Foreign speech sound discrimination and associative word learning lead to a fast reconfiguration of resting-state networks.

Learning new words in an unfamiliar language is a complex endeavor that requires the orchestration of multiple perceptual and cognitive functions. Although the neural mechanisms governing word learning are becoming better understood, little is known about the predictive value of resting-state (RS) metrics for foreign word discrimination and word learning attainment. In addition, it is still unknown which of the multistep processes involved in word learning have the potential to rapidly reconfigure RS networks. To address these research questions, we used electroencephalography (EEG), measured forty participants, and examined scalp-based power spectra, source-based spectral density maps and functional connectivity metrics before (RS1), in between (RS2) and after (RS3) a series of tasks which are known to facilitate the acquisition of new words in a foreign language, namely word discrimination, word-referent mapping and semantic generalization. Power spectra at the scalp level consistently revealed a reconfiguration of RS networks as a function of foreign word discrimination (RS1 vs. RS2) and word learning (RS1 vs. RS3) tasks in the delta, lower and upper alpha, and upper beta frequency ranges. Otherwise, functional reconfigurations at the source level were restricted to the theta (spectral density maps) and to the lower and upper alpha frequency bands (spectral density maps and functional connectivity). Notably, scalp RS changes related to the word discrimination tasks (difference between RS2 and RS1) correlated with word discrimination abilities (upper alpha band) and semantic generalization performance (theta and upper alpha bands), whereas functional changes related to the word learning tasks (difference between RS3 and RS1) correlated with word discrimination scores (lower alpha band). Taken together, these results highlight that foreign speech sound discrimination and word learning have the potential to rapidly reconfigure RS networks at multiple functional scales.

Case Report: Semantic Variant Primary Progressive Aphasia With Impaired Verbal Word Discrimination.

Some patients with primary progressive aphasia (PPA) present with various types of hearing deficits. Research on the auditory function and speech sounds in PPA, including temporal, phonemic, and prosodic processing, revealed impairment in some of these auditory processes. Many patients with PPA who present with impaired word recognition subsequently developed non-fluent variant PPA. Herein, we present a patient with semantic variant PPA (svPPA) who demonstrated impaired verbal word discrimination. Audiological examinations revealed normal auditory brainstem responses and slightly impaired pure-tone perception. By contrast, verbal word discrimination and monosyllable identification were impaired, and temporal auditory acuity deteriorated. Analyses of brain magnetic resonance images revealed a significant decrease in the gray matter volume in bilateral superior temporal areas, predominantly on the left, compared with those of patients with typical svPPA, which appeared to be associated with impaired word recognition in our patient.

Auditory gating in adults with dyslexia: An ERP account of diminished rapid neural adaptation.

OBJECTIVE: A recent functional magnetic resonance imaging (fMRI) study of adults with dyslexia showed a general deficit in suppressing responses to various types of repetitive stimuli. This diminished neural adaptation may interfere with implicit learning and forming stable word representations. With fMRI, spatial but not temporal characteristics of the adaptation response could be identified. We address this knowledge gap using event-related potentials. METHODS: Fourteen adults with dyslexia and 14 controls participated in an auditory gating paradigm using tone pairs. Response amplitudes and latencies for N1 and P2 were measured. Participants also compared word pairs consisting of identical or subtly different words, a task requiring stable word representations. RESULTS: Only the controls showed a robust gating effect in an attenuated N1 response to the second tone relative to the first. The dyslexia group was less accurate than the controls in detecting word differences. The N1 gating magnitude was associated with this detection accuracy. CONCLUSIONS: Neural adaptation occurs by approximately 100 ms after stimulus presentation and is diminished in adults with dyslexia. This complements fMRI findings of relevant brain regions by implying a time window representing sensory and pre-attentive auditory processes. SIGNIFICANCE: The association between gating magnitude and word discrimination contributes to a neurophysiological account of underspecified word representations.

Effect of signal to noise ratio on the speech perception ability of older adults.

BACKGROUND: Speech perception ability depends on auditory and extra-auditory elements. The signal- to-noise ratio (SNR) is an extra-auditory element that has an effect on the ability to normally follow speech and maintain a conversation. Speech in noise perception difficulty is a common complaint of the elderly. In this study, the importance of SNR magnitude as an extra-auditory effect on speech perception in noise was examined in the elderly. METHODS: The speech perception in noise test (SPIN) was conducted on 25 elderly participants who had bilateral low-mid frequency normal hearing thresholds at three SNRs in the presence of ipsilateral white noise. These participants were selected by available sampling method. Cognitive screening was done using the Persian Mini Mental State Examination (MMSE) test. RESULTS: Independent T- test, ANNOVA and Pearson Correlation Index were used for statistical analysis. There was a significant difference in word discrimination scores at silence and at three SNRs in both ears (p≤0.047). Moreover, there was a significant difference in word discrimination scores for paired SNRs (0 and +5, 0 and +10, and +5 and +10 (p≤0.04)). No significant correlation was found between age and word recognition scores at silence and at three SNRs in both ears (p≥0.386). CONCLUSION: Our results revealed that decreasing the signal level and increasing the competing noise considerably reduced the speech perception ability in normal hearing at low-mid thresholds in the elderly. These results support the critical role of SNRs for speech perception ability in the elderly. Furthermore, our results revealed that normal hearing elderly participants required compensatory strategies to maintain normal speech perception in challenging acoustic situations.

Neurophysiological sensitivity for impaired phonological processing in the acute stage of aphasia.

The present study aimed to investigate neurophysiological substrates of phoneme and word processing in 10 patients with acute aphasia (PWA). More specifically, phoneme discrimination was studied in a passive and active oddball task with respect to different phonemic contrasts, while lexical detection was investigated by presenting infrequent pseudowords among frequent words in a passive oddball task. Concerning phoneme discrimination, PWA in the acute stage had smaller MMN and P300 amplitudes than the norm group for voicing, whereas for place and manner they only demonstrated smaller P300 amplitudes. PWA showed a distinct pattern of impaired phonemic contrast sensitivity, with place displaying the largest amplitude and voicing the smallest. Concerning lexical detection, pseudowords elicited larger responses than words in both groups, but with a delay and larger P200 amplitude for pseudowords in PWA compared to the norm group. For clinical practice, passive tasks seem more suitable than active tasks in acute aphasia.

Sound localization and word discrimination in reverberant environment in children with developmental dyslexia / Localización sonora y discriminación de palabras en ambientes reverberantes en niños con dislexia del desarrollo

Objective Compare if localization of sounds and words discrimination in reverberant environment is different between children with dyslexia and controls. Method We studied 30 children with dyslexia and 30 controls. Sound and word localization and discrimination was studied in five angles from left to right auditory fields (-90o, -45o, 0o, +45o, +90o), under reverberant and no-reverberant conditions; correct answers were compared. Results Spatial location of words in no-reverberant test was deficient in children with dyslexia at 0º and +90o. Spatial location for reverberant test was altered in children with dyslexia at all angles, except –-90o. Word discrimination in no-reverberant test in children with dyslexia had a poor performance at left angles. In reverberant test, children with dyslexia exhibited deficiencies at -45o, -90o, and +45o angles. Conclusion Children with dyslexia could had problems when have to locate sound, and discriminate words in extreme locations of the horizontal plane in classrooms with reverberation. .

Objetivo Comparar localización de sonidos y localización-discriminación de palabras bajo reverberación y sin reverberación en niños disléxicos y controles. Método Estudiamos 30 niños disléxicos y 30 controles, pareados por edad. La localización sonora y discriminación a palabras fue estudiada en cinco ángulos horizontales en los campos izquierdo y derecho (-90o, -45o, 0o, +45o, +90o), bajo reverberación y sin reverberación; las respuestas correctas fueron comparadas Resultados: La localización sonora sin reverberación fue deficiente en niños disléxicos a 0º y +90º. La localización bajo reverberación falló en niños disléxicos en todos los ángulos, excepto –-90o. Durante la discriminación a palabras, sin reverberación, los niños disléxicos fallaron en ángulos izquierdos. En la prueba reverberante, los niños disléxicos fallaron a -–45o, -90o y +45o. Conclusion Los niños con dislexia pueden tener problemas cuando tienen que localizar sonidos y discriminar palabras en las localizaciones extremas del plano horizontal en salones de clases típicos con reverberación. .

Implantable hearing devices: the Ototronix MAXUM system.

For many hearing-impaired individuals, the benefits of conventional amplification may be limited by acoustic feedback, occlusion effect, and/or ear discomfort. The MAXUM system and other implantable hearing devices have been developed as an option for patients who derive inadequate assistance from traditional HAs, but who are not yet candidates for cochlear implants. The MAXUM system is based on the SOUNDTEC Direct System technology, which has been shown to provide improved functional gain as well as reduced feedback and occlusion effect compared to hearing aids. This and other implantable hearing devices may have increasing importance as future aural rehabilitation options.

The Discrimination of Printed Words by Prereading Children.

In addition to the discrimination of individual printed letters, beginning readers must learn to perceive individual letters within complex, whole-word stimuli. The present study shows that the discrimination of letters presented individually does not automatically entail the discrimination of 3-letter printed words that differ only in the first letter (e.g., sat, mat). Thirty-two children ranging in age from 3½ to 5½ years participated in two studies. All showed highly accurate discrimination of individual letters in identity matching-to-sample procedures before being exposed to the word-matching task. On the word-matching task, 21 of the 32 children showed accuracy of less than 85%, and 11 of these showed accuracy of 65% or less. Word-discrimination accuracy did not improve in retests of a subset of children after periods ranging from 3 weeks to 3 months. In Study 2, six children who initially showed relatively low word-matching accuracy were taught using fading procedures. Moreover, generalization to untaught words was shown. These results extend basic laboratory studies that have shown difficulties discriminating multi-element stimuli despite the discrimination of the individual component elements.

Aging effects on ERP correlates of emotional word discrimination.

OBJECTIVE: To explore age-, and valence specific ERP-characteristics of word-discrimination processes. METHODS: A group of young (mean age: 21.26 yrs) and elderly (mean age: 65.73 yrs) individuals participated. The task was to respond to a word (target) with valence (neutral, negative, positive) and disregard others (non-target) with a different valence. Behavioral indices and the N4 and late positive complex (LPC) components were analyzed. RESULTS: For words with negative valence performance was better for non-target stimuli in the young. Higher N4 was elicited by negative non-target words in the fronto-central areas. Target words elicited a P3b-like LPC in the young while a P3a-like LPC was observed in the elderly. CONCLUSION: The findings indicate that inhibition elicited by aversive events is observed for word stimuli as well, and is most effective in the young. SIGNIFICANCE: The effect of valence during emotional word discrimination shows age-dependent differences reflected by ERPs.