Table 1. Item classification through a literature review.

Item of the CDT	Sunderland (1989)	Wolf-Klein (1989)	Mendez (1992)	Freedman (1994)	Shua-Haim (1996)	Lam (1998)	Woodford (2007)
1. Behavioral response	*	*	*			*
2. Language response	*	*
3. Size of circle	*		*	*
4. Closed of circle	*		*	*
5. Symmetry of circle	*		*	*
6. Twelve numbers	*		*	*	*	*
7. Numbers other than			*	*		*
8. Location (3, 6, 9, 12)	*	*	*	*	*	*
9. Location (1, 2, 4, 5)	*	*	*	*	*	*
10. Location (7, 8, 10, 11)	*	*	*	*	*	*
11. Memory of the time (11:10)							+
12. Memory of the procedures							+
13. Hour & minute hands	*		*	*	*
14. Length of hands			*	*		*
15. Exact time	*		*	*	*	*
16. Central point			*	*
17. The time to perform							+

* Items used in each study, + suggestion item