Age-associated reduction of asymmetry in human central auditory function: a 1H-magnetic resonance spectroscopy study.
The aim of this study was to investigate the effects of age on hemispheric asymmetry in the auditory cortex after pure tone stimulation. Ten young and 8 older healthy volunteers took part in this study. Two-dimensional multivoxel 1H-magnetic resonance spectroscopy scans were performed before and after stimulation. The ratios of N-acetylaspartate (NAA), glutamate/glutamine (Glx), and γ -amino butyric acid (GABA) to creatine (Cr) were determined and compared between the two groups. The distribution of metabolites between the left and right auditory cortex was also determined. Before stimulation, left and right side NAA/Cr and right side GABA/Cr were significantly lower, whereas right side Glx/Cr was significantly higher in the older group compared with the young group. After stimulation, left and right side NAA/Cr and GABA/Cr were significantly lower, whereas left side Glx/Cr was significantly higher in the older group compared with the young group. There was obvious asymmetry in right side Glx/Cr and left side GABA/Cr after stimulation in young group, but not in older group. In summary, there is marked hemispheric asymmetry in auditory cortical metabolites following pure tone stimulation in young, but not older adults. This reduced asymmetry in older adults may at least in part underlie the speech perception difficulties/presbycusis experienced by aging adults.
Department of Otolaryngology-Head and Neck Surgery, Fuzhou General Hospital of Nanjing Command, PLA, 156 Xihuan Bei Road, Fuzhou 350025, China ; Department of Otolaryngology-Head and Neck Surgery, Dongfang Hospital, Fujian Medical University, Fuzhou 350001, China.
Xianming
X
Chen
Yonghui
Y
Liang
Yihong
Y
Deng
Jianzhong
J
Li
Shiyan
S
Chen
Cuixia
C
Wang
Ping
P
Luo
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001303:Auditory Cortex / Q000378:metabolism*; D001306:Auditory Pathways / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged