Investigating the Neural Basis of the Loud-first Principle of the Iambic-Trochaic Law.

The perception of rhythmic patterns is crucial for the recognition of words in spoken languages, yet it remains unclear how these patterns are represented in the brain. Here, we tested the hypothesis that rhythmic patterns are encoded by neural activity phase-locked to the temporal modulation of these patterns in the speech signal. To test this hypothesis, we analyzed EEGs evoked with long sequences of alternating syllables acoustically manipulated to be perceived as a series of different rhythmic groupings in English.

The relationship between sentence intelligibility, band importance, and signal covariance.

The present study investigates the relationship between sentence intelligibility, band importance, and patterns of spectro-temporal covariation between frequency bands. Sixteen listeners transcribed sentences acoustically degraded to 5, 8, or 15 frequency bands. Half of the sentences retained the frequency bands that captured more signal covariance.

Low detection rate of RT-PCR-confirmed COVID-19 using IgM/IgG rapid antibody tests in a large community sample in Lima, Peru.

Background: Rapid IgM/IgG antibody tests were largely used in lieu of RT-PCR tests as part of COVID-19 public health response activities in Lima, Peru. To assess their utility, we explored the relationship between the time since onset of several COVID-19-related symptoms and the sensitivity of a rapid combined IgM/IgG antibody test.

Methods: We collected data from a community sample of individuals (n = 492) who received concurrent RT-PCR and rapid IgM/IgG antibody testing between May 2020 and March 2021.

Language experience during the sensitive period narrows infants' sensory encoding of lexical tones-Music intervention reverses it.

The for phonetic learning (6∼12 months), evidenced by improved native speech processing and declined non-native speech processing, represents an early milestone in language acquisition. We examined the extent that sensory encoding of speech is altered by experience during this period by testing two hypotheses: (1) early sensory encoding of non-native speech declines as infants gain native-language experience, and (2) music intervention reverses this decline. We longitudinally measured the frequency-following response (FFR), a robust indicator of early sensory encoding along the auditory pathway, to a Mandarin lexical tone in 7- and 11-months-old monolingual English-learning infants.

The emergence of idiosyncratic patterns in the frequency-following response during the first year of life.

The frequency-following response (FFR) is a scalp-recorded signal that reflects phase-locked activity from neurons across the auditory system. In addition to capturing information about sounds, the FFR conveys biometric information, reflecting individual differences in auditory processing. To investigate the development of FFR biometric patterns, we trained a pattern recognition model to recognize infants ( = 16) from FFRs collected at 7 and 11 months.

Principal component decomposition of acoustic and neural representations of time-varying pitch reveals adaptive efficient coding of speech covariation patterns.

Understanding the effects of statistical regularities on speech processing is a central issue in auditory neuroscience. To investigate the effects of distributional covariance on the neural processing of speech features, we introduce and validate a novel approach: decomposition of time-varying signals into patterns of covariation extracted with Principal Component Analysis. We used this decomposition to assay the sensory representation of pitch covariation patterns in native Chinese listeners and non-native learners of Mandarin Chinese tones.

Frequency-Following Responses to Speech Sounds Are Highly Conserved across Species and Contain Cortical Contributions.

Time-varying pitch is a vital cue for human speech perception. Neural processing of time-varying pitch has been extensively assayed using scalp-recorded frequency-following responses (FFRs), an electrophysiological signal thought to reflect integrated phase-locked neural ensemble activity from subcortical auditory areas. Emerging evidence increasingly points to a putative contribution of auditory cortical ensembles to the scalp-recorded FFRs.

Bayesian Semiparametric Longitudinal Drift-Diffusion Mixed Models for Tone Learning in Adults.

Understanding how adult humans learn nonnative speech categories such as tone information has shed novel insights into the mechanisms underlying experience-dependent brain plasticity. Scientists have traditionally examined these questions using longitudinal learning experiments under a multi-category decision making paradigm. Drift-diffusion processes are popular in such contexts for their ability to mimic underlying neural mechanisms.

The neural processing of pitch accents in continuous speech.

Pitch accents are local pitch patterns that convey differences in word prominence and modulate the information structure of the discourse. Despite the importance to discourse in languages like English, neural processing of pitch accents remains understudied. The current study investigates the neural processing of pitch accents by native and non-native English speakers while they are listening to or ignoring 45 min of continuous, natural speech.

Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Antibodies Among Market and City Bus Depot Workers in Lima, Peru.

We report severe acute respiratory syndrome coronavirus 2 antibody positivity among market and city bus depot workers in Lima, Peru. Among 1285 vendors from 8 markets, prevalence ranged from 27% to 73%. Among 488 workers from 3 city bus depots, prevalence ranged from 11% to 47%.

Non-invasive peripheral nerve stimulation selectively enhances speech category learning in adults.

Adults struggle to learn non-native speech contrasts even after years of exposure. While laboratory-based training approaches yield learning, the optimal training conditions for maximizing speech learning in adulthood are currently unknown. Vagus nerve stimulation has been shown to prime adult sensory-perceptual systems towards plasticity in animal models.

Biometric identification of listener identity from frequency following responses to speech.

Objective: We investigate the biometric specificity of the frequency following response (FFR), an EEG marker of early auditory processing that reflects phase-locked activity from neural ensembles in the auditory cortex and subcortex (Chandrasekaran and Kraus 2010, Bidelman, 2015a, 2018, Coffey et al 2017b). Our objective is two-fold: demonstrate that the FFR contains information beyond stimulus properties and broad group-level markers, and to assess the practical viability of the FFR as a biometric across different sounds, auditory experiences, and recording days.

Approach: We trained the hidden Markov model (HMM) to decode listener identity from FFR spectro-temporal patterns across multiple frequency bands.

Tracing the Trajectory of Sensory Plasticity across Different Stages of Speech Learning in Adulthood.

Although challenging, adults can learn non-native phonetic contrasts with extensive training [1, 2], indicative of perceptual learning beyond an early sensitivity period [3, 4]. Training can alter low-level sensory encoding of newly acquired speech sound patterns [5]; however, the time-course, behavioral relevance, and long-term retention of such sensory plasticity is unclear. Some theories argue that sensory plasticity underlying signal enhancement is immediate and critical to perceptual learning [6, 7].

Hidden Markov modeling of frequency-following responses to Mandarin lexical tones.

Background: The frequency-following response (FFR) is a scalp-recorded electrophysiological potential reflecting phase-locked activity from neural ensembles in the auditory system. The FFR is often used to assess the robustness of subcortical pitch processing. Due to low signal-to-noise ratio at the single-trial level, FFRs are typically averaged across thousands of stimulus repetitions.

Infants adapt to speaking rate differences in word segmentation.

Throughout their development, infants are exposed to varying speaking rates. Thus, it is important to determine whether they are able to adapt to speech at varying rates and recognize target words from continuous speech despite speaking rate differences. To address this question, a series of four experiments were conducted to test whether infants can recognize words in continuous speech when rate is variable.

The Effects of Language Experience and Speech Context on the Phonetic Accommodation of English-accented Spanish Voicing.

Native speakers of Spanish with different amounts of experience with English classified stop-consonant voicing (/b/ versus /p/) across different speech accents: English-accented Spanish, native Spanish, and native English. While listeners with little experience with English classified target voicing with an English- or Spanish-like voice onset time (VOT) boundary, predicted by contextual VOT, listeners familiar with English relied on an English-like VOT boundary in an English-accented Spanish context even in the absence of clear contextual cues to English VOT. This indicates that Spanish listeners accommodated English-accented Spanish voicing differently depending on their degree of familiarization with the English norm.

Power spectral entropy as an information-theoretic correlate of manner of articulation in American English.

While all languages differentiate speech sounds by manner of articulation, none of the acoustic correlates proposed to date seem to account for how these contrasts are encoded in the speech signal. The present study describes power spectral entropy (PSE), which quantifies the amount of potential information conveyed in the power spectrum of a given sound. Results of acoustic analyses of speech samples extracted from the Texas Instruments-Massachusetts Institute of Technology database reveal a statistically significant correspondence between PSE and American English major classes of manner of articulation.

Neurocysticercosis as a cause of epilepsy and seizures in two community-based studies in a cysticercosis-endemic region in Peru.

Background: The prevalence of epilepsy added to inadequate treatment results in chronic morbidity and considerable mortality in poor populations. Neurocysticercosis (NCC), a helminthic disease of the central nervous system, is a leading cause of seizures and epilepsy in most of the world.

Methods: Taking advantage of a cysticercosis elimination program, we performed two community-based cross-sectional studies between 2006 and 2007 in 58 rural communities (population 20,610) to assess the prevalence and characteristics of epilepsy and epileptic seizures in this endemic region.

Auditory enhancement and second language experience in Spanish and English weighting of secondary voicing cues.

The role of secondary cues in voicing categorization was investigated in three listener groups: Monolingual English (n = 20) and Spanish speakers (n = 20), and Spanish speakers with significant English experience (n = 16). Results showed that, in all three groups, participants used onset f0 in making voicing decisions only in the positive voice onset time (VOT) range (short lag and long lag tokens), while there was no effect of onset f0 on voicing categorization within the negative VOT range (voicing lead tokens) for any of the participant groups. These results support an auditory enhancement view of perceptual cue weighting: Onset f0 serves as a secondary cue to voicing only in the positive VOT range where it is not overshadowed by the presence of pre-voicing.

Differential cue weighting in perception and production of consonant voicing.

This study examines English speakers' relative weighting of two voicing cues in production and perception. Participants repeated words differing in initial consonant voicing ([b] or [p]) and labeled synthesized tokens ranging between [ba] and [pa] orthogonally according to voice onset time (VOT) and onset f0. Discriminant function analysis and logistic regression were used to calculate individuals' relative weighting of each cue.

Safety and efficacy of moxifloxacin monotherapy for treatment of orthopedic implant-related staphylococcal infections.

The rifampin-ciprofloxacin combination is recommended for treatment of orthopedic implant-related staphylococcal infections to avoid the emergence of ciprofloxacin resistance; however, the efficacy of this combination is limited by the tolerability problems associated with the use of rifampin. Moxifloxacin is a quinolone up to 10 times more active against staphylococci than ciprofloxacin and the risk of resistance development during monotherapy against staphylococci is theoretically lower for moxifloxacin, but information regarding its use in bone infections is lacking. The aim of the present study was to evaluate the safety and clinical efficacy of moxifloxacin monotherapy in patients with orthopedic implant-related staphylococcal infections.