Intracranial pressure is normally transmitted to the perilymph of the cochlea via the cochlear aqueduct. The relationship between perilymphatic pressure, indirectly measured by tympanic membrane displacement, and mean intracranial pressure defined either clinically or by direct measurement has been examined in 58 patients (aged 5-77 years), with… (More)
Brainstem electric responses (BSER) were recorded simultaneously to give records which were ipsilateral and contralateral to the test ear. Eight normally hearing subjects were presented with a fixed stimulus level in one ear and various levels of masking in the other ear. Responses to binaural stimulation were also recorded. It appears from the analysis of… (More)
The patency of the cochlear aqueduct is a key factor in intra-cochlear hydromechanics. If patent, the cerebrospinal fluid (CSF) provides the reference pressure for the perilymph and also to a large extent the endolymph, since Reissner's membrane can only withstand a relatively small pressure differential. The aqueduct often becomes sealed as a natural… (More)
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A new technique which we have named 'isochronic mapping' is described. The conventional technique of plotting isopotential maps shows little or no contrast for far-field potentials such as the auditory brainstem response (ABR). However, by modifications to the mapping software, the latency values of a peak can be plotted and lines of equal time or… (More)
A young girl with objective tinnitus is presented. Using tympanic membrane displacement, the probable origin of the tinnitus has been demonstrated. The patient has responded well to treatment with a tinnitus masker.
Auditory brainstem responses (ABRs) were recorded in a group of nine normally-hearing subjects. Wide-band clicks were delivered at 70, 80 and 90 dB SL, both with and without 50 dB SL of contralateral masking. The amplitude of wave VI was significantly reduced in the presence of masking for the 90 dB SL stimulus but there was no effect at the lower stimulus… (More)