Conservation of low-frequency hearing in cochlear implantation

Kiefer, Jan; Gstœttner, Wolfgang; Baumgärtner, Wolfgang; Pok, S. M.; Tillein, Jochen; Ye, Qing; Ilberg, C. von

doi:10.1080/00016480310000755a

Cited by 270 publications

(225 citation statements)

References 14 publications

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“…If frequencies with no responses were present at the maximum output of the audiometer, then the maximum output plus 5 dB was entered to avoid losing data. This approach was used previously by Balkany et al and Kiefer et al (19,20).…”

Section: Audiometric Assessmentmentioning

confidence: 99%

Correlation of Electrophysiological Properties and Hearing Preservation in Cochlear Implant Patients

Dalbert

Sim

Gerig

et al. 2015

Otology &Amp; Neurotology

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OBJECTIVE: To monitor changes in cochlear function during cochlear implantation using electrocochleography (ECoG) and to correlate changes to postoperative hearing preservation. METHODS: ECoG responses to acoustic stimuli of 250, 500, and 1000 Hz were recorded during cochlear implantation. The recording electrode was placed on the promontory and stabilized to fix the position during cochlear implantation. Baseline recordings were obtained after completion of the posterior tympanotomy. Changes of the ongoing ECoG response at suprathreshold intensities were analyzed after full insertion of the cochlear implant electrode array. Audiometric tests were conducted before and 4 weeks after surgery and correlated with electrophysiological findings. RESULTS: Ninety-five percent (18/19) of cochlear implant subjects had measurable ECoG responses. Under unchanged conditions, recordings showed a high repeatability without significant differences between 2 recordings (p 0.01). Ninety-four percent (17/18) of subjects showed no relevant changes in ECoG recordings after insertion of the cochlear implant electrode array. One subject showed decreases in responses at all frequencies indicative of cochlear trauma. This was associated with a complete hearing loss 4 weeks after surgery compared with mean presurgical low-frequency hearing of 78 dB HL. CONCLUSION: Extracochlear ECoG is a reliable tool to assess cochlear function during cochlear implantation. Moderate threshold shifts could be caused by postoperative mechanisms or minor cochlear trauma. Detectable changes in extracochlear ECoG recordings, indicating gross cochlear trauma, are probably predictive of complete loss of residual acoustic hearing.

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Section: Audiometric Assessmentmentioning

confidence: 99%

Correlation of Electrophysiological Properties and Hearing Preservation in Cochlear Implant Patients

Dalbert

Sim

Gerig

et al. 2015

Otology &Amp; Neurotology

View full text Add to dashboard Cite

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“…Preserving inner ear function has been achieved through modification of electrode designs (Gantz and Turner 2004;Lenarz et al 2006;Gstoettner et al 2008;Fraysse et al 2006), the adoption of new surgical techniques (Lehnhardt 1993;Briggs et al 2005;Kiefer et al 2004), and more recently through the use of pharmacological treatments to the inner ear in the peri-operative period. Hearing protection can be achieved in experimental animals undergoing cochlear implantation when glucocorticosteroids are applied to the inner ear Eastwood et al 2010a, b;James et al 2008;Maini et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Direct Entry of Gadolinium into the Vestibule Following Intratympanic Applications in Guinea Pigs and the Influence of Cochlear Implantation

King

Salt

Eastwood

et al. 2011

JARO

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Although intratympanic (IT) administration of drugs has gained wide clinical acceptance, the distribution of drugs in the inner ear following IT administration is not well established. Gadolinium (Gd) has been previously used as a marker in conjunction with magnetic resonance imaging (MRI) to visualize distribution in inner ear fluids in a qualitative manner. In the present study, we applied gadolinium chelated with diethylenetriamine penta-acetic acid (Gd-DTPA) to the round window niche of 12 guinea pigs using Seprapack TM (carboxlmethylcellulose--hyaluronic acid) pledgets which stabilized the fluid volume in the round window niche. Gd-DTPA distribution was monitored sequentially with time following application. Distribution in normal, unperforated ears was compared with ears that had undergone a cochleostomy in the basal turn of scala tympani and implantation with a silastic electrode. Results were quantified using image analysis software. In all animals, Gd-DTPA was seen in the lower basal scala tympani (ST), scala vestibuli (SV), and throughout the vestibule and semi-circular canals by 1 h after application. Although Gd-DTPA levels in ST were higher than those in the vestibule in a few ears, the majority showed higher Gd-DTPA levels in the vestibule than ST at both early and later time points. Quantitative computer simulations of the experiment, taking into account the larger volume of the vestibule compared to scala tympani, suggest most Gd-DTPA (up to 90%) entered the vestibule directly in the vicinity of the stapes rather than indirectly through the round window membrane and ST. Gd-DTPA levels were minimally affected by the implantation procedure after 1 h. Gd-DTPA levels in the basal turn of scala tympani were lower in implanted animals, but the difference compared to non-implanted ears did not reach statistical significance.

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“…In addition, many of these individuals suffer from progressive hearing loss that is most severe in the basal cochlea. The specific needs of this group has led to the development of cochlear implant devices designed to stimulate the high frequency region of the cochlea while maintaining mid and low frequency acoustic function (Kiefer et al, 2004;James et al, 2005;Lenarz et al, 2006) and limited clinical trials of these devices have been reported (Turner et al, 2004;Gantz et al, 2005;Kiefer et al, 2005;Gantz et al, 2006;James et al, 2006). Animal studies will be invaluable in understanding how electrical and acoustic signals interact in the cochlea and central nervous system and how to minimize perceptual distortions resulting from these interactions through changes in signal processing and/or electrode array design (von Ilberg et al, 1999;Nourski et al, 2005;Vollmer, 2006, personal communication).…”

Section: Future Directionsmentioning

confidence: 99%