Psychometric evaluation of the Disabilities of the Arm, Shoulder and Hand (DASH) with Dupuytren’s contracture: validity evidence using Rasch modeling

Table 1 Factor loadings from principal component analysis of the 30 items

	Items	Factor loadings*
	Items	Factor 1	Factor 2	Factor 3	Factor 4
1.	Open a tight or new jar	0.80	-0.36
2.	Write	0.72	-0.38	0.32
3.	Turn a key	0.83	-0.42
4.	Prepare a meal	0.83
5.	Push open a heavy door	0.77
6.	Place an object on a shelf above head	0.78		-0.30
7.	Do heavy household chores	0.93
8.	Garden or do yard work	0.83
9.	Make a bed	0.86
10.	Carry a shopping bag or briefcase	0.86
11.	Carry a heavy object (over 10 lbs)	0.80
12.	Change a lightbulb overhead	0.83
13.	Wash or blow dry hair	0.78
14.	Wash your back	0.79	0.32
15.	Put on a pullover sweater	0.90
16.	Use a knife to cut food	0.75	-0.40
17.	Recreational activities which require little effort	0.75
18.	Recreational activities with force or impact	0.81
19.	Recreational activities which move arm freely	0.82
20.	Manage transportation needs	0.79
21.	Sexual activities	0.63
22.	Interference with normal social activities	0.56	0.35		-0.62
23.	Limitation in work or other regular daily activities	0.57
24.	Pain in arm, shoulder or hand	0.66		0.60
25.	Pain when performing specific activity	0.78		0.52
26.	Tingling	0.56			0.52
27.	Weakness	0.79
28.	Stiffness	0.61	0.45
29.	Difficulty sleeping	0.73
30.	Feeling less capable, less confident or less useful	0.67
	Eigenvalue	17.91	1.67	1.46	1.16

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