title: Diffusion tensor imaging and MR morphometry of the central auditory pathway and auditory cortex in aging.
abstract: Age-related hearing loss (presbycusis) is caused mainly by the hypofunction of the inner ear, but recent findings point also toward a central component of presbycusis. We used MR morphometry and diffusion tensor imaging (DTI) with a 3T MR system with the aim to study the state of the central auditory system in a group of elderly subjects (>65years) with mild presbycusis, in a group of elderly subjects with expressed presbycusis and in young controls. Cortical reconstruction, volumetric segmentation and auditory pathway tractography were performed. Three parameters were evaluated by morphometry: the volume of the gray matter, the surface area of the gyrus and the thickness of the cortex. In all experimental groups the surface area and gray matter volume were larger on the left side in Heschl's gyrus and planum temporale and slightly larger in the gyrus frontalis superior, whereas they were larger on the right side in the primary visual cortex. Almost all of the measured parameters were significantly smaller in the elderly subjects in Heschl's gyrus, planum temporale and gyrus frontalis superior. Aging did not change the side asymmetry (laterality) of the gyri. In the central part of the auditory pathway above the inferior colliculus, a trend toward an effect of aging was present in the axial vector of the diffusion (L1) variable of DTI, with increased values observed in elderly subjects. A trend toward a decrease of L1 on the left side, which was more pronounced in the elderly groups, was observed. The effect of hearing loss was present in subjects with expressed presbycusis as a trend toward an increase of the radial vectors (L2L3) in the white matter under Heschl's gyrus. These results suggest that in addition to peripheral changes, changes in the central part of the auditory system in elderly subjects are also present; however, the extent of hearing loss does not play a significant role in the central changes.
authors: Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Department of Otorhinolaryngology and Head and Neck Surgery, 1st Medical Faculty of Charles University, University Hospital Motol, Prague, Czech Republic. Electronic address: profant@biomed.cas.cz.
authors: O
authors: O
authors: Profant
authors: MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors: A
authors: A
authors: Škoch
authors: Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Department of Otorhinolaryngology and Head and Neck Surgery, 1st Medical Faculty of Charles University, University Hospital Motol, Prague, Czech Republic.
authors: Z
authors: Z
authors: Balogová
authors: MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors: J
authors: J
authors: Tintěra
authors: Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: J
authors: J
authors: Hlinka
authors: Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: J
authors: J
authors: Syka
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology* / Q000502:physiology; D001303:Auditory Cortex / Q000473:pathology*; D001304:Auditory Diseases, Central / Q000473:pathology*; D001306:Auditory Pathways / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011304:Presbycusis / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
keywords: AC; AP; DTI; EP; FA; GFS; GM; HG; Heschl’s gyrus; IC; MD; MP; MR morphometry; PT; ROI; SNHL; V1; WM; WM_HG; YC; aging; auditory cortex; auditory pathway; auditory pathway above IC; diffusion tensor imaging; elderly subjects with expressed presbycusis; elderly subjects with mild presbycusis; fractional anisotropy; gray matter; gyrus frontalis superior; inferior colliculus; mean diffusivity; planum temporale; presbycusis; region of interest; sensorineural hearing loss; visual cortex; white matter; white matter under Heschl’s gyrus; young subjects with physiologic hearing/young controls