Assessing toddlers' speech-sound discrimination

Objective: Valid and reliable methods for assessing speech perception in toddlers are lacking in the field, leading to conspicuous gaps in understanding how speech perception develops and limited clinical tools for assessing sensory aid benefit in toddlers. The objective of this investigation was to evaluate speech sound discrimination in toddlers using modifications to the Change/No-Change procedure [1]. Methods: Normal-hearing 2- and 3-year-olds' discrimination of acoustically dissimilar ("easy") and similar ("hard") speech-sound contrasts were evaluated in a combined repeated measures and factorial design. Performance was measured in d'. Effects of contrast difficulty and age were examined, as was test-retest reliability, using repeated measures ANOVAs, planned post hoc tests, and correlation analyses. Results: The easy contrast (M = 2.53) was discriminated better than the hard contrast (M = 1.72) across all ages (p < .0001). The oldest group of children (M = 3.13) discriminated the contrasts better than youngest (M= 1.04; p < .0001) and the mid-age children (M = 2.20; p =.037), who in turn discriminated the contrasts better than the youngest children (p = .010). Test-retest reliability was excellent (r = .886, p < .0001), Almost 90% of the children met the teaching criterion. The vast majority demonstrated the ability to be tested with the modified procedure and discriminated the contrasts. The few who did not were 2.5 years of age and younger. Conclusions: The modifications implemented resulted, at least preliminarily, in a procedure that is reliable and sensitive to contrast difficulty and age in this young group of children, suggesting that these modifications are appropriate for this age group. With further development, the procedure holds promise for use in clinical populations who are believed to have core deficits in rapid phonological encoding, such as children with hearing loss or specific language impairment, children who are struggling to read, and second-language learners. (C) 2012 Elsevier Ireland Ltd. All rights reserved.