Effect of Low Frequency Gain Attenuation on Subjective Rating Scale in Individual with SSD

Abstract

Objective: The object of the study was to evaluate the effect of low frequency gain attenuation on scale in single sided deafness. Methods: In present study total of twenty SSD post-lingual subjects with age range of 15 to 40 years. BAHA was programmed with four different settings i.e. without attenuation (WA), low frequency attenuation of 250,750 and 1500Hz. Subjective rating scale were used to determine the quality of sound in different condition on brightness, softness, clarity, reverberation, fullness, loudness. Total Time period of 2 hour were given to the subject before rate on the scale so that subject gets habituated to the sounds in which 30 minutes were given to each setting i.e. Statistical analysis and Results: Non parametric test (Friedman Test) was carried results reveal that there was a significant difference in loudness across all experimental conditions tested, indicating loudness decreases as the attenuation frequency increased from 250 Hz to 1500 Hz. Without low frequency attenuation the loudness was higher. This can be attributed to importance of low frequency in perception of loudness. Conclusion: The results from subjective rating scale indicate that there is no deleterious effect on acoustic output quality with low frequency attenuation. But there was significant difference noted in loudness without on with low frequency attenuation, indicating that low frequency gain in the BAHA only adds loudness which is not required for the speech intelligibility.