Alucinações visuais, discinesias e sintomas depressivos na doença de parkinson : um estudo de ressonância magnética e morfologia baseada em voxel

Abstract

Patients with Parkinson’s disease (PD) were clinically examined and specific symptoms related to sleep - walking cycle, visual hallucinati ons, dyskinesias, depressive symptoms were studied. Cerebral changes were evaluated using morphometric analysis voxel - by - voxel obtained by Magnetic Resonance Imaging (MRI). PD patients (N = 100, 67% male), aged from 45 to 80 years were evaluated regarding sleep disorders (Parkinson's Disease Sleep Scale, PDSS), sleep quality (Pittsburgh Sleep Quality Index, PSQI), level of daytime sleepiness (Epworth sleepiness Scale ESS) and the severity of symptoms (Unified Parkinson's Disease Scale UPDRS part I, II, III and IV). Depressive symptoms were assessed using the Beck Depression Inventory (BDI) and Hospital Anxiety Depression (HAD); cognitive function was evaluated with the MiniMental State Examination - Folstein (MMSE). The equivalent dose of levodopa was estimate d. Visual hallucinations (VHs) were observed in 28% of patients and there were no differences in gender, age, age of onset and disease duration. Vivid dreams were more common in patients with VHs. Patients with VHs showed more impairme nt of mental function s (UPDRS I ), more sleep disturbances (PDSS) and worse sleep quality (PSQI). The logistic regression analysis showed that the presence of vivid dreams and the degree of mental dysfunction were independently associated with VHs. The analysis between groups w ith and without dyskinesia showed that patients with dyskinesia were younger at onset of symptoms. PD patients with dyskinesia tended to have greater impairment of activities of daily living (UPDRS II), and motor activity (UPDRS III). Patients with depress ive symptoms tended to be worse in the activities of daily living (UPDRS II), and motor activity (UPDRS III) as compared to those without depressive symptoms. In the second phase of the study, the morphometric analysis was performed using MRI study in PD p atients (N=39) and controls (N=10). Cerebral changes were investigated regarding the presence of VHs, dyskinesia and depressive symptoms. Morphometric analysis voxel by voxel was obtained by MRI studies. The outcome variable used was the volume of gray mat ter. When compared to controls, PD patients without VHs showed a reduction in gray matter volume in the left superior frontal gyrus and left opercular frontal gyrus. As compared to PD patients without VHs, PD patients with VHs showed a reduction in gray ma tter volume in the left superior frontal gyrus. As for the presence/absence of cognitive dysfunction, patients with VHs and cognitive impairment had reduction of gray matter volume in t he left opercular gyrus . Patients with VHs without cognitive dysfunctio n had reduced gray matter in the left 10 insula and left trigonal frontal gyrus . The subgroup of patients with PD with dyskinesias showed a reduction of gray matter in the right pulvinar thalamus. PD patients with depressive symptoms showed a reduction of gra y matter in the medial right frontal gyrus as compared to PD without depression. As compared to controls, PD patients with depressive symptoms showed a reduction of gray matter in the left insula, right insula and left s uperior frontal gyrus . Our results s how that VHs are independently associated with the presence of vivid dreams and mental dysfunction. This study confirms that the operculum is an important site in the brain network for the manifestations of hallucinations and cognitive dysfunction in PD. I t also showed that changes in the posterior thalamus or pulvinar nucleus are associated with the presence of dyskinesias. The right insula and medial frontal gyrus are important sites connected to the presence of depressive symptoms in PD. This study shows that PD patients with VHs, dyskinesias and depressive symptoms have clinical and brain alterations that are specific. These results contribute to a better understanding of the pathogenesis of the disease and can direct therapies to specific targets e.g. t he use of deep brain stimulation.