Parkinson's disease dementia: Definitions, guidelines, and research perspectives in diagnosis

Abstract

Cognitive impairment is common in Parkinson's disease (PD) and involves attentional, executive, visuospatial, and memory dysfunctions. Dementia is more frequently encountered in PD than in age-matched control populations, and whereas operational definitions of Alzheimer's disease and dementia with Lewy bodies have been developed, Parkinson's disease dementia (PD-D) has remained undefined. The Movement Disorder Society developed a task force to define and develop diagnostic guidelines for PD-D. This effort was based on existing descriptive studies with special emphasis on drawing distinction among Alzheimer's disease, dementia with Lewy bodies and PD-related cognitive impairment without dementia whenever possible. The second goal was to provide practical diagnostic procedures to diagnose PD-D. This effort emphasized available bedside tools that do not require neuropsychological expertise to administer or interpret. This work recently has been completed, and two primary articles have been published. The suggested clinical diagnostic criteria for PD-D involve four domains and are anchored in core features, associated clinical features, features that make the diagnosis uncertain, and features that are not compatible with the diagnosis of PD-D. When all four criteria are satisfactorily met, probable PD-D is designated; when the first and last criteria are met, but clinical characteristics are atypical or uncertainty factors exist, possible PD-D is designated. Whereas these definitions are operative and subject to change based on future data, they are based on widely available tests. The inclusion criteria can be applied internationally and in multicenter research on treatment interventions, clinicopathological correlations, and studies of cognitive and other nonmotor elements of PD.

Apathy in Parkinson's disease: clinical features, neural substrates, diagnosis, and treatment

“…7,55 Both dopaminergic denervation and cholinergic abnormalities aff ect the lateral and medial regions of the prefrontal cortex in Parkinson's disease. Degeneration of mesencephalic dopaminergic neurons at Braak stage III of the disease leads to dopamine depletion in the mesocortical and mesolimbic systems, 56 and the spread of synucleinopathy to subcortical and cortical dopamine projection areas further impairs their functionality during Braak stages IV and V. 57,58 Delineation of the diff erent components that can lead to apathy is crucial to the planning of therapeutic strategies.…”

White Matter Alteration of the Cingulum in Parkinson Disease with and without Dementia: Evaluation by Diffusion Tensor Tract–Specific Analysis

“…18 PD was staged according to the Hoehn and Yahr scale, and the subjects underwent the Japanese version of the MMSE to assess cognitive dysfunction. 19 PDD was diagnosed in accordance with recently published guidelines, 20 and patients with probable PDD were selected. All patients with PD and PDD were taking levodopa at the time of the MR imaging and clinical examination.…”

Parkinson’s disease showing progressive conduction aphasia

“…Preserved core language functions are characteristic for PDD patients [1,3]. Our patient had no infarcts or PIB-positive amyloid accumulation, indicating no evidence of additional AD pathology in the brain.…”

“…Patients with Parkinson's disease (PD) may develop progressive dementia late in their clinical course [1][2][3]. Dementia in PD is mostly related to neuropathological findings of extensive Lewy bodies (LBs), with or without the coexistence of Alzheimer's disease (AD) pathology involving various subcorticocortical neural systems [1,4].…”