PARKINSONS-DISEASE AND DEPRESSION - EVIDENCE FOR AN ALTERATION OF THEBASAL LIMBIC SYSTEM DETECTED BY TRANSCRANIAL SONOGRAPHY

Objectives-Depression is a frequent symptom in Parkinson's disease. Co mpelling evidence suggests a role of the brainstem in the control of m ood and cognition. In patients with unipolar depression transcranial s onography (TS) studies have shown structural alteration of the mesence phalic brainstem raphe which could suggest an involvement of the basal limbic system in the pathogenesis of primary mood disorders. The obje ctive of the present study was to evaluate whether a similar alteratio n could be found in depressed patients with Parkinson's disease using TS. Methods-Thirty patients with Parkinson's disease and 30 age and se x adjusted controls were examined by TS. Raphe echogenicity was rated semiquantitatively. The severity of motor symptoms and depression was rated using standard research instruments. Results-Raphe echogenicity was significantly reduced in depressed patients with Parkinson's disea se compared with nondepressed patients with Parkinson's disease and ec hogenicity correlated negatively with degree of motor impairment, and differences in raphe echo between depressed and non-depressed patients with Parkinson's disease were upheld when motor impairment was contro lled for. Conclusion-These preliminary findings suggest that, as in un ipolar depression, a morphological alteration of the brainstem raphe m ight be involved in the pathogenesis of depression in Parkinson's dise ase. This raphe alteration may reflect involvement in the basal limbic system in the pathogenesis of secondary depression. This concept is i n line with current knowledge on the pathogenesis of both depression i n Parkinson's disease and primary depressive disorders.