Examination of the Flynn effect in German patients with epilepsy assessed with the Wechsler Adult Intelligence Scale (WAIS) III and IV

The Flynn effect describes an increase in intelligence quotient (IQ) in the general population of about 3 points per decade. While this effect is well established in healthy individuals, research exploring the link to brain pathologies is scarce. We investigated the Flynn effect in a German sample of 203 patients with epilepsy with left, right, and bilateral lesions. Intelligence quotient values were obtained using the Wechsler Adult Intelligence Scales (WAIS) III and IV. Our results showed a stable Flynn effect with nearly no difference in adjusted full scale IQ (FSIQ) scores (0.02 IQ points) between the WAIS-III and WAIS-IV samples. There were no significant interactions between the side of pathology and corrected IQ values. Our sample showed a tendency towards performing worse in the WAIS-IV in three out of four subscales independently of the Flynn effect, pointing out methodological differences between the newer Wechsler editions. However, although patients with bilateral lesions performed worst across all subscales, they exhibited a similar pattern as patients with lesions in the left or right hemisphere, indicating that also more severe forms of brain pathologies can profit from the mechanisms behind the Flynn effect.