Language processing of auditory cortex revealed by functional magnetic resonance imaging in presbycusis patients.

CONCLUSION

Contralateral temporal lobe activation decreases with aging, regardless of hearing status, with elderly individuals showing reduced right ear advantage.

BACKGROUND

Aging and hearing loss possibly lead to presbycusis speech discrimination decline.

OBJECTIVES

To evaluate presbycusis patients' auditory cortex activation under verbal stimulation.

METHOD: Thirty-six patients were enrolled: 10 presbycusis patients (mean age = 64 years, range = 60-70), 10 in the healthy aged group (mean age = 66 years, range = 60-70), and 16 young healthy volunteers (mean age = 25 years, range = 23-28). These three groups underwent simultaneous 1 kHz and 90 dB single-syllable word stimuli and (blood-oxygen-level-dependent functional magnetic resonance imaging) BOLD fMRI examinations.

RESULTS

The main activation regions were superior temporal and middle temporal gyrus. For all aged subjects, the right region of interest (ROI) activation volume was decreased compared with the young group. With left ear stimulation, bilateral ROI activation intensity held. With right ear stimulation, the aged group's activation intensity was higher. Using monaural stimulation in the young group, contralateral temporal lobe activation volume and intensity were higher vs ipsilateral, while they were lower in the aged and presbycusis groups. On left and right ear auditory tasks, the young group showed right ear advantage, while the aged and presbycusis groups showed reduced right ear advantage.