Does Early Speech Discrimination Predict Language Ability?

Abstract

Problem There is a paucity of instruments available to assess speech discrimination in normal-hearing (NH) and hearing-impaired (HI) infants. We assess the utility of a hybrid visual habituation paradigm (HVHP) in assessing speech discrimination and predicting later language ability. Methods NH infants were tested with the HVHP on an easier vowel contrast or a more difficult fricative contrast. Parents completed Macarthur Communicative Development Inventories (CDI) when infants were 14,18,24, and 30 months old to assess correlations between discrimination abilities and later language ability. Similarly, HVHP and CDI measures were obtained from HI infants at following hearing aid (HA) or cochlear implant (CI) use. Results 29% of NH infants significantly discriminated the vowel contrast. 6% of NH infants significantly discriminated the fricative contrast. Effect size of fricative discrimination at 9 months correlated with early gestures (n=10), r=.73 p=.02, and later gestures (n=10, r=.81 p = .01), at 14 months of age. HI infants tested on the vowel contrast at 3 months of HA use demonstrated significant correlations of effect size of discrimination with phrases understood at 6 months of HA use (n=4, r=.96, p=0.04) and vocabulary production at 9 months of HA use (n=5, r=.90, p=0.04). Conclusion The HVHP can be used with various contrasts to assess the speech discrimination abilities of NH and HI infants. While data collection is ongoing, it appears that performance on the HVHP may correlate with later language outcomes in both NH and HI infants. Significance This study assesses the utility of the HVHP in assessing speech discrimination, and is a step towards developing clinical tools to assess the progress of HI infants following early intervention. Support Supported by a 2007 AAO-HNSF Resident Research Award and NIH grant R01DC6235 to Indiana University.