Spatial release from masking in reverberation for school-age children

Masked speech recognition by 6-13-year-olds with early-childhood otitis media: effects of acoustic condition and otologic history

OBJECTIVE

To investigate speech recognition in school-age children with early-childhood otitis media (OM) in conditions with noise or speech maskers with or without interaural differences. To also investigate the effects of three otologic history factors.

DESIGN

Using headphone presentation, speech recognition thresholds (SRTs) were measured with simple sentences. As maskers, stationary speech-shaped noise (SSN) or two-talker running speech (TTS) were used. The stimuli were presented in a monaural and binaural condition (SSN) or a co-located and spatially separated condition (TTS). Based on the available medical records, overall OM duration, OM onset age, and time since the last OM episode were estimated.

STUDY SAMPLE

6-13-year-olds with a history of recurrent OM (N = 42) or without any ear diseases (N = 20) with normal tympanograms and audiograms at the time of testing.

RESULTS

Mixed-model regression analyses that controlled for age showed poorer SRTs for the OM group (Δ-value = 0.84 dB, p = 0.009). These appeared driven by the spatially separated, binaural, and monaural conditions. The OM group showed large inter-individual differences, which were unrelated to the otologic history factors.

CONCLUSIONS

Early-childhood OM can affect speech recognition in different acoustic conditions. The effects of the otologic history warrant further investigation.

Development of amplitude modulation, voice onset time, and consonant identification in noise and reverberation

Children's speech understanding is vulnerable to indoor noise and reverberation: e.g., from classrooms. It is unknown how they develop the ability to use temporal acoustic cues, specifically amplitude modulation (AM) and voice onset time (VOT), which are important for perceiving distorted speech. Through three experiments, we investigated the typical development of AM depth detection in vowels (experiment I), categorical perception of VOT (experiment II), and consonant identification (experiment III) in quiet and in speech-shaped noise (SSN) and mild reverberation in 6- to 14-year-old children. Our findings suggested that AM depth detection using a naturally produced vowel at the rate of the fundamental frequency was particularly difficult for children and with acoustic distortions. While the VOT cue salience was monotonically attenuated with increasing signal-to-noise ratio of SSN, its utility for consonant discrimination was completely removed even under mild reverberation. The reverberant energy decay in distorting critical temporal cues provided further evidence that may explain the error patterns observed in consonant identification. By 11-14 years of age, children approached adult-like performance in consonant discrimination and identification under adverse acoustics, emphasizing the need for good acoustics for younger children as they develop auditory skills to process distorted speech in everyday listening environments.

Children's use of spatial and visual cues for release from perceptual masking

This study examined the role of visual speech in providing release from perceptual masking in children by comparing visual speech benefit across conditions with and without a spatial separation cue. Auditory-only and audiovisual speech recognition thresholds in a two-talker speech masker were obtained from 21 children with typical hearing (7-9 years of age) using a color-number identification task. The target was presented from a loudspeaker at 0° azimuth. Masker source location varied across conditions. In the spatially collocated condition, the masker was also presented from the loudspeaker at 0° azimuth. In the spatially separated condition, the masker was presented from the loudspeaker at 0° azimuth and a loudspeaker at -90° azimuth, with the signal from the -90° loudspeaker leading the signal from the 0° loudspeaker by 4 ms. The visual stimulus (static image or video of the target talker) was presented at 0° azimuth. Children achieved better thresholds when the spatial cue was provided and when the visual cue was provided. Visual and spatial cue benefit did not differ significantly depending on the presence of the other cue. Additional studies are needed to characterize how children's preferential use of visual and spatial cues varies depending on the strength of each cue.

Can Playing a Game Improve Children's Speech Recognition? A Preliminary Study of Implicit Talker Familiarity Effects

PURPOSE

The goal was to evaluate whether implicit talker familiarization via an interactive computer game, designed for this study, could improve children's word recognition in classroom noise. It was hypothesized that, regardless of age, children would perform better when recognizing words spoken by the talker who was heard during the game they played.

METHOD

Using a one-group pretest-posttest experimental design, this study examined the impact of short-term implicit voice exposure on children's word recognition in classroom noise. Implicit voice familiarization occurred via an interactive computer game, played at home for 10 min a day for 5 days. In the game, children (8-12 years) heard one voice, intended to become the "familiar talker." Pre- and postfamiliarization, children identified words in prerecorded classroom noise. Four conditions were tested to evaluate talker familiarity and generalization effects.

RESULTS

Results demonstrated an 11% improvement when recognizing words spoken by the voice heard in the game ("familiar talker"). This was observed only for words that were heard in the game and did not generalize to unfamiliarized words. Before familiarization, younger children had poorer recognition than older children in all conditions; however, after familiarization, there was no effect of age on performance for familiarized stimuli.

CONCLUSIONS

Implicit short-term exposure to a talker has the potential to improve children's speech recognition. Therefore, leveraging talker familiarity through gameplay shows promise as a viable method for improving children's speech-in-noise recognition. However, given that improvements did not generalize to unfamiliarized words, careful consideration of exposure stimuli is necessary to optimize this approach.

Be Quiet! Effects of Competing Speakers and Individual Characteristics on Listening Comprehension for Primary School Students

Students learn in noisy classrooms, where the main sources of noise are their own voices. In this sound environment, students are not equally at risk from background noise interference during lessons, due to the moderation effect of the individual characteristics on the listening conditions. This study investigates the effect of the number of competing speakers on listening comprehension and whether this is modulated by selective attention skills, working memory, and noise sensitivity. Seventy-one primary school students aged 10 to 13 years completed a sentence comprehension task in three listening conditions: quiet, two competing speakers, and four competing speakers. Outcome measures were accuracy, listening effort (response times and self-reported), motivation, and confidence in completing the task. Individual characteristics were assessed in quiet. Results showed that the number of competing speakers has no direct effects on the task, whilst the individual characteristics were found to moderate the effect of the listening conditions. Selective attention moderated the effects on accuracy and response times, working memory on motivation, and noise sensitivity on both perceived effort and confidence. Students with low cognitive abilities and high noise sensitivity were found to be particularly at risk in the condition with two competing speakers.

Masked Speech Recognition by Normal-Hearing 6-13-Year-Olds in Conditions With and Without Interaural Difference Cues

Using the Danish 'børneDAT' corpus, the current study aimed to (1) collect normative masked speech recognition data for 6-13-year-olds in conditions with and without interaural difference cues, (2) evaluate the test-retest reliability of these measurements, and (3) compare two widely used measures of binaural/spatial benefit in terms of the obtained scores. Seventy-four children and 17 young adults with normal hearing participated. Using headphone presentation, speech recognition thresholds (SRTs) were measured twice at two separate visits in four conditions. In the first two conditions, børneDAT sentences were presented in diotic stationary speech-shaped noise, with the sentences either interaurally in-phase ('N0S0') or interaurally out-of-phase ('N0S180'). In the other two conditions, børneDAT sentences were simulated to come from 0° azimuth and two running speech maskers from either 0° azimuth ('co-located') or ±90° azimuth ('spatially separated'). In relative terms, the children achieved lower SRTs in stationary noise than in competing speech, whereas the adults showed the opposite pattern. 12-13-year-old children achieved adult-like performance in all but the co-located condition. Younger children showed generally immature speech recognition abilities. Test-retest reliability was highest for the SRTs in stationary noise and lowest for the spatial benefit scores. Mean benefit was comparable for the two measures and participant groups, and the two sets of scores were not correlated with each other. Developmental effects were most pronounced in the conditions with interaural difference cues. In conclusion, reference data for the børneDAT corpus obtained under different acoustic conditions are available that can guide future research and potential clinical applications.