Parkinson’s Disease Dementia (PDD) is a form of dementia that develops after the diagnosis of Parkinson's Disease. Patients with PD have an almost six-fold increased risk of developing dementia. By definition, Parkinson's disease dementia is cognitive decline that occurs after the onset of Parkinson's disease.
The majority of patients with Parkinson’s will experience some degree of cognitive impairment over time. The time of progression to a Parkinson's Disease dementia depends on the length and stage of disease. Some longitudinal studies have shown that the progression to dementia is inevetiable.[1] Parkinson's disease is more common in males than in females. Among individuals with Parkinson's disease, as many as 75% will develop a major neurocognitive disorder at sometime in the course of their disease.
The criteria are met for major or mild neurocognitive disorder.
The disturbance occurs in the setting of established Parkinson’s disease.
There is insidious onset and gradual progression of impairment.
The neurocognitive disorder is not attributable to another medical condition and is not better explained by another mental disorder.
Major or mild neurocognitive disorder probably due to Parkinson’s disease should be diagnosed if 1 and 2 are both met. Major or miid neurocognitive disorder possibly due to Parkinson's disease should be diagnosed if 1 or 2 is met:
The diagnosis of Parkinson's disease dementia (PDD) is most often based on the Movement Disorder Society Task Force 2007 recommendations.[2]
Criterion | Description | Asessment |
---|---|---|
1 | A diagnosis of PD | Queen's Square Brain Bank Criteria |
2 | PD developed prior to the onset of dementia | Patient/caregiver history or ancillary records |
3 | PD associated with a decreased global cognitive efficiency | MMSE < 26 |
4 | Cognitive deficiency severe enough to impair daily life | Caregiver interview or pill questionnaire |
5 | Impairment of more than one cognitive domain | Impairment of at least 2 of the following domains: attention, executive function, visuo-constructive ability, memory |
Presence of one of the following behavioural symptoms (apathy, personality changes, hallucinations, delusions or excessive daytime sleepiness) may support the diagnosis of probable PDD.