In recent years several randomized, double-blind, placebo-controlled trials of memantine in Lewy body dementias (LBD) inconsistent results, though one study showed some benefits which clinicians were able to detect, but were not well-supported by measurable changes in cognitive function. Newly available data from one of those studies using a computer-based cognitive testing tool, the CDR System, reveals that memantine improves two important areas of cognitive function in Lewy body dementias.
Researchers recruited study participants with mild to moderate dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD), 21 and 30 participants respectively in the UK, Norway and Sweden. 70% of the participants were already being treated with cholinesterase inhibitors at the start of the study. Donepezil, rivastigmine, and galantamine are part of the cholinesterase inhibitor class of drugs originally designed for treatment of dementia in Alzheimer’s disease (AD). The CDR System was used to test participants’ baseline cognition before starting memantine. Tests were repeated at week 12 and week 24 of the study and also compared against data from 373 cognitively normal age-matched controls. 48 of the 51 participants completed both the 12 and 24 week tests.
Compared to Alzheimer’s disease, people with Lewy body dementias have greater loss of attention. Those with Alzheimer’s disease on the other hand, suffer from greater loss of short term memory than those with LBD, including episodic memory or the ability to remember personal experiences. Memantine provided substantial improvements in attention and episodic memory in both study participants with DLB and PDD.
Because the improvements seen in this study approach large effect sizes, they are likely to be meaningful in everyday life and clinical care. The benefits compare favorably with those seen in studies of cholinesterase inhibitors in both AD and LBD. CDR System attention tests were previously shown to be strong predictors in LBD of activity of daily living. This is of special importance to LBD caregivers, as improvements in attention in mild to moderate Lewy body dementias may lighten caregiver responsibilities. Previous studies indicate caregiver burden may be higher in LBD than in AD. This study adds to the growing evidence of clinical benefits of memantine in Lewy body dementias.
The study was first published in the International Journal of Geriatric Psychiatry in 2014 and the work was supported by the Western Norway Regional Health Authority.
Source: Wesnes KA, Aarsland D, Ballard C et al. Memantine improves attention and episodic memory in Parkinson's disease dementia and dementia with Lewy bodies. Int. J. Geriat. Psychiatry. 2014. doi: 10.1002/gps.4109.