Depressive symptoms and changes in regional cerebral glucose metabolism in patients with MSA and PSP

Objectives: To study the association between depressive symptoms and changes in regional cerebral glucose metabolism in patients with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP).

Subjects and Methods: Eleven consecutive patients with MSA (MSA-P subtype: 8 patients, MSA-C subtype: 3 patients) and 9 patients with PSP entered the study. The control group (n=25) was recruited in two German centers participating in a prospective multicenter European study as part of the European Network for Efficiency and Standardisation of Dementia Diagnosis. Patients were screened by a psychiatrist for the diagnostic criteria of a major depressive episode (DSM-IV). The severity of depressive symptoms was assessed using the Hamilton Depression Rating Scale (21 item version; score >7 points) and the Beck Depression Inventory (score >12 points). Regional metabolic changes were measured using positron emission tomography with [18F]fluorodeoxyglucose. Data analysis was performed using statistical parametric mapping (SPM99) comparing the patient groups with and without depressive symptoms and normal controls. Between group comparison (with and without depression) was restricted to frontal cortical areas based on the hypothesis that affective symptoms reflect a fronto-striatal dysfunction.

Results: MSA patients revealed significant metabolic decreases in bilateral frontal and parietal cortex when compared to age-matched controls (corrected p<0.001) and patients with depressive symptoms (6/11) differed from depression-free patients in prefrontal metabolism (uncorrected p<0.01). In PSP patients decreased metabolism was observed in right thalamus, putamen and bilateral prefrontal cortex when compared to age-matched controls (corrected p<0.001). PSP patients with depressive symptoms (5/9) revealed significant prefrontal hypometabolism when compared to patients without depression (uncorrected p≤0.01).

Conclusion: These findings support the hypothesis that depressive symptoms in PSP and MSA are associated with fronto-striatal dysfunction.