Cochlear implantation for total deafness after ipsilateral ventriculoperitoneal shunt surgery: technical report.

BACKGROUND: Cochlear implantation (CI) becomes more challenging when a programmable ventriculoperitoneal (VP) shunt is present on the same side of the head. We report a successful ipsilateral CI in a patient who suffered bilateral hearing loss after shunt surgery. METHOD: We describe the CI case of a 49-year-old woman with an implanted VP shunt device, and perform a retrospective review of the clinical, audiological, and radiological features, surgical techniques, and postoperative functional outcomes. FINDINGS: During CI, the magnet in the core of internal antenna of the CI device was positioned approximately 8 cm from the shunt valve so that it would not be affected by the magnetic field of the programmable valve. Although the CI antenna tip and shunt catheter overlapped, we were very careful not to pull the shunt catheter out of position while the musculoperiosteal flap was elevated. CONCLUSIONS: The present result suggests that ipsilateral CI is an option for deaf adult patients who have a programmable shunt.

Petrosquamosal sinus discovered during mastoidectomy, and its radiologic appearance on temporal bone CT: case report and brief review.

We report the case of a 47-year-old woman who underwent a mastoidectomy. Preoperative computed tomography demonstrated an unusually distended bony canal that passed through the superolateral portion of the right petrous bone. Intraoperatively, we identified the anomaly as a petrosquamosal sinus (PSS). This unusually dilated venous channel had arisen from the adjacent sigmoid sinus. A PSS is an emissary vein of the posterior fossa that courses along the petrosquamosal junction, connecting the sigmoid or transverse sinus with the extracranial venous system. While it usually regresses during fetal life, a dilated PSS occasionally persists into adulthood. Its anatomic course may lead to problematic bleeding during mastoidectomy.

Time course of the suppression effect on transient evoked otoacoustic emissions by prolonged contralateral acoustic stimulation.

BACKGROUND AND OBJECTIVES: Although the suppressive effect of the medial efferent acoustic reflex is well known, the time course of this effect over prolonged periods has yet to be fully evaluated. We assessed time-dependent change in the suppression of transient evoked otoacoustic emissions (TEOAEs) by the medial efferent acoustic reflex over a relatively long period. SUBJECTS AND METHODS: We measured TEOAEs in the right ear before contralateral acoustic stimulation (CAS), and then measured serial TEOAEs in the right ear at four intervals during a total of 16 minutes of continuous CAS, followed by three more recordings after termination of CAS. RESULTS: TEOAE amplitudes were reduced with CAS during a certain period (from the immediate period to 10 minutes depending on frequency) and subsequently recovered. TEOAE suppression values in the mean amplitudes for overall frequency were 0.76 dB at the initial recording, 0.35 dB at 5 minutes, 0.44 dB at 10 minutes, and 0.33 dB at 15 minutes during CAS. The initial suppression value was significantly larger than other suppression values of 5, 10, and 15 minutes (p<0.05). In recordings obtained after CAS, TEOAE amplitude exceeded pre-acoustic amplitudes at 1 kHz, 1.5 kHz, and 2 kHz. CONCLUSIONS: The present results show the existence of the medial efferent acoustic reflex and demonstrate the time course that TEOAE suppressions present initially after CAS, showing fatigue over time. Overshooting of TEOAE was observed in recordings at several frequencies after termination of CAS.

Comparison of various treatment modalities for acute tinnitus.

OBJECTIVES/HYPOTHESIS: Because in most cases the development of tinnitus is triggered by cochlear damage, there exists the opportunity to eliminate tinnitus while the cochlear lesion is still reversible. Therefore, we evaluated the therapeutic effects of various treatment modalities on acute subjective idiopathic tinnitus (SIT) and investigated prognostic factors affecting the treatment outcome. STUDY DESIGN: Prospective, controlled, double-blind trial. METHODS: A total 107 patients who underwent treatment for unilateral SIT that had developed within the previous 3 months completed the study. The patients were randomly assigned into three groups according to the treatment modality: group I (n = 32), alprazolam orally for 3 months; group II (n = 35), as for group I plus four intratympanic dexamethasone (ITD) injections; and group III (n = 40), as for group II plus four intravenous injections of lipo-prostaglandin E(1) . RESULTS: The improvement rate of group II (75.8%) was significantly higher than that of group I (40.3%; P < .05), and there was no significant difference in the improvement rate of group III (50.0%) compared with groups I and II (P > .05). The cure rates of group II (25.8%) and group III (20.0%) were significantly higher than that of group I (9.8%; P < .05). There was a significant correlation between the cure rate and duration of symptoms. CONCLUSIONS: The results of the present study indicate that ITD injection plus alprazolam medication is the best treatment choice for acute SIT within 3 months of development.

Energy-efficient human body communication receiver chipset using wideband signaling scheme.

This paper presents an energy-efficient wideband signaling receiver for communication channels using the human body as a data transmission medium. The wideband signaling scheme with the direct-coupled interface provides the energy-efficient transmission of multimedia data around the human body. The wideband signaling receiver incorporates with a receiver AFE exploiting wideband symmetric triggering technique and an all-digital CDR circuit with quadratic sampling technique. The AFE operates at 10-Mb/s data rate with input sensitivity of -27dBm and the operational bandwidth of 200-MHz. The CDR recovers clock and data of 2-Mb/s at a bit error rate of 10(-7). The receiver chipset consumes only 5-mW from a 1-V supply, thereby achieving the bit energy of 2.5-nJ/bit.

The reference ear modeling method for internally feedback controlled digital hearing aid chip.

A reference ear modeling method for the real-time feedback controlled digital hearing aid chip is proposed and implemented. In order to reduce the modeling complexity and enhance the programmability, new ear modeling method using the acoustic filter theory is adopted to the digital hearing aid. To achieve the fully internal gain fitting and verification system, the responses from the damaged ear and the reference ear model are compared and the new gain parameters are processed for the multi-channel DSP. The digital hearing aid chip with reference ear model is fabricated in 0.18 microm CMOS technology, has a core area of 3.1 mm x 1.2 mm and dissipates less than 120 muA.