Long-term measurement of binaural intensity and pitch matches. II. Fluctuating low-frequency hearing loss

Abstract

Thirteen subjects made consecutive long-term recordings of binaural intensity and pitch matches in their homes using portable equipment to assess hearing fluctuations. Two groups of subjects were used; one with monaural fluctuating low-frequency hearing loss (FLFHL) without vertigo, and one with monaural Meniere's disease (i.e. FLFHL with vertigo). The subjects measured binaural pitch matches using a 0.25- or 1-kHz reference tone presented at 60 dB SPL to one ear, and a loudness-matched test tone of adjustable frequency presented to the other ear during one to several weeks. Their results were compared to those previously obtained from ten normal-hearing subjects. Both groups of subjects showed fluctuations in binaural intensity and pitch matches not seen in the normal-hearing group. We calculated the average day-to-day difference in matched intensity and frequency for each subject's test period as a measure of disease activity. This measure indicated that the group with Meniere's disease has a higher disease activity than the group with FLFHL without vertigo, and that both these groups of subjects had higher disease activity than normal-hearing subjects.

Altered mapping of sound frequency to cochlear place in ears with endolymphatic hydrops provide insight into the pitch anomaly of diplacusis

“…Most patients with diplacusis and unilateral Ménière’s disease (77%) perceive pitch to be lower in the affected ear 14 , 18 , 19 , which is opposite the direction found in ears with typical high-frequency sensorineural hearing loss (see above). Edolymphatic hydrops in Ménière’s ears has been hypothesized to be associated with an increased scala-media pressure that pushes on the organ of Corti and stiffens the BM 4 , 6 , 19 , 23 .…”

“…Diplacusis is present in people with sensorineural hearing loss, but is seldom more than 1.5 semitones, and tone pitch is most often at a higher frequency in the ear with the worst hearing 14 , 15 , 18 , 19 . This is consistent with the hypothesis that the higher sound levels that need to be used in the poorer-hearing ear cause a shift in cochlear place cues toward the higher-frequency cochlear base 6 , 20 .…”

Complex tone stimulation may induce binaural diplacusis with low-tone hearing loss

“…Endolymphatic hydrops plays an important part in the pathogenesis of Meniere's disease [12,13]. In addition to a human experiment that showed pitch shift with Meniere's disease [5], mechanical cochlear models of endolymphatic hydrops showed that the places of maximal displacement of the traveling waves are shifted, which must be considered the equivalent of diplacusis [14]. Our present study is not comparable to these previous studies because we used complex tones as stimulation.…”

“…Approximately half of all patients with Meniere's disease, whose representative audiological symptom is low-tone hearing loss, complain of binaural diplacusis [4]. Studies indicate that the affected ear can perceive lower, higher, or equal pitch compared to the opposite, unaffected ear [3,5]. These subjective variations in pitch are generally explained in terms of different stages of the disease.…”

Hypobaric pressure exposure effects on cochlear frequency selectivity in fluctuating, low-frequency hearing loss

“…The same equipment, equipment arrangement and calibration used for Békésy audiometry were used for recordings of psychophysical tuning curves. This method has also been previously described in detail elsewhere (see Brännström and Grenner 24 , 28 ). Psychophysical tuning curves were measured for the use of two 0.25 kHz probe tones presented at 10 dB sensation level (SL) during simultaneous narrowband noise presentation.…”