Frequency Discrimination and Speech Identification Abilities in Individuals with and without Cochlear Dead Regions

Abstract

The aim of the study was to assess the frequency discrimination and speech identification abilities and also to assess the correlation between the frequency discrimination abilities and speech identification abilities in individuals without and with cochlear dead regions at 1 kHz, 2 kHz and 4 kHz edge frequencies. TEN (HL) test was administered to assess the presence of absence of dead regions. Frequency modulation difference limens (FMDLs) were obtained and consonant- vowels (CVs) both unfiltered and filtered till the edge frequency was presented to both the groups. FMDLs were better in individuals with dead region and better near the edge frequency. The scores for filtered CVs were better in individuals with dead region than for the unfiltered CVs. However, there was no correlation between the FMDLs and the speech identification scores in individuals with dead region. The enhanced frequency discrimination in individuals with dead region might be due to cortical re- organization and better performance in filtered speech conditions helps in further rehabilitation of these individuals.