Assessing working memory capacity through picture span and feature binding with visual-graphic symbols during a visual search task with typical children and adults.

This study investigated developmental memory capacity through picture span and feature binding. Participants included third grade students and college age adults with typical development. Picture span was used to assess working memory capacity when participants were asked to identify, locate, and sequence common visual-graphic symbols from experimental grid displays.

DPOAE component estimates and their relationship to hearing thresholds.

Distortion product otoacoustic emissions (DPOAEs) recorded in the ear canal are a composite or vector sum of two underlying components. The relationship between hearing thresholds and DPOAE-component level, rather than composite level, has been of recent interest. Two different signal-processing methods, inverse fast Fourier transform (IFFT) with time-windowing and low-pass filtering, were used to obtain estimates of the levels of the two components.

Effects of a suppressor tone on distortion product otoacoustic emissions fine structure: why a universal suppressor level is not a practical solution to obtaining single-generator DP-grams.

Objectives: The use of a suppressor tone has been proposed as the method of choice in obtaining single-generator distortion product (DP) grams, the speculation being that such DP grams will be more predictive of hearing thresholds. Current distortion product otoacoustic emissions (DPOAE) theory points to the ear canal DPOAE signal being a complex interaction between multiple components. The effectiveness of a suppressor tone is predicted to be dependent entirely on the relative levels of these components.

Sources and mechanisms of DPOAE generation: implications for the prediction of auditory sensitivity.

Otoacoustic emissions (OAEs) have become a commonly used clinical tool for assessing cochlear health status, in particular, the integrity of the cochlear amplifier or motor component of cochlear function. Predicting hearing thresholds from OAEs, however, remains a research challenge. Models and experimental data suggest that there are two mechanisms involved in the generation of OAEs.

Generation of DPOAEs in the guinea pig.

In humans, distortion product otoacoustic emissions (DPOAEs) at frequencies lower than the f(2) stimulus frequency are a composite of two separate sources, these two sources involving two distinctly different mechanisms for their production: non-linear distortion and linear coherent reflection [Talmadge et al., J. Acoust.

What drives mechanical amplification in the mammalian cochlea?

The recent report by Peter Dallos and colleagues of the gene and protein responsible for outer hair cell somatic motility (Zheng, Shen, He, Long, Madison, & Dallos, 2000), and the work of James Hudspeth and colleagues demonstrating that vestibular stereocilia are capable of providing power that may boost the vibration of structures within the inner ear (Martin & Hudspeth, 1999), presents the tantalizing possibility that we may not be far away from answering the question what drives mechanical amplification in the mammalian cochlea? This article reviews the evidence for and against each of somatic motility as the motor, and a motor in the hair cell bundle, producing cochlear mechanical amplification. We consider three models based on somatic motility as the motor and two based on a motor in the hair cell bundle. Available evidence supports a hair cell bundle motor in nonmammals but the upper frequency limit of mammalian hearing in general exceeds that of nonmammals, in many cases by an order of magnitude or more.