ABSTRACT

Depressive disorders have increasing prevalence in countries in development stage in population that suffer a high level of stress (8% of the chilean population [ Minoletti, A.,Vicente,B., personal communication]). We have correlated clinical manifestations of Major Depressive disorder (DSM- 4) and NeuroSPECT findings both in basal conditions and during frontal activation by means of the Wisconsin Test. NeuroSPECT was performed in 50 patients with Major Depression; 23 in basal conditions and 27 during frontal lobe activation induced by the Winconsin Test. NeuroSPECT was displayed as tridimensional images normalized for volume and compared with an age matched normal database. Furthermore, there was exact localization of functional impairment by means of a template of the Brodmann areas that have a behavioral expression. All this image processing is performed automatically and therefore is highly reproducible. In basal NeuroSPECT there is significant hypoperfusion with a statistical certainty of 95% (two standard deviations below the normal HMPAO Tc-99m uptake) in the following regions: a) orbito-frontal region corresponding to the Brodmann areas 11 and 12, b) there is hypoperfusion also in the Brodmann area 38 in both temporal lobes. During frontal activation by means of the Wisonsin Test, there is a significant extension of hypoperfusion in the orbito-frontal area of Brodmann 12, there is also further extension of hypoperfusion in the right area 38 and in both anterior cyngulate gyri, area 24 of Brodmann. Finally, in the subgenual area of the anterior cyngulate, area 25 left, there is hypoperfusion also with high statistical significance. Areas 11 and 12 of Brodmann in the orbito-frontal region are constituents of the frontal/ subcortical circuit related to mood and personality. The area 38 of Brodmann corresponds to the polar area of the temporal lobes and is related with emotional cognitive correlations. A significant observation in Major Depressive patients is a fact that the Wisconsin Test paradoxically does not activate frontal function, but it depresses in a similar manner than the reported for schizophrenia, denoting a diminution of executive function at a high logical level in depressive patients. Equally important is the inhibition of function of both anterior cyngulate gyri and its subgenual area in the left hemisphere (areas 24 and 25) that are involved with lack of motivation and abscence of reward-punishment behavioral characteristics of depression. The definition of these aspects of depression by means of NeuroSPECT are useful in order to define the severity of the clinical presentation of Major Depression and useful also for the selection of therapy for this major psychiatric condition.

Keywords: Depression, SPECT, HMPAO, Wisconsin Test, Activation.