Effects of amplification and training on the identification and discrimination of a closed set of high-frequency dominated speech samples

Hearing-aid amplification remains the primary treatment for sensori-neural hearing loss. However, in spite of impressive developments in amplification technology in recent years, a significant proportion of hearing-aid wearers are unable to fully utilize amplified high-frequency speech. Recent studies, though, show that intensive speech training changes patterns of neural activity and improves identification and discrimination ability.; The aim of the present study was to investigate the effects of amplification and intensive high-frequency training on the ability of individuals with moderate to severe sensori-neural high-frequency hearing loss to identify and discriminate high-frequency speech samples. To accomplish this aim, three stages were developed. Stage 1 examined the perceptual performance of hearing-impaired subjects to identify differentially processed (1) vowel consonant (VC) syllables as well as their (2) excised high-frequency consonant segments. Stage 2 involved intensive durational discrimination training using high-frequency emphasized and high-pass filtered consonant segments that are easily confused. Training was completed with speech tokens appropriately amplified to compensate for individual hearing loss configuration. Finally, Stage 3 was a retest of Stage 1 with the purpose of assessing the effect of duration discrimination training on recognition ability. Special emphasis was placed on adaptive training that broadens sensory experience by focusing on relevant auditory information in a learning context that includes abundant repetition and feedback.; Six individuals with moderate to severe sensori-neural hearing loss and ten normal hearing graduate students participated in the study. Per cent recognition of syllables and consonant segments improved with high-frequency amplification but did not reach the performance levels of the normal hearing group. After six to eight weeks of extensive duration discrimination training, at preferred listening levels, hearing-impaired participants improved syllable and consonant segment recognition by a further 17-22% and 12-17%, respectively, enabling them to approach the performance levels of the normal-hearing group. These improvements suggest that recognition ability does benefit from coupling amplification with extensive training.