Towards a short questionnaire for stepwise assessment of upper limb function, pain and stiffness in Duchenne muscular dystrophy

Figures & data

Table 1. The factors and their characteristics resulting from factor analysis on each questionnaire (CUE, ABILHAND-plus, PAIN, and STIFFNESS).

Factors	N	Eigenvalues	% of explained variance	% of explained variance (total)	Cronbach’s Alpha	Kaiser–Meyer–Olkin	Bartlett’s tests of sphericity (p values)
CUE				86.6		0.91	0.001
Basic hand function	8	22.4	74.7		0.98
Heavy lifting	10	2.5	8.3		0.98
Light or no lifting	12	1.1	3.6		0.99
ABILHAND-plus				80.4		0.97	0.001
Gross hand function	16	19.7	75.7		0.97
Fine hand function	10	1.2	4.7		0.98
PAIN				86.3		0.86	0.001
Pain limitations	14	21.4	50.9		0.98
Pain severity (not shoulder)	12	6.1	14.5		0.97
Distal pain frequency	6	3.2	7.7		0.93
Shoulder pain	4	2.0	4.7		0.89
Proximal pain frequency (not shoulder)	4	1.5	3.5		0.93
Elbow pain frequency	2	1.1	2.6		0.90
STIFFNESS				87.9		0.98	0.001
Stiffness frequency	14	27.8	66.1		0.98
Stiffness limitations	14	4.3	10.3		0.99
Stiffness severity	14	2.1	5.1		0.98

Table 2. The Pearson correlation between each pair of two factors.

	CUE			ABILHAND-plus		PAIN						STIFFNESS
	Basic hand function	Heavy lifting	Light or no lifting	Gross hand function	Fine hand function	Pain limitations	Pain severity (not shoulder)	Distal pain frequency	Shoulder pain	Proximal pain frequency (not shoulder)	Elbow pain frequency	Stiffness frequency	Stiffness limitations	Stiffness severity
CUE
Basic hand function	1.00
Heavy lifting	0.71	1.00
Light or no lifting	0.81	0.88	1.00
ABILHAND-plus
Gross hand function	0.85	0.81	0.91	1.00
Fine hand function	0.75	0.86	0.88	0.91	1.00
PAIN
Pain limitations	−0.27	−0.32	−0.34	−0.31	−0.29	1.00
Pain severity (not shoulder)	−0.18	−0.30	−0.28	−0.25	−0.25	0.46	1.00
Distal pain frequency	−0.21	−0.24	−0.23	−0.19	−0.19	0.40	0.58	1.00
Shoulder pain	−0.33	−0.40	−0.38	−0.39	−0.35	0.44	0.70	0.60	1.00
Proximal pain frequency (not shoulder)	−0.15	−0.24	−0.21	−0.16	−0.17	0.40	0.56	0.74	0.64	1.00
Elbow pain frequency	−0.39	−0.40	−0.42	−0.37	−0.36	0.41	0.55	0.61	0.61	0.69	1.00
STIFFNESS
Stiffness frequency	−0.41	−0.42	−0.47	−0.46	−0.40	0.47	0.37	0.33	0.44	0.32	0.38	1.00
Stiffness limitations	−0.44	−0.43	−0.50	−0.50	−0.45	0.54	0.26	0.28	0.34	0.25	0.30	0.68	1.00
Stiffness severity	−0.34	−0.32	−0.38	−0.37	−0.31	0.57	0.23	0.23	0.28	0.22	0.24	0.64	0.82	1.00

Values with a Pearson correlation coefficient above 0.4 are printed in bold.

Table 3. Mean with 95% confidence intervals (CI) of the factor sum scores for patient groups in different disease stages and of the differences between these two groups.

	Early ambulatory stage		Late non-ambulatory stage		Difference compared to late-non-ambulatory stage
Factors (min–max)^a	N	Mean (95% CI)	N	Mean (95% CI)	Mean (95% CI)	p values
CUE
Basic hand function (8–56)	64	51.9 (50.6, 53.3)	94	31.0 (27.8, 34.2)	21.0 (16.9, 25.0)	<0.001
Heavy lifting (10–70)	64	55.1 (52.4, 57.8)	94	14.8 (13.1, 16.4)	40.3 (37.3, 43.4)	<0.001
Light or no lifting (12–84)	64	79.0 (77.3, 80.7)	94	27.4 (24.4, 30.3)	51.7 (47.8, 55.5)	<0.001
ABILHAND-plus
Gross hand function (16–48)	53	45.2 (44.3, 46.0)	88	24.9 (22.9, 26.9)	20.3 (17.6, 23.0)	<0.001
Fine hand function (10–30)	52	25.8 (24.6, 26.9)	91	12.5 (11.7, 13.4)	13.2 (11.8, 14.6)	<0.001
PAIN
Pain limitations (0–140)	66	1.1 (0.1, 2.1)	94	20.2 (13.7, 26.8)	−19.1 (−27.1, −11.2)	<0.001
Pain severity (not shoulder) (0–120)	66	2.7 (1.1, 4.3)	94	13.9 (9.4, 18.3)	−11.2 (−16.7, −5.7)	<0.001
Distal pain frequency (0–36)	66	0.6 (0.2, 1.0)	94	3.6 (2.4, 4.8)	−3.0 (−4.4, −1.5)	<0.001
Shoulder pain (0–32)	66	1.0 (0.3, 1.7)	94	5.7 (4.5, 7.0)	−4.7 (−6.3, −3.1)	<0.001
Proximal pain frequency (not shoulder) (0–24)	66	0.7 (0.3, 1.2)	94	2.7 (1.8, 3.6)	−1.9 (−3.1, −0.8)	<0.001
Elbow pain frequency (0–12)	66	0.2 (0.0, 0.3)	94	2.0 (1.5, 2.5)	−1.8 (−2.4, −1.2)	<0.001
STIFFNESS
Stiffness frequency (0–84)	66	3.4 (1.9, 4.9)	94	23.2 (17.8, 28.7)	−19.8 (−26.5, −13.2)	<0.001
Stiffness limitations (0–140)	66	4.6 (-0.2, 9.4)	94	40.6 (31.3, 50.0)	−36.0 (−48.0, −24.1)	<0.001
Stiffness severity (0–140)	66	9.9 (2.5, 17.2)	94	34.9 (27.0, 42.7)	−25.0 (−36.3, −13.7)	<0.001

^a (min–max) = minimal and maximal possible score per factor.

Table 4. The proposed upper limb short questionnaire to assess upper limb function, pain, and stiffness in patients with DMD based on the factor commonalities that can be used as a stepwise approach in clinical practice.

Factor	Initial questions	Score options^a
Heavy lifting	Do you experience problems in your arms when lifting heavy objects (>5 pounds)?	0: No 1: Yes
Light or no lifting	Do you experience problems in your arms when you reach for or lift light objects such as an empty can?	0: No 1: Yes
Basic hand function	Do you experience problems using your hands for basic functions like manipulating small objects or holding a key?	0: No 1: Yes
Gross hand function	Do you experience problems using your hands when performing daily activities that require gross hand function like washing your hands or eating with a spoon?	0: No 1: Yes
Fine hand function	Do you experience problems using your hands when performing daily activities that require fine hand function like buttoning up your shirt?	0: No 1: Yes
Pain limitations	Do you experience limitations performing daily activities due to pain in your upper limb?	0: No 1: Yes
Pain severity (not shoulder)	How severe is the pain you experience in your upper limb when performing daily activities?	0: No pain 1: Mild or severe pain
Distal pain frequency	How often do you have pain in your hands or fingers?	0: Not more than once a month 1: More than once a month
Shoulder pain	Do you experience pain in your shoulder(s)?	0: No 1: Yes
Proximal pain frequency (not shoulder)	How often do you experience pain in your upper or lower arm?	0: Not more than once a month 1: More than once a month
Elbow pain frequency	How often do you experience pain in your elbows?	0: Not more than once a month 1: More than once a month
Stiffness frequency	How often do you experience stiffness in your arms?	0: Not more than once a month 1: More than once a month
Stiffness limitations	Do you experience limitations performing daily activities due to stiffness in your upper limb?	0: No 1: Yes
Stiffness severity	How severe is the stiffness you experience in your upper limb when performing daily activities?	0: No stiffness 1: Mild or severe stiffness

^a When the Upper Limb Short Questionnaire is used for the clinical assessment of upper extremity function, pain, and stiffness, additional follow-up questions related to the initial questions can be used to gain detailed insight into the specific problems experienced by an individual patient. Follow-up questions should consist of the items that group under the factor corresponding with the initial question (see also supplementary material).