title: Pseudohypacusis in childhood and adolescence is associated with increased gray matter volume in the medial frontal gyrus and superior temporal gyrus.
abstract: Pseudohypacusis is a somatoform disorder characterized by hearing loss with discrepancies between pure-tone audiometry and auditory brainstem response (ABR), but the underlying neuronal mechanisms remain unclear. Using voxel-based morphometry (VBM) with magnetic resonance (MR) imaging for 14 unmedicated, right-handed patients and 35 healthy control subjects, we investigated whether functional hearing loss was associated with discernible changes of brain morphology. Group differences in gray matter volume (GMV) were assessed using high-resolution, T1-weighted, volumetric MR imaging datasets (3T Trio scanner; Siemens AG) and analyzed with covariant factors of age, sex, socioeconomic status (SES), and total GMV, which was increased by 27.9% in the left medial frontal gyrus (MFG) (Brodmann area 10) (p=.001, corrected cluster level) and by 14.4% in the right superior temporal gyrus (STG) and the adjacent middle temporal gyrus (MTG) (BA42 to 21) (p=.009, corrected cluster level) in patients with pseudohypacusis. The GMV in the right STG (BA42) and verbal intelligence quotient (IQ) were correlated significantly with the Wechsler Intelligence Scale for Children - Third Edition (WISC-III) (ß=-.57, p<.0001) and level of SES (ß=-.55, p<.0001). The present findings suggest that the development of the auditory association cortex involved in language processing is affected, causing insufficient pruning during brain development. We therefore assert that differences in the neuroanatomical substrate of pseudohypacusis subjects result from a developmental disorder in auditory processing.
authors.affiliation: Department of Child Development, Faculty of Life Sciences, Kumamoto University, Japan. tomo@kumamoto-u.ac.jp
authors.forename: Akemi
authors.initials: A
authors.lastname: Tomoda
authors.forename: Sumihito
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Yuki
authors.initials: Y
authors.lastname: Korenaga
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Mabe
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000374:Aggression / Q000502:physiology; D001288:Attention / Q000502:physiology; D001301:Audiometry, Pure-Tone; D002648:Child; D016000:Cluster Analysis; D003071:Cognition / Q000502:physiology; D003863:Depression / Q000523:psychology; D004644:Emotions / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006311:Hearing Disorders / Q000209:etiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012959:Socioeconomic Factors; D013001:Somatoform Disorders / Q000473:pathology* / Q000523:psychology; D013702:Temporal Lobe / Q000473:pathology*