A: Plagiocephaly (flattened portion of the skull) is not an uncommon condition in young children. A severely misshapen head can have both cosmetic and phsycial consequences. If the head is severely misshapen it can effect the position of the child's eyes and possibly their vision. The helmets that are used allow the head to slowly reform over time into a more rounded shape. The comercially available helmets need to be fit to the current shape of the child's head and adjusted frequently to ensure that a gradual change in head shape happens. The helmets are lightweight and should not be anywhere as heavy as the child's head. They should not affect muscle development. Some children have flat areas on their heads due to torticollis (tight neck muscles) that keep their head in one position most of the time. Children with torticollis need gentle streching, often under the guidance of a physical therapist to regain full movement of their neck. If you have concerns about the weight of the helmet contacting the doctor who prescribed the treatment and the company providing the helmet would be a good first step.