Search results for "Potentials"
showing 10 items of 1072 documents
Signal Characteristics of EMG with Special Reference to Reproducibility of Measurements
1975
Reliability and constancy of recordings of EMG signal characteristics were investigated from the measurements taken with miniature size surface electrodes during submaximal and maximal contraction of the rectus femoris muscle. The following EMG variables were studied: integrated EMG (IEMG) various bandwidths of the power spectral density function, mean power frequency (MPF), and rise time, amplitude and number of spikes of the averaged motor unit potential (AMUP). The results indicated that for most of the variables studied the reproducibility of measurements was better within the test session (reliability) than between the different test days (constancy). The reliability values for IEMG, M…
Audiologic profile of infants at risk: experience of a Western Sicily tertiary care centre.
2012
Objective: To identify the incidence of sensorineural hearing loss (SNHL) on infant at risk and to classify the degree and type of hearing loss describing the main causes associated in Western Sicily. To compare single TEOAE and combined TEOAE/ABR techniques studying the referral rate, the false-positive and false-negative rates through concordance test (κ coefficient), sensitivity (TPR) and specificity (TNR) for each protocol. Methods: From January 2010 to June 2011, 412 infants at risk, ranging from 4 to 20 weeks of life, transferred to Audiology Department of Palermo from the births centers of Western Sicily, underwent to audiological assessment with TEOAE, tympanometry and ABR. The foll…
Responsivity to dyslexia training indexed by the N170 amplitude of the brain potential elicited by word reading.
2016
The present study examined training effects in dyslexic children on reading fluency and the amplitude of N170, a negative brain-potential component elicited by letter and symbol strings. A group of 18 children with dyslexia in 3rd grade (9.05 ± 0.46 years old) was tested before and after following a letter-speech sound mapping training. A group of 20 third-grade typical readers (8.78 ± 0.35 years old) performed a single time on the same brain potential task. The training was differentially effective in speeding up reading fluency in the dyslexic children. In some children, training had a beneficial effect on reading fluency (‘improvers’) while a training effect was absent in others (‘non-im…
L-type calcium channel activity in human atrial myocytes as influenced by 5-HT.
1993
5-Hydroxytryptamine (10 mumol/l; 5-HT) exerted a positive inotropic effect associated with an increase in the Ca2+ current (ICa) in the human right atrium. For detailed analysis, L-type Ca2+ channel currents were recorded from cell-attached patches using 100 mmol/l Ba2+ as charge carrier. Ca2+ channel activity was identified, first, by burst-like inwardly directed currents and, second, by the appearance of long channel openings promoted by Bay K 8644 (1 mumol/l) upon repetitive depolarizations from -80 to 0 mV. The unitary conductance of the Ca2+ channel amounted to 25.8 pS. During superfusion with 5-HT, ensemble averaged (mean) current was enhanced by about 60%. The increase in mean curren…
T-complex measures in bilingual Spanish-English and Turkish-German children and monolingual peers
2015
BackgroundLateral temporal neural measures (Na and T-complex Ta and Tb) of the auditory evoked potential (AEP) index maturation of auditory/speech processing. These measures are also sensitive to language experience in adults. This paper examined neural responses to a vowel sound at temporal electrodes in four- to five-year-old Spanish-English bilinguals and English monolinguals and in five- to six-year-old Turkish-German bilinguals and German monolinguals. The goal was to determine whether obligatory AEPs at temporal electrode sites were modulated by language experience. Language experience was defined in terms of monolingual versus bilingual status as well as the amount and quality of the…
Representation and Processing of Lexical Tone and Tonal Variants: Evidence from the Mismatch Negativity
2015
Pronunciation variation is ubiquitous in the speech signal. Different models of lexical representation have been put forward to deal with speech variability, which differ in the level as well as the nature of mental representation. We present the first mismatch negativity (MMN) study investigating the effect of allophonic variation on the mental representation and neural processing of lexical tones. Native speakers of Standard Chinese (SC) participated in an oddball electroencephalography (EEG) experiment. All stimuli have the same segments (ma) but different lexical tones: level [T1], rising [T2], and dipping [T3]. In connected speech with a T3T3 sequence, the first T3 may undergo allopho…
Statistical language learning in neonates revealed by event-related brain potentials
2009
Abstract Background Statistical learning is a candidate for one of the basic prerequisites underlying the expeditious acquisition of spoken language. Infants from 8 months of age exhibit this form of learning to segment fluent speech into distinct words. To test the statistical learning skills at birth, we recorded event-related brain responses of sleeping neonates while they were listening to a stream of syllables containing statistical cues to word boundaries. Results We found evidence that sleeping neonates are able to automatically extract statistical properties of the speech input and thus detect the word boundaries in a continuous stream of syllables containing no morphological cues. …
Processing of prosodic changes in natural speech stimuli in school-age children.
2012
Speech prosody conveys information about important aspects of communication: the meaning of the sentence and the emotional state or intention of the speaker. The present study addressed processing of emotional prosodic changes in natural speech stimuli in school-age children (mean age 10 years) by recording the electroencephalogram, facial electromyography, and behavioral responses. The stimulus was a semantically neutral Finnish word uttered with four different emotional connotations: neutral, commanding, sad, and scornful. In the behavioral sound-discrimination task the reaction times were fastest for the commanding stimulus and longest for the scornful stimulus, and faster for the neutra…
Validating rationale of group-level component analysis based on estimating number of sources in EEG through model order selection
2012
This study addresses how to validate the rationale of group component analysis (CA) for blind source separation through estimating the number of sources in each individual EEG dataset via model order selection. Control children, typically reading children with risk for reading disability (RD), and children with RD participated in the experiment. Passive oddball paradigm was used for eliciting mismatch negativity during EEG data collection. Data were cleaned by two digital filters with pass bands of 1-30 Hz and 1-15 Hz and a wavelet filter with the pass band narrower than 1-12 Hz. Three model order selection methods were used to estimate the number of sources in each filtered EEG dataset. Un…
Cognitive vs. affective listening modes and judgments of music - An ERP study
2010
The neural correlates of processing deviations from Western music rules are relatively well known. Less is known of the neural dynamics of top-down listening modes and affective liking judgments in relation with judgments of tonal correctness. In this study, subjects determined if tonal chord sequences sounded correct or incorrect, or if they liked them or not, while their electroencephalogram (EEG) was measured. The last chord of the sequences could be congruous with the previous context, ambiguous (unusual but still enjoyable) or harmonically inappropriate. The cognitive vs. affective listening modes were differentiated in the event-related potential (ERP) responses already before the end…