Neuropsychological profiles of adults with Klinefelter syndrome

Children and adolescents with Klinefelter syndrome (XXY) have been reported to show deficits in language processing including VIQ < PIQ and a learning disability in reading and spelling. However, whether this is characteristi c of adults with Klinefelter syndrome has not been established. Thirty-five men with Klinefelter syndrome, aged 16 to 61, and 22 controls were evaluat ed with a comprehensive neuropsychological battery. The Klinefelter patient s scored significantly below controls in language skills, verbal processing speed, verbal and nonverbal executive abilities, and motor dexterity. With in the Klinefelter sample, three cognitive subgroups were identified: VIQ 7 or more points below PIQ (n = 10), VIQ within 6 points of PIQ (, = 12), an d PIQ 7 or more points below VIQ (n = 12). The deficits detected in languag e, verbal processing speed, and verbal executive skills were found to be is olated to the VIQ < PIQ subgroup, while the abnormalities in motor dexterit y and nonverbal executive skills were confined to the PIQ < VIQ subgroup. O lder age was significantly correlated with increases in VIQ relative to PIQ in the patient group, which suggests the intriguing possibility that the P IQ < VIQ subgroup primarily emerges in young adulthood, perhaps in response to the reported hormonal abnormalities detected in Klinefelter syndrome pa tients during puberty.