The Impact of Magnetoencephalography-Directed Stereo-Electroencephalography Depth Electrode Implantation on Seizure Control Outcome in Children.

Introduction The use of magnetoencephalography (MEG) in localizing epileptic foci and directing surgical treatment of medically refractory epilepsy is well established in clinical practice; however, it has not yet been incorporated into the routine planning of stereo-electroencephalography (EEG) (SEEG) depth electrode trajectories during invasive intracranial evaluation for epileptic foci localization. In this study, we assess the impact of MEG-directed SEEG on seizure outcomes in a pediatric cohort. Methods A retrospective analysis was performed on a single-institution cohort of pediatric patients with medically refractory epilepsy who underwent epilepsy surgery. The primary endpoint was the reduction in seizure burden as determined by dichotomized Engel scores (favorable outcome: Engel scores I and II; poor outcome: Engel scores III and IV). Results Thirty-seven patients met the inclusion criteria (24 males and 13 females). The median age at seizure onset was three years, the median age at surgery was 14.1 years, and the median follow-up length was 30.8 months. Concordance was noted in 7/10 (70%) patients who received MEG-directed SEEG. Good clinical outcomes were achieved in 70% of MEG-directed SEEG patients, compared to 59.4% in their counterparts; however, this difference was not statistically significant (p=0.72). We noted no statistically significant association between sex, disease laterality, or age at surgery and good clinical outcomes. Conclusions Patients who underwent MEG-directed SEEG had favorable clinical outcomes, which demonstrated the practicability of this technique for determining SEEG electrode placement. Although no significant difference in clinical outcomes was obtained between the two groups, this may have been due to low statistical power. Future prospective, multi-institutional investigations to assess the benefit of MEG-directed SEEG are warranted.

Controlled comparative clinical trial of hearing benefit outcomes for users of the Cochlear™ Nucleus® 7 Sound Processor with mobile connectivity.

OBJECTIVES: To assess subjective benefits and objective speech recognition performance following a take-home trial with the new Cochlear™ Nucleus® 7 Sound Processor (SP), in experienced users of compatible cochlear implants from Cochlear Limited. METHODS: A total of 37 adult participants were fitted with the Nucleus 7 SP and used the device for up to one year. Baseline speech recognition was assessed at the initial fitting session, using each participant's own SP, and Client Oriented Scale of Improvement (COSI) goals were identified. Speech recognition was measured after 3 months of device use and outcomes of the COSI and a non-validated Processor Comparison Questionnaire (PCQ) were collected. After 11 months, a subset of subjects were tested on speech recognition delivered via direct wireless streaming from an Apple® smartphone to the SP and compatible hearing aid on the opposite side (if worn). RESULTS: The COSI and PCQ instruments both indicated significant improvement in perceived subjective benefits in comparison to the participants' previous SPs. Direct streaming via an Apple mobile phone showed improvements when compared with the acoustic alone condition. Standard speech recognition in quiet and noise was equivalent to that obtained using a previous generation SP which uses the same basic processing as the Nucleus 7 Sound Processor. CONCLUSIONS: The incremental refinements provided by the Nucleus 7 Sound Processor provide real-world benefits in key areas such as upgraded wireless connectivity. The COSI proved to be an effective tool for individualized assessment of specific benefits that may not be addressed by more standardized instruments.

The use of cone-beam computed tomography to determine cochlear implant electrode position in human temporal bones.

OBJECTIVE: To assess the utility of cone-beam computed tomography (CBCT) imaging in the estimation of cochlear implant (CI) electrode position in implanted temporal bones. STUDY DESIGN: Eight fresh frozen temporal bones were mounted and oriented as for standard surgery and were implanted with Cochlear Slim-Straight (SS) or Contour Advance electrode arrays by 2 CI surgeons. The bones were then imaged using an Accuitomo F170 CBCT scanner (isometric 250 µm voxel size) and were then processed for histologic sectioning (500 µm sections). MAIN OUTCOME MEASURES: The CBCT images and the histologic micrographs (providing the "gold standard") were examined independently by several observers who assessed the scalar position (tympani or vestibuli) of each electrode in each temporal bone specimen. RESULTS: Examination of the histologic micrographs confirmed that all electrodes were positioned within the scala tympani in all 8 bones. Similar judgments were made by the observers rating the CBCT images, except that one of the 2 observers estimated some of the apical electrodes to be located in the scala vestibuli in two of the bones implanted with the SS electrode. CONCLUSION: Cone-beam CT imaging is able to provide a good indication of the scalar position of implanted electrodes, although estimation may be slightly less reliable for apical electrodes and for straight electrode designs. Additional advantages of using CBCT for this purpose are shorter acquisition time and reduction of radiation dose as compared with conventional CT.

Amalgam dental fillings and hearing loss.

In this study we investigated the effects of amalgam dental fillings on auditory thresholds. Participants (n=39) were non-smoking women age 40 to 45. Regression and correlation analyses were performed between auditory thresholds, measured from 0.25 to 16 kHz, and the number/surface area of dental fillings, using the ASHA criteria for ototoxic change as a reference for comparison. No significant correlation (p>0.05) was found between composite (non-amalgam) filling or drilling data and auditory thresholds. However, there was a significant positive linear correlation between amalgam filling data and auditory thresholds at 8, 11.2, 12.5, 14, and 16 kHz. The strongest association (r=0.587, n=39, p<.001, r(2)=0.345) was at 14 kHz, where each additional amalgam filling was associated with a 2.4 dB decline in hearing threshold (95% confidence interval [CI], 1.3-3.5 dB). The results suggest an association between more amalgam fillings and poorer thresholds at higher frequencies, which could contribute to presbyacusis in developed countries. This provides further argument for the use of amalgams to be phased out where suitable alternatives exist.