Interesting article on PDD...

Neuropsychiatric symptoms in patients with Parkinson's disease and dementia: frequency, profile and associated care giver stress.
Aarsland D, Bronnick K, Ehrt U, De Deyn PP, Tekin S, Emre M, Cummings JL.
Centre for Clinical Neuroscience Research, Stavanger University Hospital, Stavanger, Norway.
J Neurol Neurosurg Psychiatry. 2007 Jan;78(1):36-42.

"Objective: To explore the profile of neuropsychiatric symptoms in patients with dementia associated with Parkinson’s disease (PDD).

Methods: 537 patients with PDD drawn from an international multicentre clinical trial of rivastigmine were assessed using the 10-item Neuropsychiatric Inventory (NPI). A cluster analysis was used to investigate the inter-relationship of NPI items. Associations between the clusters and demographic and clinical variables were analysed.

Results: 89% of the patients presented at least one symptom on the NPI, 77% had two or more symptoms and 64% had at least one symptom with a score >4. The most common symptoms were depression (58%), apathy
(54%), anxiety (49%) and hallucinations (44%). Patients with more severe dementia and advanced Parkinson’s disease had more neuropsychiatric symptoms. Nearly 60% of the care givers reported at least one NPI symptom to be of at least moderate severe distress. Five NPI clusters were identified: one group with few and mild symptoms (52%); a mood cluster (11%, high scores on depression, anxiety and apathy); apathy (24%; high apathy and low scores on other items); agitation (5%, high score on agitation and high total NPI score); and a psychosis cluster (8%; high scores on delusions and hallucinations). The psychosis and agitation clusters had the lowest Mini-Mental State Examination score and the highest Unified Parkinson’s Disease
Rating Scale and care giver distress scores.

Conclusion: Neuropsychiatric symptoms are common in patients with PDD. The profile of these symptoms differs from that in other types of dementia. Subgroups with different neuropsychiatric profiles were identified. These subgroups may be associated with distinct neurobiological changes, which should be explored in future studies."

(PubMed ID # is 16820421)

PDD is defined in the fourth edition of the Diagnostic and statistical manual of mental disorders (Code 294.1). And, in this article, "dementia with Lewy bodies" is described as "a disorder with clinical and neurobiological similarities with PDD."

The editorial associated with the article describes the Neuropsychiatric Inventory (NPI) as "the gold standard of the assessment for neuropsychiatric symptoms."

The data was collected for this paper during a trial of Exelon's (rivastigmine) safety and efficacy with PDD. This is the largest sample of PDD patients (537) looked at to date.

The most interesting result was: PDD patients with psychosis and agitation were found to have more cognitive impairment and worse parkinsonian symptoms. The caregivers for this group were in the most distress. (Not a surprise)

One interesting note late in the article is: "(S)everal studies have shown that antiparkinsonian agents are only weakly associated with visual hallucinations." I would have to look up the referenced article but I'm assuming that Sinemet is an antiparkinsonian agent.