Key requirements for dementia associated with Parkinson's disease:
(1) The patient has Parkinson's disease.
(2) The onset of the cognitive impairment is after the onset of the Parkinsonian motor symptoms.
(3) It shows "typical" features: insidious onset, slow progression, common deficits (with attention, executive, visuospatial functions) and behavioral features.
Other neurodegenerative disorders with parkinsonism:
(1) Dementia with Lewy Bodies
(2) progressive supranuclear palsy
(3) corticobasal degeneration
Concurrent dementia arising independently of the PD:
(1) Alzheimer's Disease
(2) vascular dementia
Consequence of Parkinson Disease therapy:
(1) adverse effect of dopaminergic agent
(2) drug interaction involving a PD medication
(3) adverse effects of an anticholinergic agent
(4) related to change in cognition while in an "off" period
Other potentially reversible cognitive impairment:
(1) major depression
(2) sleep deprivation
(3) delirium
(4) normal pressure hydrocephalus
(5) intracranial mass effect
(6) head trauma and/or subdural hematoma
(7) thyroid or other endocrine disorder
(8) nutritional deficiency
(9) toxic or hypoxic event
(10) adverse effect of non-PD medications
In the future advances in imaging techniques may be helpful when clinical findings are insufficient.
