. Author manuscript; available in PMC: 2017 Dec 1.

Published in final edited form as: Mov Disord. 2016 Nov 7;31(12):1865–1873. doi: 10.1002/mds.26847

Table 3.

Age-Based Statistically Significant DIF

Age-Based NU-DIF: Impact magnitude of identified significant DIF
	Item		R²	Magnitude

Part 1 N=5381	1.10 Urinary symptoms	52-75 vs. all others	0.0024	Negligible
	1.12 Lightheadedness	> 75 vs. all others	0.0013	Negligible
	1.13 Fatigue	> 75 vs. all others	0.0018	Negligible

Age-based U-DIF: Impact magnitude of identified significant DIF
	Item		R²	Magnitude

Part 1 N=5381	1.1 Cognition
		< 52 vs. all others	0.0068	Negligible
		52-75 vs. all others	0.0021	Negligible
		> 75 vs. all others	0.0198	Negligible
	1.2 Hallucinations
		< 52 vs. all others	0.0069	Negligible
		> 75 vs. all others	0.0147	Negligible
	1.8 Daytime sleepiness	< 52 vs. all others	0.0012	Negligible
	1.11 Constipation
		< 52 vs. all others	0.0086	Negligible
		> 75 vs. all others	0.0068	Negligible

Part 2 N=5375	2.13 Freezing
		52-75 vs. all others	0.0015	Negligible
		> 75 vs. all others	0.0012	Negligible

Part 3 N=5159	3.2 Facial expression	< 52 vs. all others	0.0013	Negligible
	3.3b Rigidity right UE	< 52 vs. all others	0.0011	Negligible
	3.3c Rigidity Left UE	< 52 vs. all others	0.0011	Negligible
	3.9 Arising from Chair
		< 52 vs. all others	0.0036	Negligible
		52-75 vs. all others	0.0090	Negligible
		> 75 vs. all others	0.0207	Negligible
	3.10 Gait
		< 52 vs. all others	0.0034	Negligible
		52-75 vs. all others	0.0039	Negligible
		> 75 vs. all others	0.0131	Negligible
	3.11 Freezing
		< 52 vs. all others	0.0031	Negligible
		> 75 vs. all others	0.0016	Negligible
	3.12 Postural Stability
		< 52 vs. all others	0.0046	Negligible
		52-75 vs. all others	0.0036	Negligible
		> 75 vs. all others	0.0126	Negligible
	3. 13 Posture
		< 52 vs. all others	0.0092	Negligible
		52-75 vs. all others	0.0030	Negligible
		> 75 vs. all others	0.0170	Negligible
	3.14 Global Spontaneity
		52-75 vs. all others	0.0019	Negligible
		> 75 vs. all others	0.0041	Negligible
	3.16a Tremor right UE
		52-75 vs. all others	0.0021	Negligible
		> 75 vs. all others	0.0036	Negligible

Part 4 N=5397	4.6 Painful Off dystonia	>75 vs. all others	0.0044	Negligible

Legend: Most of the MDS-UPDRS items did not meet the minimal statistical criteria for DIF (see text). The Table lists items with DIF identified by both lordif and MIMIC as independent approaches (p values shown in Supplemental Materials). McFadden's R² and impact Magnitude are shown in the columns.⁷