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Objective Auditory neuropathy spectrum disorders (ANSD) are defined by the association of a preserved outer hair cell function and an impaired auditory nerve neural response, and present mostly bilaterally. Unilateral ANSD are consequently only seldom described, and most frequently as isolated cases. This study aims to describe the audiological, vestibular and radiological characteristics of a population of children with unilateral ANSD. Material and methods We isolated 22 patients with unilateral ANSD, 12 boys and 10 girls from 0 to 95 months, in a database of auditory evoked potentials. We reviewed the audiological, radiological and vestibular assessments. The audiological assessment included tympanometry, otoacoustic emission recording and auditory evoked potential. Otolithic function was assessed by performing cervical vestibular evoked myogenic potential. The canal function was determined by video head impulse test and/or caloric test. The radiological evaluation consisted of an MRI of the internal auditory canal. Results Many patients with a type A tympanometry had no response to otoacoustic emission (53,8%), in the presence of a cochlear microphonic potential. Vestibular assessment was performed in 9 of the 22 patients. 4 children had impaired otolithic and/or canal function. MRI evaluation of the inner ear was performed in 18 patients. Aplasia or hypoplasia of the cochlear nerve was found in 17 of them. MRI showed additional vestibular or brainstem abnormalities in 7 of the 18 children. All children with impaired vestibular function had vestibular or brainstem radiological alterations in addition to cochlear branch aplasia or hypoplasia. Conclusions Radiological and vestibular abnormalities are common in children with unilateral ANSD and suggest that a radiological and vestibular assessment is required.

Multiple auditory structures, from cochlea to cortex, phase-lock to the envelope of complex stimuli. The relative contributions of these structures to the human surface-recorded envelope-following response (EFR) are still uncertain. Identification of the active contributor(s) is complicated by the fact that even the simplest two-tone ( f 1 & f 2 ) stimulus, targeting its ( f 2 − f 1 ) envelope, evokes additional linear ( f 1 & f 2 ) and non-linear ( 2 f 1 − f 2 ) phase-locked components as well as a transient auditory brainstem response (ABR). Here, we took advantage of the generalized primary tone phase variation method to isolate each predictable component in the time domain, allowing direct measurements of onset latency, duration and phase discontinuity values from which the involved generators were inferred. Targeting several envelope frequencies (0.22–1 kHz), we derived the EFR transfer functions along a vertical vertex-to-neck and a horizontal earlobe-to-earlobe recording channels, yielding respectively EFR-V and EFR-H waveforms. Subjects (N= 30) were sleeping children with normal electrophysiological thresholds and normal oto-acoustic emissions. Both EFR-H and EFR-V phase-locking values (PLV) transfer functions had a low-pass profile, EFR-V showing a lower cut-off frequency than EFR-H. We also computed the frequency-latency relationships of both EFRs onset latencies. EFR-H data fitted a power-law function incorporating a frequency-dependent traveling wave delay and a fixed one amounting to 1.2 ms. The fitted function nicely fell within five published estimations of the latency-frequency function of the ABR wave-I, thus pointing to a cochlear nerve origin. The absence of phase discontinuity and overall response durations that were equal to that of the stimulus indicated no contribution from a later generator. The recording of an entirely similar EFR-H response in a patient who had severe brainstem encephalitis with a normal, isolated, ABR wave-I but complete absence of later waves, further substantiated a cochlear nerve origin. Modeling of the EFR-V latency-frequency functions indicated a fixed transport time of 2 ms with respect to EFR-H onset, suggesting a cochlear nucleus (CN) origin, here also, without indication for multiple generators. Other features of the EFR-V response pointing to the CN were, at least for the EFR frequency below the cut-off values of the transfer functions, higher PLVs coupled with increased harmonic distortion. Such a behavior has been described in the so-called highly-synchronized neurons of the ventral cochlear nucleus (VCN). The present study compellingly demonstrated the advantage of isolating the EFR in the temporal domain so as to extract detailed spectro-temporal parameters that, combined with orthogonal recording channels, shed new light on the involved neural generators.

Necroptosis is emerging among possible mechanisms underlying cell death in neurodegenerative diseases. In this line, we hypothesize that necroptosis might be implicated in neuronal cell death in amyotrophic lateral sclerosis (ALS). To support this hypothesis, we hereby provide pilot data as well as some findings from the literature about the expression of key markers of the necroptotic pathway in ALS. Our preliminary data indicate the upregulation of key markers of necroptosis activation in lower motor neurons of the spinal cord. These human-derived data combined with some clinical and preclinical findings support our hypothesis testing the involvement of necroptosis in lower motor neurons death in ALS patients. These results pave the way to deepen the role of necroptosis in ALS using both preclinical and clinical approaches. If confirmed, this hypothesis might raise new interventional strategies to alleviate neurodegenerative process in ALS.

Recent research found that sexualized bodies are visually processed similarly to objects. This article examines the effects of skin-to-clothing ratio and posture suggestiveness on cognitive objectification. Participants were presented images of upright versus inverted bodies while we recorded the N170. We used the N170 amplitude inversion effect (larger N170 amplitudes for inverted vs. upright stimuli) to assess cognitive objectification, with no N170 inversion effect indicating less configural processing and more cognitive objectification. Contrary to Hypothesis 1, skin-to-clothing ratio was not associated with cognitive objectification (Experiments 1-3). However, consistent with Hypothesis 2, we found that posture suggestiveness was the key driver of cognitive objectification (Experiment 2), even after controlling for body asymmetry (Experiment 3). This article showed that high (vs. low) posture suggestiveness caused cognitive objectification (regardless of body asymmetry), whereas high (vs. low) skin-to-clothing ratio did not. The implications for objectification and body perception literatures are discussed., SCOPUS: ar.j, info:eu-repo/semantics/published

At an early stage of visual processing, human faces and bodies are typically associated with larger N170s when presented in an inverted (vs. upright) position, indexing the involvement of configural processing. We challenged this view and hypothesized that sexualized bodies would not be sensitive to inversion, thereby suggesting that they would be processed similarly to objects. Participants saw sexualized male and female bodies, nonsexualized male and female bodies, as well as objects in both upright and inverted positions while we recorded the N170. Results indicated that inverted (vs. upright) nonsexualized male and female bodies were associated with larger N170 amplitudes. In contrast, no N170 amplitude inversion effect emerged for sexualized male and female bodies or objects. These results suggest that sexualized bodies are processed similarly to objects and quite differently than nonsexualized bodies. We discuss the results and their implications in the light of the literatures in person perception and objectification.

Objectives In patients with Friedreich ataxia (FRDA), mitochondrial failure leads to impaired cellular energetics. Since many FRDA patients have impaired hearing in noise, we investigated the objective consequences on standard auditory brainstem-evoked responses (ABRs). Methods In 37 FRDA patients, among whom 34 with abnormal standard ABRs, hearing sensitivity, speech-in-noise intelligibility and otoacoustic emissions were controlled. ABR recordings were split into four consecutive segments of the total time frame used for data collection, thus allowing the dynamics of ABR averaging to be observed. Results Most ears showed features of an auditory neuropathy spectrum disorder with flattened ABRs and impaired speech-in-noise intelligibility contrasting with near-normal hearing sensitivity and normal preneural responses. Yet split-ABRs revealed short-lived wave patterns in 26 out of 68 ears with flattened standard ABRs (38%). While averaging went on, the pattern of waves shifted so that interwave latencies increased by 35% on average. Conclusions In FRDA, the assumption of stationarity used for extracting standard ABRs is invalid. The preservation of early split-ABRs indicates no short-term dyssynchrony of action potentials. A large decrease in conduction velocity along auditory neurons occurs within seconds, attributed to fast energetic failure. Significance This model of metabolic sensory neuropathy warns against exposure of metabolically-impaired patients to sustained auditory stimulation.

Recent studies reported over-expression of a cytokine (Interleukin (IL)-18) in the serum of sporadic amyotrophic lateral sclerosis (sALS) patients. Here, we report on the first-time detection of in-situ expression of activated IL-18 in the human brain in sALS patients. We also detected cerebral in-situ expression of key-molecules known to be closely related to the molecular network associated with the activation/secretion of IL-18 cytokine, namely, the receptor-interacting serine/threonine-protein kinase 3 (RIPK3 or RIP3), NOD-like receptor pyrin domain containing 3 (NLRP3)-inflammasome, and activated caspase-1. These findings suggest and allow to hypothesize that there might be a role for this cytokine network in molecular mechanisms associated with or implicated in the physiopathology of this neurodegenerative disorder.

Objective This study was designed to test the effect of the featured/featureless nature of deviant stimuli on mismatch negativity (MMN), P300 (P3a and P3b) and on behavioral discrimination performances. Methods Ten healthy adults were submitted to stimuli contrasted by the presence or absence of a frequency sweep. Discrimination performances were collected during the neurophysiological sessions. Results MMN, P3a and P3b were much larger for featured deviants than for featureless ones. Behavioral data ( d ', at ceiling level, and reaction times) were not affected by the featured/featureless nature of the deviant stimulus. Conclusion Behavioral results and MMN amplitudes are in accordance with our previous study, using the same design albeit in an ignore condition and with collection of the behavioral data deferred until after the neurophysiological sessions. The present study strengthens previous evidence suggesting that two mechanisms contribute to the MMN evoked by featured deviants: the memory comparison process and the adaptation/fresh-afferent phenomenons. Significance We here demonstrate that the neurophysiological processes underlying P300 generation are also impacted by the featured/featureless nature of the deviant stimulus and that the dissociation from behavioral data, which are not impacted, is also observed when both types of data are recorded simultaneously.

OBJECTIVES: Interference between a target and simultaneous maskers occurs both at the cochlear level through energetic masking and more centrally through informational masking (IM). Hence, quantifying the amount of IM requires a strict control of the energetic component. Presenting target and maskers on different sides (i.e., dichotically) reduces energetic masking but provides listeners with important lateralization cues that also drastically reduce IM. The main purpose of this study (Experiment 1) was to evaluate a “switch” manipulation aiming at restoring most of the IM despite dichotic listening. Experiment 2 was designed to investigate the source of the difficulty induced by this switching dichotic condition. DESIGN: In Experiment 1, the authors presented 60 normal-hearing young adults with a detection task in which a regularly repeating target was embedded in a randomly varying background masker. The authors evaluated spatial masking release induced by three different dichotic listening conditions in comparison with a diotic baseline. Dichotic stimuli were presented in either a nonswitching or a switching condition. In the latter case, the presentation sides of dichotic target and maskers alternated several times throughout 10 sec sequences. The impact of the number of switches on IM was investigated parametrically, with both pure and complex tone sequences. In Experiment 2, the authors compared performance of 13 young, normal-hearing listeners in a monotic and dichotic version of the rapidly switching condition, using pure-tone sequences. RESULTS: When target and maskers switched rapidly within sequences, IM was significantly stronger than in nonswitching dichotic sequences and was comparable with the masking effect induced by diotic sequences. Furthermore, Experiment 2 suggests that rapidly switching target and maskers prevent listeners from relying on lateralization cues inherent to the dichotic condition, hence preserving important amounts of IM. CONCLUSIONS: This paradigm thus provides an original tool to isolate IM in signal and maskers having overlapping spectra.

The primary tone phase variation (PTPV) technique combines selective sub-averaging with systematic variation of the phases of multitone stimuli. Each response component having a known phase relationship with the stimulus components phases can be isolated in the time domain. The method was generalized to the frequency-following response (FFR) evoked by a two-tone (f1 and f2) stimulus comprising both linear and non-linear, as well as transient components. The generalized PTPV technique isolated each spectral component present in the FFR, including those sharing the same frequency, allowing comparison of their latencies. After isolation of the envelope component f2 - f1 from its harmonic distortion 2f2 - 2f1 and from the transient auditory brainstem response, a computerized analysis of instantaneous amplitudes and phases was applied in order to objectively determine the onset and offset latencies of the response components. The successive activation of two generators separated by 3.7 ms could be detected in all (N = 12) awake adult normal subjects, but in none (N = 10) of the sleeping/sedated children with normal hearing thresholds. The method offers an unprecedented way of disentangling the various FFR subcomponents. These results open the way for renewed investigations of the FFR components in both human and animal research as well as for clinical applications., SCOPUS: ar.j, info:eu-repo/semantics/published

Recent research found that configural information is less important for the processing of sexualized bodies than for the processing of nonsexualized bodies. The present investigation aims to expand these findings by directly manipulating configural versus analytic processing of sexualized and nonsexualized bodies. We posited that disrupting first-order relational information through scrambling should be associated with larger N170 amplitudes (scrambling effect) for nonsexualized bodies, whereas the scrambling manipulation should not modulate N170 amplitudes associated with sexualized bodies and objects. We presented images of scrambled versus intact sexualized bodies, nonsexualized bodies, and objects while the N170 was recorded. Consistent with our hypothesis, we found that the scrambling manipulation was associated with larger N170 amplitudes for nonsexualized bodies (i.e. scrambling effect), whereas no scrambling effect emerged for sexualized bodies and objects. This research is the first to show that sexualized bodies are processed analytically at a neural level. Implications for the literature in body perception and objectification will be discussed.

Summary Objective To study the effect of clonidine administrated as a co-analgesic during scoliosis surgery, on the neuromonitoring of spinal motor pathways. Methods Using standardized intraoperative monitoring, we compared the time course of peripherally and transcranially electrically evoked motor potentials (TcEMEPs) before and after injection of a single bolus of clonidine in children under total intravenous anesthesia (TIVA). MEP data were obtained from 9 patients and somatosensory evoked potentials (SSEPs) were obtained from 2 patients. The potential effect of clonidine on mean blood pressure (BP) was controlled. Results TcEMEPs from upper and lower limbs rapidly showed significant drops in amplitude after the injection of clonidine. Amplitudes reached minimal values within five minutes and remained very weak for at least 10–20 minutes during which monitoring of the central motor pathways was severely compromised. SSEPs were not altered during maximal amplitude depression of the TcEMEPS. Conclusions This is the first report showing that clonidine severely interferes with neuromonitoring of the spinal cord motor pathways. The results are discussed in light of the literature describing the effects of dexmedetomidine, another α-2 adrenergic agonist. The experimental and literature data point to central mechanisms taking place at both the spinal and cerebral levels. Therefore, clonidine as well as other α-2 adrenergic agonists should be used with extreme caution in patients for whom neuromonitoring of the motor pathways is required during surgery.

Background: Ecto/nucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) loss-of-function mutations have been described in patients with autosomal recessive hypophosphatemic rickets (HR), in patients with generalized arterial calcification of infancy (GACI) and in several patients with both conditions. Out of more than 50 cases of homozygous or compound heterozygous ENPP1 loss-of-function mutations published so far, 1 case with labyrinthine deafness probably due to occlusion of inner ear supplying arteries and 2 cases of conductive hearing loss due to stapedovestibular calcification diagnosed in childhood have been reported. Aims: To report a case of ENPP1 loss-of-function novel mutation presenting with HR and very early onset and severe hearing loss. Methods: Case report and review of the literature. Results: We report on a patient homozygous for a novel 1-bp deletion in ENPP1 that presented with GACI evolving towards HR associated with a mixed hearing loss (both labyrinthine and conductive) diagnosed at 9 days of life that evolved towards profound labyrinthine deafness. Conclusion: Hearing loss is a rare finding in patients with ENPP1 loss-of-function mutations. Interestingly, it has already been described in other affected patients, in ENPP1 knock-out mice and in other diseases of pyrophosphate metabolism. Conversely it seems to be absent in children with the X-linked form of HR.

The aim of the present study was to investigate the effect of auditory training on voicing perception in French children with specific language impairment (SLI). We used an adaptive discrimination training that was centred across the French phonological boundary (0 ms voice onset time – VOT). One group of nine children with SLI attended eighteen twenty-minute training sessions with feedback, and a control group of nine children with SLI did not receive any training. Identification, discrimination and categorical perception were evaluated before, during and after training as well as one month following the final session. Phonological awareness and vocabulary were also assessed for both groups. The results showed that children with SLI experienced strong difficulties in the identification, discrimination and categorical perception of the voicing continuum prior to training. However, as early as after the first nine training sessions, their performance in the identification and discrimination tasks increased significantly. Moreover, phonological awareness scores improved during training, whereas vocabulary scores remained stable across sessions.

The aim of the present paper was to compare the development of perceptual categorization of voicing, colors and facial expressions in French-speaking children (from 6 to 8 years) and adults. Differences in both categorical perception, i.e. the correspondence between identification and discrimination performances, and in boundary precision, indexed by the steepness of the identification slope, were investigated. Whereas there was no significant effect of age on categorical perception, boundary precision increased with age, both for voicing and facial expressions though not for colors. These results suggest that the development of boundary precision arises from a general cognitive maturation across different perceptual domains. However, this is not without domain specific effects since we found (1) a correlation between the development of voicing perception and some reading performances and (2) an earlier maturation of boundary precision for colors compared to voicing and facial expressions. These comparative data indicate that whereas general cognitive maturation has some influence on the development of perceptual categorization, this is not without domain-specific effects, the structural complexity of the categories being one of them.

Dysfunction in vital brainstem centers, including those controlling cardiorespiratory- and sleep/arousal pathophysiology, is reported in sudden infant death syndrome (SIDS). Biological mechanisms underlying SIDS, however, remain unclear. Cytokines are inter-cellular signaling chemicals. They can interact with neurotransmitters and might thus modify neural and neuroimmune functions. Cytokines could therefore act as neuromodulators. Interleukin (IL)-2 is a major immune-related cytokine. It has not been previously depicted in vital brainstem centers. We detected intense neuronal IL-2 immune-reactivity in the SIDS brainstem, namely in vital neural centers. This IL-2 overexpression might interfere with neurotransmitters in those critical brainstem centers, causing disturbed homeostatic control of cardiorespiratory and arousal responses, possibly leading to SIDS.

OBJECTIVE: To look for the presence of neurophysiological correlates of language-general voicing boundaries in French by analyzing the morphology of two N100 subcomponents (N1b and T-complex). METHODS: /d/ and/t/ syllables with a voice onset time (VOT) value varying evenly from -75 and +75 ms were presented to French-speaking adults as stimuli for scalp-recorded auditory evoked-potentials. Morphologies and peak latencies of N1b and T-complex subcomponents were assessed. RESULTS: The Na subcomponent of the T-complex was double-peaked for VOT values below -30 ms and above +30 ms. N1b subcomponent revealed a double-peaked response above +30 ms VOT and a single-peaked response for all other VOT values. Whenever the response was double-peaked, there was a correlation between the VOT value and the N1b or Na supplementary peak latency. CONCLUSIONS: The combined morphologies of N1b and Na yield clear neurophysiological correlates of the language-general boundaries. For negative VOT values, the differential behavior of N1b and Na subcomponents suggests that only Na possesses physiological properties indexing the two language-general boundaries. SIGNIFICANCE: Rather than being lost, the universal sensitivity of human newborns to language-general boundaries remains present even if in some languages such as French, they do not separate phonological categories.

OBJECTIVES: Assess the feasibility of drawing tuning curves from the masking function of steady state potentials. Develop a noninvasive tool for research applications on cochlear frequency selectivity in sedated animals. Obtain pilot human data validating auditory steady state evoked potential-derived (ASSEP) tuning curves against psychophysical data. DESIGN: ASSEP tuning curves were drawn in 10 Beagle puppies and six human adults using amplitude-modulated probes. Two probe frequencies (1 and 2 kHz) were used in dogs and only one (2 kHz) in humans. The modulation rates of the two probes were set to 81 and 88 Hz, respectively. Psychophysical tuning curves were obtained in 12 normal human subjects using the same maskers and either a pure-tone or an amplitude-modulated probe to verify if the latter had a specific effect on tuning curve parameters. Six of these 12 subjects participated in the electrophysiologic measurements. For each tuning curve, the intensity of the narrowband masker required just to mask the fixed probe was plotted for different masker center frequencies. Masker center frequencies extended to about half an octave above and an octave below the probe frequencies in 100-Hz steps. Tuning curve width (Q10 dB values), high- and low-frequency slopes (in dB/octave) and the masker frequency yielding the lowest masking threshold (maximal masker frequency) were computed. Canine Q10 dB values obtained were compared with those published for several species with other techniques. For humans, ASSEP and psychophysical tuning curves were directly compared in the same subjects and with published data. RESULTS: In dogs, the ASSEP method yielded reproducible tuning curves with qualitative and quantitative parameters similar to other physiologic measures of tuning obtained in various animals. Q10 dB values were greater at 2 than at 1 kHz, reflecting the well-known correlation between sharpness of tuning and central frequency. In humans, ASSEP Q10 dB values were slightly smaller than the psychophysical ones, but were greater by a factor of 2 than those obtained with previously published electrophysiologic procedures. In both species, detuning-a shift of the tip of the curve away from the probe frequency-was frequently observed as upward shifts with a maximal value of 200 Hz. Human psychophysical tuning curves also showed a certain amount of upward detuning. The intraindividual comparison of the two types of probes performed on human subjects with the psychophysical method did not indicate a specific effect of the amplitude-modulated probe on the curve parameters. Neither did the intraindividual comparisons indicate that an amplitude-modulated probe per se promoted detuning. Detuning has been observed with several other techniques and is usually attributed to nonlinear interactions between masker and probe in simultaneous masking. CONCLUSIONS: The results demonstrate the feasibility of measuring realistic ASSEP tuning curves in sedated dogs and in sleeping human adults. The ASSEP tuning curves exhibit a series of classical features similar to those obtained with time-honored methods. These results pave the way for the development of a noninvasive electrophysiologic method for tuning curve recording and its applications in noncooperative experimental animals or clinical subjects., Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

OBJECTIVE: Rhythm perception appears to be non-linear as human subjects are better at discriminating, categorizing and reproducing rhythms containing binary vs non-binary (e.a. 1:2 vs 1:3) as well as metrical vs non-metrical (e.a. 1:2 vs 1:2.5) interval ratios. This study examined the representation of binary and non-binary interval ratios within the sensory memory, thus yielding a truly sensory, pre-motor, attention-independent neural representation of rhythmical intervals. METHODS: Five interval ratios, one binary, flanked by four non-binary ones, were compared on the basis of the MMN they evoked when contrasted against a common standard interval. RESULTS: For all five intervals, the larger the contrast was, the larger the MMN amplitude was. The binary interval evoked a significantly much shorter (by at least 23 ms) MMN latency than the other intervals, whereas no latency difference was observed between the four non-binary intervals. CONCLUSIONS: These results show that the privileged perceptual status of binary rhythmical intervals is already present in the sensory representations found in echoic memory at an early, automatic, pre-perceptual and pre-motor level. SIGNIFICANCE: MMN latency can be used to study rhythm perception at a truly sensory level, without any contribution from the motor system.

Studies evaluating speech perception in noise have reported inconsistent results regarding a potential deficit in dyslexic children. So far, most of them investigated energetic masking. The present study evaluated situations inducing mostly informational masking, which reflects cognitive interference induced by the masker. Dyslexic children were asked to identify a female target syllable presented in quiet, babble, unmodulated, and modulated speech-shaped noise. Whereas their performance was comparable to normal-reading children in quiet, it dropped significantly in all noisy conditions compared to age-, but not reading level-matched controls. Interestingly, noise affected similarly the reception of voicing, place, and manner of articulation in dyslexic and normal-reading children.

This study evaluates the effects of a high-frequency hearing loss simulated by the high-pass-noise masking method, on the click-evoked brain stem-evoked potentials (BAEP) characteristics in dogs. BAEP were obtained in response to rarefaction and condensation click stimuli from 60 dB normal hearing level (NHL, corresponding to 89 dB sound pressure level) to wave V threshold, using steps of 5 dB in eleven 58 to 80-day-old Beagle puppies. Responses were added, providing an equivalent to alternate polarity clicks, and subtracted, providing the rarefaction-condensation potential (RCDP). The procedure was repeated while constant level, high-pass filtered (HPF) noise was superposed to the click. Cut-off frequencies of the successively used filters were 8, 4, 2 and 1 kHz. For each condition, wave V and RCDP thresholds, and slope of the wave V latency-intensity curve (LIC) were collected. The intensity range at which RCDP could not be recorded (pre-RCDP range) was calculated. Compared with the no noise condition, the pre-RCDP range significantly diminished and the wave V threshold significantly increased when the superposed HPF noise reached the 4 kHz area. Wave V LIC slope became significantly steeper with the 2 kHz HPF noise. In this non-invasive model of high-frequency hearing loss, impaired hearing of frequencies from 8 kHz and above escaped detection through click BAEP study in dogs. Frequencies above 13 kHz were however not specifically addressed in this study.

This research assesses how audiovisual speech integration mechanisms are modulated by sensory and cognitive variables. For this purpose, the McGurk effect (McGurk & MacDonald, 1976) was used as an experimental paradigm. This effect occurs when participants are exposed to incongruent auditory and visual speech signals. For example, when an auditory /b/ is dubbed onto a visual /g/, listeners are led to perceive a fused phoneme like /d/. With the reverse presentation, they experience a combination such as /bg/. In two experiments, auditory intensity (40 dB, 50 dB, 60 dB, and 70 dB), face size (large: 19 × 23 cm and small: 1.8 × 2 cm) and instructions ("multiple choice" and "free response") were manipulated. Face size and instruction were between-participants variables in both experiments, whereas intensity was a within-participants variable in the first experiment and a between-participants variable in the second one. The main effect of instruction manipulation was highly significant in both experiments, the "multiple choice" condition giving rise to more illusions than the "free response" condition. Intensity was significant in the second experiment only. Illusions were more numerous at 40 dB than at the other three intensities. Finally, a small effect of face size was observed in the second experiment only, illusions being slightly more numerous with the large face. Those results indicate that the processing chain underlying audiovisual speech perception is modulated by the perceptual salience of the visual and auditory inputs as well as by cognitive variables. © 2005 Psychology Press Ltd., info:eu-repo/semantics/published

Noise typically induces both peripheral and central masking of an auditory target. Whereas the idea that a deficit of speech in noise perception is inherent to dyslexia is still debated, most studies have actually focused on the peripheral contribution to the dyslexics’ difficulties of perceiving speech in noise. Here, we investigated the respective contribution of both peripheral and central noise in three groups of children: dyslexic, chronological age matched controls (CA), and reading-level matched controls (RL). In all noise conditions, dyslexics displayed significantly lower performance than CA controls. However, they performed similarly or even better than RL controls. Scrutinizing individual profiles failed to reveal a strong consistency in the speech perception difficulties experienced across all noise conditions, or across noise conditions and reading-related performances. Taken together, our results thus suggest that both peripheral and central interference contribute to the poorer speech in noise perception of dyslexic children, but that this difficulty is not a core deficit inherent to dyslexia.

The aim of the present study was to investigate changes in voicing identification, discrimination, and categorical perception induced by identification training centered on three different training values. One group of French-speaking adults was trained across a universal auditory boundary (−30 ms voice onset time), and two other groups were trained across arbitrary boundaries (−45 or −60 ms voice onset time). A control group did not receive any training. The results showed that both the −30 and the −45 training groups exhibited a 10 ms shift in the identification boundary. Moreover, for the −30 training group, discrimination and categorical perception changed around the French phonological boundary. These results illustrate the possibility of modifying the French phonological perception after short-time training, particularly when centered on a universal boundary. However, training only had limited effects and even strengthened the phonological boundary, congruent with the hypothesis that this boundary is acquired by a perceptual “coupling” between universal boundaries.

PURPOSE: To evaluate the effects of exposure to routine magnetic resonance (MR) imaging at 1.5 T during pregnancy on fetal growth and neonatal hearing function in relation to the dose and timing of in utero exposure in a group of newborns at low risk for congenital hearing impairment or deafness. MATERIALS AND METHODS: This retrospective case-control study was approved by the local ethics committee, and written informed consent was waived. Between January 2008 and December 2012, a group of 751 neonates exposed to MR imaging in utero and a group of control subjects comprising 10 042 nonexposed neonates, both groups with no risk factors for hearing impairment at birth, were included. Neonatal hearing screening was performed by means of otoacoustic emission testing and auditory brain stem response according to national guidelines, and the prevalence of hearing impairment in the two groups was compared by using a noninferiority test with Wilson score confidence intervals. The effect of MR exposure on birth weight percentile was examined between the singleton neonates in the exposed group and a randomly chosen subset of 1805 singleton newborns of the nonexposed group by performing an analysis of variance. RESULTS: The rate of hearing impairment or deafness was found to be 0% (0 of 751) in the neonates in the exposed group and was not inferior to that in the nonexposed group (34 of 10 042 [0.34%], P < .05). There was no between-group difference in birth weight percentiles (50.6% for exposed vs 48.4% for nonexposed; P = .22). CONCLUSION: This study showed no adverse effects of exposure to 1.5-T MR imaging in utero on neonatal hearing function or birth weight percentiles.

The objective of this study was to build audiograms from thresholds of brainstem tone-evoked potentials in dogs and to evaluate age-related change of the audiogram in puppies. Results were obtained from 9 Beagle puppies 10-47 days of age. Vertex to mastoid brainstem auditory-evoked potentials in response to 5.1-millisecond Hanning-gated sine waves with frequencies octave-spaced from 0.5 to 32 kHz were recorded. Three dogs were examined at 10, 13, 19, 25, and 45 days. Four other dogs were examined at 16 days. Data from 7 dogs between 42 and 47 days of age were pooled to obtain audiogram reference values in 1.5-month-old puppies. The best auditory threshold lowered from above 60 dB sound pressure level (SPL) to values close to 0 dB SPL between 13 and 25 days of age and then stabilized. The audible frequency range widened, including 32 kHz in all tested dogs from the 19th day. In the 7 1.5-month-old puppies, the mean auditory threshold decreased by 11 dB per octave from 0.5 to 2 kHz. The auditory threshold was lowest and held the same value from 2 to 8 kHz. The mean auditory threshold increased by 20 dB per octave from 8 to 32 kHz. Near threshold, click-evoked potentials test only a small part of the audible frequency range in dogs. Use of tone-evoked potentials may become a powerful tool in investigating dogs with possible partial hearing loss, including during the auditory system maturation period.

In complex auditory scenes, perceiving a given target signal is often complicated by the presence of competing maskers. In addition to energetic masking (EM), which arises because of peripheral interferences between target and maskers at the cochlear level, informational masking (IM), which takes place at a more central level, is also responsible for the difficulties encountered in typical ecological auditory environments. While recent research has led to mixed results regarding a potential speech-perception-in-noise deficit in dyslexic children, most of them actually investigated EM situations. The current study aimed at evaluating dyslexic children's sensitivity to pure IM in complex auditory sequences. Performance of the control normally-reading children increased throughout the experiment, reaching a significantly better level than dyslexics' in the last blocks. Our results provide evidence for a general auditory deficit in noise in dyslexic children. Although due to central mechanisms, this deficit does not seem to stem from a mere auditory attention impairment. Further research is needed to examine the precise nature of the auditory difficulty, and its link with reading acquisition in dyslexic children.

Histopathological investigation was conducted on both inner ears from a 4.5-month-old Rottweiler puppy with electrophysiologically confirmed bilateral deafness. The lesions were restricted to the organ of Corti and spiral ganglion that both displayed severe degenerative changes. The outer hair cells were less affected than the inner hair cells. The number of spiral ganglion neurons was reduced, and remaining neurons were altered. The basal and middle cochlear turns were more affected than the apical one. The vestibules were normal. Immunostaining with calbindin, calretinin, S100A1 and S100A6 polyclonal antisera was helpful in identifying different cell-types in the degenerated cochlea. The early and severe spiral ganglion cell degeneration is an uncommon finding no matter the species. Such lesions bear significance within the frame of cochlear implants technology for deaf infants.

Objective—To evaluate auditory maturation in puppies. Animals—Ten clinically normal Beagle puppies. Procedure—Puppies were examined repeatedly from days 11 to 36 after birth (8 measurements). Clickevoked brain stem auditory-evoked potentials (BAEP) were obtained in response to rarefaction and condensation click stimuli from 90 dB normal hearing level to wave V threshold, using steps of 10 dB. Responses were added, providing an equivalent to alternate polarity clicks, and subtracted, providing the rarefaction-condensation differential potential (RCDP). Steps of 5 dB were used to determine thresholds of RCDP and wave V. Slope of the low-intensity segment of the wave V latency-intensity curve was calculated. The intensity range at which RCDP could not be recorded (ie, pre-RCDP range) was calculated by subtracting the threshold of wave V from threshold of RCDP. Results—Slope of the wave V latency-intensity curve low-intensity segment evolved with age, changing from (mean ± SD) –90.8 ± 41.6 to –27.8 ± 4.1 μs/dB. Similar results were obtained from days 23 through 36. The pre-RCDP range diminished as puppies became older, decreasing from 40.0 ± 7.5 to 20.5 ± 6.4 dB. Conclusion and Clinical Relevance—Changes in slope of the latency-intensity curve with age suggest enlargement of the audible range of frequencies toward high frequencies up to the third week after birth. Decrease in the pre-RCDP range may indicate an increase of the audible range of frequencies toward low frequencies. Age-related reference values will assist clinicians in detecting hearing loss in puppies. (Am J Vet Res 2000;61:1343–1348)

We report the clinical, radiological and electrophysiological signs in two unrelated girls with the connatal form of Pelizaeus-Merzbacher disease (PMD). MRI plays an important role in the diagnosis, demonstrating the virtual absence of myelination. PMD is classically described as an X-linked leukodystrophy. Our two cases reinforce the hypothesis of a possible autosomal recessive transmission of the connatal form of PMD in some families, as recently presented.

We report 3 children without any brainstem auditory evoked potential (BAEP) neural component who all retained isolated cochlear microphonic potentials as well as click-evoked otoacoustic emissions. Two of them demonstrated only moderately impaired audiometric thresholds. These features correspond to a peculiar pattern of auditory dysfunction recently coined 'auditory neuropathy'. In contrast with the published previous cases of auditory neuropathy presenting with an acquired hearing deficit as children or young adults, all 3 children had a history of major neonatal illness and the auditory neuropathy was already demonstrated in the first months of their lives. (C) 1997 Elsevier Science Ireland Ltd.

When special pseudo-random stimuli sequences (maximum length sequences: MLS) are combined with a deconvolution analysis technique, it is possible to derive new evoked potential components that are called kernels. The kernels give a measure of the temporal interactions that take place between the responses to successive stimuli. This may provide an objective neurophysiological test for the exploration of a dimension of hearing which has hitherto been limited to psychophysical methods. Until now, auditory short-latency kernels obtained by the MLS method have been related to the late portion of the brainstem auditory evoked potential (BAEP), suggesting that temporal interactions occur rather late in the auditory pathways. We report 4 children without any BAEP neural components, who all retained isolated cochlear microphonic potentials. Three of them produced click-evoked otoacoustic emissions and two of them demonstrated only moderately impaired audiometric thresholds. This combination of absent BAEP neural components with preserved otoacoustic emissions and cochlear microphonic potential corresponds to a peculiar pattern of auditory dysfunction recently coined 'auditory neuropathy'. All 4 children exhibited well-defined kernels at latencies consistent with the microphonic potential. These data indicate that the cochlea itself can generate kernels at a presynaptic level. They open up the question of the identification of the physiological site(s) responsible for the generation of MLS-evoked kernels. (C) 1997 Elsevier Science Inland Ltd.

With prevalence figures close to 0.2% at birth and rising to 0.35% during adolescence, hearing loss is the most frequent sensory impairment in childhood. This silent handicap has to be actively sought for without delay as it will seriously interfere with the development of speech, language, cognitive and socio-emotional behavior. Objective physiological techniques (evoked potentials, oto-acoustic emissions, tympanometry) combined according to the cross-check principle allow early diagnosis. Objective testing yields invaluable information about the mechanism of the loss and the contribution of disruption of the neural code to the handicap. Among the acquired causes, cytomegalovirus (CMV) infections plays a major role and may take elusive forms. Aminoglycoside ototoxicity has a genetic determinant. Meningitis can lead to rapid endocochlear ossification prompting for rapid cochlear implantation. Genetic causes account for more than 60% of congenital hearing loss, new genetic causes being discovered at an amazing rate. The high number of genetic entities and their huge heterogeneity among them requires guidelines for requesting genetic testing when desirable. Several syndromes prone to request neuropediatricians' attention as an early diagnosis followed by specific treatment can considerably limit the ensuing handicap. Whatever the type of assistive device fitted (amplifying hearing aid or cochlear implant) and the importance of associated handicaps, a multidisciplinary rehabilitation combined with educated parental commitment is necessary for optimal results.

Most usual speech masking situations induce both energetic and informational masking. Energetic masking (E.M.) arises because both signal and maskers contain energy in the same critical bands. Informational masking (I.M.) prevents the listeners from disentangling acoustical streams even when they are well separated in frequency, and is thought to reflect central mechanisms. In order to quantify I.M. without E.M. contamination in complex auditory situations, target and maskers can by presented dichotically. However, this manipulation provides the listeners with important lateralisation cues, which reduces I.M. Therefore, this study aimed at restoring a fair amount of I.M. using complex tones in a new dichotic paradigm. Regularly repeating signals and random-frequency multitone maskers were presented dichotically, but switched from one ear to the other within a 10s sequence. Switches could either appear at a slow or rapid rate. We compared listeners' detection performance in these switching situations to th...

With prevalence figures close to 0.2% at birth and rising to 0.35% during adolescence, hearing loss is the most frequent sensory impairment in childhood. This silent handicap has to be actively sought for without delay as it will seriously interfere with the development of speech, language, cognitive and socio-emotional behavior. Objective physiological techniques (evoked potentials, oto-acoustic emissions, tympanometry) combined according to the cross-check principle allow early diagnosis. Objective testing yields invaluable information about the mechanism of the loss and the contribution of disruption of the neural code to the handicap. Among the acquired causes, cytomegalovirus (CMV) infections plays a major role and may take elusive forms. Aminoglycoside ototoxicity has a genetic determinant. Meningitis can lead to rapid endocochlear ossification prompting for rapid cochlear implantation. Genetic causes account for more than 60% of congenital hearing loss, new genetic causes being discovered at an amazing rate. The high number of genetic entities and their huge heterogeneity among them requires guidelines for requesting genetic testing when desirable. Several syndromes prone to request neuropediatricians' attention as an early diagnosis followed by specific treatment can considerably limit the ensuing handicap. Whatever the type of assistive device fitted (amplifying hearing aid or cochlear implant) and the importance of associated handicaps, a multidisciplinary rehabilitation combined with educated parental commitment is necessary for optimal results.

The rarefaction-condensation differential potential (RCDP) obtained by subtracting brainstem auditory-evoked potentials (BAEPs) to C clicks from those to R clicks has been studied in 32 normal subjects and 31 cases of cochlear hearing loss. In normal subjects, no RCDP was recorded along the lower 30-55 dB of the JV latency-intensity function, thus defining the pre-RCDP range. The pre-RCDP range was always abolished in losses unmasking BAEPs from lower (1 kHz) tonotopic regions. When the BAEP originated from higher (1 kHz) tonotopic regions, the pre-RCDP range was either reduced or abolished. These results led to a working hypothesis based on single-unit data and stating a dual dependence of polarity effects on variables distributed along the tonotopic and intensity dimensions, with respective break-points at 1 kHz, and at the junction of the tip and tail of unit frequency tuning curves. The 1 kHz break-point could represent the upper frequency limit for phase locking in man.

Cytokines interact with neurotransmitters and modify neuronal and neuroimmune functions. Intense in situ neuronal IL-2 immunoreactivity was detected in vital human brainstem neuronal centers which are principally implicated in cardio-respiratory control mechanisms. These observations were made in critically-ill aging adult as well as in young infant patients dying from various clinico-pathological conditions. We suggested that this in situ cytokine over-expression might tip a delicate balance in molecular interactions in those vital neuro-vegetative centers, causing disturbed homeostatic control of cardio-respiratory functions and impaired arousal responses; we further hypothesized that this IL-2-induced neuro-molecular disequilibrium in the brainstem microenvironment might thus be part of a final common pathway leading to death.

Dachy B, Denis L, Deltenre P. Usefulness of transcranial magnetic stimulation to predict the development of reflex sympathetic dystrophy poststroke: a pilot study. Arch Phys Med Rehabil 2002;83:730-2. Objective: To investigate the predictive value of transcranial magnetic stimulation (TMS) for the development of reflex sympathetic dystrophy (RSD) poststroke. Design: Blind clinical assessment of 2 groups of stroke patients defined on the basis of absent or preserved motor evoked potentials (MEPs) on the affected side. Setting: Stroke rehabilitation center. Patients: Twenty stroke patients between the ages of 41 and 85 years, undergoing rehabilitation. Interventions: Not applicable. Main Outcome Measures: MEPs from upper limbs 30 days poststroke, Motricity Index, and scoring of RSD using the Enjalbert Scale 73 days poststroke. Results: A good correlation was found between Motricity Index and TMS results ( P P =.03). No significant correlation was found between Enjalbert scores and the Motricity Index. Conclusions: Although no significant relationship was found between upper-limb motor impairment and intensity of RSD 10 weeks after stroke, the TMS responses permitted the early categorization of patients into 2 groups that developed significantly different average Enjalbert scores 1 to 2 months later when this clinical condition was fully developed. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Objective: This study was designed to separately test the effect of the cued/cueless nature of deviant stimuli and that of temporal distance between sound and deviance onsets on the mismatch negativity (MMN) as well as to look for discrepancies between behavioural discrimination performances and MMN amplitude when deviants are cueless. Methods: Ten healthy adults passively listened to stimuli that were contrasted by the presence or absence of a frequency sweep starting early or late within the sound. Discrimination performances were collected after the electrophysiological sessions. Results: MMNs were much larger for cued than for cueless deviants. The temporal distance between sound and deviance onsets affected MMNs evoked by both cued and cueless deviants, even to the point of abolishing the MMN when cueless deviance occurred late in the stimulus. Behavioural data were at ceiling levels for all conditions, contrasting with the absence of MMN evoked by cueless deviants with late onset. Conclusions: Two mechanisms contribute to the MMN evoked by cued deviants: the memory comparison process and the adaptation/fresh-afferent one. Within the temporal window of integration, the delay at which each component disappears is different. Significance: Comparing waveforms evoked by cued versus cueless deviants provides a fairly simple way of isolating the MMN memory-based component. © 2012 International Federation of Clinical Neurophysiology., SCOPUS: ar.j, info:eu-repo/semantics/published

Auditory steady-state evoked potential (ASSEP) tuning curves were compared to compound action potential (CAP) tuning curves, both measured at 2 Hz, using sedated beagle puppies. The effect of two types of masker (narrowband noise and sinusoidal) on the tuning curve parameters was assessed. Whatever the masker type, CAP tuning curve parameters were qualitatively and quantitatively similar to the ASSEP ones, with a similar inter-subject variability, but with a greater incidence of upward tip displacement. Whatever the procedure, sinusoidal maskers produced sharper tuning curves than narrow-band maskers. Although these differences are not likely to have significant implications for clinical work, from a fundamental point of view, their origin requires further investigations. The same amount of time was needed to record a CAP and an ASSEP 13-point tuning curve. The data further validate the ASSEP technique, which has the advantages of having a smaller tendency to produce upward tip shifts than the CAP technique. Moreover, being non invasive, ASSEP tuning curves can be easily repeated over time in the same subject for clinical and research purposes.