Motor function in Parkinson's disease and supranuclear palsy: simultaneous factor analysis of a clinical scale in several populations

Table 3 Model selection: All three groups: PD-On-Group, PD-Off-Group, and PSP Group

		χ²	df	RMSEA	TLI	CFI	St.RMR	Comments
PP1	Same model as PD1	--	--	--	--	--	--	Empirically not identified
PP2	As PP1: Loadings PD-On = Loadings PD-Off = Loadings PSP	1949	930	0.070	0.97	0.97	0.09	Baseline model 95% Confidence Interval of RMSEA: 0.065 – 0.075
PP3	As PP2: Also factor correlation matrices equal¹	2376	972	0.081	0.89	0.90	0.22	Outside confidence limits PP2
PP4	As PP3: In PSP all factor (co)variances related to the factor Tremor estimated rather than set equal to those of the PD groups	2099	966	0.073	0.96	0.97	0.14	Within confidence limits of PP2 Preferred model

¹The model modification indices of the factor variance for Tremor-at-rest were moderately large to large (PSP: 70; PD-On: 19; PD-Off : 12) indicating that the common values were not very accurate for these variances, suggesting separate estimations of these quantities. RMSEA = Root mean square residual, CFI = comparative fit index, TLI = Tucker-Lewis Index, St.RMR = standardised root mean residual correlation.