Relationship Between Behavioral and Physiological Spectral-Ripple Discrimination

Abstract

Previous studies have found a significant correlation between spectral-ripple discrimination and speech and music perception in cochlear implant (CI) users. This relationship could be of use to clinicians and scientists who are interested in using spectral-ripple stimuli in the assessment and habilitation of CI users. However, previous psychoacoustic tasks used to assess spectral discrimination are not suitable for all populations, and it would be beneficial to develop methods that could be used to test all age ranges, including pediatric implant users. Additionally, it is important to understand how ripple stimuli are processed in the central auditory system and how their neural representation contributes to behavioral performance. For this reason, we developed a singleinterval, yes/no paradigm that could potentially be used both behaviorally and electrophysiologically to estimate spectral-ripple threshold. In experiment 1, behavioral thresholds obtained using the single-interval method were compared to thresholds obtained using a previously established three-alternative forcedchoice method. A significant correlation was found (r=0.84, p=0.0002) in 14 adult CI users. The spectralripple threshold obtained using the new method also correlated with speech perception in quiet and noise. In experiment 2, the effect of the number of vocoderprocessing channels on the behavioral and physiological threshold in normal-hearing listeners was determined. Behavioral thresholds, using the new singleinterval method, as well as cortical P1-N1-P2 responses changed as a function of the number of channels. Better behavioral and physiological performance (i.e., better discrimination ability at higher ripple densities) was observed as more channels added. In experiment 3, the relationship between behavioral and physiological data was examined. Amplitudes of the P1-N1-P2 "change" responses were significantly correlated with d′ values from the single-interval behavioral procedure. Results suggest that the single-interval procedure with spectral-ripple phase inversion in ongoing stimuli is a valid approach for measuring behavioral or physiological spectral resolution.

Evidence of across-channel processing for spectral-ripple discrimination in cochlear implant listeners

“…In principle, the available cues are larger at greater modulation depths. Our previous reports used a spectral ripple modulation depth of 30 dB (Won et al, 2007(Won et al, , 2011, whereas Experiment 1 in the present study used a spectral modulation depth of 13 dB. This experiment compared spectral-ripple discrimination thresholds obtained with spectral modulation depths of 13 and 30 dB.…”

“…Spectral-ripple discrimination, originally developed to investigate the spectral resolution of the normal auditory system (e.g., Supin et al, 1994Supin et al, , 1998Supin et al, , 1999, has recently gained a wide range of attention in the cochlear implant (CI) research field (e.g., Henry and Turner, 2003;Henry et al, 2005;Won et al, 2007;Litvak et al, 2007;Saoji et al, 2009;Drennan et al, 2010;Won et al, 2010Won et al, , 2011Anderson et al, 2011). These previous studies demonstrated that spectral-ripple discrimination correlates with vowel and consonant recognition in quiet (Henry et al, 2003(Henry et al, , 2005Saoji et al, 2009), speech perception in noise (Won et al, 2007), and music perception .…”

“…Henry et al (2005) demonstrated that normal-hearing listeners showed best spectral-ripple discrimination performance followed by hearing-impaired listeners and CI users. Spectral-ripple discrimination is also useful to compare CI sound encoding strategies (Berenstein et al, 2008;Drennan et al, 2010), and for evaluating the brain-behavior relationship for spectral sensitivity using an electrophysiological acoustic change complex in response to spectral-ripple phase inversion (Won et al, 2011). All of those previous reports suggest that spectral-ripple discrimination is an efficient measure of spectral resolution, which is useful for multiple clinically relevant research purposes.…”

Neural Correlates of the Binaural Masking Level Difference in Human Frequency-Following Responses

“…For the FFR recordings, 100 unique versions of the narrowband noise were generated and randomly ordered. Presenting multiple versions of the noise reduces the likelihood that envelope-following responses would be elicited because the envelope would be different for each noise version (e.g., Won et al 2011). A single stimulus onset polarity was used, which emphasizes phase-locked responses to the fine structure of the 500 Hz carrier frequency (for a review, see Aiken and Picton 2008).…”

Psycho acoustical Measures in Individuals with Congenital Visual Impairment

“…Spectral ripple task can predict spectral resolution ability 8 . Short term memory and other cognitive abilities are the most essential factors for the discrimination of the stimulus 13 . There is enhanced memory in visually impaired individuals as compared to sighted participants 14 .…”