Functional magnetic resonance imaging (fMRI) was used to study language lateralization in 15 self-referred right-handed 47,XXY adult males (average age 36.9, SD 11.8; mean IQ 94.5, 95% CI 86.9 to 102.1) and 14 controls matched on age, handedness, and years of education (average age 35.5, SD 9.5, IQ not provided) [van Rijn et al., 2008]. Fourteen of the 47,XXY males were on testosterone supplementation (mean age of testosterone initiation 23.9, SD 7.1 years). Although none of the subjects met the criteria for a psychiatric disorder, an earlier analysis of a larger group of which the subjects in the present study was a subset had found higher scores on measures sensitive to schizophrenia-spectrum pathology [van Rijn et al., 2006]. The investigators therefore also explored the relationship of brain activation to scores on the Schizotypal Personality Questionnaire (SPQ) [Raine, 1991] and the Positive and Negative Symptoms Scale (PANSS) [Kay et al., 1987].
