International consensus on middle ear implants.
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Adult↗
Biomedical subjects
A Snik
Publications and source records attributed to A Snik.
Audiometric evaluation of an attempt to optimize the fixation of the transducer of a middle-ear implant to the ossicular chain with bone cement.
Typically, an implantable hearing device consists of a transducer that is coupled to the ossicular chain and electronics. The coupling is of major importance. The Vibrant Soundbridge (VSB) is such an implantable device; normally, the VSB transducer is fixed to the ossicular chain by means of a special clip that is crimped around the long process of the incus. In addition to crimping, bone cement was used to optimize the fixation in six patients. Long-term results were compared to those of five controls with crimp fixation alone. To assess the effect of bone cement (SerenoCem, Corinthian Medical Ltd, Nottingham, UK) on hearing thresholds, long-term post-surgery thresholds were compared to pre-surgery thresholds. Bone cement did not have any negative effect. Next, to test the hypothesis that aided thresholds might be better with the use of bone cement, aided thresholds were studied. After correction for the severity of hearing loss, only a small difference was found between the two groups at one frequency, viz. 2 kHz. It was concluded that there was no negative effect of using bone cement; however, there is also no reason to use bone cement in VSB users on a regular basis.
Adult↗
[Cochlear implantation in deaf children].
OBJECTIVE: To evaluate the results of cochlear implantation in deaf children. DESIGN: Descriptive. SETTING: Ear, nose and throat department, Academic Hospital, Nijmegen, and Institute for the Deaf St. Michielsgestel, the Netherlands. METHODS: The results in 29 totally deaf children implanted with a 22-channel Nucleus implant--partly in a project supported by the National Fund for Investigative Medicine--in the period 1990-1996 were determined. Six of the children had congenital deafness, the others were deaf as a sequel to meningitis. The operation had no serious complications. All children were followed for at least two years. Progress in auditory perception and speech-language development were measured with structured tests. RESULTS: There was a marked improvement in auditory performance, and language development (measured with Reynell test), although the level of normal hearing children was not reached by most of the operated children. The results were better for children with total insertion of the electrodes than for those with partial insertion (n = 4); of these last, one stopped using the implant. CONCLUSION: Cochlear implantation can limit the consequences of total deafness in children.
Adolescent↗
Pediatric cochlear implantation in The Netherlands. Selection criteria and initial results.
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Child↗
Hyperventilation syndrome and muscle fatigue.
Fatigue is a frequent complaint from patients suffering from the hyperventilation syndrome. Fatigue was quantified in terms of the endurance time that a certain force can be generated in a sustained handgrip contraction, and in terms of the time course of changes in certain parameters of the EMG-power spectrum of the contracting muscles. This was done in a group of 25 normal subjects and a group of 30 patients suffering from the hyperventilation syndrome. No difference in endurance times was found. The EMG-fatiguability in the hyperventilation group developed even slower than in the normal group. In three normals the fatigue parameters were also measured in three conditions of normo-, hypo-, and hyper-capnia. No intraindividual correlations were found between fatigue parameters and CO2-levels. Neither were such correlations found between individuals in the hyperventilation group and the normal group. It is concluded that the subjective feelings of fatigue in the hyperventilation patients cannot be corroborated by the objective measurements used in this study. Thus their fatigue is not of a peripheral type. The levels of CO2 do not have an effect on objectively measured fatigue parameters. The hypothesis that lactate accumulation in contracting muscles mediates EMG-fatiguability, cannot explain the present results, and therefore is not supported by results from this study.
Adult↗
On the clinical relevance of mismatch negativity: results from subjects with normal hearing and cochlear implant users.
Mismatch negativity (MMN) provides an objective measure for evaluating subjects with problems related to speech processing. For a valid neurophysiological profile of speech-processing mechanisms, an efficient procedure to elicit MMNs is needed. In Experiment 1 of this study, MMN recordings were conducted in adults with normal hearing on the effects of decreasing the duration of the interstimulus interval (ISI). Shortening ISI duration does not seem to have a high impact on the individual MMN quality, whereas it does influence group MMN quality. In Experiment 2, MMNs were elicited in a group of cochlear implant users by using a speech sound contrast/ba/-/da/. A group of good performers produced a significant MMN, whereas a group of moderate performers did not. There seems to be a relation between speech perception ability and MMN quality. To fundamentally understand the effects of electrical stimulation of the inner ear and to clinically adjust rehabilitation, diverse data are needed on different aspects of auditory processing. Optimizing the procedure to elicit and MMN is therefore of great clinical value.
Adult↗
Electrically evoked auditory middle latency responses versus perception abilities in cochlear implant users.
Electrical auditory middle latency responses (EAMLRs) were recorded in a group of 12 postlingually and 4 congenitally deaf cochlear implant users. The EAMLRs of the postlingually deaf cochlear implant users were compared to behavioral measures of speech perception. All the cochlear implant users showed pronounced EAMLR morphology and amplitude. EAMLRs of congenitally deaf cochlear implant users were remarkably similar to those of postlingually deaf cochlear implant users. The difference in speech perception ability between congenitally deaf and postlingually deaf cochlear implant users did not seem to be caused by integrity differences of the neural generators of the auditory middle latency response. For the postlingually deaf subjects, EAMLR amplitude variation and interlatency variation seemed to be related to specific aspects of speech perception. The poorer performers demonstrated more diversity in the amplitude of the EAMLR component peaks and a more diffuse EAMLR peak latency organization across the electrodes than the better performers.
Adolescent↗