Alpha rhythm oscillations and MMSE scores are differently modified by transdermal or oral rivastigmine in patients with Alzheimer's disease.

Abstract

Background: Alzheimer's disease (AD) is the most common cause of dementia in older patients. Rivastigmine, a reversible cholinesterase inhibitor, has been shown to improve the clinical manifestations of AD by delaying the breakdown of acetylcholine (ACh) released into synaptic clefts. Moreover, there is evidence that ACh modulates EEG alpha frequency.

Objectives: the objectives of this pilot study in patients with AD were to determine the effects of two formulations of RV (transdermal and oral) on Mini-Mental State Examination (MMSE) scores and on alpha frequency in particular the posterior dominant rhythm.

Methods: twenty subjects with AD were randomly assigned to receive either RV transdermal patch (RV-TDP, n=10) or RV capsules (RV-CP, n=10) according to the standard recommended dosage regimen. All patients were driven to the maximum drug dosage. Diagnosis of AD was made according to NINCDS-ADRDA criteria and the Diagnostic and Statistical Manual of Mental Disorders IV. All patients underwent EEG recordings at the beginning and at the end of the 18-month study period using P3, P4, O1 and O2 electrodes each at high (10.5-13.0 Hz) and low (8.0-10.5 Hz) frequency. MMSE scores were determined at the start of the study and at three successive 6-month intervals (T0, T1, T2, and T3).

Results: administration of RV-DP increases the spectral power of alpha waves in the posterior region and is associated with improved cognitive function as evidenced by significant changes in MMSE scores.

Conclusion: RV-DP provides an effective and long-term management option in patients with AD.