title: PET evidence of neuroplasticity in adult auditory cortex of postlingual deafness.
abstract: Controversy regarding functional reorganization in the adult brain remains. To investigate whether neuroplasticity is present in adults with postlingual deafness, we examined the pattern of cerebral glucose metabolism on (18)F-FDG brain PET images of postlingually deaf patients by comparing the auditory cortical activation pattern with those of age- and sex-matched healthy control subjects. We also correlated the cerebral glucose metabolism in deaf patients with the duration of deafness using statistical parametric mapping.
  
  
  METHODS
  In the resting state (eye closed, ears unoccluded in a dark and quiet environment), (18)F-FDG brain PET scans were performed on 9 postlingually deaf patients and 9 age- and sex-matched healthy volunteers. Significant increases and decreases of regional cerebral metabolism in the patient group were estimated by comparing their PET images with those of the healthy volunteers using t statistics at every voxel. To reveal regions in which metabolism was significantly correlated with the duration of deafness, the general linear model with the duration of deafness as a covariate was tested at each voxel.
  
  
  RESULTS
  When we compared (18)F-FDG brain PET images of postlingually deaf patients with those of age- and sex-matched healthy control subjects by performing a t test at every voxel, the glucose metabolism of deaf patients was significantly (P < 0.001) lower than that of the control subjects in both anterior cingulate gyri (Brodmann area 24 [BA24]) and superior temporal cortices (BA41, BA42) and in the right parahippocampal gyrus. No area showed a significant increase of metabolism in deaf patients with the same threshold. When we correlated glucose metabolism of deaf patients with the duration of deafness after total deprivation of hearing capability using a general linear model with the duration of deafness as a covariate at every voxel, metabolism in both anterior cingulate gyri (BA24) and superior temporal cortices (BA41, BA42) showed a significant (P < 0.005) positive correlation with the duration of deafness.
  
  
  CONCLUSIONS
  This study suggests that plasticity is present in adult brains of postlingually deaf patients. In the mature brain, auditory deprivation decreased neuronal activity transiently in primary auditory and auditory-related cortices, and, over time, functional reorganization likely takes place in the auditory cortex. Plasticity was prominent in superior temporal and anterior cingulate gyri in the sensory-deprived mature brain and militated against postimplantation improvement in patients with cochlear implants.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Lee
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.forename: Seung Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Chong Sun
authors.initials: CS
authors.lastname: Kim
authors.forename: Jeong-Whun
authors.initials: JW
authors.lastname: Kim
authors.forename: Chan Ho
authors.initials: CH
authors.lastname: Hwang
authors.forename: Jawon
authors.initials: J
authors.lastname: Koo
authors.forename: Eunjoo
authors.initials: E
authors.lastname: Kang
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000000981:diagnostic imaging* / Q000378:metabolism*; D001931:Brain Mapping / Q000379:methods; D003054:Cochlear Implants; D003638:Deafness / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012016:Reference Values; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose