Objectives: The objectives of this study were to (1) evaluate the extent to which school-age children benefit from fundamental frequency (F₀) differences between target words and competing two-talker speech, and (2) assess whether this benefit changes with age. It was predicted that while children would be more susceptible to speech-in-speech masking compared to adults, they would benefit from differences in F₀ between target and masker speech. A second experiment was conducted to evaluate the relationship between frequency discrimination thresholds and the ability to benefit from target/masker differences in F₀. Design: Listeners were children (5 to 15 years) and adults (20 to 36 years) with normal hearing. In the first experiment, speech reception thresholds (SRTs) for disyllabic words were measured in a continuous, 60-dB SPL two-talker speech masker. The same male talker produced both the target and masker speech (average F₀ = 120 Hz). The level of the target words was adaptively varied to estimate the level associated with 71% correct identification. The procedure was a four-alternative forced-choice with a picture-pointing response. Target words either had the same mean F₀ as the masker or it was shifted up by 3, 6, or 9 semitones. To determine the benefit of target/masker F₀ separation on word recognition, masking release was computed by subtracting thresholds in each shifted-F₀ condition from the threshold in the unshifted-F₀ condition. In the second experiment, frequency discrimination thresholds were collected for a subset of listeners to determine whether sensitivity to F₀ differences would be predictive of SRTs. The standard was the syllable /ba/ with an F₀ of 250 Hz; the target stimuli had a higher F₀. Discrimination thresholds were measured using a three-alternative, three-interval forced choice procedure. Results: Younger children (5 to 12 years) had significantly poorer SRTs than older children (13 to 15 years) and adults in the unshifted-F₀ condition. The benefit of F₀ separations generally increased with increasing child age and magnitude of target/masker F₀ separation. For 5- to 7-year-olds, there was a small benefit of F₀ separation in the 9-semitone condition only. For 8- to 12-year-olds, there was a benefit from both 6- and 9-semitone separations, but to a lesser degree than what was observed for older children (13 to 15 years) and adults, who showed a substantial benefit in the 6- and 9-semitone conditions. Examination of individual data found that children younger than 7 years of age did not benefit from any of the F₀ separations tested. Results for the frequency discrimination task indicated that, while there was a trend for improved thresholds with increasing age, these thresholds were not predictive of the ability to use F₀ differences in the speech-in-speech recognition task after controlling for age. Conclusions: The overall pattern of results suggests that children’s ability to benefit from F₀ differences in speech-in-speech recognition follows a prolonged developmental trajectory. Younger children are less able to capitalize on differences in F₀ between target and masker speech. The extent to which individual children benefitted from target/masker F₀ differences was not associated with their frequency discrimination thresholds.

Purpose: The purpose of this study was to examine the independent and combined contributions of fundamental frequency (F0) and vocal tract length (VTL) differences on children's speech-in-speech recognition in the presence of a competing two-talker masker. Method: Participants were 64 children (5–17 years old) and 25 adults (18–39 years old). Sentence recognition thresholds were measured in a two-talker masker. Target sentences had either the same mean F0 and VTL of the masker or were digitally altered so that the target and masker differed in F0 (Experiment 1), differed in VTL (Experiment 2), or differed in both F0 and VTL (Experiment 3). To determine the benefit, masking release was computed by subtracting thresholds in each shifted condition from the threshold in the unshifted condition. Results: Results demonstrate that children's ability to benefit from either F0 or VTL differences (Experiments 1 and 2) depended on listener age, with younger children showing less improvement in speech reception thresholds compared to older children and adults. Age effects were also evident in the combined-cue conditions (Experiment 3), but children showed greater improvements compared to F0-only or VTL-only manipulations. Conclusions: There was a prolonged pattern of development in children's ability to benefit from F0 or VTL differences between target and masker speech. Young children failed to capitalize on F0 and VTL differences to the same extent as older children and adults but did show a robust benefit when the cues were combined, supporting the hypothesis that younger children rely more heavily on redundant cues compared to older children and adults.

Frequency discrimination was measured in 5- to 11-year-olds and adults with normal hearing. The standard stimulus was either a 250-Hz tone or the syllable /ba/ with a fundamental frequency (F0) of 250 Hz. Target stimuli were higher in frequency than the standard, and the threshold for frequency discrimination was determined adaptively for each of the two stimulus types separately. For both the tone and /ba/ stimuli, thresholds improved approximately linearly with the log of child age, reaching adult levels by 11.5 years of age. There was no evidence of an effect of stimulus type.

Objectives: This study explored the effects of different face masks on school-age children’s and young adults’ word recognition. Design: Speech recognition thresholds were measured adaptively in a two-talker speech masker using a closed-set picture pointing task. Target words were recorded by a female talker in five conditions: no mask, transparent mask, face shield, N95 mask and surgical mask. Study samples: Thirty children (8–12 years) and 25 adults (18–25 years) with normal hearing. Results: Both children’s and adults’ word recognition was most negatively impacted by the face shield. Children’s recognition was also impaired by the transparent mask. No negative effects were observed for the N95 or surgical mask for either age group. Conclusion: School-age children, like young adults, are negatively affected by face masks when recognising speech in a two-talker speech masker, but the effects depend on the type of face mask being worn. Acoustic analyses suggest that the reflective materials used for masks impact speech signal quality and impair word recognition.

Objectives: The objectives of the study were to (1) evaluate the impact of hearing loss on children’s ability to benefit from F0 differences between target/masker speech in the context of aided speech-in-speech recognition and (2) to determine whether compromised F0 discrimination associated with hearing loss predicts F0 benefit in individual children. We hypothesized that children wearing appropriately fitted amplification would benefit from F0 differences, but they would not show the same magnitude of benefit as children with normal hearing. Reduced audibility and poor suprathreshold encoding that degrades frequency discrimination were expected to impair children’s ability to segregate talkers based on F0. Design: Listeners were 9 to 17 year olds with bilateral, symmetrical, sensorineural hearing loss ranging in degree from mild to severe. A four-alternative, forced-choice procedure was used to estimate thresholds for disyllabic word recognition in a 60-dB-SPL two-talker masker. The same male talker produced target and masker speech. Target words had either the same mean F0 as the masker or were digitally shifted higher than the masker by three, six, or nine semitones. The F0 benefit was defined as the difference in thresholds between the shifted-F0 conditions and the unshifted-F0 condition. Thresholds for discriminating F0 were also measured, using a three-alternative, three-interval forced choice procedure, to determine whether compromised sensitivity to F0 differences due to hearing loss would predict children’s ability to benefit from F0. Testing was performed in the sound field, and all children wore their personal hearing aids at user settings. Results: Children with hearing loss benefited from an F0 difference of nine semitones between target words and masker speech, with older children generally benefitting more than younger children. Some children benefitted from an F0 difference of six semitones, but this was not consistent across listeners. Thresholds for discriminating F0 improved with increasing age and predicted F0 benefit in the nine-semitone condition. An exploratory analysis indicated that F0 benefit was not significantly correlated with the four-frequency pure-tone average (0.5, 1, 2, and 4 kHz), aided audibility, or consistency of daily hearing aid use, although there was a trend for an association with the low-frequency pure-tone average (0.25 and 0.5 kHz). Comparisons of the present data to our previous study of children with normal hearing demonstrated that children with hearing loss benefitted less than children with normal hearing for the F0 differences tested. Conclusions: The results demonstrate that children with mild-to-severe hearing loss who wear hearing aids benefit from relatively large F0 differences between target and masker speech during aided speech-in-speech recognition. The size of the benefit increases with increasing age, consistent with previously reported age effects for children with normal hearing. However, hearing loss reduces children’s ability to capitalize on F0 differences between talkers. Audibility alone does not appear to be responsible for this effect; aided audibility and degree of loss were not primary predictors of performance. The ability to benefit from F0 differences may be limited by immature central processing or aspects of peripheral encoding that are not characterized in standard clinical assessments.