Correlation analysis of depression and executive function impairment in patients with early Parkinson′s disease

Objective To assess the overall cognitive performance and executive function in patients with early non-demented Parkinson′s disease(PD),and the effect of variables such as depression and education on cognitive function.Methods 41 patients underwent clinical assessment including the Unified Parkinson′s Disease Rating Scale,Hoehn-Yahr Scale,the scale of elderly cognitive function(SECF),performance intelligence quotient(PIQ) of Wechsler Adult Intelligence Scale-Revised for China(WAIS-RC) Test and Hamilton Rating Scale for Depression(HAMD).Results Patients with higher education background,younger age,and whose onset at a younger age performed better on SECF and WAIS-RC.Severity of disease was negatively correlated with cognitive performance.Performance on PIQ instead of SECF worsened with increased severity of depressive symptoms.When patients were divided into groups with lower(≤5 yrs of schooling,n=21) and higher(6 yrs schooling,n=20),the PIQ and HAMD were negatively correlated only in the group with lower educational level.Conclusion Patients with non-demented PD may exhibit cognitive impairment even at an early stage.Depression may exacerbate the executive dysfunction,especially in patients with lower educational level.