[Memantine (akatinol) therapy of cognitive impairment in Parkinson's disease complicated by dementia]

Abstract

The study has investigated the effect of NMDA-glutamate receptor antagonist memantine in the 52-weeks therapy of 32 PD patients with dementia (PDD) compared with the control group (30 cases). Patients of the active group received memantine (20 mg per day) additionally to dopaminergic therapy. Patients from the control group continued the treatment with antiparkinsonian drugs. Cognitive, psychiatric and motor symptoms have been assessed before and after 12, 24 and 52 weeks of the study using clinical assessment as well as rating scales including the Unified Parkinson's Disease Rating Scale (UPDRS), the Mini-Mental State Examination (MMSE), ADAS-cog, clock drawing test, D-KEFS Verbal Fluency test, the Frontal Assessment Battery (FAB), the Neuropsychiatric Inventory (NPI-12) and the Disability Assessment for Dementia Scale (DAD). The plasma total Hcy level was determined by high-performance liquid chromatography. Patients treated with memantine had better MMSE (p<0,05), ADAS-cog (p<0,05), clock drawing test (p<0,05) and FAB (p<0,01) scores compared to patients in the control group at week 24. Patients with elevated Hcy demonstrated a significantly better response to memantine therapy versus the controls with elevated Hcy at week 24, 52 with respect to all efficacy measures (UPDRS, MMSE, ADAS-cog, D-KEFS, Verbal Fluency test, FAB, NPI, DAD, p<0,05). The NPI individual item scores changes from baseline to week 52 have shown benefits to memantine treatment compared with the controls with significant treatment differences for disinhibition (p<0,006), irritability (p<0,04), anxiety (p<0,04) and hallucinations (p<0,048). Hyperhomocysteinemia may indicate the more rapid cognitive and motor decline in PD. The prolonged therapy with memantine in PDD led to improvements in cognitive functions and preservation of motor functional abilities as well as the amelioration of neuropsychiatric symptoms, especially in patients with hyperhomocysteinemia.