ACHE and Parkinson disease: Several studies, albeit with a small sample size or short trial duration, have shown that acetylcholinesterase inhibitors, such as donepezil at a dose of 10 mg and rivastigmine at 12 mg may have some positive effects on cognitive function without worsening parkinsonism.135,136 In line with this, PD patients treated with donepezil at a dose of 5 mg scored higher on the Mini-Mental State Examination (MMSE) and on an auditory memory task over a period of almost 2 years compared to those treated with placebo.