||Metabolic presbycusis is the term applied to one of the common patterns of sensorineural hearing loss that occurs in the later decades of life.
The characteristic audiometric findings consist of a relatively flat audiometric pattern, with excellent speech discrimination scores. The progression of the hearing loss is relatively slow, and usually does not reach the stage of profound deafness.
The common pathologic finding is the scattered areas of atrophy of the stria vascularis in the apical half of the cochlea. The strial atrophy does not appear to be associated with any other degenerative changes within the inner ear.
This type of presbycusis has been called metabolic presbycusis since it appears that the atrophy of the stria vascularis alters the bioelectrical, biochemical, and energy-producing properties of the entire scala media, thereby accounting for the uniform loss of sensitivity at all frequencies.
The excess osteoid formation at the lamina spiralis foraminosa that is sometimes seen may be an additional contributing factor in presbycusis. It has been suggested that this osteoid overgrows the bony channels and chokes off the afferent neural processes that travel toward the brain stem nuclei.