Cochlear implantation for hearing loss due to an A8296G mitochondrial DNA mutation

Objective: To characterize the clinical findings in a patient with hearing loss harboring an A8296G mitochondrial DNA mutation and the outcome of cochlear implantation. Patients: A case report of a patient with hearing loss caused by an A8296G mitochondrial DNA mutation. Intervention: The patient underwent cochlear implantation (CI).Main outcome and results: Bilateral moderate to severe hearing loss was found at high school age and progressed to severe hearing loss bilaterally at the age of 22. The patient's low-tone hearing was relatively well preserved compared to high frequency, although it eventually declined. Speech perception in silence and at S/N10 improved to 100% and 92% for sentences, respectively, 3 years after CI. Conclusions: We detailed the case of a patient with hearing loss due to an A8296G mitochondrial DNA mutation. Bilateral progressive hearing loss starting from high frequency was observed. Speech discrimination after CI was very good, indicating that a patient with this mutation is a good candidate for CI. Keywords: Mitochondrial DNA mutation, Hearing loss, Cochlear implantatio

Cochlear Implantation in Patients with Mitochondrial Gene Mutation: Decline in Speech Perception in Retrospective Long-Term Follow-Up Study

Clinical evidence of the effectiveness of cochlear implantation for hearing loss with mitochondrial DNA mutation is limited. Most reports have only described short-term postoperative speech perception, which may not reflect the limitations of cochlear implantation caused by progressive retrocochlear dysfunction. The present study aimed to investigate long-term speech perception after cochlear implantation in patients with severe to profound hearing loss associated with mitochondrial DNA mutation. A retrospective chart review was performed on patients with mitochondrial DNA mutation who had undergone cochlear implantation at the Department of Otolaryngology and Head and Neck Surgery at the University of Tokyo Hospital. We extracted data on causative mutations, clinical types, clinical course, perioperative complications, and short-term and long-term postoperative speech perception. Nine patients with mitochondrial DNA mutation underwent cochlear implantation. The mean observation period was 5.5 ± 4.2 years (range, 1–13 years), and seven patients were followed for more than 3 years. Two of the seven patients who initially showed good speech perception exhibited deterioration during long-term follow-up. The absence of an acute progression of cognitive decline in patients, showing a gradual decrease in speech perception, suggests that the deterioration of speech perception was caused by progressive retrocochlear degeneration. Although most patients with mitochondrial DNA mutation maintained good speech perception for more than 3 years after cochlear implantation, retrocochlear degeneration could cause the deterioration of speech perception during long-term follow-up

17.4 Hierarchical Power Distribution and Power Management Scheme for a Single Chip Mobile Processor

A hierarchical power distribution methodology that enables more than dozen power domains in a chip and a power management scheme using 20 power domains are described. This method can achieve very low leakage current in the partial active mode of a single chip mobile processor. The single chip mobile processor embedded three CPU’s that is baseband processor, application processor, and multi-media processor. In the “waiting for calling” mode of the mobile handsets, application processor and multimedia processor part can be power-off. This chip can power off these power domains although the some of baseband parts are actively operating.. Many new techniques for multiple power domains in the chip are described