Streaming before dreaming could be worse for young people than first thought.

Otago University researchers are monitoring young people's screen-use at bedtime to see if it impacts sleep quality.

The study's recruiting a group of 11 to 14 year olds, surveyed through a camera on their bedside table.

Study co-leader Brad Bronson told Heather du Plessis-Allan screens are bad for sleep - but we don't know just how bad.

"There's quite a few flaws in the research. They don't usually look at the in-bed screen use, which is interesting because 80 per cent of teens in this country seem to be doing it."

He says in the study they'll also look at the impact of different kinds of content.

"We're looking at if Netflix is as bad as playing your Nintendo. We don't really know the answers to those questions yet."

LISTEN ABOVE