[The 3-kHz formant--a criterion for the carrying capacity of voice? II. The trained singing voice].
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Adult↗
Biomedical subjects
R D Battmer
Publications and source records attributed to R D Battmer.
[Diagnostic reliability of ipsilateral evoked impedance changes of the tympanic membrane (author's tranl)].
The ipsilateral registration of impedance change is necessary in case of unilateral cochlear or retrocochlear disease with middle ear impairment of the other ear and, therefore, impossibility of contralateral evocation of the reflex. If contralateral evocation fails, moreover, it will be useful in order to clarify, whether the evocation did not succeed or the registration at the contralateral ear; thus enabling a differentiation between lesions of the reflexe's afferent and efferent way. In ipsilateral impedance-change-measurements it should be distinguished between an increase of the acoustic impedance (as searched for--turn to the right at the balancemeter) and a decrease of it (turn to the left at the balancemeter). The "turns to the left" at ipsilateral evocation occur without latency and only at SPL 100 dB or more. They can be observed in patients suffering from otosclerosis, complete deafness and indissected temporal bones as well. This acoustic-mechanical effect rises at high sound pressures from the non-linearity of the sound-field, which produces an extra pressure unbalancing the pressure before and behind the tympanic membrane. This effect may interfere with the real reflex-response, but only at more than 100 dB SPL; however, it must be distinguished from the proper response in order not to find the reflex falsely positive. In three clinical examples (angioblastoma of the right cerebellum hemisphere, multiple sclerosis, cerebello-pontine angle lesion) the absence of ipsilateral impedance reflexes (isolated or additional) is demonstrated.
Acoustic Impedance Tests↗
[A new method of testing directional hearing (author's transl)].
Directional hearing is demonstrated by a test in which a model "hears" loudspeaker impulses at known changes of angle. The sounds are recorded and then presented via headphones to listeners. If the subject notices a change he gives a visual signal and the appropriate change of direction is noted by the tester. -In 40 normal hearing test subjects, 20 who were blind recognized more than 50% of changes of direction of 4 degrees, and 20 with normal vision achieved similar success with direction changes of 5 degrees. Utilizing tape recorder and headphones the advantage of this method is its simplicity.
Blindness↗
Multicentric field evaluation of a new speech coding strategy for cochlear implants.
In a multicentric study involving 4 European cochlear implant centers, the speech perception abilities of 20 native German-speaking individuals implanted with the Nucleus 22 Channel Cochlear Implant System when using a new spectral peak (SPEAK) speech coding strategy were investigated. This strategy continuously analyzes the speech signal using 20 digital programmable bandpass filters and presents up to 10 spectral maxima to the 22 implanted electrodes. Each subject's performance on a variety of auditory perceptual tasks was evaluated with the experimental encoder (SPEAK), relative to his or her performance in a reference condition. An ABAB experimental design was used whereby each strategy was reversed and replicated. The reference levels of auditory performance were established using the multipeak (MPEAK) speech-processing strategy of the Nucleus speech processor. Only subjects who achieved open-set monosyllable word recognition in the reference condition were included in this study. Significant differences in group mean scores for most speech recognition subtests were obtained for the SPEAK versus the MPEAK strategy. The largest overall improvements were observed for the sentence tests under noisy conditions.
Cochlear Implants↗