Neural response telemetry in patients with the double-array cochlear implant.

This study aimed to evaluate the neural response in double-array cochlear implant as well as to describe the refractory recovery and the spread of excitation functions. In a prospective study 11 patients were implanted with the double-array cochlear implant. Neural response telemetry (NRT) was performed intra-operatively. NRT threshold could be registered in 6 of the 11 patients, at least in one electrode. The remaining five patients did not show measurable neural response intra-operatively. It was noted that although recovery and spread of excitation functions could be recorded in all the tested electrodes with measurable neural responses, the responses were shown to be different from the usual register in patients with other etiologies.

The role of magnetic resonance imaging in the postoperative management of cholesteatomas.

UNLABELLED: Conventional CT and MRI scans have low specificity when it comes to differentiating granulation tissue from relapsing cholesteatoma. AIM: this paper aims to analyze the use of DWI and delayed post-contrast T1-weighed imaging in the detection of recurring cholesteatomas. MATERIALS AND METHOD: this is a cross-sectional prospective study that looked at 17 cholesteatoma patients postoperatively. All patients underwent diffusion magnetic resonance imaging at 1.5T, T1, T2, and delayed post-contrast T1 and images were produced from both coronal and axial planes. Two radiologists assessed the images and decided consensually that the presence of hyperintensive signal in DWI on T2, iso/hypointensive signal on T1, and absence of contrast uptake were indicative of relapsing cholesteatoma. Surgical review findings were compared to DWI scans. RESULTS: eleven of the twelve cases of recurring cholesteatoma presented hyperintensive signal in the DWI scans. None of the patients with granulation tissue in the surgical wound presented hyperintensive signal in the DWI scans. A patient with an abscess in the internal acoustic meatus also presented a hyperintensive signal in the DWI scans. Sensibility, specificity, positive predictive value and negative predictive value were 91.6%, 60.0%, 84.6%, and 75.0%, respectively. CONCLUSION: DWI combined with delayed post-contrast T1 SE sequence proved to be useful in the differential diagnosis of granulation tissue and recurring cholesteatoma.

Psychoacoustic dynamic range and cochlear implant speech-perception performance in nucleus 22 users.

BACKGROUND: Cochlear implant speech processors compress a wide acoustical dynamic range of sounds into a smaller electrical dynamic range. Some patients show wider electrical dynamic ranges than others and most of them have good speech perception performance. The knowledge of the average psycho-acoustical dynamic range in adults will help the audiologist program children who do not give reliable responses. AIM: This study was conducted to analyse the dynamic ranges of experienced Nucleus 22 cochlear implant users with good speech-perception and patients with poor speech-perception performances. METHOD: Thirty-one maps of adult subjects with Nucleus 22 cochlear implants using the SPEAK processing strategy, in bipolar stimulation were analysed. By the time of this study, all of them had used a cochlear implant for over a year. They were divided into two groups: group 1, composed of those with good speech perception for sentences (better than 80%), and group 2, composed of those with speech perception results for sentences worse than 70%. RESULTS: Results showed that both dynamic ranges were wide in the two groups (average 50 units). CONCLUSION: Although dynamic ranges vary among subjects and electrodes, a lower variability was observed within the group of patients with better speech perception.