Successful outcomes of cochlear implantation in long-term unilateral deafness : brain plasticity?

To investigate the implications of duration of deafness in the rehabilitation of unilateral deafness utilizing cochlear implantation. From the ongoing prospective cochlear implantation in unilateral deafness study, we looked at five adults who received a cochlear implant for long-term unilateral deafness. Speech perception in noise and subjective evaluation of the benefits of cochlear implantation were measured at 3, 6, and 12 months after implantation. The results were analyzed and compared with published data from normal hearing individuals and adults using cochlear implants bilaterally. Analysis of speech perception in noise showed significant improvement for three spatial configurations: speech and noise from the front (S0/N0; P=0.003), speech from the front and noise from the normal hearing ear (S0/NHE; P=0.001), speech from the implanted ear, and noise from the normal hearing ear (SCI/NHE; P<0.001). The scores obtained at 12 months after surgery improved to values similar to those obtained by individuals with normal hearing. The results of subjective measures showed significant improvement in hearing over time to the scores obtained by individuals with a bilateral cochlear implants and those with normal hearing. In this study, older adults with more than 25 years of unilateral deafness obtained scores in speech perception testing and in subjective evaluation that are similar to those attained by individuals with normal hearing and/or those with bilateral cochlear implants. Therefore, patients with postlingual unilateral deafness should not be excluded as cochlear implant candidates on the basis of a long duration of deafness.6 page(s

Using aided cortical assessment as an objective tool to evaluate cochlear implant fitting in users with single-sided deafness.

To assess the use of cortical auditory evoked potentials (CAEPs) to verify, and if necessary, optimize the cochlear implant (CI) fitting of adult CI users with postlingual single-sided deafness (SSD).Sound field cortical responses to the speech tokens /m/, /g/, /t/, and /s/ were recorded from input to the CI while the normal hearing ear was masked. Responses were evaluated by visual inspection and classified as presence or absence of the CAEPs components P1, N1, P2. In case of an absence fitting was adjusted accordingly. After fitting, subjects were asked to use their new setting for 2-3 weeks for acclimatization purposes and then return for retesting. At retesting, new CAEP recordings were performed to objectively ensure that the new fitting maps effectively activated the auditory cortex.In 14/19 subjects, as per visual inspection, clear CAEPs were recorded by each speech token and were, therefore, not refit. In the other 5 subjects, CAEPs could not be evoked for at least one speech token. The fitting maps in these subjects were adjusted until clear CAEPs were evoked for all 4 speech tokens.CAEP can be used to quickly and objectively verify the suitability of CI fitting in experienced adult CI users with SSD. If used in the early post-implantation stage, this method could help CI users derive greater benefit for CI use and, therefore, be more committed to auditory training

Morbidity Profile and Functional Outcome of Modified Facial Translocation Approaches for Skull Base Tumors

The primary objective of this study was to evaluate morbidity associated with facial translocation approaches for skull base and results of various technical modifications. Forty consecutive patients who underwent facial translocation approaches for accessing skull base tumors from July 2005 to June 2010 were included in this study. There were 25 patients who underwent standard facial translocation, 4 patients medial mini, and 11 patients underwent extended facial translocation. Thirteen patients had benign disease and 27 patients had malignant disease. Resection was R0 in 36 and R1 in 4 patients. Most patients had acceptable cosmetic results. None of the patients had problems related to occlusion or speech and swallowing. The commonest complication observed was nasal crusting in 16 patients. Grade 2 trismus and exposure of mini plate was seen in three patients. Two patients developed necrosis of translocated bone. Three patients developed palatal fistula before modification of palatal incision. Facial translocation provides a satisfactory access for adequate clearance of skull base tumors with satisfactory aesthetic and functional results. With modifications of the surgical technique and implementation of new surgical tools, the morbidity of facial translocation approaches will continue to decrease

A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System : Is Meniere's Disease Caused by an Acute Endolymph Backflow?

Background: The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. Material and Methods: We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Results: Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. Discussion: The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K+-intoxication theory

Subject S1’s CAEP traces evoked by speech tokens /s/, /g/, /t/, /m/ with CI off and his normal hearing ear masked with 60 dB HL (1a), 65 dB HL (1b), and 70 dB HL (1c) broad-band noise.

<p>Subject S1’s CAEP traces evoked by speech tokens /s/, /g/, /t/, /m/ with CI off and his normal hearing ear masked with 60 dB HL (1a), 65 dB HL (1b), and 70 dB HL (1c) broad-band noise.</p

Before and after CAEP traces for the 5 subjects (#s 9, 10, 12, 15, 17) whose fitting maps had to be adjusted.

<p>Before and after CAEP traces for the 5 subjects (#s 9, 10, 12, 15, 17) whose fitting maps had to be adjusted.</p

Demographic data.

<p>Demographic data.</p