Spectral ripple test measures spectral modulation detection thresholds in cochlear implant users
Evidence
2.3.2 Spectral Modulation Threshold We used the spectral ripple test presented by (Litvak et al. 2007 ) to estimate the spectral modulation thresholds of each CI user. This task uses a cued two interval, two-alternative, forced choice procedure. In the first interval the standard stimulus was always presented. The standard stimulus had a flat spectrum with bandwidth extending from 350 to 5600 Hz. The signal and the second standard were randomly presented in the other two intervals. Both signals were generated in the frequency domain assuming a sampling rate of 44,100 Hz. The spectral shape of the standard and the signal were generated using the equation: where F is the amplitude of a bin with center frequency f (in Hertz), f c is the spectral modulation frequency (in cycles/octave), and θ 0 is the starting phase. Next, noise was added to the phase of each bin prior to computing the inverse Fourier transform. The standard was generated using a spectral contrast c equal to 0. The amplitude of each stimulus was adjusted to an overall level of 60 dB sound pressure level (SPL). Independent noise stimuli were presented on each observation interval. The stimulus duration was 400 ms. A 400 ms pause was used between the stimuli. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1844
Categorization
- DEFINE: Defines the spectral ripple test procedure with specific parameters (350-5600 Hz band, random phase noise, 60 dB SPL, 400 ms duration).
- XREF: Connects to the reader’s earlier interest in psychoacoustic test methods and signal-processing techniques for evaluating spectral resolution in hearing.
- corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1844