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. 2010 Apr;262(1-2):1-8.
doi: 10.1016/j.heares.2010.02.003. Epub 2010 Feb 6.

Sensitivity of psychophysical measures to signal processor modifications in cochlear implant users

Ward R Drennan  1 , Jong Ho Won, Kaibao Nie, Elyse Jameyson, Jay T Rubinstein
Affiliations

Sensitivity of psychophysical measures to signal processor modifications in cochlear implant users

Ward R Drennan et al. Hear Res. 2010 Apr.

Abstract

Experienced users of the Clarion cochlear implant were tested acutely with the HiResolution (HiRes) and HiRes Fidelity120 (F120) processing strategies. Three psychophysically-based tests were used including spectral-ripple discrimination, Schroeder-phase discrimination and temporal modulation detection. Three clinical outcome measures were used including consonant-nucleus-consonant (CNC) word recognition in quiet, word recognition in noise and the clinical assessment of music perception (CAMP). Listener's spectral-ripple discrimination ability improved with F120, but Schroeder-phase discrimination was worse with F120 than with HiRes. Listeners who had better than average acuity showed the biggest effects. There were no significant effects of the processing strategy on any of the clinical abilities nor on temporal modulation detection. Additionally, the listeners' day-to-day clinical strategy did not appear to influence the result suggesting that experience with the strategies did not play a significant role. The results underscore the value of acoustic psychophysical measures through the sound processor as a tool in clinical research, because these measures are more sensitive to changes in the processing strategies than traditional clinical measures, e.g. speech understanding. The measures allow for the evaluation of sensitivity to specific acoustic attributes revealing the extent to which different processing strategies affect these basic abilities and could thus improve the efficiency of the development of processing strategies.

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Figures

Figure 1
Figure 1
The figure shows the acoustic stimuli used in the psychophysical experiments. The left panel shows a representation of the standard and inverted ripple stimuli for the spectral-ripple tests in the frequency domain; the middle panel shows a 20 ms sample of the positive (middle right) and negative (middle left) Schroeder-phase stimuli, and the right panel shows the modulated and unmodulated stimuli used for the modulation detection experiment
Figure 2
Figure 2
Individual and average thresholds for spectral-ripple discrimination
Figure 3
Figure 3
Percent correct scores for individual and average data for 50- and 200-Hz Schroeder phase discrimination.
Figure 4
Figure 4
Shows average percent-correct scores at each frequency of modulation detection (N = 5).
Figure 5
Figure 5
The top panel shows individual and average scores for CNC-word tests. The bottom panel shows individual and average speech reception thresholds in noise.
Figure 6
Figure 6
Shows the results for each component of the clinical assessment of music perception.
Figure 7
Figure 7
The figure shows electrodograms for the positive and negative Schroeder-phase stimuli for HiRes and F120 processing.
See this image and copyright information in PMC

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