Publications by authors named "Ewen MacDonald"

This study investigated the effects of noise and hearing impairment on conversational dynamics between pairs of young normal-hearing and older hearing-impaired interlocutors. Twelve pairs of normal-hearing and hearing-impaired individuals completed a spot-the-difference task in quiet and in three levels of multitalker babble. To achieve the rapid response timing of turn taking that has been observed in normal conversations, people must simultaneously comprehend incoming speech, plan a response, and predict when their partners will end their turn.

View Article and Find Full Text PDF

To achieve human-like behaviour during speech interactions, it is necessary for a humanoid robot to estimate the location of a human talker. Here, we present a method to optimize the parameters used for the direction of arrival (DOA) estimation, while also considering real-time applications for human-robot interaction scenarios. This method is applied to binaural sound source localization framework on a humanoid robotic head.

View Article and Find Full Text PDF

Objective: The aim of this study was to investigate whether consumer-grade mobile audio equipment can be reliably used as a platform for the notched-noise test, including when the test is conducted outside the laboratory.

Design: Two studies were conducted: Study 1 was a notched-noise masking experiment with three different setups: in a psychoacoustic test booth with a standard laboratory PC; in a psychoacoustic test booth with a mobile device; and in a quiet office room with a mobile device. Study 2 employed the same task as Study 1, but compared circumaural headphones to insert earphones.

View Article and Find Full Text PDF

There is a long-standing tradition to assess hearing-aid benefits using lab-based speech intelligibility tests. Towards a more everyday-like scenario, the current study investigated the effects of hearing-aid amplification and noise on face-to-face communication between two conversational partners. Eleven pairs, consisting of a younger normal-hearing (NH) and an older hearing-impaired (HI) participant, solved spot-the-difference tasks while their conversations were recorded.

View Article and Find Full Text PDF

Linearized encoding models are increasingly employed to model cortical responses to running speech. Recent extensions to subcortical responses suggest clinical perspectives, potentially complementing auditory brainstem responses (ABRs) or frequency-following responses (FFRs) that are current clinical standards. However, while it is well-known that the auditory brainstem responds both to transient amplitude variations and the stimulus periodicity that gives rise to pitch, these features co-vary in running speech.

View Article and Find Full Text PDF

This study provides a framework for measuring conversational dynamics between conversational partners (interlocutors). Conversations from 20 pairs of young, normal-hearing, native-Danish talkers were recorded when speaking in both quiet and noise (70 dBA sound pressure level [SPL]) and in Danish and English. Previous studies investigating the intervals from when one talker stops talking to when the next one starts, termed floor-transfer offsets (FTOs), suggest that typical turn-taking requires interlocutors to predict when the current talker will finish their turn.

View Article and Find Full Text PDF

While an audiogram is a useful method of characterizing hearing loss, it has been suggested that including a complementary, suprathreshold measure, for example, a measure of the status of the cochlear active mechanism, could lead to improved diagnostics and improved hearing-aid fitting in individual listeners. While several behavioral and physiological methods have been proposed to measure the cochlear-nonlinearity characteristics, evidence of a good correspondence between them is lacking, at least in the case of hearing-impaired listeners. If this lack of correspondence is due to, for example, limited reliability of one of such measures, it might be a reason for limited evidence of the benefit of measuring peripheral compression.

View Article and Find Full Text PDF

There is conflicting evidence about the relative benefit of slow- and fast-acting compression for speech intelligibility. It has been hypothesized that fast-acting compression improves audibility at low signal-to-noise ratios (SNRs) but may distort the speech envelope at higher SNRs. The present study investigated the effects of compression with a nearly instantaneous attack time but either fast (10 ms) or slow (500 ms) release times on consonant identification in hearing-impaired listeners.

View Article and Find Full Text PDF

Purpose: Studying the variations in speech levels with changing background noise level and talker-to-listener distance for talkers wearing hearing protection devices (HPDs) can aid in understanding communication in background noise.

Method: Speech was recorded using an intra-aural HPD from 12 different talkers at 5 different distances in 3 different noise conditions and 2 quiet conditions.

Results: This article proposes models that can predict the difference in speech level as a function of background noise level and talker-to-listener distance for occluded talkers.

View Article and Find Full Text PDF
Article Synopsis
  • Pure-tone audiometry alone doesn't fully explain individual hearing loss, and alternative methods like forward masking could enhance diagnostics.
  • The study explored modifications to the temporal masking curve (TMC) tests to make them more time-efficient, including a new method called the "gap method".
  • Results indicated that while knee point estimates were reliable, there were challenges with measuring the compression ratio, highlighting pros and cons of both testing approaches.
View Article and Find Full Text PDF

This study investigated the relationship between speech perception performance in spatially complex, lateralized listening scenarios and temporal fine-structure (TFS) coding at low frequencies. Young normal-hearing (NH) and two groups of elderly hearing-impaired (HI) listeners with mild or moderate hearing loss above 1.5 kHz participated in the study.

View Article and Find Full Text PDF

This study proposes a binaural extension to the multi-resolution speech-based envelope power spectrum model (mr-sEPSM) [Jørgensen, Ewert, and Dau (2013). J. Acoust.

View Article and Find Full Text PDF

Objective: Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD).

View Article and Find Full Text PDF

Objectives: Previous work has shown that individuals with lower working memory demonstrate reduced intelligibility for speech processed with fast-acting compression amplification. This relationship has been noted in fluctuating noise, but the extent of noise modulation that must be present to elicit such an effect is unknown. This study expanded on previous study by exploring the effect of background noise modulations in relation to compression speed and working memory ability, using a range of signal to noise ratios.

View Article and Find Full Text PDF

Past studies have shown that speakers spontaneously adjust their speech acoustics in response to their auditory feedback perturbed in real time. In the case of formant perturbation, the majority of studies have examined speaker's compensatory production using the English vowel /ɛ/ as in the word "head." Consistent behavioral observations have been reported, and there is lively discussion as to how the production system integrates auditory versus somatosensory feedback to control vowel production.

View Article and Find Full Text PDF
Article Synopsis
  • Facial configuration is crucial for perceiving identity and expression from faces, and it influences visual speech perception, particularly when faces are upright, as seen in the Thatcher effect.
  • The McThatcher effect illustrates how the Thatcherization of faces disrupts the McGurk illusion, which shows how visual speech can affect auditory speech perception.
  • The study found that Thatcherization impacts the strength of the McGurk illusion and its corresponding auditory response (McGurk-MMN) primarily for upright faces, suggesting that a stronger visual cue is necessary for it to influence auditory perception.
View Article and Find Full Text PDF

Previous research employing a real-time auditory perturbation paradigm has shown that talkers monitor their own speech attributes such as fundamental frequency, vowel intensity, vowel formants, and fricative noise as part of speech motor control. In the case of vowel formants or fricative noise, what was manipulated is spectral information about the filter function of the vocal tract. However, segments can be contrasted by parameters other than spectral configuration.

View Article and Find Full Text PDF

Masking release (MR) is the improvement in speech intelligibility for a fluctuating interferer compared to stationary noise. Reduction in MR due to vocoder processing is usually linked to distortions in the temporal fine structure of the stimuli and a corresponding reduction in the fundamental frequency (F0) cues. However, it is unclear if envelope periodicity related to F0, produced by the interaction between unresolved harmonics, contributes to MR.

View Article and Find Full Text PDF

The everyday act of speaking involves the complex processes of speech motor control. An important component of control is monitoring, detection, and processing of errors when auditory feedback does not correspond to the intended motor gesture. Here we show, using fMRI and converging operations within a multivoxel pattern analysis framework, that this sensorimotor process is supported by functionally differentiated brain networks.

View Article and Find Full Text PDF

The exponential increase of intensity for an approaching sound source provides salient information for a listener to make judgments of time to arrival (TTA). Specifically, a listener will experience a greater rate of increasing intensity for higher than for lower frequencies during a sound source's approach. To examine the relative importance of this spectral information, listeners were asked to make judgments about the arrival times of nine 1-octave-band sound sources (the bands were consecutive, nonoverlapping single octaves, ranging from 40-80 Hz to ~10-20 kHz).

View Article and Find Full Text PDF

Objectives: The purpose of Experiment 1 was to measure word recognition in younger adults with normal hearing when speech or babble was temporally or spectrally distorted. In Experiment 2, older listeners with near-normal hearing and with hearing loss (for pure tones) were tested to evaluate their susceptibility to changes in speech level and distortion types. The results across groups and listening conditions were compared to assess the extent to which the effects of the distortions on word recognition resembled the effects of age-related differences in auditory processing or pure-tone hearing loss.

View Article and Find Full Text PDF

Species-specific vocalizations fall into two broad categories: those that emerge during maturation, independent of experience, and those that depend on early life interactions with conspecifics. Human language and the communication systems of a small number of other species, including songbirds, fall into this latter class of vocal learning. Self-monitoring has been assumed to play an important role in the vocal learning of speech and studies demonstrate that perception of your own voice is crucial for both the development and lifelong maintenance of vocalizations in humans and songbirds.

View Article and Find Full Text PDF

Past studies have shown that when formants are perturbed in real time, speakers spontaneously compensate for the perturbation by changing their formant frequencies in the opposite direction to the perturbation. Further, the pattern of these results suggests that the processing of auditory feedback error operates at a purely acoustic level. This hypothesis was tested by comparing the response of three language groups to real-time formant perturbations, (1) native English speakers producing an English vowel /ε/, (2) native Japanese speakers producing a Japanese vowel (/e([inverted perpendicular])/), and (3) native Japanese speakers learning English, producing /ε/.

View Article and Find Full Text PDF