The latest medical research on Neurology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about neurology gathered by our medical AI research bot.

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Meta-analyses identify differentially expressed microRNAs in Parkinson's disease.

Annals Neurology

MicroRNA-mediated (dys)regulation of gene expression has been implicated in Parkinson's disease (PD), although results of microRNA expression studies remain inconclusive. We aimed to identify microRNAs that show consistent differential expression across all published expression studies in PD.

We performed a systematic literature search on microRNA expression studies in PD and extracted data from eligible publications. After stratification for brain, blood, and cerebrospinal fluid (CSF)-derived specimen we performed meta-analyses across microRNAs assessed in three or more independent datasets. Meta-analyses were performed using effect-size and p-value based methods, as applicable.

After screening 599 publications we identified 47 datasets eligible for meta-analysis. On these, we performed 160 meta-analyses on microRNAs quantified in brain (n=125), blood (n=31), or CSF samples (n=4). Twenty-one meta-analyses were performed using effect sizes. We identified 13 significantly (Bonferroni-adjusted α=3.13x10-4 ) differentially expressed microRNAs in brain (n=3) and blood (n=10) with consistent effect directions across studies. The most compelling findings were with hsa-miR-132-3p (p=6.37x10-5 ), hsa-miR-497-5p (p=1.35x10-4 ), and hsa-miR-133b (p=1.90x10-4 ) in brain, and with hsa-miR-221-3p (p=4.49x10-35 ), hsa-miR-214-3p (p=2.00x10-34 ), and hsa-miR-29c-3p (p=3.00x10-12 ) in blood. No significant signals were found in CSF. Analyses of GWAS data for target genes of brain microRNAs showed significant association (α=9.40x10-5 ) of genetic variants in nine loci.

We identified several microRNAs that showed highly significant differential expression in PD. Future studies may assess the possible role of the identified brain miRNAs in pathogenesis and disease progression as well as the potential of the top blood microRNAs as biomarkers for diagnosis, progression or prediction of PD. This article is protected by copyright. All rights reserved.

Extraciliary roles of the ciliopathy protein JBTS17 in mitosis and neurogenesis.

Annals Neurology

JBTS17 is a major gene mutated in ciliopathies such as Joubert syndrome and oral-facial-digital syndrome type VI. Most patients with loss of function mutations in JBTS17 exhibit cerebellar vermis hypoplasia and brain stem malformation. However, some patients with JBTS17 mutations show microcephaly and abnormal gyration. We examined potential roles of JBTS17 in neurogenesis to understand the pathological mechanism of JBTS17-related cortical abnormalities.

We examined subcellular localization and cell cycle-dependent expression of JBTS17 proteins using anti-JBTS17 antibodies and JBTS17 expression vectors. We also performed knockdown experiments to determined roles of JBTS17 in human cells, and demonstrated mitotic functions of JBTS17 using immunostaining and live imaging. We examined the involvement of JBTS17 in cortical neurogenesis using mouse in utero electroporation technique.

We found that JBTS17 localizes to the kinetochore and the level of JBTS17 is regulated by cell cycle-dependent proteolysis. Depletion of JBTS17 disrupts chromosome alignment and spindle pole orientation, resulting in mitotic delay. JBTS17 interacts with LIS1 and influences LIS1 localization. Depletion of Jbts17 in the developing mouse cortex interferes with the mitotic progression of neural progenitors and the migration of postmitotic neurons.

LIS1 is implicated in lissencephaly, but altered dosage of LIS1 has been also associated with microcephaly syndromes. Our results suggest that JBTS17 contributes to mitotic progression by interacting with LIS1, and abnormal mitosis is an underlying mechanism of the microcephaly phenotype in JBTS17-related ciliopathies. We propose that understanding extraciliary roles of ciliopathy proteins is important to elucidate pathological mechanisms underlying diverse ciliopathy phenotypes. This article is protected by copyright. All rights reserved.

First-in-man study of ACT-709478, a novel selective triple T-type calcium channel blocker.

Epilepsia

Increased activity of T-type Ca2+ channels is linked to idiopathic generalized epilepsies, thus blocking these channels may be a new treatment option. ACT-709478 is an orally available triple T-type Ca2+ channel blocker. The aim of this first-in-man study was to investigate the pharmacokinetics, pharmacodynamics, tolerability, and safety of single doses of ACT-709478 in healthy subjects.

This double-blind, placebo-controlled, randomized study included 65 healthy male subjects. Ascending single oral doses of 1-400 mg ACT-709478 or placebo were administered to sequential groups of eight subjects (6 on active, 2 on placebo). Effect of food was tested in a crossover part at 60 mg. Blood and saliva sampling for pharmacokinetic evaluations and safety assessments was performed regularly. Effects on the central nervous system were assessed with a battery of pharmacodynamic tests.

The maximum plasma concentration (Cmax ) was reached within 3 to 4 hours (≤60 mg) and within 20 to 28 hours (>60 mg), and across all dose levels the terminal half-life (95% confidence interval) ranged from 36 (29-45) to 43 (22-86) hours. Multiple peaks were observed and Cmax and area under the plasma concentration-time curve (AUC)0-∞ increased in a less than dose-proportional manner. A 1.6-fold increase in Cmax and no change in AUC0-∞ was observed in fed compared to fasted conditions. A significant correlation (P < 0.0001) between plasma and saliva concentrations was established using linear regression. All adverse events were transient and of mild or moderate intensity. No treatment-related effects on vital signs, clinical laboratory, telemetry, or electrocardiography were detected. The results of pharmacodynamic tests did not show relevant mean changes compared to baseline or placebo.

ACT-709478 exhibits good tolerability and safety after single-dose administration and its pharmacokinetic and pharmacodynamic properties warrant further investigations.

Epilepsy and seizures in young people with 22q11.2 deletion syndrome: Prevalence and links with other neurodevelopmental disorders.

Epilepsia

The true prevalence of epileptic seizures and epilepsy in 22q11.2 deletion syndrome (22q11.2DS) is unknown, because previous studies have relied on historical medical record review. Associations of epilepsy with other neurodevelopmental manifestations (eg, specific psychiatric diagnoses) remain unexplored.

The primary caregivers of 108 deletion carriers (mean age 13.6 years) and 60 control siblings (mean age 13.1 years) completed a validated epilepsy screening questionnaire. A subsample (n = 44) underwent a second assessment with interview, prolonged electroencephalography (EEG), and medical record and epileptologist review. Intelligence quotient (IQ), psychopathology, and other neurodevelopmental problems were examined using neurocognitive assessment and questionnaire/interview.

Eleven percent (12/108) of deletion carriers had an epilepsy diagnosis (controls 0%, P = 0.004). Fifty-seven of the remaining 96 deletion carriers (59.4%) had seizures or seizurelike symptoms (controls 13.3%, 8/60, P < 0.001). A febrile seizure was reported for 24.1% (26/107) of cases (controls 0%, P < 0.001). One deletion carrier with a clinical history of epilepsy was diagnosed with an additional type of unprovoked seizure during the second assessment. One deletion carrier was newly diagnosed with epilepsy, and two more with possible nonmotor absence seizures. A positive screen on the epilepsy questionnaire was more likely in deletion carriers with lower performance IQ (odds ratio [OR] 0.96, P = 0.018), attention-deficit/hyperactivity disorder (ADHD) (OR 3.28, P = 0.021), autism symptoms (OR 3.86, P = 0.004), and indicative motor coordination disorder (OR 4.56, P = 0.021).

Even when accounting for deletion carriers diagnosed with epilepsy, reports of seizures and seizurelike symptoms are common. These may be "true" epileptic seizures in some cases, which are not recognized during routine clinical care. Febrile seizures were far more common in deletion carriers compared to known population risk. A propensity for seizures in 22q11.2DS was associated with cognitive impairment, psychopathology, and motor coordination problems. Future research is required to determine whether this reflects common neurobiologic risk pathways or is a consequence of recurrent seizures.

PRRT2 missense mutations cluster near C-terminus and frequently lead to protein mislocalization.

Epilepsia

Variants in human PRRT2 cause paroxysmal kinesigenic dyskinesia (PKD) and other neurological disorders. Most reported variants resulting in truncating proteins failed to localize to cytoplasmic membrane. The present study identifies novel PRRT2 variants in PKD and epilepsy patients and evaluates the functional consequences of PRRT2 missense variations.

We investigated two families with PKD and epilepsies using Sanger sequencing and a multiple gene panel. Subcellular localization of mutant proteins was investigated using confocal microscopy and cell surface biotinylation assay in Prrt2-transfected cells.

Two novel PRRT2 variants, p.His232Glnfs*10 and p.Leu298Pro, were identified, and functional study revealed impaired localization of both mutant proteins to the plasma membrane. Further investigation of other reported missense variants revealed decreased protein targeting to the plasma membrane in eight of the 13 missense variants examined (p.Trp281Arg, p.Ala287Thr, p.Ala291Val, p.Arg295Gln, p.Leu298Pro, p.Ala306Asp, p.Gly324Glu, and p.Gly324Arg). In contrast, all benign variants we tested exhibited predominant localization to the plasma membrane similar to wild-type Prrt2. Most likely pathogenic variants were located at conserved amino acid residues near the C-terminus, whereas truncating variants spread throughout the gene.

PRRT2 missense variants clustering at the C-terminus often lead to protein mislocalization. Failure in protein targeting to the plasma membrane by PRRT2 variants may be a key mechanism in causing PKD and related neurological disorders.

Nonadherence to treatment regimens in epilepsy from the patient's perspective and predisposing factors: Differences between intentional and unintentional lack of adherence.

Epilepsia

Nonadherence to recommended antiepileptic drug (AED) treatment regimens can result in seizure relapse with increased health risks. Nonadherence can...

The effects of valproic acid on early pregnancy human placentas: Pilot ex vivo analysis in cultured placental villi.

Epilepsia

Valproic acid is an established structural and neurodevelopmental teratogen. Recently, we demonstrated that valproate alters the barrier function o...

Burden and epidemiology of status epilepticus in infants, children, and adolescents: A population-based study on German health insurance data.

Epilepsia

Status epilepticus (SE) is an important medical emergency condition with particularly unfavorable outcome in refractory and superrefractory SE (SRSE). The economic impact of SE and especially of SRSE in the pediatric population remains unclear. We aimed to determine the burden of illness of SE in a pediatric patient population.

Insurance records for patients aged 0-18 years admitted between 2008 and 2015 were selected from a nationwide insurance research database utilizing International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) codes for SE (G41), epilepsy (G40), or febrile convulsions (R56). Patients were further classified based on admission to the intensive care unit and use of mechanical ventilation.

The algorithm identified 11 693 seizure-related admissions and classified 4% as SE. Of these cases, 282 (60.4%) were classified by the algorithm as nonrefractory SE (NRSE), 125 (26.8%) as refractory SE (RSE), and 60 (12.8%) as SRSE. The crude SE incidence was 17.6/100 000, with NRSE being 11.4/100 000, RSE 3.9/100 000, and SRSE 2.3/100 000. SRSE incidence peaked in the 0- to 1-year-old age subgroup accounting for 48.3% of all pediatric SRSE admissions. The median length of stay (LOS) for all SE cases was 7 days, with median 44.5 days in SRSE, 5 days in NRSE, and 12 days in RSE. Mean admission costs for total SE were €15 880, with a mean expense for SRSE of €75 358, for NRSE of €4119, and for RSE of €13 864. The mean LOS for non-SE epilepsy admissions was 3 days, with mean costs of €2697 for epilepsy and €1614 for febrile convulsion admissions. There were no deaths in non-SE and NRSE admissions, whereas the overall mortality for SE was 3%, with 5.6% in RSE and 11.7% in SRSE.

Although cases classified as SE represented 4% of the seizure-associated admissions, they accounted for 22% of the overall costs. These costs were disproportionately represented by SRSE cases, which accounted for 62% of all SE-associated costs.

Surgical outcomes and prognostic factors of drug-resistant epilepsy secondary to encephalomalacia.

Epilepsia

To evaluate long-term outcomes and prognostic factors in patients who underwent surgical resection for drug-resistant epilepsy secondary to encephalomalacia.

A total of 143 patients with drug-resistant epilepsy who underwent surgical resection with a follow-up of at least 5 years were included. Seizure outcomes were evaluated based on the International League Against Epilepsy classification. Univariate analysis and a multivariate logistic regression model in a backward fashion were used to identify the potential predictors of seizure outcomes.

Three months after surgery, 102 of 143 (71.3%) patients had achieved favorable seizure outcomes. Five years after surgery, 107 of 143 (74.8%) patients had achieved favorable seizure outcomes. Changes in the postoperative seizure status were observed in 22 of 143 (15.4%) patients during follow-up, but the difference in the seizure-free rate between 3 months and 5 years after surgery was not significant. Univariate and multivariate analyses revealed that only a monthly seizure frequency of >30 seizures (odds ratio = 3.42, 95% confidence interval = 1.19-9.76) and bilateral ictal onset rhythms (odds ratio = 4.46, 95% confidence interval = 1.61-12.39) were independent predictors of unfavorable seizure outcomes.

Surgical resection is an effective treatment for patients with drug-resistant epilepsy secondary to encephalomalacia. Knowledge of the predictors of seizure outcomes may help during preoperative counseling and selection of optimal candidates for epilepsy surgery among patients with drug-resistant epilepsy secondary to encephalomalacia.

Randomized controlled trial of motivational interviewing for psychogenic nonepileptic seizures.

Epilepsia

We conducted a randomized controlled trial of motivational interviewing (MI) as an intervention to improve psychotherapy adherence and outcomes, including frequency of psychogenic nonepileptic seizures (PNES), quality of life, and emergency department utilization, among participants with PNES.

Sixty participants were randomized to receive either psychotherapy alone or MI plus psychotherapy. Participants and therapists were contacted at 16-week follow-up. Participants were considered adherent with psychotherapy if they attended at least eight sessions within 16 weeks following referral.

Among control participants, 31.0% were adherent, whereas among MI participants, 65.4% were adherent (P = 0.015, absolute risk reduction = 34.4%, number needed to treat = 2.9). In the control arm, PNES frequency decreased by 34.8% (standard deviation [SD] = 89.7%), whereas in the MI arm, PNES frequency decreased by 76.2% (SD = 39.2%; P = 0.034, Cohen's d = 0.59). Among control participants, 10.7% achieved PNES freedom versus 30.8% of MI participants (P = 0.095). Quality of Life in Epilepsy-10 scores (a 40-point scale) improved by an average of 1.8 (SD = 7.9) points among control participants, and by 7.2 (SD = 10.0) points among MI participants (P = 0.047, Cohen's d = 0.60). Monthly emergency department visits increased by 0.06 (SD = 0.47) visits per month among control participants versus a decrease of 0.15 (SD = 0.76) among MI participants (P = 0.23).

Motivational interviewing improved treatment adherence, PNES frequency, and quality of life among our participants with PNES. Our study is limited in that it was conducted at a single quaternary care medical center, and MI was provided by a single neurologist, which may limit generalization of results.

Hip Surveillance in Children With Cerebral Palsy.

Cerebral Palsy

Hip dysplasia is common in children with cerebral palsy (CP), especially in those children with notable functional impairment. Severity of hip dysp...

Development of MRC Centre MRI calf muscle fat fraction protocol as a sensitive outcome measure in Hereditary Sensory Neuropathy Type 1.

Journal Neurol Neurosurg Psychiatry

Hereditary sensory neuropathy type 1 (HSN1) is a rare, slowly progressive neuropathy causing profound sensory deficits and often severe motor loss. L-serine supplementation is a possible candidate therapy but the lack of responsive outcome measures is a barrier for undertaking clinical trials in HSN1. We performed a 12-month natural history study to characterise the phenotype of HSN1 and to identify responsive outcome measures.

Assessments included Charcot-Marie-Tooth Neuropathy Score version 2 (CMTNSv2), CMTNSv2-Rasch modified, nerve conduction studies, quantitative sensory testing, intraepidermal nerve fibre density (thigh), computerised myometry (lower limbs), plasma 1-deoxysphingolipid levels, calf-level intramuscular fat accumulation by MRI and patient-based questionnaires (Neuropathic Pain Symptom Inventory and 36-Short Form Health Survey version 2 [SF-36v2]).

35 patients with HSN1 were recruited. There was marked heterogeneity in the phenotype mainly due to differences between the sexes: males generally more severely affected. The outcome measures that significantly changed over 1 year and correlated with CMTNSv2, SF-36v2-physical component and disease duration were MRI determined calf intramuscular fat accumulation (mean change in overall calf fat fraction 2.36%, 95% CI 1.16 to 3.55, p=0.0004), pressure pain threshold on the hand (mean change 40 kPa, 95% CI 0.7 to 80, p=0.046) and myometric measurements of ankle plantar flexion (median change -0.5 Nm, IQR -9.5 to 0, p=0.0007), ankle inversion (mean change -0.89 Nm, 95% CI -1.66 to -0.12, p=0.03) and eversion (mean change -1.61 Nm, 95% CI -2.72 to -0.51, p=0.006). Intramuscular calf fat fraction was the most responsive outcome measure.

MRI determined calf muscle fat fraction shows validity and high responsiveness over 12 months and will be useful in HSN1 clinical trials.