Randall Children's hospital has opened a first of its kind Children's Sleep Medicine Clinic in Portland.  Sleep specialist Dr. Teng Ji says up to half of children between the ages of 1 and ten have sleep disorders.  Dewey Halpaus' 21-month-old son Grayson was recently diagnosed with a mild form of the problem during an overnight sleep study at the center.  He has been referred to a specialist for treatment, before the disorder causes any other health problems.  The center has been open since April.