Bobble-head doll syndrome (BHDS) is a rare neurological condition thatis typically first seen in childhood. The signs and symptoms of BHDS includecharacteristic up and downhead movements that increase during walking and excitement and decrease during concentration.Although the specific cause of this condition is unknown, BHDS is often seen with cysts in the third ventricle of the brain that alsocause hydrocephalus (water on the brain). Treatment for BHDS may involve surgical removal of the cyst causing the condition or using a shunt to drain excess water on the brain.