Neurons in the dorsal cochlear nucleus (DCN) exhibit nonlinearities in spectral processing, which make it difficult to predict the neurons' responses to stimuli. Here, we consider two possible sources of nonlinearity: nonmonotonic responses as sound level increases due to inhibition and interactions between frequency components. A spectral weighting function model of rate responses is used; the...

BACKGROUND The main goal of this study was to compare contrast-enhanced spectral mammography (CESM) and breast magnetic resonance imaging (MRI) with histopathological results and to compare the sensitivity, accuracy, and positive and negative predictive values for both imaging modalities. MATERIAL/METHODS After ethics approval, CESM and MRI examinations were performed in 102 patients who had ...

A digital processing method is described for altering spectral contrast (the difference in amplitude between spectral peaks and valleys) in natural utterances. Speech processed with programs implementing the contrast alteration procedure was presented to listeners with moderate to severe sensorineural hearing loss. The task was a three alternative (/b/,/d/, or /g/) stop consonant identification...

We introduce and investigate the band gap sturcture of the frequency spectrum for classical electromagnetic and acoustic waves in a high contrast two-component periodic medium. The asymptotics with respect to the high contrast is considered. The limit medium is described in terms of appropriate see-adjoint operators and the convergence to the limit is proven. These limit operators give an idea ...

Amplitude compression processing is used to reduce the amplitude level variations of speech to fit the reduced dynamic ranges of sensorineural impaired listeners. However this processing results in spectral smearing due in part to reduced peak-to-valley ratios. Presented here are two variations of a compression processing algorithm based on a sinusoidal speech model that preserves the important...

PURPOSE To clarify if large numbers of wide dynamic range compression channels provide advantages for vowel identification and to measure its acoustic effects. Methods Eight vowels produced by 12 talkers in the /hVd/ context were compressed using 1, 2, 4, 8, and 16 channels. Formant contrast indices (mean formant peak minus mean formant trough; maximum formant peak minus minimum formant trough)...

Spectral contrast effects may help "normalize" the incoming sound and produce perceptual constancy in the face of the variable acoustics produced by different rooms, talkers, and backgrounds. Recent studies have concentrated on the after-effects produced by the long-term average power spectrum. The present study examined contrast effects based on spectral motion, analogous to visual-motion afte...

Neurons in the dorsal cochlear nucleus (DCN) exhibit nonlinearities in spectral processing, which make it difficult to predict the neurons' responses to stimuli. Here, we consider two possible sources of nonlinearity: non-monotonic responses as sound level increases due to inhibition; and interactions between frequency components. A spectral weighting function model of rate responses is used; t...