Parkinson disease Cognitive impairment

Cognitive impairment in Parkinson's disease can manifest as executive dysfunction, visuospatial difficulties, or memory deficits. Treatment options include cholinesterase inhibitors (e.g., rivastigmine, donepezil) and memantine. Cholinesterase inhibitors may have mild benefits but can cause side effects, while memantine's effectiveness needs further confirmation.

Overview of Cognitive Impairment:

Cognitive impairment usually manifests as either an executive dysfunction; such as, attention and planning difficulties, impaired visuospatial function with a relatively preserved language function or to lesser extent, memory deficits. (1, 2, 3)

Treatment Options:

Treatment includes cholinesterase inhibitors, and/ or memantine. Cholinesterase inhibitors, such as rivastigmine at a starting dose of 1.5 mg twice daily, donepezil at an initial dose of 5 mg once daily ; showed mild benefit from clinical trials but was associated with an increased risk of side effects, for example, worsening tremors and nausea. So, they are only advisable in early stage disease. (4) Memantine (5 mg once daily) has showed modest activity in Parkinson disease. Also, its application was associated with hallucination and worsening neuropsychiatric symptoms. More phase 3 clinical trials are required to confirm its benefit in the current setting. (5)

References

1- Levin BE, Llabre MM, Reisman S, et al. Visuospatial impairment in Parkinson's disease. Neurology 1991; 41:365.

2-Aarsland D, Brønnick K, Larsen JP, et al. Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study. Neurology 2009; 72:1121.

3-Stern Y, Richards M, Sano M, Mayeux R. Comparison of cognitive changes in patients with Alzheimer's and Parkinson's disease. Arch Neurol 1993; 50:1040.