Search results for "reflex"
showing 10 items of 622 documents
Long-term effects on motor cortical excitability induced by repeated muscle vibration during contraction in healthy subjects
2008
article i nfo Objective: The effects of a novel repeated muscle vibration intervention (rMV; 100 Hz, 90 min over 3 consecutive days) on corticomotor excitability were studied in healthy subjects. Methods: rMV was applied over the flexor carpi radialis (FCR) during voluntary contraction (experiment 1), during relaxation and during contraction without vibration (experiment 2). Focal transcranial magnetic stimulation (TMS) was applied before rMV and one hour, and one, two and three weeks after the last muscle vibration intervention. At each of these time points, we assessed the motor map area and volume in the FCR, extensor digitorum communis (EDC) and abductor digiti minimi (ADM). Short-inter…
Basic cardiovascular variability signals: mutual directed interactions explored in the information domain.
2017
The study of short-term cardiovascular interactions is classically performed through the bivariate analysis of the interactions between the beat-to-beat variability of heart period (RR interval from the ECG) and systolic blood pressure (SBP). Recent progress in the development of multivariate time series analysis methods is making it possible to explore how directed interactions between two signals change in the context of networks including other coupled signals. Exploiting these advances, the present study aims at assessing directional cardiovascular interactions among the basic variability signals of RR, SBP and diastolic blood pressure (DBP), using an approach which allows direct compar…
Effect of age on complexity and causality of the cardiovascular control: comparison between model-based and model-free approaches.
2014
The proposed approach evaluates complexity of the cardiovascular control and causality among cardiovascular regulatory mechanisms from spontaneous variability of heart period (HP), systolic arterial pressure (SAP) and respiration (RESP). It relies on construction of a multivariate embedding space, optimization of the embedding dimension and a procedure allowing the selection of the components most suitable to form the multivariate embedding space. Moreover, it allows the comparison between linear model-based (MB) and nonlinear model-free (MF) techniques and between MF approaches exploiting local predictability (LP) and conditional entropy (CE). The framework was applied to study age-related…
Extended Granger causality: a new tool to identify the structure of physiological networks.
2015
Granger causality (GC) is a very popular tool for assessing the presence of directional interactions between two time series of a multivariate data set. In its original formulation, GC does not account for zero-lag correlations possibly existing between the observed time series. In the present study we compare the GC with a novel measure, termed extended GC (eGC), able to capture instantaneous causal relationships. We present a two-step procedure for the practical estimation of eGC based on first detecting the existence of zero-lag correlations, and then assigning them to one of the two possible causal directions using pairwise measures of non-Gaussianity. The proposed method was validated …
Blink reflex R2 changes and localisation of lesions in the lower brainstem (Wallenberg's syndrome): an electrophysiological and MRI study
1999
OBJECTIVES—Pathways of late blink reflexes are detected by high resolution MRI. Electronically matched stroke lesions superimposed to an anatomical atlas show the suspected course. METHODS—Fifteen patients with infarction of the lower brainstem, MRI lesions and electrically elicited blink reflexes were examined. The involved structures in patients with R2 and R2c blink reflex changes were identified by biplane high resolution MRI with individual slices matched to an anatomical atlas at 10 different levels using digital postprocessing methods. RESULTS—The blink reflexes were normal in five of 15 patients (33%) and showed loss or delay of R2 and R2c to stimulation ipsilaterally to lesion (R2-…
Migraine and cranial autonomic symptoms in children and adolescents: a clinical study.
2014
The frequency of cranial autonomic symptoms in children affected by primary headaches is uncertain. The aim of our study was to estimate the frequency of symptoms in pediatric headaches and correlate it with main migraine characteristics. A questionnaire investigating the presence of cranial autonomic symptoms was administered to all children with primary headache for 2 years. A total of 230 children with primary headache (105 males, 125 females) were included. Two hundred two children were affected by migraine and 28 (12.2%) by other primary headaches. Cranial autonomic symptoms were significantly complained by migraineurs (55% vs 17.8%) ( P < .001) and by children with higher frequenc…
The point prevalence of otitis media with eVusion among primary school children in Western Sicily
2009
The objective of this study is to identify the prevalence of otitis media with effusion (OME) in primary school children and to value the possible predisposing factors focusing on relationship between allergy and OME in Western Sicily. 2,097 children attending primary school were screened from September 2006 to June 2007 in Sciacca. Children underwent pneumatic otoscopy, skin tests, tympanogram and acoustic reflex tests. Audiogram was performed if the child had a type B or a type C tympanogram. The criteria for diagnosis of OME were: documented persistent middle ear effusion by otoscopic examination for a minimum of 3 months, presence of B or C tympanogram, absence of ipsilateral acoustic r…
Otitis media with effusion with or without atopy: audiological findings on primary schoolchildren
2011
Objective: The objective of the study was to evaluate the role of atopy in otitis media with effusion (OME) in children attending primary school, focusing on the audiometric and tympanometric measurements among atopic and nonatopic subjects suffering from OME. Materials and Methods: Three hundred ten children (5-6 years old) were screened in Western Sicily by skin tests and divided into atopics (G1) and nonatopics (G2). The samples were evaluated for OME by pneumatic otoscopy, tympanogram, and acoustic reflex tests. The parameters considered were as follows: documented persistent middle ear effusion by otoscopic examination for a minimum of 3 months, presence of B or C tympanogram, absence …
Serial measurements of transient evoked otoacoustic emissions (TEOAEs) in healthy newborns and in newborns with perinatal infection.
1993
Detection of hearing impairment in early childhood is difficult. We serially recorded transient evoked otoacoustic emissions (TEOAEs) to search for signs of ototoxicity in term, healthy newborns and compared the results to a second group of term babies treated for perinatally acquired bacterial infection with ampicillin plus either cefotaxime or plus aminoglycoside. At initial evaluation, in the group of 45 healthy children born at term, well reproducible emissions were observed in all but two children. In each of these two, initially well reproducible TEOAEs were detected in one ear only. At the time of the second recording (mean at day 8.5) excellent emissions were seen in all ears of all…
The role of atopy in otitis media with effusion among primary school children: audiological investigation
2010
The objective of this study was to evaluate the role of atopy in otitis media with effusion (OME) in children attending primary school in western Sicily focusing on the audiological characteristics among atopic and non-atopic subjects suffering from OME. A total of 310 children (5-6 years old) were screened by skin tests and divided into atopics (G1) and non-atopics (G2). The samples were evaluated for OME by pneumatic otoscopy, tympanogram and acoustic reflex tests. The parameters considered were: documented persistent middle ear effusion by otoscopic examination for a minimum of 3 months; presence of B or C tympanogram; absence of ipsilateral acoustic reflex and a conductive hearing loss …