P19 Perception of low pass filtered speech in Hindi: A cross-sectional study across age
Spectrally modified speech stimuli like filtered speech have been used as a monaural low redundancy test to assess auditory processing disorder (APD). Filtered speech helps to understand the contribution of different frequencies in the perception of speech. Approximately 490 million people speak the Hindi language across the world. There are limited studies that have attempted to determine the effect of age on the perception of low pass filtered speech. Hence, the current study aimed to observe the effect of age on low pass filtered speech scores. Ninety individuals having normal hearing (hearing sensitivity less than or equal to 15 dB HL) participated in the study. Thirty were children in the age range of 7-12 years, 30 were adolescents in the age range of 12-18 years, and 30 were adults in the age range of 18-30 years. Twenty-five phonetically balanced words in Hindi were low pass filtered with a cut-off frequency of 800 Hz and 1000 Hz. The scores obtained were compared across the three age groups for both cut-off frequencies. The study results showed that the scores increased across age, and children obtained the lowest scores, followed by adolescents and adults. However, there was no significant difference in scores between adolescents and adults. Similar results were obtained for the two cut-off frequencies. Thus, the results of the study show that the low-pass filtered speech scores increase with age and reach adult-like scores by the age of 12 years. This is consistent with the neurophysiological studies which report that temporal cortex is matured and adult-like by the age of 12 years. The results of the study are essential to understand the developmental trend for the perception of filtered speech in Hindi. This information can be used effectively while interpreting the test results in a disordered population.