Influence of leukoaraiosis on the cognition of patients with Parkinson disease

OBJECTIVE: To explore the role of leukoaraiosis (LA) on the cognitive function in patients with Parkinson disease (PD). METHODS: The cohort for this study included 63 patients with PD, whom were divided into 3 groups according to cognitive status:with intact cognition (PD-IC, n = 23), with mild cognitive impairment (PD-MCI, n = 23) and with dementia (PDD, n = 17). All the patients were recruited from the Department of Neurology, First Affiliated Hospital, Anhui Medical University between September 2011 and July 2012. The cognitive functions were evaluated by mini-metal state examination (MMSE), the Cambridge cognitive examination-Chinese version (CAMCOG-C), clinical dementia rating (CDR), clock drawing task (CDT) and verbal fluency test, etc. Depression symptoms were assessed by the geriatric depression scale (GDS) while motor symptoms by the Unified Parkinson's Disease Rating Scale-motor (UPDRS-motor) and the Hoehn and Yahr scale (HY). All the patients underwent magnetic resonance imaging (MRI) with a 3.0-T system. LA was rated using the semiquantitative visual rating system proposed by scheltens et al. RESULTS: Both the PD-IC (2.43 ± 2.79) and PD-MCI (4.48 ± 4.33) groups showed significantly lower deep hyperintensities (DHs) scores than the PDD group (7.88 ± 6.69, P = 0.004 and 0.040, respectively), especially in frontal (1.09 ± 1.31; 1.83 ± 1.90; 3.24 ± 2.64, P 0.05), basal ganglia (0.09 ± 0.42; 0.30 ± 0.77; 0.53 ± 1.33, P > 0.05) and infratentorial white matter hyperintensities scores (--; 0.13 ± 0.63; 0.18 ± 0.73, P > 0.05) among three groups. The DHs showed a significant correlation with age (P = 0.003), MMSE (P = 0.009), verbal fluency test (P = 0.009), orientation (P = 0.047) and executive function (P = 0.027) in CAMCOG-C. The multiple regression analysis showed that the MMSE scores were associated significantly with education (P < 0.001, β = 0.600), DHs (P = 0.001, β = -0.678) and HY (P = 0.035, β = -0.480). DHs were the most significantly associated with MMSE scores. CONCLUSION: There was a significant correlation between DHs and multiple domain cognitive impairment in PD, especially in executive function. DHs, which were the most significantly variable associated with MMSE scores, may contribute to cognitive impairment in PD.