (five-day interval) according to the test-retest method. Data analysis was performed with SPSS software. RESULTS: Thirty dyads were recruited and eighteen completed the study. Bela-A-K showed strong temporal stability, though it was weak for the social relationships dimension. Bela-P-k showed strong internal consistency, but significant test-retest differences for ten items due to day-by-day changes in patient status. CONCLUSIONS: The questionnaires are useful and reliable for dyad-centered follow-up in case of PD. Some items of the Bela-P-k were simplified to improve its temporal stability, considering the patient's changing status through the day. The items concerning social relationships were adjusted for the Bela-A-k.

Quantitative brainstem and spinal MRI in amyotrophic lateral sclerosis: implications for predicting noninvasive ventilation needs.

BACKGROUND: Respiratory complications resulting from motor neurons degeneration are the primary cause of death in amyotrophic lateral sclerosis (ALS). Predicting the need for non-invasive ventilation (NIV) in ALS is important for advance care planning and clinical trial design. The aim of this study was to assess the potential of quantitative MRI at the brainstem and spinal cord levels to predict the need for NIV during the first six months after diagnosis. METHODS: Forty-one ALS patients underwent MRI and spirometry shortly after diagnosis. The need for NIV was monitored according to French health guidelines for 6 months. The performance of four regression models based on: clinical variables, brainstem structures volumes, cervical spinal measurements, and combined variables were compared to predict the need for NIV within this period. RESULTS: Both the clinical model (R2 = 0.28, AUC = 0.85, AICc = 42.67, BIC = 49.8) and the brainstem structures' volumes model (R2 = 0.30, AUC = 0.85, AICc = 40.13, BIC = 46.99) demonstrated good predictive performance. In addition, cervical spinal cord measurements model similar performance (R2 = 0.338, AUC = 0.87, AICc = 37.99, BIC = 44.49). Notably, the combined model incorporating predictors from all three models yielded the best performance (R2 = 0.60, AUC = 0.959, AICc = 36.38, BIC = 44.8). These findings are supported by observed positive correlations between brainstem volumes, cervical (C4/C7) cross-sectional area, and spirometry-measured lung volumes. CONCLUSIONS: Our study shows that brainstem volumes and spinal cord area are promising measures to predict respiratory intervention needs in ALS.

Comparison of spinal magnetic resonance imaging and classical clinical factors in predicting motor capacity in amyotrophic lateral sclerosis.

BACKGROUND: Motor capacity is crucial in amyotrophic lateral sclerosis (ALS) clinical trial design and patient care. However, few studies have explored the potential of multimodal MRI to predict motor capacity in ALS. This study aims to evaluate the predictive value of cervical spinal cord MRI parameters for motor capacity in ALS compared to clinical prognostic factors. METHODS: Spinal multimodal MRI was performed shortly after diagnosis in 41 ALS patients and 12 healthy participants as part of a prospective multicenter cohort study, the PULSE study (NCT00002013-A00969-36). Motor capacity was assessed using ALSFRS-R scores. Multiple stepwise linear regression models were constructed to predict motor capacity at 3 and 6 months from diagnosis, based on clinical variables, structural MRI measurements, including spinal cord cross-sectional area (CSA), anterior-posterior, and left-to-right cross-section diameters at vertebral levels from C1 to T4, and diffusion parameters in the lateral corticospinal tracts (LCSTs) and dorsal columns. RESULTS: Structural MRI measurements were significantly correlated with the ALSFRS-R score and its sub-scores. And as early as 3 months from diagnosis, structural MRI measurements fit the best multiple linear regression model to predict the total ALSFRS-R (R2 = 0.70, p value = 0.0001) and arm sub-score (R2 = 0.69, p value = 0.0002), and combined with DTI metric in the LCST and clinical factors fit the best multiple linear regression model to predict leg sub-score (R2 = 0.73, p value = 0.0002). CONCLUSIONS: Spinal multimodal MRI could be promising as a tool to enhance prognostic accuracy and serve as a motor function proxy in ALS.

Indication for molecular testing by multiplex ligation-dependent probe amplification in parkinsonism.

BACKGROUND AND PURPOSE: The monogenic forms of Parkinson's disease represent <10% of familial cases and a still lower frequency of sporadic cases. However, guidelines to orient genetic testing are lacking. The aim was to establish the interest of multiplex ligation-dependent probe amplification (MLPA) as a primary screening test and to propose clinical criteria to guide genetic diagnostic tests for patients with suspected Mendelian Parkinson's disease. METHODS: In all, 567 patients with parkinsonism from 547 unrelated families were recruited and two MLPAs were performed for each. All pathogenic G2019S variants in the LRRK2 gene were confirmed by Sanger sequencing and the PRKN gene was screened for a second mutation in the cases of one heterozygous structural variant in the PRKN gene. RESULTS: The performance of MLPA was 51/567 (9%) for the entire cohort and included 27 (4.8%) LRRK2 G2019S mutations, 19 (3.4%) PRKN mutations and five (0.9%) SNCA locus duplications. The variables significantly associated with a positive test in the total cohort were North African ancestry (p < 0.0001), female sex (p = 0.004) and younger age at onset (p < 0.0008). CONCLUSIONS: Retrospective analysis allowed us to refine our indication criteria: (i) North African ancestry, (ii) an age at onset <40 years or (iii) a familial history of parkinsonism with at least one affected first-degree relative. Our study highlights the interest of MLPA testing for other parkinsonism cases with a family history, especially for patients with dementia with Lewy bodies or a multiple-system-atrophy-like phenotype.

SARS-CoV-2-related Multisystem Inflammatory Syndrome in Adult complicated by myocarditis and cardiogenic shock.

Multisystem Inflammatory Syndrome in Adult (MIS-A) is a rare COVID-19 complication, presenting as fever with laboratory evidence of inflammation, severe illness requiring hospitalization and multisystem organ involvement. We report on a 25-year-old man presenting with fever, rash, abdominal pain, diarrhoea and vomiting following prior asymptomatic COVID-19 infection. He developed refractory shock and type 1 respiratory insufficiency requiring mechanical ventilation. Diagnostic testing revealed significant inflammation, anemia, thrombocytopenia, acute kidney injury, hepatosplenomegaly, colitis, lymphadenopathy and myocarditis necessitating inotropy. Ventilatory, vasopressor and inotropic support was weaned following pulse corticosteroids and intravenous immunoglobulins. Heart failure therapy was started. Short-term follow-up shows resolution of inflammation and cardiac dysfunction.

Use of levodopa-carbidopa intestinal gel to treat patients with multiple system atrophy.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) is an effective treatment for late-stage Parkinson's disease (PD) but had not been evaluated in levodopa-responsive patients with the parkinsonian variant of multiple system atrophy (MSA-P) and motor fluctuations. We aimed to assess the safety of LCIG in MSA-P patients. METHODS: In a retrospective, single-center study, we analyzed clinical and treatment-related data for all patients with MSA-P or PD treated with LCIG between December 2004 and November 2017. Adverse events (AEs) were classified into three classes: AEs related to gastrointestinal effects or to the PEG-J procedure, AEs related to the device, and AEs related to the pharmacological effect of LCIG. RESULTS: 7 MSA-P and 63 PD patients had been treated with LCIG for a median [interquartile range] period of 31 [16;43] and 19 [8;45] months, respectively. There were no significant intergroup differences in safety. Enteral nutrition was introduced at the same time as LCIG treatment in 4 (57%) MSA-P patients. In the MSA-P and PD groups, LCIG was associated with a better Global Clinical Impression score and discontinuation of oral anti-parkinsonian drugs (in 43% and 27% of cases, respectively). CONCLUSIONS: LCIG treatment is feasible in MSA-P patients with severe motor complications. The safety profile is similar to that seen in PD.

Deciphering the natural history of SCA7 in children.

BACKGROUND AND PURPOSE: Childhood-onset autosomal dominant cerebellar ataxia type 7 (SCA7) is a severe disease which leads to premature loss of ambulation and death. Early diagnosis of SCA7 is of major importance for genetic counselling and still relies on specific genetic testing, driven by clinical expertise. However, the precise phenotype and natural history of paediatric SCA7 has not yet been fully described. Our aims were to describe the natural history of SCA7 in a large multicentric series of children of all ages, and to find correlates to variables defining this natural history. METHODS: We collected and analysed clinical data from 28 children with proven SCA7. All had clinical manifestations of SCA7 and either a definite number of CAG repeats in ATXN7 or a long expansion > 100 CAG. RESULTS: We identified four clinical presentation patterns related to age at onset. Children of all age groups had cerebellar atrophy and retinal dystrophy. Our data, combined with those in the literature, suggest that definite ranges of CAG repeats determine paediatric SCA7 subtypes. The number of CAG repeats inversely correlated to all variables of the natural history. Age at gait ataxia onset correlated accurately to age at loss of walking ability and to age at death. CONCLUSION: SCA7 in children has four presentation patterns that are roughly correlated to the number of CAG repeats. Our depiction of the natural history of SCA7 in children may help in monitoring the effect of future therapeutic trials.

Safety and effectiveness of levodopa-carbidopa intestinal gel for advanced Parkinson's disease: A large single-center study.

BACKGROUND: Treatment with levodopa-carbidopa intestinal gel (LCIG) can effectively relieve motor and non-motor symptoms in advanced Parkinson's disease (PD). However, adverse events (AEs) are frequent. OBJECTIVE: To describe AEs associated with LCIG treatment and the main reasons for treatment discontinuation. We also looked for factors that were potentially predictive of serious AEs and assessed the effectiveness of and satisfaction with LCIG. METHOD: We retrospectively analyzed data on AEs in patients treated with LCIG at a French university medical center. For patients still receiving treatment at last follow-up, effectiveness was assessed according to the Clinical Global Impression (CGI) scale and the Movement Disorders Society - Unified Parkinson's Disease Rating Scale motor score. RESULTS: Of the 63 patients treated with LCIG for a mean (range) of 19 months (8-47), 57 (90%) experienced at least one AE (340 AEs in total). Most of the AEs (in 69.8% of the patients) were related to percutaneous endoscopic gastrostomy with a jejunal tube (PEG-J) or affected the gastrointestinal tract (granuloma, leakage, or a local infection). Device-related AEs (such as PEG-J removal and device occlusion) were frequent (in 63.5% of patients). Forty-three patients (68%) required at least one additional endoscopic procedure. Dopatherapy-related AEs occurred in 30 patients (48%). Most of the AEs occurred long after treatment initiations, and only a small proportion led to discontinuation. On the CGI scale, 53 patients (84.4%) considered that their condition had improved during LCIG treatment. CONCLUSION: Despite the high frequency of AEs, patients with advanced PD gain clinical benefit from treatment with LCIG. This treatment requires a competent, multidisciplinary team on site.

[Supervised off-label prescribing of methylphenidate in adult ADHD]. / Prescriptions hors AMM supervisées de méthylphénidate dans le TDAH de l'adulte.

OBJECTIVE: Off-label prescription is a common practice in psychiatry, raising health and economic concerns. Collegial consultation could allow a framed prescription of treatments that are not authorized in specific indications. Attention Deficit Hyperactivity in adult populations (ADHD) is a striking example of a pathology where off-label prescription is frequent. First considered to be a childhood disorder, the awareness of this condition in adults is increasing, leading to the development of new clinical practices and treatments. However, the adult ADHD diagnosis and its management are still emerging in France despite a high prevalence. Treatment of adult ADHD relies on methylphenidate prescription, but the initiation of this drug is not authorized in adult populations. Methylphenidate is a central nervous system stimulant that is structurally close to amphetamine and acts as a norepinephrine and dopamine reuptake inhibitor. Due to these pharmacological properties, neuropsychiatric and cardiovascular side-effects could occur. Furthermore, its addictive potential has led France to classify it as a psychoactive drug, dispensed via secured prescription. The first prescription and the one-year follow-up are restricted to neurologists, paediatrics, psychiatrists and sleep disorders specialists at hospital. The objective of this article is to propose a multidisciplinary framework for the off-label prescription of methylphenidate in adult ADHD. METHODS: The Multidisciplinary Advice Consultation for Exceptional Addiction Treatments (Consultation d'Avis Multidisciplinaire de Traitements d'Exception en Addictologie CAMTEA) was first set up in Lille for the prescription of baclofen in alcohol dependence and was then extended to topiramate in binge eating disorder. This procedure has been adapted to the particularities of ADHD in adult populations, the differential diagnosis (bipolar disorder, depressive disorder, anxious disorder, personality disorder, substance use disorder) and the co-morbidities requiring a full psychiatric and neuropsychological assessment. Moreover, a particular attention has been paid to the monitoring of neuropsychiatric, cardiovascular and misuse risk because of the potential side-effects of methylphenidate. RESULTS: The proposed prescription framework is structured into several specialized consultations. A first psychiatric evaluation aims to diagnose adult ADHD, using the French version of the Diagnostisch Interview Voor ADHD 2.0 questionnaire (DIVA 2.0), and to assess the quality of life impact with the Weiss Functional Inventory Rating Scale (WIFRS). It also searches for the presence of differential diagnosis or co-morbidities. The second appointment consists of a pharmacological evaluation that aims to search for contraindications and potential drug interaction. A neuropsychological evaluation based on standardized tests (Weschler Adulte Intelligence Scale [WAIS IV], Conner's Continuous Performance Test 3 [CPT] and the Minnesota Multiphasic Personnality Inventory [MMPI]) is also required to evaluate neurocognitive disabilities and personality features. Once the parameters of the different assessments have been collected, the synthesis is presented during a multidisciplinary meeting in order to assess the risk-benefit ratio for each patient. Several specialties are involved in this multidisciplinary meeting: psychiatry, addictology, general medicine, addictovigilance, pharmacovigilance and neuropsychology. One strategy among three possibilities can be decided: (1) contraindication to treatment with methylphenidate, (2) attention deficit disorder that does not require medication management, and (3) indication of treatment with methylphenidate with the choice of the pharmacological form (immediate or prolonged release). A biological check-up and an electrocardiogram are carried out systematically before any treatment. If the decision is made to initiate treatment, it is started at the lowest dosage and followed by a titration phase. A weekly follow-up is carried out during the titration phase in order to assess treatment efficacy and safety. After treatment stabilization, the general practitioner can carry out the renewal, and the patient will be reassessed within the framework of the multidisciplinary consultation every 3 months. CONCLUSION: When an off-label prescription is being considered, it must comply with the basic rules of good clinical practice, and the benefit/risk ratio should be constantly reassessed. The proposed multidisciplinary framework, adapted to the characteristics of adult ADHD and the pharmacological properties of methylphenidate, appears to be an interesting strategy to meet the requirements of the good clinical practice. The complementary assessments carried out and the collegial framework allow enhancing the patient's follow-up and minimize the drug risk, particularly in the psychiatric, addictive and cardiovascular adverse events. Finally, this framework could also help the monitoring of other off-label treatments for ADHD, such as atomoxetine or guanfacine.

MRI of the cervical spinal cord predicts respiratory dysfunction in ALS.

For patients with amyotrophic lateral sclerosis (ALS), the primary therapeutic goal is to minimize morbidity. Non-invasive ventilation improves survival. We aim to assess whether Magnetic Resonance Imaging (MRI) of the cervical spinal cord predicts the progression of respiratory disorders in ALS. Brain and spinal MRI was repeatedly performed in the SOD1G86R mouse model, in 40 patients and in healthy controls. Atrophy, iron overload, white matter diffusivity and neuronal loss were assessed. In Superoxide Dismutase-1 (SOD1) mice, iron accumulation appeared in the cervical spinal cord at symptom onset but disappeared with disease progression (after the onset of atrophy). In ALS patients, the volumes of the motor cortex and the medulla oblongata were already abnormally low at the time of diagnosis. Baseline diffusivity in the internal capsule was predictive of functional handicap. The decrease in cervical spinal cord volume from diagnosis to 3 months was predictive of the change in slow vital capacity at 12 months. MRI revealed marked abnormalities at the time of ALS diagnosis. Early atrophy of the cervical spinal cord may predict the progression of respiratory disorders, and so may be of value in patient care and as a primary endpoint in pilot neuroprotection studies.

Ethical considerations and palliative care in patients with amyotrophic lateral sclerosis: A review.

Amyotrophic lateral sclerosis (ALS) is not a curable disease, but it is treatable. By definition, much of the care provided to ALS patients is palliative, even though active life-sustaining strategies are available to prolong survival. Healthcare professionals must develop communication skills that help patients cope with the inexorable progression of the disease and the inevitability of death. Symptomatic treatments as well as respiratory insufficiency and nutritional life-sustaining therapies must be regularly evaluated as the disease progresses, without losing sight of the burden placed on the patient's non-professional caregivers. The decision-making process regarding tracheostomy with invasive ventilation (TIV) is of greater complexity. Providing full information is crucial. Several long interviews are necessary to explain, discuss and allow assimilation of the information. Also, physicians should be careful not to focus exclusively on the biomedical aspects of disease, as ALS patients generally welcome the opportunity to discuss end-of-life issues with their physicians. Psychological factors, education level and cognitive status (especially the level of executive dysfunction) have a major influence on their decisions. However, as many patients do not complete advance directives with regard to TIV, advance care planning may instead be suggested in anticipation of emergency interventions. This should be discussed by healthcare professionals and the patient, and based on the wishes of the patient and caregiver(s), and communicated to all healthcare professionals. Many healthcare professionals are involved in the management of an ALS patient: they include not only those at ALS centers who provide diagnosis, follow-up and treatment initiation (particularly for respiratory and nutritional care), but also the medical and social care networks involved in disability support and home care. Specialist palliative care teams can work in partnership with ALS centers early in the course of the disease, with the center coordinating information-sharing and collaborative discussions.

Clinical features of amyotrophic lateral sclerosis and their prognostic value.

In classic amyotrophic lateral sclerosis (ALS), the relative degree of impairment of cortical vs spinal motor neurons serving the different body regions is highly variable. This means that an accurate, systematic assessment of the patient's clinical presentation is essential for both the diagnosis and prognosis. The patient's phenotype, rate of disease progression, time of onset (if early) of respiratory failure and nutritional status all have prognostic value, and should be specified in the nosological classification of the disease.

Continuous cerebroventricular administration of dopamine: A new treatment for severe dyskinesia in Parkinson's disease?

In Parkinson's disease (PD) depletion of dopamine in the nigro-striatal pathway is a main pathological hallmark that requires continuous and focal restoration. Current predominant treatment with intermittent oral administration of its precursor, Levodopa (l-dopa), remains the gold standard but pharmacological drawbacks trigger motor fluctuations and dyskinesia. Continuous intracerebroventricular (i.c.v.) administration of dopamine previously failed as a therapy because of an inability to resolve the accelerated dopamine oxidation and tachyphylaxia. We aim to overcome prior challenges by demonstrating treatment feasibility and efficacy of continuous i.c.v. of dopamine close to the striatum. Dopamine prepared either anaerobically (A-dopamine) or aerobically (O-dopamine) in the presence or absence of a conservator (sodium metabisulfite, SMBS) was assessed upon acute MPTP and chronic 6-OHDA lesioning and compared to peripheral l-dopa treatment. A-dopamine restored motor function and induced a dose dependent increase of nigro-striatal tyrosine hydroxylase positive neurons in mice after 7days of MPTP insult that was not evident with either O-dopamine or l-dopa. In the 6-OHDA rat model, continuous circadian i.c.v. injection of A-dopamine over 30days also improved motor activity without occurrence of tachyphylaxia. This safety profile was highly favorable as A-dopamine did not induce dyskinesia or behavioral sensitization as observed with peripheral l-dopa treatment. Indicative of a new therapeutic strategy for patients suffering from l-dopa related complications with dyskinesia, continuous i.c.v. of A-dopamine has greater efficacy in mediating motor impairment over a large therapeutic index without inducing dyskinesia and tachyphylaxia.

The value of magnetic resonance imaging as a biomarker for amyotrophic lateral sclerosis: a systematic review.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal, rapidly progressive neurodegenerative disease that mainly affects the motor system. A number of potentially neuroprotective and neurorestorative disease-modifying drugs are currently in clinical development. At present, the evaluation of a drug's clinical efficacy in ALS is based on the ALS Functional Rating Scale Revised, motor tests and survival. However, these endpoints are general, variable and late-stage measures of the ALS disease process and thus require the long-term assessment of large cohorts. Hence, there is a need for more sensitive radiological biomarkers. Various sequences for magnetic resonance imaging (MRI) of the brain and spinal cord have may have value as surrogate biomarkers for use in future clinical trials. Here, we review the MRI findings in ALS, their clinical correlations, and their limitations and potential role as biomarkers. METHODS: The PubMed database was screened to identify studies using MRI in ALS. We included general MRI studies with a control group and an ALS group and longitudinal studies even if a control group was lacking. RESULTS: A total of 116 studies were analysed with MRI data and clinical correlations. The most disease-sensitive MRI patterns are in motor regions but the brain is more broadly affected. CONCLUSION: Despite the existing MRI biomarkers, there is a need for large cohorts with long term MRI and clinical follow-up. MRI assessment could be improved by standardized MRI protocols with multicentre studies.

Powerhouse failure and oxidative damage in autosomal recessive spastic ataxia of Charlevoix-Saguenay.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neurodegenerative disease due to mutations in SACS, which encodes sacsin, a protein localized on the mitochondrial surface and possibly involved in mitochondrial dynamics. In view of the possible mitochondrial involvement of sacsin, we investigated mitochondrial activity at functional and molecular level in skin fibroblasts obtained from ARSACS patients. We observed remarkable bioenergetic damage in ARSACS cells, as indicated by reduced basal, adenosine triphosphate (ATP)-linked and maximal mitochondrial respiration rate, and by reduced respiratory chain activities and mitochondrial ATP synthesis. These phenomena were associated with increased reactive oxygen species production and oxidative nuclear DNA damage. Our results suggest that loss of sacsin is associated with oxidative stress and mitochondrial dysfunction, and thus highlight a novel mechanism in the pathogenesis of ARSACS. The involvement of mitochondria and oxidative stress in disease pathogenesis has been described in a number of other neurodegenerative diseases. Therefore, on the basis of our findings, which suggest a potential therapeutic role for antioxidant agents, ARSACS seems to fall within a larger group of disorders.

Brain metabolic abnormalities during gait with freezing in Parkinson's disease.

INTRODUCTION: Freezing of gait (FoG) is a debilitating gait disorder in Parkinson's disease (PD). In advanced PD patients with FoG, the supraspinal locomotor network may be dysregulated (relative to similar patients without FoG) during gait. Here, we sought to characterize the metabolism of locomotor networks involved in FoG. METHODS: Twenty-two PD patients (11 with off-drug FoG and 11 without) each underwent two [(18)F]-fluorodeoxyglucose PET brain scans in the off-drug state: one at rest and another during radiotracer uptake while performing a standardized gait trajectory that incorporated the usual triggers for FoG. RESULTS: For the 11 freezers, FoG was present for 39% (± 23%) of the time during the gait trajectory. The FoG-associated abnormalities were characterized by (i) hypometabolism in frontal regions (the associative premotor, temporopolar and orbitofrontal areas, i.e. Brodmann areas 6 and 8), (ii) hypermetabolism in the paracentral lobule (Brodmann area 5), and (iii) deregulation of the basal ganglia output (the globus pallidus and the mesencephalic locomotor region). CONCLUSION: FoG during a real gait task was associated with impaired frontoparietal cortical activation, as characterized by abnormally low metabolic activity of the premotor area (involved in the indirect locomotor pathway) and abnormally high metabolic activity of the parietal area (reflecting the harmful effect of external cueing).

Clinical implications of neuropharmacogenetics.

INTRODUCTION: Pharmacogenetics aims to identify the underlying genetic factors participating in the variability of drug response. Indeed, genetic variability at the DNA or RNA levels can directly or indirectly modify the pharmacokinetic or the pharmacodynamic parameters of a drug. The ultimate aim of pharmacogenetics is to move towards a personalised medicine by predicting responders and non-responders, adjusting the dose of the treatment, and identifying individuals at risk of adverse drug effects. METHODS: A literature research was performed in which we reviewed all pharmacogenetic studies in neurological disorders including neurodegenerative diseases, multiple sclerosis, stroke and epilepsy. RESULTS: Several pharmacogenetic studies have been performed in neurology, bringing insights into the inter-individual drug response variability and in the pathophysiology of neurological diseases. The principal implications of these studies for the management of patients in clinical practice are discussed. CONCLUSION/DISCUSSION: Although several genetic factors have been identified in the modification of drug response in neurological disorders, most of them have a marginal predictive effect at the single gene level, suggesting mutagenic interactions as well as other factors related to drug interaction and disease subtypes. Most pharmacogenetic studies deserve further replication in independent populations and, ideally, in pharmacogenetic clinical trials to demonstrate their relevance in clinical practice.

Gait and attentional performance in freezers under methylphenidate.

BACKGROUND: Attentional resources appear to be involved in the occurrence of FoG. The Parkgait study recently reported that methylphenidate reduces gait hypokinesia and freezing of gait (FoG) in advanced PD patients receiving STN-DBS in the off-dopaminergic drug condition. Methylphenidate is considered to improve attention. The primary objective of the present ancillary study was to determine whether methylphenidate reduced the interference between a cognitive task and gait in patients with FoG. The study's secondary objective was to compare attentional performance in methylphenidate-treated and placebo-treated patients. METHODS: A total of 24 patients (from two centers) were included in the study. Patients were randomly assigned 1:1 to a three-month course of methylphenidate (1mg/kg/day) or placebo. Patients were assessed after an acute L-dopa challenge. The primary outcome criterion was the stride length ratio ((dual-task stride length minus free gait stride length)/free gait stride length). Trials with FoG episodes were excluded from the analysis. Secondary outcomes included changes in reaction times for computerized attention tasks and FoG severity. RESULTS: When comparing patients receiving methylphenidate with those receiving placebo, we did not observe any significant differences in the interaction between the dual task and gait or in attentional performance. CONCLUSION: As in the main Parkgait study, methylphenidate did not reduce gait hypokinesia in patients receiving dopaminergic treatment. Our present results suggest that the reduction in the number of FoG episodes previously observed in patients on methylphenidate was neither due to interaction between a dual-task and gait nor an increase in attentional performance.

Comparative analysis of targeted metabolomics: dominance-based rough set approach versus orthogonal partial least square-discriminant analysis.

BACKGROUND: Metabolomics is an emerging field that includes ascertaining a metabolic profile from a combination of small molecules, and which has health applications. Metabolomic methods are currently applied to discover diagnostic biomarkers and to identify pathophysiological pathways involved in pathology. However, metabolomic data are complex and are usually analyzed by statistical methods. Although the methods have been widely described, most have not been either standardized or validated. Data analysis is the foundation of a robust methodology, so new mathematical methods need to be developed to assess and complement current methods. We therefore applied, for the first time, the dominance-based rough set approach (DRSA) to metabolomics data; we also assessed the complementarity of this method with standard statistical methods. Some attributes were transformed in a way allowing us to discover global and local monotonic relationships between condition and decision attributes. We used previously published metabolomics data (18 variables) for amyotrophic lateral sclerosis (ALS) and non-ALS patients. RESULTS: Principal Component Analysis (PCA) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA) allowed satisfactory discrimination (72.7%) between ALS and non-ALS patients. Some discriminant metabolites were identified: acetate, acetone, pyruvate and glutamine. The concentrations of acetate and pyruvate were also identified by univariate analysis as significantly different between ALS and non-ALS patients. DRSA correctly classified 68.7% of the cases and established rules involving some of the metabolites highlighted by OPLS-DA (acetate and acetone). Some rules identified potential biomarkers not revealed by OPLS-DA (beta-hydroxybutyrate). We also found a large number of common discriminating metabolites after Bayesian confirmation measures, particularly acetate, pyruvate, acetone and ascorbate, consistent with the pathophysiological pathways involved in ALS. CONCLUSION: DRSA provides a complementary method for improving the predictive performance of the multivariate data analysis usually used in metabolomics. This method could help in the identification of metabolites involved in disease pathogenesis. Interestingly, these different strategies mostly identified the same metabolites as being discriminant. The selection of strong decision rules with high value of Bayesian confirmation provides useful information about relevant condition-decision relationships not otherwise revealed in metabolomics data.