The development and validation of the speech quality instrument.

OBJECTIVE: Although speech perception tests are available to evaluate hearing, there is no standardized validated tool to quantify speech quality. The objective of this study is to develop a validated tool to measure quality of speech heard. STUDY DESIGN: Prospective instrument validation study of 35 normal hearing adults recruited at a tertiary referral center. METHODS: Participants listened to 44 speech clips of male/female voices reciting the Rainbow Passage. Speech clips included original and manipulated excerpts capturing goal qualities such as mechanical and garbled. Listeners rated clips on a 10-point visual analog scale (VAS) of 18 characteristics (e.g. cartoonish, garbled). RESULTS: Skewed distribution analysis identified mean ratings in the upper and lower 2-point limits of the VAS (ratings of 8-10, 0-2, respectively); items with inconsistent responses were eliminated. The test was pruned to a final instrument of nine speech clips that clearly define qualities of interest: speech-like, male/female, cartoonish, echo-y, garbled, tinny, mechanical, rough, breathy, soothing, hoarse, like, pleasant, natural. Mean ratings were highest for original female clips (8.8) and lowest for not-speech manipulation (2.1). Factor analysis identified two subsets of characteristics: internal consistency demonstrated Cronbach's alpha of 0.95 and 0.82 per subset. Test-retest reliability of total scores was high, with an intraclass correlation coefficient of 0.76. CONCLUSION: The Speech Quality Instrument (SQI) is a concise, valid tool for assessing speech quality as an indicator for hearing performance. SQI may be a valuable outcome measure for cochlear implant recipients who, despite achieving excellent speech perception, often experience poor speech quality. LEVEL OF EVIDENCE: 2b. Laryngoscope, 128:1622-1627, 2018.

Reduction of the Harmonic Series Influences Musical Enjoyment With Cochlear Implants.

OBJECTIVE: Cochlear implantation is associated with poor music perception and enjoyment. Reducing music complexity has been shown to enhance music enjoyment in cochlear implant (CI) recipients. In this study, we assess the impact of harmonic series reduction on music enjoyment. STUDY DESIGN: Prospective analysis of music enjoyment in normal-hearing (NH) individuals and CI recipients. SETTING: Single tertiary academic medical center. PATIENTS: NH adults (N = 20) and CI users (N = 8) rated the Happy Birthday song on three validated enjoyment modalities-musicality, pleasantness, and naturalness. INTERVENTION: Subjective rating of music excerpts. MAIN OUTCOME MEASURES: Participants listened to seven different instruments play the melody, each with five levels of harmonic reduction (Full, F3+F2+F1+F0, F2+F1+F0, F1+F0, F0). NH participants listened to the segments both with and without CI simulation. Linear mixed effect models (LME) and likelihood ratio tests were used to assess the impact of harmonic reduction on enjoyment. RESULTS: NH listeners without simulation rated segments with the first four harmonics (F3+F2+F1+F0) most pleasant and natural (p <0.001, p = 0.004). NH listeners with simulation rated the first harmonic alone (F0) most pleasant and natural (p <0.001, p = 0.003). Their ratings demonstrated a positive linear relationship between harmonic reduction and both pleasantness (slope estimate = 0.030, SE = 0.004, p <0.001, LME) and naturalness (slope estimate = 0.012, SE = 0.003, p = 0.003, LME). CI recipients also found the first harmonic alone (F0) to be most pleasant (p = 0.003), with a positive linear relationship between harmonic reduction and pleasantness (slope estimate = 0.029, SE = 0.008, p <0.001, LME). CONCLUSION: Harmonic series reduction increases music enjoyment in CI and NH individuals with or without CI simulation. Therefore, minimization of the harmonics may be a useful strategy for enhancing musical enjoyment among both NH and CI listeners.

Impact of Noise Reduction Algorithm in Cochlear Implant Processing on Music Enjoyment.

OBJECTIVE: Noise reduction algorithm (NRA) in speech processing strategy has positive impact on speech perception among cochlear implant (CI) listeners. We sought to evaluate the effect of NRA on music enjoyment. STUDY DESIGN: Prospective analysis of music enjoyment. SETTING: Academic medical center. PATIENTS: Normal-hearing (NH) adults (N = 16) and CI listeners (N = 9). INTERVENTION: Subjective rating of music excerpts. MAIN OUTCOME MEASURES: NH and CI listeners evaluated country music piece on three enjoyment modalities: pleasantness, musicality, and naturalness. Participants listened to the original version and 20 modified, less complex versions created by including subsets of musical instruments from the original song. NH participants listened to the segments through CI simulation and CI listeners listened to the segments with their usual speech processing strategy, with and without NRA. RESULTS: Decreasing the number of instruments was significantly associated with increase in the pleasantness and naturalness in both NH and CI subjects (p < 0.05). However, there was no difference in music enjoyment with or without NRA for either NH listeners with CI simulation or CI listeners across all three modalities of pleasantness, musicality, and naturalness (p > 0.05): this was true for the original and the modified music segments with one to three instruments (p > 0.05). CONCLUSION: NRA does not affect music enjoyment in CI listener or NH individual with CI simulation. This suggests that strategies to enhance speech processing will not necessarily have a positive impact on music enjoyment. However, reducing the complexity of music shows promise in enhancing music enjoyment and should be further explored.