Rodrigo Ordoñez

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The objective of our study was to apply a quantitative analysis to the dynamic contrast enhanced MR imaging of the breast. Automated criteria increase the objectivity and reproducibility of the diagnostic interpretation of the imaging for differentiating benign and malignant lesions. The validation of this applied method was evaluated by analysing the time-(More)
The effects of overexposure on the properties of distortion product otoacoustic emissions (DPOAEs) are investigated. In total, 39 normal-hearing humans were monaurally exposed to a 1-kHz tone lasting for 3 min at an equivalent threshold sound-pressure level of 105.5 dB. The effects of overexposure were studied in two experiments (1) on the broadband DPOAE(More)
A better understanding of the vulnerability of the fine structures of distortion-product otoacoustic emissions (DPOAEs) after acoustic overexposure may improve the knowledge about DPOAE generation, cochlear damage, and lead to more efficient diagnostic tools. It is studied whether the DPOAE fine structures of 16 normal-hearing human subjects are(More)
Physiological noise levels in the human ear canal often exceed naturally low levels of otoacoustic emissions (OAEs) near the threshold of hearing. Low-frequency noise, and electronic filtering to cope with it, has effectively limited the study of OAE to frequencies above about 500 Hz. Presently, a custom-built low-frequency acoustic probe was put to use in(More)
Otoacoustic emissions (OAEs) are weak sounds that can be recorded in the external ear. They are generated by the active amplification of the outer hair cells, and by many, are considered to reflect the status of the most vulnerable part of the hearing better than ordinary behavioral thresholds. Distortion product OAEs (DPOAES) are generated in response to a(More)
Active amplifiers within the cochlea generate, as a by-product of their function, distortion-product otoacoustic emissions (DPOAEs) in response to specific two-tone stimuli. Focus has been on invoking emissions in a mid-frequency range from ∼0.5 to 4 kHz. The present study investigates stimulus parameters of the DPOAE at 2f1-f2 frequencies below 0.5 kHz.(More)
The objectives of this investigation were to document sound exposures at concerts and to relate them to measurable changes on hearing. Changes in the auditory function of human subjects were measured using Distortion Product Otoacoustic Emissions (DPOAE) and Transient Evoked Otoacoustic Emissions (TEOAE). Sound exposures were measured using a Behind the Ear(More)
It is studied whether the +5 dB penalty for impulsiveness established by ISO 1999:1990 accounts for a higher risk of noise-induced hearing loss. A total of 16 normal-hearing human subjects were exposed for 10 min to two types of binaural industrial-recordings: (1) a continuous broad-band noise normalized to L(EX,8 h)=80 dBA and (2) the combination of the(More)
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