Dayong Wang1, Binbin Xiong2,3, Fen Xiong1,2, Guang-Di Chen2, Bo Hua Hu2, Wei Sun2. 1. a Department of Otolaryngology , Chinese PLA General Hospital , Beijing , PR China. 2. b Center for Hearing & Deafness, Department of Communicative Disorders and Science , State University of New York at Buffalo , Buffalo , NY , USA. 3. c Department of Otolaryngology , Zhuhai Hospital Affiliated with Jinan University , Guangdong , PR China.
Abstract
CONCLUSION: This study indicates that the lesion of hair cells in the apical turn of the cochlea can cause the change in the summating potential (SP)/Compound potential (CAP) ratio. OBJECTIVES: Electrocochleography is a valuable clinic test for diagnosis of cochlear pathologies and the ratio of SP to CAP has been used to identify Meniere's disease. However, it remains controversial whether the increase of the SP/CAP ratio represents exclusively the endolymphatic hydrops. METHOD: This study measured the SP and CAP in mice that displayed outer hair cell (OHC) degeneration in the apical section of the cochlea as their age increased. RESULTS: As compared with the mice aged 8-10 months, the 24-month old mice displayed a significant increase in the amplitude of SP at 12-16 kHz. This result suggests that the degeneration of OHCs in the apical turn leads to the increase of the + SP at the middle frequencies. In contrast, the aging mice did not have a significant change in the CAP amplitude at super-threshold levels.
CONCLUSION: This study indicates that the lesion of hair cells in the apical turn of the cochlea can cause the change in the summating potential (SP)/Compound potential (CAP) ratio. OBJECTIVES: Electrocochleography is a valuable clinic test for diagnosis of cochlear pathologies and the ratio of SP to CAP has been used to identify Meniere's disease. However, it remains controversial whether the increase of the SP/CAP ratio represents exclusively the endolymphatic hydrops. METHOD: This study measured the SP and CAP in mice that displayed outer hair cell (OHC) degeneration in the apical section of the cochlea as their age increased. RESULTS: As compared with the mice aged 8-10 months, the 24-month old mice displayed a significant increase in the amplitude of SP at 12-16 kHz. This result suggests that the degeneration of OHCs in the apical turn leads to the increase of the + SP at the middle frequencies. In contrast, the aging mice did not have a significant change in the CAP amplitude at super-threshold levels.