The Computer-Aided Speech Perception Assessment (CASPA) is a clinical measure of speech recognition that uses 10-item, isophonemic word lists to derive performance intensity (PI) functions for adult listeners. Because CASPA was developed for adults, the ability to obtain PI functions in children has not been evaluated directly. This study sought to evaluate PI functions for adults and four age groups of children with normal hearing to compare speech recognition as a function of age using CASPA. Comparisons between age groups for scoring by words and phonemes correct were made to determine the relative benefits of available scoring methods in CASPA.
Speech recognition using CASPA was completed with 12 adults and four age groups of children (5- to 6-, 7- to 8-, 9- to 10-, and 11- to 12-yr olds), each with 12 participants. Results were scored by the percentage of words, phonemes, consonants, and vowels correct. All participants had normal hearing and age-appropriate speech production skills.
Differences in speech recognition were significant across all age groups when responses were scored by the percentage of words correct. However, only differences between adults and the two youngest groups of children were significant when results were scored by the number of phonemes correct. Speech recognition scores decreased as a function of signal to noise ratio for both children and adults. However, the magnitude of degradation at poorer signal to noise ratios did not vary between adults and children, suggesting that mean differences could not be explained by interference from noise.
Obtaining PI functions in noise using CASPA is feasible with children as young as 5 yrs. Statistically significant differences in speech recognition were observed between adults and the two youngest age groups of children when scored by the percentage of words correct. When results were scored by the percentage of phonemes correct, however, the only significant difference was between the youngest group of children and the adults. These results suggest that phoneme scoring may help to minimize differences between recognition scores of adults and children because children may be more likely to provide responses that are phonemic approximations when words are outside their lexicon.
The Computer Aided Speech Perception Assessment (CASPA) is a speech perception test that has been validated with adults. CASPA uses twenty lists of ten consonant-vowel-consonant words to construct PI functions. CASPA was originally designed for adults, however, and has not been evaluated with children. Results were obtained for normal-hearing children (5-12 yrs) and adults at five signal-to-noise ratios. Differences in performance were observed between adults and children when results were scored based on the number of words correct, but significant differences were not observed for phoneme scoring. Implications for clinical speech recognition are discussed.
Hearing and Amplification Research Laboratory, Boys Town National Research Hospital, Omaha, Nebraska.
This study was supported by grants from the National Institute of Deafness and Other Communication Disorders (R01 DC04300, P30 DC-4662, and T35 DC008757).
Address for correspondence: Ryan McCreery, Audiology Department, Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE. E-mail: firstname.lastname@example.org.
Rindy Ito is currently at the University of Arizona, Tucson, Arizona.
Received July 30, 2008; accepted July 29, 2009.