Early hyperdopaminergic state following sub-thalamic nucleus deep brain stimulation in Parkinson disease.

BACKGROUND: Hyperdopaminergic state (HS), especially impulse control behaviors (ICBs), are not rare in Parkinson's disease (PD). Controversial data regarding HS prevalence one year following sub-thalamic nucleus deep brain stimulation (STN-DBS) are reported. OBJECTIVE: Our objectives were to describe early postoperative HS (PoOHS) including ICBs, hypomania and psychotic symptoms during the first 3 months following STN-DBS (V1) and their prognosis at 1 year (V2). METHODS: This descriptive study included 24 PD patients treated successively with bilateral STN-DBS between 2017 and 2019. The primary endpoint was prevalence of PoOHS at V1 according to the Ardouin Scale of Behaviour in Parkinson's Disease. RESULTS: Prior to STN-DBS (V0), 25% patients had HS (only ICBs) whereas at V1 (during the 3 first months), 10 patients (41.7%) had one or several HS (P=0.22) (de novo in 29.2%): 7 (29.2%) ICBs, 4 (16.7%) hypomanic mood, 1 (4.7%) psychotic symptoms. At V2, all V0 and V1 HS had disappeared, while 1 patient (4.2%) presented de novo HS (P<0.01). No correlation was found between the occurrence of PoOHS at V1 and any V0 data. Higher levodopa equivalent dose of dopamine agonists at V1 was correlated with ICB at V1 (P=0.04). CONCLUSION: We found that early PoOHS are frequent in PD after STN-DBS, mostly de novo, with ICBs and hypomania being the most frequent. Despite a good prognosis of PoOHS at one year, our work emphasizes the importance of both a cautious adjustment of dopamine agonist doses and a close non-motor monitoring pre- and post-STN-DBS in PD.

[Medical biostatistics with GMRC Shiny Stats - learning by doing]. / Biostatistiques médicales avec GMRC Shiny Stats ­ un outil de formation par la pratique.

Biostatistics are omnipresent in the scientific and medical literature and are an essential skill for any health student. We have developed a practical training tool - GMRC Shiny stats - an interactive application specifically dedicated to medical data statistical analysis. The application has been designed to provide an analysis workflow corresponding to the usual progression of an experienced statistician during data analysis. The most common statistical analyses can be performed (descriptive statistics, inferences according to frequentist methods, survival analyses, correlation, agreement measurements, etc.). GMRC Shiny stats is intuitive and user-friendly and assists students in choosing the most appropriate statistical tests. With all these functionalities, students can learn statistical analysis by doing. Getting involved in the statistical analysis and processing of their own data is likely to improve their biostatistics skills.

Clonidine GH stimulation test to differentiate MSA from idiopathic late onset cerebellar ataxia: a prospective, controlled study.

INTRODUCTION: Despite the consensus criteria for multiple system atrophy (MSA), the diagnosis of MSA of cerebellar type (MSA-C) may be difficult in the early stage of the disease. There are several differential diagnoses including idiopathic late-onset cerebellar ataxias (ILOCA) and it is often necessary to wait for clinical worsening so that the criteria can be met. Our aim was to assess the efficacy of clonidine growth hormone test (CGH test) to distinguish MSA-C from ILOCA in the early stage of the disease. METHODS: Within our cohort of late-onset sporadic, progressive cerebellar ataxia, the group of patients meeting the criteria for possible or probable MSA was compared to the ILOCA group. Clinical and paraclinical examination including CGH test were repeated during the prospective follow-up. RESULTS: Eighty-six patients were recruited, including 42 patients in the MSA group and 44 ILOCA patients with a mean follow-up of 33 months. At the inclusion visit, CHG test was pathological for 31% MSA of patients and 18.2% of ILOCA patients (p = 0.35). During the follow-up, 52.4% of MSA-C had a pathological CGH test, while only 20.5% of ILOCA (p < 0.01). CGH test had a sensitivity of 69.1% and a specificity of 68.2%, (p < 0.001) for MSA-C patients; CGH test allows in three quarters of cases, if negative, to rule out a probable MSA-C (negative predictive value of 75%, p = 0.0014). CONCLUSION: This prospective, controlled study showed that CGH test could be helpful in clinical practice to differentiate MSA-C from ILOCA in the early stage of the disease.