Effect of Age and Sex on Temporal Resolution Threshold and Speech Recognition Score in Noise (SIN) Among Individuals with Normal Hearing

Speech in noise test (SINT) surveys the ability of person in extracting speech from ambient noise. Temporal resolution (TR) is ability of person to understand changes of stimulus over time that has important role in speech perception. The aim of this study was to determine the effects of age and sex on SINT and TR in individuals with normal hearing. SINT was done in the most comfortable level in 3 SNRs 0،-10 and -20 dB and Gap detection test (GDT) in 4 intensity levels in two age groups 25-40 yrs old (included 14 persons) and 41 -55 yrs old (included 15 persons). There was a significant difference between word recognition scores (WRSs) in quiet and in the presence of noise in each age group (P<0. 0001). Significant difference was shown between two age groups in WRS s in two SINs of - 10 and- 20 dB (P≤0. 02). WRS difference between silence and 3 SINs in two sexes was significant (P≤0. 04). Significant difference was the revealed between GDT thresholds in 4 intensity levels (P<0. 0001). Sex and age had no effects on GDT thresholds. According to our results، despite of normal hearing thresholds with increasing age WRS and GDT are reduced. It seems that، WRS and speech perception in female are better than male.