Auditory recognition of Persian digits in multi-talker babble noise: a preliminary study

Digits are suitable materials for hearing assessment of wide range of patients including children and adults with various language abilities. Single monosyllabic 1-10 digits in triplet formant have been used for measuring speech recognition threshold in signal-to-noise ratio. The purpose of this study was to determine signal-to-noise ratio (SNR) needed for 50 percent correct recognition of Persian monosyllabic digits (1-10) in multi-talker babble noise. Thirty unique triplet set of nine 1-10 monosyllabic Persian digits were created and mixed with multi-talker babble noise. Signal-to-noise ratio varied from -18 to +3 dB in 3-dB steps. Digits were presented binaurally to 17 normal hearing young adults aged 18-25 years. Speech recognition threshold in SNR (SRTsnr) was measured by Spearman-Karber equation and probit regression method. Mean SRTsnr of Persian digits, had minimum value of -12.7 dB for digit 3 and maximum value of -6.8 dB for digit 9. Mean (standard deviation) of SRTsnr was -9.5 (2.1) dB. There was no statistically significant difference between mean SRTsnr of the males and the females for all digits (p>0.05). Persian 1-10 monosyllabic digits are not homogeneous in terms of SNR needed for reaching 50% correct recognition. Mean SRTsnr of Persian digits is comparable to German and Polish digits but is higher than English digits.