Normalization of auditory evoked potential and visual evoked potential in patients with idiot savant

Objective To investigate the variations of auditory evoked potentials (AEP) and visual evoked potentials (VEP) of patients with idiot savant (IS) syndrome. Methods Both AEP and VEP were recorded from 7 patients with IS syndrome, 21 mentally retarded (MR) children without the syndrome and 21 normally age matched controls, using a Dantec concerto SEEG 16 BEAM instrument. Results Both AEP and VEP of MR group showed significantly longer latencies (P1 and P2 latencies of AEP, P<0.01; N1 and N2 latencies of VEP, P< 0.01/0.05), lower P2 amplitudes (P<0.01) and higher P3 amplitudes (P<0.01), as compared with normal controls. But none of above mentioned changes was found with IS group. Almost all MR patients (90.1%) presented P4 component in both AEP and VEP, which was also in sharp contrast with its incidence in other 2 groups (IS: 14.3%; normal controls: 9.5%). Conclusion Patients with idiot savant syndrome presented normalized AEP and VEP.