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Effect of Compression, Digital Noise Reduction and Directionality on Envelope Difference Index, Log-Likelihood Ratio and Perceived Quality.

Geetha C, Manjula P - Audiol Res (2014)

Bottom Line: The aim of the present study was to evaluate the use of the envelope difference index (EDI) and log-likelihood ratio (LLR) to quantify the independent and interactive effects of wide dynamic range compression, digital noise reduction and directionality, and to carry out self-rated quality measures.However, at a higher level of presentation, temporal cues are better preserved if all of these algorithms are deactivated.The results also indicate the importance of quality rating as this helps in considering whether the spectral and/or temporal deviations created in the hearing aid are desirable or not.

View Article: PubMed Central - PubMed

Affiliation: Department of Audiology, All India Institute of Speech and Hearing , Mysore, India.

ABSTRACT
The aim of the present study was to evaluate the use of the envelope difference index (EDI) and log-likelihood ratio (LLR) to quantify the independent and interactive effects of wide dynamic range compression, digital noise reduction and directionality, and to carry out self-rated quality measures. A recorded sentence embedded in speech spectrum noise at +5 dB signal to noise ratio was presented to a four channel digital hearing aid and the output was recorded with different combinations of algorithms at 30, 45 and 70 dB HL levels of presentation through a 2 cc coupler. EDI and LLR were obtained in comparison with the original signal using MATLAB software. In addition, thirty participants with normal hearing sensitivity rated the output on the loudness and clarity parameters of quality. The results revealed that the temporal changes happening at the output is independent of the number of algorithms activated together in a hearing aid. However, at a higher level of presentation, temporal cues are better preserved if all of these algorithms are deactivated. The spectral components speech tend to get affected by the presentation level. The results also indicate the importance of quality rating as this helps in considering whether the spectral and/or temporal deviations created in the hearing aid are desirable or not.

No MeSH data available.


Related in: MedlinePlus

Log-likelihood ratio values for different aided conditions at 30 dB, 45 dB and 70 dB HL. DNR, digital noise reduction.
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fig002: Log-likelihood ratio values for different aided conditions at 30 dB, 45 dB and 70 dB HL. DNR, digital noise reduction.

Mentions: Temporal and spectral differences of different aided conditions in comparison with original signal were analyzed using EDI and LLR respectively. Figures 1 and 2 show the EDI and LLR values for the eight aided conditions at three different input levels.


Effect of Compression, Digital Noise Reduction and Directionality on Envelope Difference Index, Log-Likelihood Ratio and Perceived Quality.

Geetha C, Manjula P - Audiol Res (2014)

Log-likelihood ratio values for different aided conditions at 30 dB, 45 dB and 70 dB HL. DNR, digital noise reduction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4627141&req=5

fig002: Log-likelihood ratio values for different aided conditions at 30 dB, 45 dB and 70 dB HL. DNR, digital noise reduction.
Mentions: Temporal and spectral differences of different aided conditions in comparison with original signal were analyzed using EDI and LLR respectively. Figures 1 and 2 show the EDI and LLR values for the eight aided conditions at three different input levels.

Bottom Line: The aim of the present study was to evaluate the use of the envelope difference index (EDI) and log-likelihood ratio (LLR) to quantify the independent and interactive effects of wide dynamic range compression, digital noise reduction and directionality, and to carry out self-rated quality measures.However, at a higher level of presentation, temporal cues are better preserved if all of these algorithms are deactivated.The results also indicate the importance of quality rating as this helps in considering whether the spectral and/or temporal deviations created in the hearing aid are desirable or not.

View Article: PubMed Central - PubMed

Affiliation: Department of Audiology, All India Institute of Speech and Hearing , Mysore, India.

ABSTRACT
The aim of the present study was to evaluate the use of the envelope difference index (EDI) and log-likelihood ratio (LLR) to quantify the independent and interactive effects of wide dynamic range compression, digital noise reduction and directionality, and to carry out self-rated quality measures. A recorded sentence embedded in speech spectrum noise at +5 dB signal to noise ratio was presented to a four channel digital hearing aid and the output was recorded with different combinations of algorithms at 30, 45 and 70 dB HL levels of presentation through a 2 cc coupler. EDI and LLR were obtained in comparison with the original signal using MATLAB software. In addition, thirty participants with normal hearing sensitivity rated the output on the loudness and clarity parameters of quality. The results revealed that the temporal changes happening at the output is independent of the number of algorithms activated together in a hearing aid. However, at a higher level of presentation, temporal cues are better preserved if all of these algorithms are deactivated. The spectral components speech tend to get affected by the presentation level. The results also indicate the importance of quality rating as this helps in considering whether the spectral and/or temporal deviations created in the hearing aid are desirable or not.

No MeSH data available.


Related in: MedlinePlus