Alterações do sono, alteração cognitiva e avaliação de estruturas cerebrais através de ressonância magnética e morfometria baseada em voxel na doença de Parkinson

Abstract

The present study evaluates clinical abnormalities, sleep disturbances, cognitive alterations and structural brain changes using Magnetic Resonance Imaging (MRI) with Voxel Based Morphometry (VBM) in patients with Parkinson`s Disease (PD). In the first phase of the study one hundred patients (71% male), aged between 40 and 80 years (66,1+9,5) were studied. Patients were recruited from a movement disorders clinics at Walter Cantídio University Hospital. The study is part of a larger longitudinal cohort study (Sleep-For-PD study). Sleep abnormalities and their associated and predictive factors were scrutinized. Many clinical questionnaires were used, including the Parkinson`s Disease Sleep Scale (PDSS), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and the Unified Parkinson’s Disease Rating Scale (UPDRS part I, II, III e IV). Depressive symptoms were evaluated with Beck Depression Inventory (IDB-II) and Hospital Anxiety Depression scale (HAD). The Minimental state examination (Folstein) (MMSE) evaluated the extent of cognitive dysfunction. REM sleep symptoms were evaluated by the REM Sleep Behavior Disorder (RBD) Scale. The levodopa equivalent dose was evaluated (DEL). Patients with sleep abnormalities (PDSS) had more diurnal visual hallucinations, cognitive dysfunction, anxiety, depression and worse parkinsonian symptoms (p<0.05). Patients with worse sleep quality (PSQI) had more depressive symptoms. PDSS scores were correlated with cognitive function (MEEM), depressive symptoms (BDI and HAD), sleep quality (PSQI), severity of PD and the RBD scale. PSQI scores were correlated with MMSE scores, activity of daily living symptoms (UPDRS II) and depression / anxiety (BDI e HAD). Activities of daily living (p=0.002), depressive symptoms (p=0.01) and anxiety (p=0.01) were independent predictors of sleep abnormalities (PDSS). The levodopa equivalent dose and MMSE scores were independent predictors of worse sleep quality (p=0.02). The RBD scale (p=0.002) and UPDRS I (p=0.02) were independent predictors of somnolence. We conclude that sleep disorders, disturbed sleep quality and excessive diurnal somnolence are common in PD. The PDSS, PSQI and ESS scales have distinct associated and predictive factors. PDSS scale is associated with a greater number of factors in PD patients. In the second phase of the study thirty-nine PD patients and ten control subjects were evaluated with regard to the presence of cognitive alterations. Structural brain abnormalities were also evaluated with MRI and VBM technique. The Gray matter volume was used as the ending variable. PD patients had more cognitive impairment and more anxiety. Patients with PD and cognitive alterations had worse disease severity. We found no difference in the volume of gray matter between the subgroups of PD patients with and without cognitive alterations, probably due to early brain atrophy in the patients without cognitive abnormalities. A significant reduction in gray matter volume in the left insula and left prefrontal cortex was observed when comparing PD patients in relation to controls. These findings indicate an asymmetrical brain involvement in PD, the left hemisphere being more affected.