Evaluation of phoneme compression schemes designed to compensate for temporal and spectral masking in background noise

The effect of phonemic compression has been studied on speech intelligibility in background noise in hearing-impaired listeners with moderate-to-severe high-frequency losses. One configuration, anti-upward-spread-of-masking (anti-USOM) focuses on a release from spectral masking of high-frequency speech cues by selective spectral tilting. Release from temporal masking is the main goal of a second configuration, high-pass filtered compression (HFC), which reduces the speech modulations within a high-pass filtered compression channel. Speech intelligibility was measured with consonant-vowel-consonant (CVC) words in a multi-talker babble and a single-talker background noise. Anti-USOM has a significant negative effect on the phoneme scores in background noise. HFC compression tends to improve vowel intelligibility in a single-talker background noise, especially for the listeners with a relatively poor speech score. In a multi-talker babble noise the effects of HFC compression tend to be negative. It can be concluded that no significant release from spectral or temporal masking is obtained by the applied processin

The effects of phonemic compression and anti-upward-spread-of-masking (anti-USOM) on the perception of articulatory features in hearing-impaired listeners

The effect of speech processing on articulatory-feature recognition was studied in a group of hearing-impaired listeners with high-frequency sensorineural losses. Individual difference scaling (INDSCAL) and sequential information analysis (SINFA) were applied to a set of consonant-vowel-consonant responses measured under various conditions of speech processing. The processing consisted of high-frequency phonemic compression combined with compensation for anti-upward-spread-of-masking (i.e. anti-USOM). In quiet, we found an improved recognition of frication with compression, whereas additional anti-USOM improved the recognition of the second and third vowel-formants. In background noise, we found remarkably negative effects of anti-USOM on the recognition of features containing low-frequency cues, such as voicing and nasality. We conclude that the combined results of SINFA and INDSCAL provide important insights into the possibilities and limitations of phonemic compression and anti-USO