PubMed · 1991 · 34 citations · 34 references
Health ProfessionsAudiologyAuditory ElectrophysiologyDiagnostic AudiologyHearing ScienceAudiologic EvaluationAuditory ProcessingAuditory Processing DisordersHearing ImpairmentMiddle Latency ResponsesSound LocalizationAudiometric AbnormalitiesAuditory Late ResponsesAuditory Middle Latency ResponsesInteraural Time Difference PerceptionLate-latency Auditory Evoked PotentialsLong-latency Auditory Evoked PotentialsMiddle Latency Auditory Evoked PotentialsMiddle Latency Response Thresholds
Extensive audiologic, electrophysiologic, and neuropsychologic testing was conducted on a young woman reporting difficulty hearing in her educational environment. Although audiometry and basic auditory processing tests were normal, the patient exhibited a consistent left‑ear deficit on dichotic sentence identification, speech‑in‑noise, and cued‑target tasks, indicating a central auditory processing disorder with asymmetric binaural processing that impairs background suppression when the target is presented to the left ear.
We carried out extensive audiologic, electrophysiologic, and neuropsychologic testing on a young woman who complained that she had difficulty hearing in her educational environment. Conventional audiometric results, including pure-tone, speech, and immittance audiometry, were all within normal limits. The subject performed normally on tests involving the processing of rapidly changing temporal information, interaural time and intensity difference detection, and both absolute and relative sound localization. Early, middle, late and task-related auditory evoked potentials were essentially normal, although some asymmetry was observed in the middle latency (MLR) and late (LVR) responses. There was, however, a consistent left-ear deficit on dichotic sentence identification, on threshold and suprathreshold speech measures in the left sound field when various types of competition were delivered in the right sound field, and on cued-target identification in the left sound field in the presence of multitalker babble. Results suggest a central auditory processing disorder characterized by an asymmetric problem in the processing of binaural, noncoherent signals in auditory space. When auditory space was structured such that the target was directed to the left ear, and the competition to the right ear, unwanted background was less successfully suppressed than when the physical arrangement was reversed.
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