RESUMO
Several alternative ear-canal measures are similar to absorbance in their requirement for prior determination of a Thévenin-equivalent sound source. Examples are (1) sound intensity level, (2) forward pressure level, (3) time-domain ear-canal reflectance, and (4) cochlear reflectance. These four related measures are similar to absorbance in their utilization of wideband stimuli and their focus on recording ear-canal sound pressure. The related measures differ from absorbance in how the ear-canal pressure is analyzed and in the type of information that is extracted from the recorded response. Sound intensity level and forward pressure level have both been shown to be better as measures of sound level in the ear canal compared with sound pressure level because they reduced calibration errors due to standing waves in studies of behavioral thresholds and otoacoustic emissions. Time-domain ear-canal reflectance may be used to estimate ear-canal geometry and may have the potential to assess middle ear pathology. Cochlear reflectance reveals information about the inner ear that is similar to what is provided by other types of otoacoustic emissions, and may have theoretical advantages that strengthen its interpretation.
Assuntos
Testes de Impedância Acústica/métodos , Audiologia/instrumentação , Meato Acústico Externo , Terminologia como Assunto , Estimulação Acústica , HumanosRESUMO
Georg von Békésy designed the instruments needed for his research. He also created physical models of the cochlea allowing him to manipulate the parameters (such as volume elasticity) that could be involved in controlling traveling waves. This review is about the specific devices that he used to study the motion of the basilar membrane thus allowing the analysis that lead to his Nobel Prize Award. The review moves forward in time mentioning the subsequent use of von Békésy's methods and later technologies important for motion studies of the organ of Corti. Some of the seminal findings and the controversies of cochlear mechanics are mentioned in relation to the technical developments.