Testing sentence-level speech perception in noise in

children’s developmental level (Mendel, 2008; Schafer, 2010). For example,

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the test material should only use vocabulary that HI children aged 5–12 are familiar with. The test sentences should also be short, as children’s

auditory memory span is still developing. Complex structure can also decrease the accuracy of a sentence-level speech perception test in noise in children, as young children may have difficulties remembering and repeating correctly sentences with complex structure, even if the audibility is good (Van Der Hoek-Snieders et al., 2020). HL can increase the listening effort and load on the working memory, and children with HL may have a shorter auditory working memory span than NH children of the same age (Moore, Zobay and Ferguson, 2020). Therefore, sentence-level speech perception tests in noise that are reliable in young NH children may not be as applicable to HI children of the same age (Vroegop et al., 2021). Children also have a higher lapse rate in psychophysical tasks than do adults

(Witton, Talcott and Henning, 2017), and ideally children’s speech

perception tests in noise should aim to minimize this, or at least include an estimate of the reliability of the result. Since speech perception in noise develops with age, children also require age-specific reference values.

To accommodate these requirements, separate pediatric versions of popular sentence-level speech perception tests in noise have been developed (Table 4). One of the first pediatric speech perception tests in noise still in use is the Hearing in Noise Test for Children (HINT-C), first published in 1996. Similar to the original HINT, HINT-C has been adapted to multiple languages (Vaillancourt et al., 2008; Myhrum et al., 2016; Wong, Chen and Leung, 2019; Hjertman et al., 2021). The pediatric versions of the HINT were constructed by presenting the original HINT sentences to NH children (aged 5–11) to assess which of the sentences in the original test material were reliably recognized by young NH children. These sentences were then compiled into test lists while maintaining equal intelligibility and phonemic distribution between the lists. During evaluation measurements, age-group-specific refence values were obtained for NH children. While the basic construction is similar for all HINT-Cs, some minor differences exist.

For example, the Swedish HINT-C uses a fixed speech level instead of a fixed noise level (Hjertman et al., 2021). The Swedish HINT-C also uses lists

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with 20 sentences per list (Hjertman et al., 2021), while the Cantonese and Norwegian HINT-C use test lists of 10 sentences (Myhrum et al., 2016;

Wong, Chen and Leung, 2019). The Canadian French HINT-C also uses test lists with 10 sentences per list, but three test lists are presented in each condition, and the final SRT is the average of the best two scores

(Vaillancourt et al., 2008). The HINT-Cs also differ in the number of available test lists, ranging from 17 lists (10 sentences per list, Canadian French HINT-C (Vaillancourt et al., 2008)) to eight (20 sentences per list, Swedish HINT-C (Hjertman et al., 2021)).

Similar to the HINT-C, the simplified matrix tests use the speech material from the original test. The standard MST uses five-word sentences, and to simplify the test material these were shortened to three-word pseudo- sentences. For example, “Johanna ostaa neljä keltaista kuppia.” (“Johanna buys four yellow cups.”) would become “neljä keltaista kuppia” (“four yellow cups”) (Wagener and Kollmeier, 2005). The original speech matrix consists of 50 words, and in addition to omitting all proper nouns and verbs from the simplified version’s word matrix, three nouns, adjectives, and numerals were also omitted. This resulted in a word matrix of 21 words. The

selection of which nouns, adjectives, and numerals to omit was based on the professional opinion of experienced pediatric speech and language pathologists. Test lists for the simplified MST contain only 14 pseudo- sentences, but the test procedure is similar to the standard MST (Wagener and Kollmeier, 2005; Prang et al., 2021).

The developers of BabyBio adopted a different method for constructing the test material. The sentences of the original AzBio were from the

everyday life of adults, and many of them were not appropriate for younger children due to their content (“He did not like smokey bars.”) or complex vocabulary (“Project your imagination to the point of visualizing success.”) (Spahr et al., 2012). A new sentence material was therefore collected for BabyBio by recording sentences children aged 5 to 12 years used spontaneously in their everyday life (Spahr et al., 2014). Another difference between BabyBio and the original AzBio is the talker: AzBio uses

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four different talkers, while only one female speaker was used for the BabyBio material. The final test material for BabyBio comprises 16 test lists with 20 unique sentences per list. The sentence length varies from three (“Everyone makes mistakes.”) to 11 words (“His favorite shirt had a picture of a skeleton on it.”) (Spahr et al., 2014). The recommended background noise is the same 20-talker babble noise that is used for AzBio.

Even though BKB-SIN is commonly used to test adults, the original BKB test was designed to be suitable for HI children, as the test material was collected from sentences HI school-age children used (Bench, Kowal and Bamford, 1979). In addition to reference data for adults, the reference manual for BKB-SIN contains age-stratified test reliability measures and critical differences for comparison for NH children (‘BKB-SIN Test’, 2005).

Sentence-level speech perception tests in noise designed for adults have also been used with children. Holder et al. (Holder, Sheffield and Gifford, 2016) evaluated the QuickSIN (Killion, Niquette and Gudmundsen, 2004) in NH children for reference values, and observed systematic age-related improvements. The speech material of the QuickSIN is more demanding than that of BKB-SIN, as it has fewer contextual cues (Killion, Niquette and Gudmundsen, 2004). Holder et al. (Holder, Sheffield and Gifford, 2016) stated that the QuickSIN could be used for children 10 years of age and older, whereas BKB-SIN would be suitable also for younger HI children. The OLSA (Wagener, Brand and Kollmeier, 1999b, 1999a; Wagener, Kühnel and Kollmeier, 1999) has also been evaluated in NH children and found suitable for children aged 10 or more (Wagener and Kollmeier, 2005).

Age-specific NH reference values are available for the different versions of the HINT-C (Myhrum et al., 2016; Wong, Chen and Leung, 2019; Chen and Wong, 2020; Hjertman et al., 2021), for some of the simplified MSTs (Wagener and Kollmeier, 2005; Ebner, Steffens and Hellbrück, 2008; Prang et al., 2021), and for the BabyBio, QuickSIN, and BKB-SIN (Holder, Sheffield and Gifford, 2016). Only limited data is available on the effects of age on the slope of the psychometric speech perception function. No age-specific slope data for NH or HI children could be found for the BabyBio, QuickSIN

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or BKB-SIN in the standard S0N0 listening configuration. Wagener and Kollmeier (Wagener and Kollmeier, 2005) observed that for NH primary school age children, the slopes for OLSA were less steep than for NH

adults. This was attributed to a slightly larger variability of the OLSA speech material in children, as the standard deviation of the SRT estimates is inversely proportional to the slope of the intelligibility function. A similar, small slope difference between NH children and adults was observed for the Norwegian HINT-C (Myhrum et al., 2016). Other studies (MacPherson and Akeroyd, 2014; Buss et al., 2019; Bonino et al., 2021) did not find significant age effects on the slope in steady state noise for custom speech perception tests in noise or for individual words in noise.

However, Sobon et al. (Sobon et al., 2019) observed age-related slope differences between NH children and adults in fluctuating noise. Typically, NH adults have better SRTs and shallower psychometric function slopes in fluctuating background noise than in steady state noise (Wagener and Brand, 2005; MacPherson and Akeroyd, 2014; Buss, Calandruccio and Hall, 2015; Sobon et al., 2019), reflecting their ability to use glimpsing, i.e., to listen during the short instances of favorable SNRs that are present in fluctuating noise but not in steady state noise. Children appear to benefit less from fluctuations in background noise, and fluctuating background noise highlights the age-related differences in speech perception in noise (Buss et al., 2019; Sobon et al., 2019), even in NH children.

In one of the few studies evaluating slopes in HI children, Ebner et al.

(Ebner, Steffens and Hellbrück, 2008) observed significant differences in SRTs and slopes with the German Oldenburg Sentence Test for Children (Oldenburg Kinder Satztest, OLKISA (the simplified version of the OLSA)) in NH and HI children. NH children (1st and 2nd grade students) had

significantly better (i.e., more negative) SRTs and slopes almost twice as steep as same-age children with CIs. Slope differences between NH and HI listeners have been reported in adults (Hey et al., 2014; Dietz et al., 2015), though the differences for adult listeners were smaller.

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Table 4. Pediatric versions of commonly used sentence-level speech perception tests in noise and other sentence level speech perception tests used with children.

Name Ages (years) Test material Background noiseTest procedure No. of test lists and sentences

No. of scored words / sentence

Examples of test sentences Hearing in Noise Test Children (HINT- C)1,2,3,4

6+

Sentences from the original HINT that young children recognized easily

Speech- shaped noise

Adaptive procedure similar to the original HINT 8-17 lists, 10 or 20 sentences / list

Sentence scoring

She is listening to the radio. He buys fresh vegetables. QuickSIN (Killion, Niquette and Gudmunds en, 2004)

10+

Institute of Electrical and Electronics Engineers sentences 4-talker babble Six fixed SNR with the noise increasing in 5 dB SNR steps (25 to 0 dB SNR) after each sentence

15 lists, 6 sentences / list

5 key words

The lake sparkled in the red hot sun. Fake stones shine but cost little.9 BKB-SIN (‘BKB-SIN Test’, 2005)5+

“Americanized” Bamford- Kowal-Bench sentences 4-talker babble Fixed SNRs starting at +21 dB with the SNR decreasing by 3 dB SNR after each sentence

18 lists, 8 or 10 sentences / list

3 or 4 key words She spoke to her son. The little baby is sleeping.

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Table 4. Continued SNR, signal-to-noise ratio; dB SNR, decibel signal-to-noise ratio; MST, matrix sentence test. 1 Vaillancourt et al., 2008; 2 Myhrum et al., 2016;3 Wong, Chen and Leung, 2019; 4 Hjertman et al., 2021; 5 Wagener and Kollmeier, 2005; 6 Willberg et al., 2020; 7 Prang et al., 2021;8 MATRIX of the Hörzentrum Oldenburg gGmbH, 2022;9Quick Speech in Noise (QuickSIN), 2022; 10Pediatric Az Bio Sentence Test Score Sheet Name Ages (years) Test material Background noiseTest procedure

No. of test lists and sentences

No. of scored words / sentence

Examples of test sentences BabyBio (Spahr et al., 2014) 5+

Sentences spoken by children from 5 to 12 years of age 20-talker babble The same fixed presentation level for all sentences

16 lists, 20 sentences / list 3-12 key words

I like to play with my sister. Green jellybeans are my favorite.10 Simplified matrix sentence test5,6,7,8 5+

3-word pseudo- sentences with similar structure

Speech- shaped noise

Adaptive test procedure similar to the MSTs 20 lists, 14 sentences / list 3 words Three red cups. Six yellow busses. One small car.

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Very little large-scale, age-group-specific data on the results of sentence- level speech perception tests in noise is available for children with HL.

Though some exceptions exist (Ebner, Steffens and Hellbrück, 2008; Walker et al., 2019), much of the published data on children has been analyzed and reported as one large group of children without any stratification for age, which eliminates the possibility to compare individual results with age- specific NH reference values, or with results from other clinics (Park et al., 2019; Chweya et al., 2021; Wolfe et al., 2021). Some studies have, however, used the age-specific NH reference values to compute a standard score for all participants, which enables more accurate analysis by acknowledging age-related improvements (Torkildsen et al., 2019). Even though the Pediatric Minimum Speech Test Battery recommends the use of either BKB-SIN or BabyBio as a sentence-level speech perception test in noise for children (Uhler et al., 2017), some researchers have opted to use their own custom speech perception tests. For example, McCreery et al. (McCreery et al., 2017, 2019, 2020) have conducted multiple studies on the associations between cognition, language skills, HL, and speech perception in noise in children with their own adaptive speech perception test in noise, and Buss et al. (Buss et al., 2019) used sentence materials developed for a previous study (Stelmachowicz et al., 2000) to evaluate masker type effects.

One of the rationales behind using custom sentence-level speech perception tests in noise might be the lack of informational or modulated maskers in commercially available ones. Multiple studies have shown that informational maskers, for example two-talker babble, are more difficult for HI children and that speech perception tests with informational

maskers may detect individual differences more accurately than tests with stationary speech-shaped noise or multi-talker babble (Corbin et al., 2016;

Buss et al., 2017; Leibold and Buss, 2019). Hillock-Dunn et al. (Hillock-Dunn et al., 2015) observed that a speech perception test (four-alternative, forced choice spondee recognition task) with a two-talker masker correlated better with parent-reported communication difficulties than PTAs or speech recognition in quiet. However, as Table 4 shows,

commercially available pediatric sentence-level speech perception tests in

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noise use either speech shaped noise or multi-talker babble as maskers, with no standardized alternatives available.

Sentence-level speech perception tests in noise are likely too difficult for the youngest children and may remain too difficult for older children with developmental delays. The Pediatric minimum speech test battery

recommends an individualized stepwise approach to speech perception testing starting with the easiest tasks (i.e., speech detection or

discrimination) and progressing to more difficult tasks (i.e., speech recognition and comprehension) as the child’s speech and language

develops, instead of rigidly sticking to a fixed guideline for age-appropriate tests (Uhler et al., 2017)