The neurodevelopmental spectrum of congenital Zika infection: a scoping review.

AIM: To describe the standardized neurodevelopmental outcomes after the first year of life in children with congenital Zika syndrome (CZS) and those exposed to Zika virus (ZIKV) during fetal life, but without microcephaly at birth. METHOD: This scoping review included observational studies about the standardized neurodevelopmental outcome in children with CZS or exposed to ZIKV, but without microcephaly, assessed after 12 months of age. The databases searched were MEDLINE/Pubmed, LILACS, Scielo, Scopus, PsycINFO, CINAHL, and Embase. Risk of bias was assessed with the Joanna Briggs Institute Critical Appraisal Checklists. RESULTS: Seventeen papers were included: 12 focused on children with CZS, four on children born without microcephaly, and one described both. Only one of the studies about CZS reported a child with microcephaly and typical development; the remainder described a severe pattern of global developmental delay and cerebral palsy. The prevalence of epilepsy was 74.6%. In the reports about children born without microcephaly, 6.9% to 8.7% had some domain with a score below -2 SD, and three children developed autism spectrum disorder. INTERPRETATION: CZS is associated with severe global developmental delay and cerebral palsy after 1 year of age. In children born without microcephaly, although most have typical development, some may be at risk for impairments.

Noninvasive motor cortex stimulation effects on quantitative sensory testing in healthy and chronic pain subjects: a systematic review and meta-analysis.

ABSTRACT: One of the potential mechanisms of motor cortex stimulation by noninvasive brain stimulation (NIBS) effects on pain is through the restoration of the defective endogenous inhibitory pain pathways. However, there are still limited data on quantitative sensory testing (QST), including conditioned pain modulation (CPM), supporting this mechanism. This systematic review and meta-analysis aimed to evaluate the effects of noninvasive motor cortex stimulation on pain perception as indexed by changes in QST outcomes. Database searches were conducted until July 2019 to include randomized controlled trials that performed sham-controlled NIBS on the motor cortex in either the healthy and/or pain population and assessed the QST and CPM. Quality of studies was assessed through the Cochrane tool. We calculated the Hedge's effect sizes of QST and CPM outcomes and their 95% confidence intervals (95% CIs) and performed random-effects meta-analyses. Thirty-eight studies were included (1178 participants). We found significant increases of pain threshold in healthy subjects (ES = 0.16, 95% CI = 0.02-0.31, I2 = 22.2%) and pain populations (ES = 0.48, 95% CI = 0.15-0.80, I2 = 68.8%), and homogeneous higher CPM effect (pain ratings reduction) in healthy subjects (ES = -0.39, 95% CI = -0.64 to -0.14, I2 = 17%) and pain populations (ES = -0.35, 95% CI = -0.60 to -0.11, I2 = 0%) in the active NIBS group compared with sham. These results support the idea of top-down modulation of endogenous pain pathways by motor cortex stimulation as one of the main mechanisms of pain reduction assessed by QST, which could be a useful predictive and prognostic biomarker for chronic pain personalized treatment with NIBS.

Decreased neural inhibitory state in fibromyalgia pain: A cross-sectional study.

OBJECTIVES: Chronic pain is one of the most common and challenging symptoms in fibromyalgia (FM). Currently, self-reported pain is the main criterion used by clinicians assessing patients with pain. However, it is subjective, and multiple factors can affect pain levels. In this study, we investigated the neural correlates of FM pain using conditioned pain modulation (CPM), electroencephalography (EEG), and transcranial magnetic stimulation (TMS). METHODS: In this cross-sectional neurophysiological analysis of a randomized, double-blind controlled trial, 36 patients with fibromyalgia were included. We analyzed CPM, EEG variables and TMS measures and their correlation with pain levels as measured by a visual analog scale. Univariate and multivariate linear regression analyses were performed to identify the predictors of pain severity. RESULTS: We found: (1) no association between pain levels and CPM; (2) an association between reduced alpha and beta power over the central region in resting-EEG and higher pain levels; (3) an association between smaller event-related desynchronization (ERD) responses in theta and delta bands over the central region and higher pain levels; (4) an association between smaller ERD responses in theta and delta bands and smaller intracortical inhibition and higher intracortical facilitation ratios; (5) an association between smaller ERD responses in delta band and reduced CPM. CONCLUSIONS: Our results do not support CPM as a biomarker for pain intensity in FM. However, our specific EEG findings showing the relationship between pain, CPM and TMS measures suggest that FM leads to a disruption of inhibitory neural modulators and thus support CPM as a likely predictive marker of disrupted pain modulation system. These neurophysiological markers need to be further explored in potential future trials as to find novel targets for the treatment of FM.