Table 1.

Classification criteria based on MDS criteria and literature review.

	Main criteria	Secondary criteria (for doubtful cases)*
PDD	1 Clinical criteria:    - CDR ≥1    - DSM IV compatible with dementia    - CISI-PD cognitive status ≥3 + Objective criteria:    - MMSE <26 + ≥2 cognitive domains affected	≥2 Clinical criteria:    - CDR ≥1    - DSM IV compatible with dementia    - CISI-PD cognitive status ≥3
PD-MCI	1 Clinical criteria:    - CDR = 0.5    - CISI-PD cognitive status = 1–2 + Objective criteria:    - SCOPA Cog 17–23	2 Clinical criteria:    - CDR = 0.5    - CISI-PD cognitive status = 1–2
NC	1 Clinical criteria:    - CDR = 0    - CISI-PD cognitive status = 0 + Objective criteria:    - SCOPA Cog ≥24	≥2 Clinical criteria:    - CDR=0    - CISI-PD cognitive status = 0

PDD, Parkinson's disease dementia; PD-MCI, Parkinson's disease-Mild cognitive impairment; NC, normal cognition; CDR, Clinical Dementia Rating; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, fourth edition; CISI-PD, Clinical Impression of Severity Index-Parkinson's disease; MMSE, Mini Mental State Examination; SCOPA-Cog, Scales for Outcomes in Parkinson's disease-Cognition. *Cases that did not fulfill all the criteria.