[A version of this item appears in: Dementia: the Latest Evidence Newsletter (RWHT), Volume 2 Issue 9, April 2012].
Earlier Cochrane reviews have examined the use of cholinesterase inhibitors in both Parkinson’s Disease with dementia (PDD) and dementia with Lewy bodies (DLB). Both DLB and PDD have a lot in common; their being distinguished mainly according to whether parkinsonism precedes dementia by more than a year. Both conditions are marked by severe deficits in cortical acetylcholine. Blocking the breakdown of acetylcholine using cholinesterase inhibitors therefore seemed a promising approach.
The authors of this systematic review assessed the efficacy, safety and tolerability of cholinesterase inhibitors in DLB, PDD and cognitive impairment in Parkinson’s Disease falling short of dementia (CIND-PD). Six trials were considered in this review, covering 1236 participants. They found evidence of a positive effect of cholinesterase inhibitors on the Mini-Mental State Examination (MMSE) in patients with PDD but not in one DLB trial. Behavioural disturbance rating scales also showed treatment with cholinesterase inhibitors to have some benefit. Activities of daily living, similarly, indicated treatment with cholinesterase inhibitors to be beneficial.
Patients taking a cholinesterase inhibitor were more likely, however, to experience an adverse event and to drop out from the studies. Adverse events appear to be more common among patients taking rivastigmine, but not for those taking donepezil. Parkinsonian symptoms, in particular tremour, appear to be worse in people treated, but not significantly. Fewer deaths occurred in the treatment group
The authors conclude that current evidence supports the use of cholinesterase inhibitors in patients with PDD, with a benefit on global assessment, cognitive function, behavioural disturbance and activities of daily living rating scales. The use of these drugs for DLB is unclear, and there is no unambiguous evidence to support their use for CIND-PD as yet.
Rolinski, M. Fox, C. [and] Maidment, I. [et al] (2012). Cholinesterase inhibitors for dementia with Lewy bodies, Parkinson’s disease dementia and cognitive impairment in Parkinson’s disease. Cochrane Database of Systematic Reviews (Online), March 14th 2012, Issue 3, No. CD006504. (Click here to view the PubMed abstract).