Age-related primary cochlear neuronal degeneration in human temporal bones

Chadi A. Makary, Jennifer Shin, Sharon G. Kujawa, M. Charles Liberman, Saumil N. Merchant

Research output: Contribution to journalArticlepeer-review

281 Scopus citations


In cases of acquired sensorineural hearing loss, death of cochlear neurons is thought to arise largely as a result of sensory-cell loss. However, recent studies of acoustic overexposure report massive degeneration of the cochlear nerve despite complete hair cell survival (Kujawa and Liberman, J Neurosci 29:14077-14085, 2009). To assess the primary loss of spiral ganglion cells (SGCs) in human ears, neuronal counts were performed in 100 temporal bones from 100 individuals, aged newborn to 100 years, selected to include only cases with a normal population of inner and outer hair cells. Ganglion cell counts declined at a mean rate of 100 cells per year of life. There were no significant gender or inter-aural differences, and a slight increase in degeneration in the basal turn re upper turns was not statistically significant. The agerelated decline in SGCs was significantly less than that in prior studies that included ears with hair cell loss (Otte et al., Laryngoscope 88:1231-1246, 1978), but significantly more than for analogous data on vestibular ganglion cells in cases without vestibular hair cell loss (Velazquez-Villasenor et al., Ann Otol Rhinol Laryngol Suppl 181:14-19, 2000). The age-related decline in SGC counts may contribute to the wellknown decline in hearing-in-noise performance, and the data will help in interpretation of histopathological findings from temporal bones with known otologic disease.

Original languageEnglish (US)
Pages (from-to)711-717
Number of pages7
JournalJARO - Journal of the Association for Research in Otolaryngology
Issue number6
StatePublished - Dec 2011
Externally publishedYes


  • Cochlear neurons
  • Histopathology
  • Otopathology
  • Spiral ganglion

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Sensory Systems


Dive into the research topics of 'Age-related primary cochlear neuronal degeneration in human temporal bones'. Together they form a unique fingerprint.

Cite this