Major Neurocognitive Disorders Due to Parkinson’s Disease

Parkinson’s disease (PD) is the fastest growing neurological condition. The number of patients suffering from this condition is expected to double to 12 million by 2040. PD is commonly associated with cognitive impairment. About one-third of the patients develop dementia, and about a third have mild cognitive impairment (MCI). The timeline from the onset of motor symptoms to dementia is variable, although most patients who have PD for more than 10 years will likely have impairment secondary to dementia. Diagnosing Parkinson’s disease dementia involves excluding other conditions that mimic dementia and other potential etiologies of dementia. Executive, attentional, and visuospatial cognitive domains are typically affected, although the presentation can be quite heterogenous, with memory impairment being commonly found as well. Development of neuropsychiatric symptoms (NPSs) often parallels dementia and manifests as mood, anxiety, psychotic symptoms, apathy, aggression, and behavioral disturbances. Care for these patients is complex and difficult, and the optimal treatment strategy involving both pharmacological and non-pharmacological measures should be developed to target motor, cognitive, and behavioral symptoms.