Auditory middle latency responses in patients with intracranial space-occupying lesions.
Auditory middle latency responses (MLRs) and auditory brainstem responses (ABRs) were investigated pre- and postoperatively in three patients operated on of intracranial tumor (craniopharyngioma in cases 1 and 2, left-temporal cystic astrocytoma in case 3). In each case examined, preoperative MLRs were informative in evaluating the damage to supratentorial neural structures owing to the tumor; furthermore, they allowed a precious evaluation of the functional integrity of these structures after surgery. Likewise, in case 2 the ABRs indicated a brainstem injury secondary to overzealous manipulation of the right temporal lobe. Finally, in case 3, the most prominent complex of the MLRs, ie Na-Pa, was abnormal both before and after intervention; indeed, in pre- and postoperative MLRs, Na could be identified in both ears, whereas Pa was greatly reduced in amplitude or absent: this finding would seem to suggest that Na and Pa have different generator sites.
Vizioli
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Cattedra di Neurochirurgia, II Facoltà di Medicina e Chirurgia dell'Università degli Studi di Napoli, Italy.
Bucciero
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A
Quaglietta
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Mosca
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F
D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D003397:Craniopharyngioma / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D013702:Temporal Lobe; D013997:Time Factors; D014057:Tomography, X-Ray Computed