German scientists examined 304 children at five primary schools that reported persistent head lice infestations. First, a researcher examined their scalps, parting the hair at five places where eggs or lice are often found. Then a different investigator, unaware of the results of the first test, examined the same children, this time wetting the hair with conditioner and running a fine-tooth comb from the scalp to the end of the hair. The results appear in the March issue of The Archives of Dermatology.
This short NY Times article is a good jumping off place.

