Linguistic Factors Influencing Speech Audiometric Assessment

In speech audiometric testing, hearing performance is typically measured by calculating the number of correct repetitions of a speech stimulus. We investigate to what extent the repetition accuracy of Dutch speech stimuli presented against a background noise is influenced by nonauditory processes. We show that variation in verbal repetition accuracy is partially explained by morpholexical and syntactic features of the target language. Verbs, prepositions, conjunctions, determiners, and pronouns yield significantly lower correct repetitions than nouns, adjectives, or adverbs. The reduced repetition performance for verbs and function words is probably best explained by the similarities in the perceptual nature of verbal morphology and function words in Dutch. For sentences, an overall negative effect of syntactic complexity on speech repetition accuracy was found. The lowest number of correct repetitions was obtained with passive sentences, reflecting the cognitive cost of processing a noncanonical sentence structure. Taken together, these findings may have important implications for the audiological practice. In combination with hearing loss, linguistic complexity may increase the cognitive demands to process sentences in noise, leading to suboptimal functional hearing in day-to-day listening situations. Using test sentences with varying degrees of syntactic complexity may therefore provide useful information to measure functional hearing benefits

Linguistic Factors Influencing Speech Audiometric Assessment

In speech audiometric testing, hearing performance is typically measured by calculating the number of correct repetitions of a speech stimulus. We investigate to what extent the repetition accuracy of Dutch speech stimuli presented against a background noise is influenced by nonauditory processes. We show that variation in verbal repetition accuracy is partially explained by morpholexical and syntactic features of the target language. Verbs, prepositions, conjunctions, determiners, and pronouns yield significantly lower correct repetitions than nouns, adjectives, or adverbs. The reduced repetition performance for verbs and function words is probably best explained by the similarities in the perceptual nature of verbal morphology and function words in Dutch. For sentences, an overall negative effect of syntactic complexity on speech repetition accuracy was found. The lowest number of correct repetitions was obtained with passive sentences, reflecting the cognitive cost of processing a noncanonical sentence structure. Taken together, these findings may have important implications for the audiological practice. In combination with hearing loss, linguistic complexity may increase the cognitive demands to process sentences in noise, leading to suboptimal functional hearing in day-to-day listening situations. Using test sentences with varying degrees of syntactic complexity may therefore provide useful information to measure functional hearing benefits

LiCoS: A new linguistically controlled sentences test to assess functional hearing performance

Purpose: To overcome the potential tension between clinical and ecological validity in speech audiometric assessment by creating a new set of sentence materials with high linguistic validity for the Dutch-speaking area. Methods: A linguistic "fingerprint" of modern spoken Dutch and Flemish served to generate a set of sentences recorded from 1 male and 1 female talker. The sentences were presented to 30 normal-hearing listeners in stationary speech noise at a signal-to-noise ratio (SNR) of -5 dB sound pressure level (SPL). A list design criterion was used to achieve perceptive homogeneity across the test lists, by scrambling lists of sentences of different syntactic types while controlling for linguistic complexity. The original set of test materials was narrowed down to 360 sentences, and list equivalency was evaluated at the audiological and linguistic levels. A psychometric curve was generated with a resolution of 2 dB based on a second group of 60 young normal-hearing native speakers of Dutch and Flemish. Results: Sentence understanding showed an average repetition accuracy of 63.40% (SD 1.01) across the lists at an SNR of -5 dB SPL. No significant differences were found between the lists at the level of the individual listener. At the linguistic level, the sentence lists showed an equal distribution of phonological, morphological, and syntactic features. Conclusion: LiCoS combines the clinical benefit of acoustic control at the list level with the high ecological validity of linguistically representative test items. The new speech audiometric test is particularly appropriate to assess sentence understanding in individuals who would otherwise exhibit near-ceiling performance when tested with linguistically more simplified test stimuli. In combination with pure tone audiometric assessment, LiCoS provides valuable complementary information with respect to the functional hearing of patients