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Biomedical subjects

P Montandon

Publications and source records attributed to P Montandon.

At least 37 records · Page 2Linked to original sources
PubMed1990

Binaural interaction in a cochlear implant patient.

Binaural interaction was demonstrated in electrically evoked brainstem responses (EBRs) of a bilaterally implanted patient. A clear binaural difference waveform (BD), consisting of a negative peak near 3.6 ms followed by a positive peak near 4.4 ms, was found by subtracting the recordings with diotic stimulation from the sum of the recordings with monotic stimulation. These results are consistent with those reported for normal subjects and suggest that neural processing in this patient might resemble those ordinarily used in binaural hearing. They strengthen the argument that EBRs in cochlear implant patients do result from activity in auditory brainstem neurons and suggest a method for aligning the positions of the intracochlear electrodes.

Brain Stem↗
PubMed1990

Wegener's granulomatosis with otological disorders as primary symptoms.

Otological symptoms as initial manifestations of Wegener's granulomatosis have been observed in 3 patients. In one of them, symptoms consisted of a bilateral sensorineural hearing loss, improved by corticoid therapy. No other organ system was involved and laboratory tests remained within normal limits for 2 years after the onset of otological signs. In the other 2 patients, Wegener's granulomatosis manifested mainly as serous otitis media. Otologic involvement underscores the role of the otolaryngologist in the early diagnosis and treatment of this disease.

Adult↗
PubMed1990

Multi-channel cochlear implant patients with different open speech understanding show some similar basic psychophysical results.

A series of tests was recently undertaken on three multi-channel cochlear implant patients showing different degrees of open speech understanding in order to try to determine underlying differences in inner ear excitation. First we wanted to determine whether these patients showed notable differences in basic psychophysical tasks. This article reports a series of measures including absolute and differential thresholds, simultaneous and forward masking, and some polarity and phase perception. Absolute and differential sensitivities were found to be similar. In forward or simultaneous masking, the patients often showed no masking at all and in cases of masking, no frequency selectivity. In forward masking, their time constants were found to be longer than those in normal hearing. Multi-harmonic signals differing only in phase relations to produce large differences in peak amplitude did not seem to elicit different perceptions. In stimulating with very low-frequency square waves, only negative going fronts were perceived. The similarity of results for the 3 patients in this study suggest that individual differences lie in more complex stimulus processing and perhaps in qualitative aspects of perception.

Adult↗
PubMed1989

Electrically evoked responses in Cochlear implant patients.

Highly reproducible recordings of evoked responses elicited by electrical stimulation of the auditory nerve were obtained in a group of 4 totally deaf patients implanted with a multichannel intracochlear prosthesis. They were compared to auditory evoked responses obtained in a normal-hearing subject tested with the same equipment. The most striking observation drawn from these data is certainly the close resemblance, at all latencies, between evoked responses elicited by electrical stimulation and those elicited by acoustic stimulation. The remarkable correspondence of waveform morphology, waveform amplitude and interpeak latencies provides indirect evidence that the same sequence of events is triggered in the central auditory system in both cases. Those aspects of the responses which differ significantly are easily interpreted by the physical and physiological properties of the different types of stimulation.

Auditory Perception↗
PubMed1988

Noninvasive extratympanic electrical stimulation of the auditory nerve.

We have developed a noninvasive technique for extratympanic stimulation of the auditory nerve. 119 ears of 76 subjects with either normal, residual or no hearing were tested. 73% of the subjects with experience of hearing reported definite auditory sensations. Subjects with no certain experience of hearing could not describe accurately the nature of their sensations. Electrical stimulation of normal ears failed to elicit auditory sensations. These results compare well with those of promontory stimulation in cochlear implant candidates.

Adolescent↗
PubMed1988

Prevention of vertigo in Ménière's syndrome by means of transtympanic ventilation tubes.

The insertion of a transtympanic ventilation tube prevented the occurrence of vertiginous attacks in 82% of a series of 28 patients suffering typical Ménière's syndrome with incapacitating vertigo resistant to medical treatment. The follow-up time exceeds 2 years for all cases. It ranges from 2 to 4 years with an average of 2.5 years. This treatment had no effect on drop attacks. Also, hearing loss does not seem to be influenced. The presence of a transtympanic ventilation tube has not caused any major complications in these patients. Obstruction or loss of the tube was in some cases followed by the reappearance of vertigo. It is therefore important to check the patency of the tube before concluding that treatment has failed. The apparent benefit of ventilation tubes in reducing the occurrence of vertiginous attacks suggests that patients with endolymphatic hydrops are particularly sensitive to middle ear pressure.

Adolescent↗
PubMed1986

Activation of the auditory cortex by cochlear stimulation in a deaf patient.

We have recorded cerebral electric and magnetic responses to electric stimulation of the auditory nerve in a deaf patient with multichannel cochlear prosthesis. The electric response peaked with a vertex-negative deflection at 65 ms. Clear magnetic responses, coinciding with the vertex potential, were obtained only over the hemisphere ipsilateral to the stimulation; the field pattern indicated activation of the auditory cortex within the Sylvian fissure. The results suggest modification of the central auditory pathways in this patient deaf from early childhood.

Auditory Cortex↗