Table 4.

Pearson correlation values of individual item scores to the total NDI [11]

Study	Present study			Hains et al.*
NDI item	Item total correlations (r) (n = 160)	95% CI	P value	Item total correlations (r) (n = 237)
1. Pain intensity	0.53	0.41–0.63	<0.001	0.70
2. Personal care	0.60	0.49–0.69	<0.001	0.68
3. Lifting	0.49	0.36–0.60	<0.001	0.75
4. Reading	0.64	0.54–0.72	<0.001	0.77
5. Headaches	0.45	0.31–0.56	<0.001	0.64
6. Concentration	0.53	0.41–0.63	<0.001	0.76
7. Work	0.59	0.47–0.68	<0.001	0.87
8. Driving	0.61	0.50–0.70	<0.001	0.87
9. Sleeping	0.61	0.51–0.70	<0.001	0.76
10. Recreation	0.66	0.56– 0.74	<0.001	0.83

*Chiropractic Out Patient Department