Relationship Between Working Memory, Compression, and Beamformers in Ideal Conditions.

Objectives: Previous research has shown that speech recognition with different wide dynamic range compression (WDRC) time-constants (fast-acting or Fast and slow-acting or Slow) is associated with individual working memory ability, especially in adverse listening conditions. Until recently, much of this research has been limited to omnidirectional hearing aid settings and colocated speech and noise, whereas most hearing aids are fit with directional processing that may improve the listening environment in spatially separated conditions and interact with WDRC processing. The primary objective of this study was to determine whether there is an association between individual working memory ability and speech recognition in noise with different WDRC time-constants, with and without microphone directionality (binaural beamformer or Beam versus omnidirectional or Omni) in a spatial condition ideal for the beamformer (speech at 0 , noise at 180 ).

Investigating the Utility of a Compact Loudspeaker Array for Audiometric Testing.

Purpose: This project addressed the uses of a loudspeaker array for audiometric measurements. It sought to evaluate a prototype compact array in terms of the reliability of test results across sound booths.

Method: A seven-loudspeaker array was developed to deliver sounds from -60° to +60° on an arc with a radius of 0.

An Exploratory Study of Walking, Listening, and Remembering in Younger and Middle-Aged Adults.

Purpose: The purpose of this study was to assess how needing to listen and remember information while walking affects speech perception, memory task performance, and gait in younger and middle-aged adults.

Method: Four gait parameters (stride duration, step variability, whole-body center of mass acceleration, and mediolateral head acceleration) were measured when younger and middle-aged participants stood or walked on a treadmill while they simultaneously completed a speech-on-speech perception task and a preload memory task, singly and in combination.

Results: Speech perception was significantly poorer for middle-aged than for younger participants.

Spatial release from informational masking enhances the early cortical representation of speech sounds.

Introduction: Spatial separation between competing speech streams reduces their confusion (informational masking), improving speech processing under challenging listening conditions. The precise stages of auditory processing involved in this benefit are not fully understood. This study used event-related potentials to examine the processing of target speech under conditions of informational masking and its spatial release.

Early aging and postural control while listening and responding.

It is not unusual for communication to take place while people are involved in another activity. This paper describes a study that measures the impact of listening while also completing an active postural control task. The focus was on whether the combination of listening and balancing was more detrimental to middle-aged adults than it was to younger adults as age-related changes in both hearing and postural control can occur within this age range.

Postural Control While Listening in Younger and Middle-Aged Adults.

Objectives: The motivation for this research is to determine whether a listening-while-balancing task would be sensitive to quantifying listening effort in middle age. The premise behind this exploratory work is that a decrease in postural control would be demonstrated in challenging acoustic conditions, more so in middle-aged than in younger adults.

Design: A dual-task paradigm was employed with speech understanding as one task and postural control as the other.

Auditory Comprehension in School-Aged Children With Normal Hearing and With Unilateral Hearing Loss.

Purpose The purpose of this study was to measure auditory comprehension performance in school-aged children with unilateral hearing loss (UHL) and with normal hearing (NH) in quiet and in the presence of child-produced two-talker babble (TTB). Method Listeners were school-aged children (7-12 years) with permanent UHL ( = 25) or NH ( = 14). Comprehension of three short stories taken from the Test of Narrative Language (Gillam & Pearson, 2004) was measured in quiet and in the presence of TTB at two signal-to-noise ratios (SNRs): (a) +6 dB and (b) the individualized SNR required to achieve 50% sentence understanding in the presence of the same TTB masker in a prior study (Griffin, Poissant, & Freyman, 2019).

Speech-in-Noise and Quality-of-Life Measures in School-Aged Children With Normal Hearing and With Unilateral Hearing Loss.

Objectives: (1) Measure sentence recognition in co-located and spatially separated target and masker configurations in school-aged children with unilateral hearing loss (UHL) and with normal hearing (NH). (2) Compare self-reported hearing-related quality-of-life (QoL) scores in school-aged children with UHL and NH.

Design: Listeners were school-aged children (6 to 12 yrs) with permanent UHL (n = 41) or NH (n = 35) and adults with NH (n = 23).

How repetition influences speech understanding by younger, middle-aged and older adults.

Objective: To examine benefit from immediate repetition of a masked speech message in younger, middle-aged and older adults.

Design: Participants listened to sentences in conditions where only the target message was repeated, and when both the target message and its accompanying masker (noise or speech) were repeated. In a follow-up experiment, the effect of repetition was evaluated using a square-wave modulated noise masker to compare benefit when listeners were exposed to the same glimpses of the target message during first and second presentation versus when the glimpses differed.

Can monaural temporal masking explain the ongoing precedence effect?

The precedence effect for transient sounds has been proposed to be based primarily on monaural processes, manifested by asymmetric temporal masking. This study explored the potential for monaural explanations with longer ("ongoing") sounds exhibiting the precedence effect. Transient stimuli were single lead-lag noise burst pairs; ongoing stimuli were trains of 63 burst pairs.

The Effects of Musical Training on Speech Detection in the Presence of Informational and Energetic Masking.

Recent research has suggested that musicians have an advantage in some speech-in-noise paradigms, but not all. Whether musicians outperform nonmusicians on a given speech-in-noise task may well depend on the type of noise involved. To date, few groups have specifically studied the role that informational masking plays in the observation of a musician advantage.

Strength of onset and ongoing cues in judgments of lateral position.

This study describes the contributions to auditory image position of an interaural time delay (ITD) cue at onset relative to subsequent ITDs during the ongoing part of a stimulus. Test stimuli were trains of 1-ms binaural noise bursts; lateral position was measured with a wideband acoustic pointer that subjects adjusted to match the intracranial position of test stimuli. In different conditions the ongoing part of the stimulus (the bursts following the first one) either had a consistent ITD (the same ITD on each ongoing burst), or had alternating leading and lagging components with ITDs that opposed one another.

The Effect of Aging and Priming on Same/Different Judgments Between Text and Partially Masked Speech.

Objectives: It is well known from previous research that when listeners are told what they are about to hear before a degraded or partially masked auditory signal is presented, the speech signal "pops out" of the background and becomes considerably more intelligible. The goal of this research was to explore whether this priming effect is as strong in older adults as in younger adults.

Design: Fifty-six adults-28 older and 28 younger-listened to "nonsense" sentences spoken by a female talker in the presence of a 2-talker speech masker (also female) or a fluctuating speech-like noise masker at 5 signal-to-noise ratios.

Age equivalence in the benefit of repetition for speech understanding.

Although repetition is the most commonly used conversational repair strategy, little is known about its relative effectiveness among listeners spanning the adult age range. The purpose of this study was to identify differences in how younger, middle-aged, and older adults were able to use immediate repetition to improve speech recognition in the presence of different kinds of maskers. Results suggest that all groups received approximately the same amount of benefit from repetition.

Aging and the effect of target-masker alignment.

Similarity between target and competing speech messages plays a large role in how easy or difficult it is to understand messages of interest. Much research on informational masking has used highly aligned target and masking utterances that are very similar semantically and syntactically. However, listeners rarely encounter situations in real life where they must understand one sentence in the presence of another (or more than one) highly aligned, syntactically similar competing sentence(s).

Temporal effects in priming of masked and degraded speech.

When listeners know the content of the message they are about to hear, the clarity of distorted or partially masked speech increases dramatically. The current experiments investigated this priming phenomenon quantitatively using a same-different task where a typed caption and auditory message either matched exactly or differed by one key word. Four conditions were tested with groups of normal-hearing listeners: (a) natural speech presented in two-talker babble in a non-spatial configuration, (b) same as (a) but with the masker time reversed, (c) same as (a) but with target-masker spatial separation, and (d) vocoded sentences presented in speech-spectrum noise.

Attention is critical for spatial auditory object formation.

The precedence effect provides a novel way to examine the role of attention in auditory object formation. When presented with two identical sounds from different locations separated by a short stimulus onset asynchrony (SOA), listeners report a single auditory object at the location of the lead sound. When the SOA is above the echo threshold, listeners report hearing two auditory objects with different locations.

Stimulus and listener factors affecting age-related changes in competing speech perception.

The purpose of this study was to examine associations among hearing thresholds, cognitive ability, and speech understanding in adverse listening conditions within and between groups of younger, middle-aged, and older adults. Participants repeated back sentences played in the presence of several types of maskers (syntactically similar and syntactically different competing speech from one or two other talkers, and steady-state speech-shaped noise). They also completed tests of auditory short-term/working memory, processing speed, and inhibitory ability.

Threshold of the precedence effect in noise.

Three effects that show a temporal asymmetry in the influence of interaural cues were studied through the addition of masking noise: (1) The transient precedence effect-the perceptual dominance of a leading transient over a similar lagging transient; (2) the ongoing precedence effect-lead dominance with lead and lag components that extend in time; and (3) the onset capture effect-determination by an onset transient of the lateral position of an otherwise ambiguous extended trailing sound. These three effects were evoked with noise-burst stimuli and were compared in the presence of masking noise. Using a diotic noise masker, detection thresholds for stimuli with lead/lag interaural delays of 0/500 μs were compared to those with 500/0 μs delays.

Influence of musical training on understanding voiced and whispered speech in noise.

This study tested the hypothesis that the previously reported advantage of musicians over non-musicians in understanding speech in noise arises from more efficient or robust coding of periodic voiced speech, particularly in fluctuating backgrounds. Speech intelligibility was measured in listeners with extensive musical training, and in those with very little musical training or experience, using normal (voiced) or whispered (unvoiced) grammatically correct nonsense sentences in noise that was spectrally shaped to match the long-term spectrum of the speech, and was either continuous or gated with a 16-Hz square wave. Performance was also measured in clinical speech-in-noise tests and in pitch discrimination.

Priming of lowpass-filtered speech affects response bias, not sensitivity, in a bandwidth discrimination task.

Priming is demonstrated when prior information about the content of a distorted, filtered, or masked auditory message improves its clarity. The current experiment attempted to quantify aspects of priming by determining its effects on performance and bias in a lowpass-filter-cutoff frequency discrimination task. Nonsense sentences recorded by a female talker were sharply lowpass filtered at a nominal cutoff frequency (F) of 0.

Intelligibility of whispered speech in stationary and modulated noise maskers.

This study investigated the role of natural periodic temporal fine structure in helping listeners take advantage of temporal valleys in amplitude-modulated masking noise when listening to speech. Young normal-hearing participants listened to natural, whispered, and/or vocoded nonsense sentences in a variety of masking conditions. Whispering alters normal waveform temporal fine structure dramatically but, unlike vocoding, does not degrade spectral details created by vocal tract resonances.

Characteristics of noise exposure during solitary trumpet playing: immediate impact on distortion-product otoacoustic emissions and long-term implications for hearing.

Objectives: The objectives of this investigation were to quantify noise exposures generated during a 1 hr trumpet practice session and to determine whether distortion-product otoacoustic emissions (DPOAEs) are affected by such exposure, to describe the distribution of intensity levels and temporal characteristics of noise produced by trumpet practice, and to determine the effect of earplug use on generated noise levels and DPOAEs.

Design: In experiment 1, eight college-age trumpeters underwent an otoscopic inspection, tympanometry, and pure-tone threshold testing. Using a Grason-Stadler 60 DPOAE system, DPOAEs were recorded just before a 1 hr practice session, at 2 min after the practice session, 4 min after the session, and at 4 min intervals thereafter for a total period of 1 hr.

Effect of priming on energetic and informational masking in a same-different task.

Objectives: The primary goal of this study was to investigate how speech perception is altered by the provision of a preview or "prime" of a sample of speech just before it is presented in masking. A same-different test paradigm was developed which enabled the effect of priming to be measured with energetic maskers in addition to those that most likely produced both energetic and informational masking. Using this paradigm, the benefit of priming in overcoming energetic and informational masking was compared.

Manipulations of listeners' echo perception are reflected in event-related potentials.

To gain information from complex auditory scenes, it is necessary to determine which of the many loudness, pitch, and timbre changes originate from a single source. Grouping sound into sources based on spatial information is complicated by reverberant energy bouncing off multiple surfaces and reaching the ears from directions other than the source's location. The ability to localize sounds despite these echoes has been explored with the precedence effect: Identical sounds presented from two locations with a short stimulus onset asynchrony (e.