Refining Stimulus Parameters in Assessing Infant Speech Perception Using Visual Reinforcement Infant Speech Discrimination: Sensation Level

Abstract

Background Speech perception measures have long been considered an integral piece of the audiological assessment battery. Currently, a prelinguistic, standardized measure of speech perception is missing in the clinical assessment battery for infants and young toddlers. Such a measure would allow systematic assessment of speech perception abilities of infants as well as the potential to investigate the impact early identification of hearing loss and early fitting of amplification have on the auditory pathways. Purpose To investigate the impact of sensation level (SL) on the ability of infants with NH to discriminate /a-i/ and /ba-da/ and to determine if performance on the two contrasts are significantly different in predicting the discrimination criterion. Research Design The design was based on a survival analysis model for event occurrence and a repeated measures logistic model for binary outcomes. The outcome for survival analysis was the minimum SL for criterion and the outcome for the logistic regression model was the presence/absence of achieving the criterion. Criterion achievement was designated when an infant’s proportion correct score was ≥0.75 on the discrimination performance task. Study Sample Twenty-two infants with NH sensitivity participated in this study. There were 9 males and 13 females, aged 6–14 months. Data Collection and Analysis Testing took place over two to three sessions. The first session consisted of a hearing test, threshold assessment of the two speech sounds (/a/ and /i/), and if time and attention allowed, Visual Reinforcement Infant Speech Discrimination (VRISD). The second session consisted of VRISD assessment for the two test contrasts (/a-i/ and /ba-da/). The presentation level started at 50 dBA. If the infant was unable to successfully achieve criterion (≥0.75) at 50 dBA, the presentation level was increased to 70 dBA followed by 60 dBA. Data examination included an event analysis, which provided the probability of criterion distribution across SL. The second stage of the analysis was a repeated measures logistic regression where SL and contrast were used to predict the likelihood of speech discrimination criterion. Results Infants were able to reach criterion for the /a-i/ contrast at statistically lower SLs when compared to /ba-da/. There were six infants who never reached criterion for /ba-da/ and one never reached criterion for /a-i/. The conditional probability of not reaching criterion by 70 dB SL was 0% for /a-i/ and 21% for /ba-da/. The predictive logistic regression model showed that children were more likely to discriminate the /a-i/ even when controlling for SL. Conclusions Nearly all normal-hearing infants can demonstrate discrimination criterion of a vowel contrast at 60 dB SL, while a level of 70 dB SL may be needed to allow all infants to demonstrate discrimination criterion of a difficult consonant contrast.

Learning from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study: summary of 5-year findings and implications

“…Recent research has shown that measurements of objective auditory evoked potentials could reveal speech discrimination abilities in infants and young children (Cheour-Luhtanen et al, 1995; Cone, 2015; Small et al, 2017). Other research groups have demonstrated the use of behavioural measures of discrimination by using a visual reinforcement paradigm (Uhler et al, 2015). Our current research builds on these approaches, with the ultimate goal of developing clinical tools to identify infants with hearing loss who may have deficits in speech discrimination despite optimal amplification.…”

The relationship between mismatch response and the acoustic change complex in normal hearing infants

“…Two naturally produced vowel sounds, /i/ (“ee” as in “bee”) and /a/ (“ah” as in “law”) were recorded from a female talker (Uhler et al, 2011, 2015) and used as the contrasting stimuli in both the MMR and ACC preparations (Figure 1). Speech stimuli were digitally edited and pitch-matched using the Adobe Audition CC 2015 (Adobe Systems Inc., San Jose, CA) and Melodyne (Celemony Software, Munich, Germany) audio editing platforms.…”

Refining Stimulus Parameters in Assessing Infant Speech Perception Using Visual Reinforcement Infant Speech Discrimination in Infants with and without Hearing Loss: Presentation Level

“…Data were collected for 43 children aged 7 to 28 months ( M =13.91, SD =5.81). The data for the 21 children with NH were previously reported (Uhler et al, 2015). The 22 infants with bilateral sensorineural hearing loss had losses ranging from mild to profound.…”

“…In a recent VRISD study Uhler et al (2015) showed that the level at which NH infants successfully discriminated /a-i/ and /ba-da/ ranged from 35 to 70 dB SL. NH infants needed a higher presentation level to discriminate /ba-da/ than /a-i/, and consistent with the results of Nozza (1987), 29% were unable to discriminate /ba-da/ at the highest presentation level (70 dBA).…”