OBJECTIVES: The present study was undertaken in order to verify the hypothesis stating that patients with depression exhibit some abnormalities concerning a cerebral symmetry. For this purpose, an analysis of the relationship between the VEPs (Visual Evoked Potentials) results and the depressive symptoms intensification, as well interrelation between depressive and diabetic symptoms were performed.
MATERIAL AND METHODS: VEPs recordings were obtained from the two study groups (both aged 20-45 years), 20 healthy subjects and 32 diabetic patients with clinically documented depression. The VEPs examination was carried out using a computer system called STELLA (Stimulated Electroencephalogram on Line Analyzer).
RESULTS: VEPs examinations revealed a cerebral symmetry in the all control subjects and in 10 out of 32 diabetic patients with depressive disorders. It is noteworthy that 22 of 32 diabetic patients (68.8%) showed a hemispheric asymmetry in the VEPs recordings. Of 12 patients with a moderate depression, 10 showed the left cerebral laterality, and 2--the right laterality. In turn, all 10 patients with major depressive disorder (MDD) demonstrated in the VEPs recordings a significant cerebral laterality with the right hemisphere dominance.
CONCLUSIONS: The obtained results suggest that interhemispheric cerebral asymmetry might be considered a specific feature of depression, and, if this is a case, it could justify a conclusion that right hemisphere dominance could be a neurophysiological marker of MDD. It should be emphasized that intensification of the depressive symptoms has an unfavorable influence on course of diabetes mellitus, its self-control and severity of following complications.