[Neurophysiological correlates of pedophilia: a study of EEG evoked oscillations]

To study the changes of evoked EEG oscillations in response to erotic visual stimuli to identify specific patterns in subjects with different variants of pedophilia.

Forty-eight right-handed male offenders who have committed sexual acts against children participated in the study. Seventeen subjects without paraphilic disorders were included in group 1, 17 subjects with heterosexual pedophilia were included in group 2, and 13 subjects with homosexual pedophilia were included in group 3. The stimuli were colored pictures of neutral, heterosexual normative, hetero- and homosexual pedophilic content shortly demonstrated with backward masking. Spectral power of delta, theta, alpha, and beta evoked oscillations (EO) was analyzed. Further, the number of significant changes of EO power in response to erotic stimuli relative to neutral ones was calculated, and topography changes of EO power in response to specific erotic pictures compared to neutral ones were analyzed for each group.

The diminished number of significant reactions to specific stimuli was found in the pedophilia groups (18 and 4 in groups 2 and 3, respectively) in comparison with the group without paraphilia (25). The specific changes of EO power in response to specific erotic visual pictures were found for each group. Increased power of delta, theta and alpha EO in the 104-164 ms time window, and decreased power of alpha EO in the 344-920 ms time window were found in group 1. In group 2, specific stimulation elicited decline of delta and theta EO power, possibly related to impaired motivational and emotional aspects of erotic stimuli perception. The weak changes were found in group 3 - increased power of beta EO in the frontal area.

The obtained frequency and spatial patterns of EO changes in response to erotic visual pictures are related to specificity of hetero- and homosexual pedophilia.