Reliability and Validity of Infant Speech-Sound Discrimination-in-Noise Thresholds

TLDR

The study discusses the advantages of an adaptive threshold procedure and its potential applications in research and clinical settings. Infants and adults were tested with a visual reinforcement infant speech discrimination procedure using an adaptive up‑down threshold protocol on synthetic /ba/ and /ga/ sounds presented in band‑passed noise at 48 dB SPL. Test‑retest reliability was good for both groups, with infants showing an average difference of 5.2 dB and 87.5 % of infants having less than a 10‑dB change, and infants’ discrimination thresholds were 6.9 dB higher than adults, consistent with prior detection‑in‑noise studies.

Abstract

Infants were tested on a speech-sound discrimination-in-noise task using the visual reinforcement infant speech discrimination (VRISD) procedure with an adaptive (up-down) threshold protocol. An adult control group was tested using the same stimuli and apparatus. The speech sounds were synthetic /ba/ and /ga/. The masker was band-passed noise presented continuously at 48 dB SPL. Test-retest reliability was good for both groups, although test-retest differences were smaller for adults. For infants the mean of the absolute values of the differences between tests was only 5.2 dB, and there was less than a 10-dB difference between the two tests of 14 (87.5%) of the 16 infants completing the study. The infant-adult difference in discrimination threshold in noise was 6.9 dB, which agrees well with detection-in-noise thresholds from earlier studies and with discrimination-in-noise thresholds obtained on a subset of subjects in our earlier work. Advantages of the adaptive threshold procedure and its possible applications both in research studies and in the clinic are discussed.