A study on the calibration characteristics of twenty impedance bridges in clinical use.
Explore the source record for details and available documents.
Acoustic Impedance Tests↗
Biomedical subjects
R H Brey
Publications and source records attributed to R H Brey.
Effects of the visual modality on acoustic reflex magnitude.
Acoustic reflex magnitude for nine normal hearing subjects was measured with eyes opened and closed under three visual modality conditions: (1) in darkness; (2) in light without the ability to focus; and (3) in light with the ability to focus. Reflex magnitude decreased with eyes open for all three visual modality conditions; however, greater magnitude reduction occurred when the eyes were able to focus. Magnitude reduction for the three visual conditions was: 7% in darkness; 11% without visual focusing; and 20% with visual focusing. Additional data presented suggests reflex magnitude changes occur when eyes are held open with visual stimulation as a variable.
Accommodation, Ocular↗
Comparison of measurements of the characteristics of directional microphone hearing aids in an IAC test room and an anechoic chamber.
The purpose of this study was to assess the possibility of measuring directional microphone hearing aids (DMHAs) using standard hearing aid test instruments in a sound field environment. The use of DMHAs is increasing and research has shown that under certain difficult listening situations, superior results are obtained by hearing impaired individuals with directional versus omnidirectional microphone arrangements. However, valid electroacoustic evaluation of the DMHAs cannot be accomplished using the conventional hearing aid test box. The ideal environment for such evaluations is an anechoic chamber, a facility not found in most audiological clinics. Results show that if the proper precautions are observed, the electroacoustic characteristics of DMHAs can be measured in a sound field environment using conventional hearing aid test instrumentation. Validation of this procedure was carried out by comparing sound field results with those obtained in an anechoic chamber.
Acoustics↗