Low BDNF is associated with cognitive impairments in patients with Parkinson's disease.

OBJECTIVE: Increasing evidence show that brain-derived neurotrophic factor (BDNF) plays a critical role in neuroplasticity in the hippocampus that is related to learning and memory. Parkinson disease (PD) is associated with impairment of cognitive function that may evolve from decreased BDNF. The aim of the present study was to examine the association of BDNF with cognitive impairment in PD.

METHODS: We compared 97 PD patients to 102 healthy controls on serum BDNF and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Hoehn-Yahr staging test was used to assess motor abilities.

RESULTS: Serum BDNF levels were significantly lower in PD patients than in healthy controls (p < 0.01). Cognitive performance shown on the RBANS total and all of its five index scores were significantly lower in PD patients than normal controls (all p < 0.05). For the patients only, BDNF was positively associated with all five index and total scores of RBANS.

CONCLUSIONS: Our findings suggest extensive cognitive impairments and decreased BDNF in PD patients. Moreover, decreased BDNF is associated with cognitive deficits of Parkinson's disease.