Dysregulation of energy metabolism in multiple sclerosis measured in vivo with diffusion-weighted spectroscopy.

OBJECTIVE: We employed diffusion-weighted magnetic resonance spectroscopy (DW-MRS), which allows to measure in vivo the diffusion properties of metabolites, to explore the functional neuro-axonal damage and the ongoing energetic dysregulation in multiple sclerosis (MS). METHODS: Twenty-five patients with MS and 18 healthy controls (HC) underwent conventional magnetic resonance imaging (MRI) and DW-MRS. The apparent diffusion coefficient (ADC) of total N-acetyl-aspartate (tNAA) and creatine-phosphocreatine (tCr) were measured in the parietal normal-appearing white matter (NAWM) and in the thalamic grey matter (TGM). Multiple regressions were used to compare metabolite ADCs between groups and to explore clinical correlations. RESULTS: In patients compared with HCs, we found a reduction in ADC(tNAA) in the TGM, reflecting functional and structural neuro-axonal damage, and in ADC(tCr) in both NAWM and TGM, possibly reflecting a reduction in energy supply in neurons and glial cells. Metabolite ADCs did not correlate with tissue atrophy, lesional volume or metabolite concentrations, while in TGM metabolite ADCs correlated with clinical scores. CONCLUSION: DW-MRS showed a reduction in tCr diffusivity in the normal-appearing brain of patients with MS, which might reflect a state of ongoing energy dysregulation affecting neurons and/or glial cells. Reversing this energy dysregulation before neuro-axonal degeneration arises may become a key objective in future neuroprotective strategies.

French validation of the questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS).

INTRODUCTION: The management of impulse control disorders (ICDs) in Parkinson's disease (PD) relies on their early identification, allowing adjustment of antiparkinsonian treatment before these manifestations lead to major social, financial or legal consequences. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) is an English-developed and -validated PD-specific rating scale constructed to support the rating of ICDs and related disorders and the assessment of changes in symptom severity over time, but it has not to date been validated in French. METHODS: We conducted an observational, multicenter, cross-sectional study among a subset of patients (n = 280) from the Drug Interacting with Genes in PD (DIG-PD) cohort, aiming to assess psychometric properties of the French version of QUIP-RS: acceptability, internal consistency, factor analysis, reproductibility and hypotheses testing. In addition to this scale, the following measures were applied: MDS-Unified Parkinson's Disease Rating Scale, Mini-Mental State Examination, Frontal Assessment Behavior, and Ardouin Scale of Behavior in Parkinson's Disease (ASBPD). RESULTS: Cronbach's alpha coefficient was 0.72 and ranged from 0.25 to 0.55. Regarding test-retest reliability and inter-rater reliability, the Lin concordance coefficient for items was higher than 0.58. The correlations between QUIP-RS and ASBPD were moderate to high except for dopaminergic addiction and hobbyism (r = 0.41 and 0.40 respectively, p < 0.001). No clinically significant correlation was found between QUIP-RS total score (and items) and other scales. CONCLUSION: The French version of the QUIP-RS appears to be a valid, reliable, and precise instrument for the assessment of ICDs and related disorders in PD. REGISTRATION NUMBER: clinicaltrials.gov number NCT01564992.