Presbycusis: A human temporal bone study of individuals with flat audiometric patterns of hearing loss using a new method to quantify stria vascularis volume

Abstract

Objective: The purpose of this study was to determine the prevalence of stria vascularis atrophy in individuals with presbycusis and flat audiometric patterns of hearing loss. Individuals with presbycusis have historically been categorized by the shape of their audiograms, and flat audiometric thresholds have been reported t o be associated with atrophy of the stria vascularis. Stria vascularis volume was not measured in these studies. Study Design:Retrospective case review. Methods: Archival human temporal bones from individuals with presbycusis were selected on the basis of strict audiometric criteria for flat audiometric thresholds. Six temporal bones that met these criteria were identified and compared with 10 temporal bones in individuals with normal hearing. A unique quantitative method was developed to measure the stria vascularis volume in these temporal bones. The hair cell and spiral ganglion cell populations also were quantitatively evaluated. Results: Only one of the six individuals with presbycusis and flat audiometric thresholds had significant atrophy of the stria vascularis. This individual with stria vascularis atrophy also had reduced inner hair cell, outer hair cell, and ganglion cell populations. Three of the individuals with presbycusis had spiral ganglion cell loss, three individuals had inner hair cell loss, and all six individuals had outer hair cell loss. Concluclions: The results of this investigation suggest that individuals with presbycusis and flat audiometric patterns of hearing loss infrequently have stria vascularis atrophy. Outer hair cell loss alone or

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Audiometric pattern as a predictor of cardiovascular status: Development of a model for assessment of risk

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“…This pattern is histologically correlated with degeneration within the stria vascularis, although reports are variable. 11,12 As described below, strial hearing loss reflects a reduced endocochlear potential, but with an intact sensory system. As such, word discrimination is commonly better than expected for the threshold of hearing.…”

Absence of strial melanin coincides with age-associated marginal cell loss and endocochlear potential decline

“…Human temporal bone studies have applied measures of strial thickness, volume, or area to quantify age-related strial changes, and the probable contribution of strial pathology to hearing loss (Kusunoki et al, 2004;Nelson and Hinojosa, 2003;Pauler et al, 1988;Suzuki et al, 2006). We have argued that without EP recordings these measures may over diagnose strial presbycusis (Ohlemiller, 2006).…”