Table 1.

Criteria for the diagnosis of PD-MCI

Inclusion criteria:  Diagnosis of Parkinson’s disease as based on the UK PD Brain Bank Criteria  Gradual decline, in the context of established PD, in cognitive ability reported by either the patient or informant, or observed by the clinician  Cognitive deficits on either formal neuropsychological testing or a scale of global cognitive abilities  Cognitive deficits are not sufficient to interfere significantly with functional independence, although subtle difficulties on complex functional tasks may be present

Exclusion criteria:  Diagnosis of PD dementia based on MDS Task Force proposed criteria  Other primary explanations for cognitive impairment (e.g. delirium, stroke, major depression, metabolic abnormalities, adverse effects of medication or head trauma)  Other PD-associated comorbid conditions (e.g. motor impairment or severe anxiety, depression, excessive daytime sleepiness or psychosis) that, in the opinion of the clinician, significantly influence cognitive testing

PD-MCI level guidelines:  A. Level I (abbreviated assessment)   • Impairment on a scale of global cognitive abilities validated for use in PD   or   • Impairment on at least two tests, when a limited battery of neuropsychological tests is performed (i.e. the battery includes less than two tests within each of the five cognitive domains, or less than five cognitive domains are assessed)  B. Level II (comprehensive assessment)   • Neuropsychological testing that includes two tests within each of the five cognitive domains (i.e. attention and working memory, executive, language, memory and visuospatial)   • Impairment on at least two neuropsychological tests, represented by either two impaired tests in one cognitive domain or one impaired test in two different cognitive domains   • Impairment on neuropsychological tests may be demonstrated by any one of the following:    ○ Performance approximately 1 to 2 SDs below appropriate norms    ○ Significant decline demonstrated on serial cognitive testing    ○ Significant decline from estimated premorbid levels

Subtype classification for PD-MCI (optional, requires two tests from each of the five cognitive domains assessed and is strongly suggested for research purposes):  PD-MCI single-domain—abnormalities on two tests within a single cognitive domain (specify the domain), with other domains unimpaired or  PD-MCI multiple-domain—abnormalities on at least one test in two or more cognitive domains (specify the domains)

From Litvan et al. (2012, with permission