Table 1.

Evolution of numbers of dementia in Parkinson's disease

Authors	Year	Frequency of dementia	Criteria – Comments
Mayeux et al	1988	10.9%	Retrospective, DSM-III
Girotti et al	1988	14.28%	Examination, Npsy
Hietanen, Teräväinen	1988	2% < 60 yrs, 25% > 60 yrs	Examination, DSM-III
Pillon et al	1991	18%	Examination, NPsy 2SD
Mayeux et al	1992	41%, 0% < 50 yrs, 61% > 80 yrs	Examination, DSM-III
Tison et al	1995	17.6%	Examination, DSM-IIIR
Aarsland et al	1996	27.7%	Examination, DSM-IIIR
Reid et al	1996	9% < 70 yrs → 17% 37% > 70 yrs → 62%	Follow-up 5 ys
Hobson, Meara	1999	41%	Examination, CAMCOG
Marder et al	1995	1.7 Relative Risk	Follow up-controls
Aarsland et al	2001	5.9 relative risk	Follow up 4.2 ys-controls
Aarsland et al	2003	78% incidence in 8 years	Follow up 4 – 8 yrs