Table 1.

Comparison of reported numbers of participants found with lice and with louse nymphs following first treatment using different dimeticone based products

Study	Lice present before day 7	Percent	Nymphs present before day 7	Percent	Probability
Hedrin lotion overnight [1] *	91/127	71.6	86/127	67.7	a
ISRCTN47755726 Hedrin lotion overnight [2] *	32/43	74.4	27/43	62.8	a
ISRCTN15117709 Nyda L lotion overnight [6] **	26/73	35.6	Data not available	-	b
ISRCTN50373146 Hedrin liquid gel 1 hour *	3/42	7.1	2/42	4.8	c
ISRCTN59227204 Hedrin liquid gel 15 min	0/41	0.0	0/41	0.0	c

* Treatments used with two applications 7 days apart

** Treatment instructions originally recommended two applications with combing but now indicate one application may be effective with a repeat after 8 days if lice persist

Probability: Differences between groups were determined using Fisher's exact test. Groups with the same letter were not significantly different from each other. Differences were detected between groups 'a' and 'b' (p < 0.001) and groups 'b' and 'c' (p < 0.001)