Metabolic changes in the auditory cortex in presbycusis demonstrated by MR spectroscopy

• Published in: Experimental gerontology Vol. 48; no. 8; pp. 795 - 800
• Main Authors: Profant, Oliver, Balogová, Zuzana, Dezortová, Monika, Wagnerová, Dita, Hájek, Milan, Syka, Josef
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.08.2013
• Subjects: Adult; Aged; Aging - metabolism; Aspartic Acid - analogs & derivatives; Aspartic Acid - metabolism; Audiometry, Pure-Tone; Auditory cortex; Auditory Cortex - metabolism; Case-Control Studies; Female; GABA; Glutamate; Glutamates - metabolism; Humans; Lactate; Lactates - metabolism; Magnetic Resonance Spectroscopy; Male; MR spectroscopy; N-acetylaspartate; Presbycusis; Presbycusis - metabolism; VOI; MP; Lactate; GABA; YC; EP; Glutamate; Presbycusis; Auditory cortex; N-acetylaspartate; NAA; MR spectroscopy; elderly subjects with mild presbycusis; young subjects with physiologic hearing; elderly subjects with expressed presbycusis; volume of interest
• ISSN: 0531-5565; 1873-6815; 1873-6815
• DOI: 10.1016/j.exger.2013.04.012

In humans, aging is accompanied by the deterioration of the hearing function — presbycusis. The major etiology for presbycusis is the loss of hair cells in the inner ear; less well known are changes in the central auditory system. Therefore, we used 1H magnetic resonance spectroscopy at 3T tomograph to examine metabolite levels in the auditory cortex of three groups of subjects: young healthy subjects less than 30years old and subjects older than 65years either with mild presbycusis corresponding to their age or with expressed presbycusis. Hearing function in all subjects was examined by pure tone audiometry (125–16000Hz). Significant differences were found in the concentrations of glutamate and N-acetylaspartate, with lower levels in aged subjects. Lactate was particularly increased in subjects with expressed presbycusis. Significant differences were not found in other metabolites, including GABA, between young and elderly subjects. The results demonstrate that the age-related changes of the inner ear are accompanied by a decrease in the excitatory neurotransmitter glutamate as well as a lactate increase in the auditory cortex that is more expressed in elderly subjects with large hearing threshold shifts. •MRS demonstrated age-related changes of metabolite levels in the human AC.•Significant decreases of glutamate and N-acetylaspartate was found in the elderly.•Lactate levels changed significantly according to degree of presbyacusis.•GABA concentration did not change in the AC of the elderly.