Effect of Abstract Phonemic Complexity on Mismatch Negativity Amplitude.

Purpose:  Mismatch negativity (MMN) reflects a preperceptual neurophysiological response that is generated subconsciously due to the interruption of a memory trace of ongoing sensory events in the environment. It has been widely used by researchers to understand complex perceptual mechanisms. Furthermore, it has been recommended as an objective tool to investigate disorders related to auditory cognition in hearing aid and cochlear implant users.

Diabetes and Auditory-Vestibular Pathology.

The relationship between diabetes mellitus (DM) and the auditory/vestibular system has been investigated for more than a century. Most population-based investigations of hearing loss in persons with diabetes (PWD) have revealed a slow progressive, bilateral, high-frequency sensorineural hearing loss. Despite the growing research literature on the pathophysiology of DM-related hearing loss using various animal models and other human studies, knowledge of specific mechanism of the degenerative changes of the inner ear and/or auditory nerve is far from full elucidation.

Temporal processing in low-frequency channels: effects of age and hearing loss in middle-aged listeners.

Background: Hearing loss and age interfere with the auditory system's ability to process temporal changes in the acoustic signal. A key unresolved question is whether high-frequency sensorineural hearing loss (HFSNHL) affects temporal processing in the low-frequency region where hearing loss is minimal or nonexistent. A second unresolved question is whether changes in hearing occur in middle-aged subjects in the absence of HFSNHL.

A cross-linguistic examination of cortical auditory evoked potentials for a categorical voicing contrast.

Behavioral perceptions and cortical auditory evoked potentials (CAEPs) from native English (N=10) and Spanish speakers (N=10) were recorded for speech stimuli that constitute phonetically relevant categories of voicing. The stimuli were synthesized bilabial stop consonant-vowel syllables in a continuum ranging from/ba/to/pa/that varied in voice onset time (VOT) from 0 to 60 ms. Different behavioral perceptions were evidenced by significantly different categorical phonetic boundaries between the two groups (p<.

Natural boundaries in gap detection are related to categorical perception of stop consonants.

Objectives: The hypothesis that a natural auditory psychophysical discontinuity contributes to a perceptual category boundary between voiced and voiceless English stop consonants was examined.

Design: The relationships between voice onset time (VOT) phonetic boundary and gap-detection thresholds for conditions in which the sounds delimiting the gap were acoustically identical or different were examined in 18 native young adult English speakers. It was specifically hypothesized that between-channel gap-detection thresholds, in contrast to within-channel gap thresholds, would be better predictors of categorical VOT values for listeners.

Auditory temporal resolution in normal-hearing preschool children revealed by word recognition in continuous and interrupted noise.

The purpose of this study was to examine temporal resolution in normal-hearing preschool children. Word recognition was evaluated in quiet and in spectrally identical continuous and interrupted noise at signal-to-noise ratios (S/Ns) of 10, 0, and -10 dB. Sixteen children 4 to 5 years of age and eight adults participated.

A comparison of the mismatch negativity and a differential waveform response.

A mismatch negativity response (MMN) and a new differential waveform were derived in an effort to evaluate a neural refractory or recovery effect in adult listeners. The MMN was elicited using oddball test runs in which the standard and deviant stimuli differed in frequency To derive the differential waveform, the same standard and deviant stimuli were presented alone. MMN responses were obtained by subtracting the averaged responses to standards from the deviants.

Interactive effects of high-pass filtering and masking noise on word recognition.

Objectives: This study sought to examine the word recognition performance in noise of individuals with a simulated low-frequency hearing loss. The goal was to understand how low-frequency hearing impairment affects performance on tasks that challenge temporal processing skills.

Methods: Twenty-two normal-hearing young adults participated.

Effects of discrimination task difficulty on N1 and P2 components of late auditory evoked potential.

The present study investigated the question of whether, in healthy young listeners, increases in discrimination task difficulty will alter the amplitude of either the N1 or P2 components of the late auditory evoked potential (LAEP). Using a stimulus oddball procedure, listeners discriminated changes in the frequency of ongoing tonal stimuli. On different test runs, task difficulty was manipulated by decreasing the size of the frequency differences and/or adding competing speech babble to the nontest ear.

Preschool hearing screening: pass/refer rates for children enrolled in a head start program in eastern North Carolina.

This 4-year project investigated the pass/refer rates of preschool children in a hearing screening program. Three- and 4-year-old children who attended Head Start centers in rural, traditionally medically underserved, eastern North Carolina participated (n = 1,462). Screening procedures and pass/refer criteria were based on the Guidelines for Audiologic Screening (American Speech-Language-Hearing Association [ASHA], Panel on Audiologic Assessment, 1997).

Internet-based tele-audiometry system for the assessment of hearing: a pilot study.

The application of tele-audiology is in its infancy. Several systems have been developed to screen hearing, yet the application of real-time diagnostic audiology to a remote location is new. This paper describes a tele-audiometric system developed for the application of realtime diagnostic audiometry via the Internet.

Internet application to tele-audiology--"nothin' but net".

The Telehealth program at East Carolina University has developed a system for real-time assessment of auditory thresholds using computer driven control of a remote audiometer via the Internet. The present study used 45 adult participants in a double-blind study of 2 different systems: a conventional audiometer and an audiometer operated remotely via the Internet. The audiometric thresholds assessed by these 2 systems varied by no more than 1.

Potential contamination effects of neuronal refractoriness on the speech-evoked mismatch negativity response.

The mismatch negativity response (MMN) is an event-related potential that is believed to reflect the automatic (possibly preconscious) neural processing of changes in ongoing environmental sounds. The MMN involves a negative voltage shift of baseline electroencephalographic (EEG) activity in the approximate latency window of the N1 and P2 cortical potentials in response to new or novel sounds. The most commonly used laboratory tests for extracting the MMN from EEG activity all involve oddball stimulus presentation procedures in which the interstimulus intervals (ISIs) of the frequently occurring standard sounds are shorter in length then that of the infrequently occurring deviant sounds.