Cognitive impairment is a common outcome in PD and mild cognitive impairment may be seen in some patients at the point of diagnosis. Better biomarkers and neuroprotective strategies to prevent descent into dementia are essential...
Parkinsonism Relat Disord. 2015 Sep 21. pii: S1353-8020(15)00425-3. doi: 10.1016/j.parkreldis.2015.09.034. [Epub ahead of print]
Parkinson's disease (PD) and dementia with Lewy bodies (DLB) share clinical and pathological similarities. The defining features are motor parkinsonism and cognitive impairment, often accompanied by visual hallucinations, fluctuating consciousness, autonomic and sleep disturbances, and a number of other non-motor symptoms. Mild cognitive impairment (MCI) can be identified in 15% of PD patients at time of diagnosis, and may even precede motor symptoms. MCI usually progresses further, and dementia is a common endpoint. Cognitive impairment is usually the initial symptom of DLB, and the disease course is severe. A variety of biomarkers can assist in the diagnosis and prognosis of PD and DLB, including structural and functional imaging, cerebrospinal fluid, and EEG. Compared to the many treatments available for motor symptoms, relatively few systematic studies exist to guide the treatment of cognitive impairment in PD, and even less in DLB. However, there is good evidence for cholinesterase inhibitors in both DLB and PD with dementia, and some indications that memantine is helpful. Emerging evidence suggest that physical exercise and cognitive training are also effective, as are some reports of various brain stimulation techniques. Disease-modifying agents that delay the rate of cognitive decline in PD and DLB are urgently needed.