Simplification and validation of the spectro-temporal ripple direction discrimination test in children

Spectral and temporal resolution are important for speech perception, particularly in noisy environments. The Spectro-temporal Ripple Direction Discrimination (STRt_dir) test, originally developed for adults, assesses the spectro-temporal resolution. This study aimed to simplify the STRt_dir paradigm for paediatric use and evaluate its criterion and construct validity.

A within-subjects design was employed to compare STRt_dir thresholds across different carrier frequencies, including a broadband noise (BBN) carrier and narrowband noise (NBN) carriers centred at 500, 1000, 2000, and 4000 Hz, and to examine the relationship between STRt_dir thresholds and speech perception scores (in quiet and noise) in children.

The STRt_dir test was simplified based on a pilot study conducted on ten children and fifteen adults with normal hearing. The simplified STRt_dir was administered to thirty-five children aged 7-10 years with normal hearing.

A repeated-measures ANOVA across all carriers showed significant negative correlations between STRt_dir and SNR-50, indicating that children with better spectro-temporal resolution have lower SNR-50, reflecting superior speech-in-noise perception. No correlation was found with speech-in-quiet. Multiple regression revealed that STRt_dir thresholds explained 41.3% of the variance in SNR-50.

The simplified STRt_dir is a valid, reliable, child-friendly, and language-independent measure of spectro-temporal resolution for paediatric populations.