Use of a compound approach to derive auditory-filter-wide frequency-importance functions for vowels and consonants

Abstract

Speech recognition in noise presumably relies on the number and spectral location of available auditory-filter outputs containing a relatively undistorted view of local target signal properties. The purpose of the present study was to estimate the relative weight of each of the 30 auditory-filter wide bands between 80 and 7563 Hz. Because previous approaches were not compatible with this goal, a technique was developed. Similar to the "hole" approach, the weight of a given band was assessed by comparing intelligibility in two conditions differing in only one aspect-the presence or absence of the band of interest. In contrast to the hole approach, however, random gaps were also created in the spectrum. These gaps were introduced to render the auditory system more sensitive to the removal of a single band and their location was randomized to provide a general view of the weight of each band, i.e., irrespective of the location of information elsewhere in the spectrum. Frequency-weighting functions derived using this technique confirmed the main contribution of the 400-2500 Hz frequency region. However, they revealed a complex microstructure, contrasting with the "bell curve" shape typically reported.

Band importance functions of listeners with cochlear implants using clinical maps

“…3) followed the characteristic inverted "U" shape that has been previously observed (ANSI, 1969(ANSI, , 1997Apoux and Healy, 2012;Healy et al, 2013). Band importance peaked at about 1-2 kHz, with bands outside of this frequency region contributing less to speech intelligibility.…”

“…This approach described here is a mix of the compound method of measuring BIFs described by Apoux and Healy (2012) and the correlational method described by Doherty and Turner (1996). Apoux and Healy (2012) chose target bands and presented pairs of trials that had the target band present or absent, in addition to a random subset of other bands.…”

“…Apoux and Healy (2012) chose target bands and presented pairs of trials that had the target band present or absent, in addition to a random subset of other bands. By taking the difference in speech perception when the target band was present or absent, the improvement in speech intelligibility provided by that band was estimated.…”

“…Several alternative methods have been devised to address this issue. One approach is to simply randomize the combination of bands presented with or without the target band (Apoux and Healy, 2012;Healy et al, 2013), to average band importance for the target band across all potential interactions with other bands. Others have removed individual bands from the spectrum, to observe the loss in intelligibility due to the missing information (Henry et al, 2000;Sladen and Ricketts, 2015).…”

Fuzzy information transmission analysis for continuous speech features

“…Both the boundary locations and the number of categories per feature differ substantially between these three studies. Another study performed a FITA on the consonants recorded by Hillenbrand et al but did not perform a FITA on the vowels because they could not determine reasonable ways to group the stimuli (Apoux and Healy, 2012).…”