Shunt failure can cause excess pressure in the brain, which in turn can cause brain damage. This damage could include memory and speach problems. If the physician truely has the best interest of your child in mind, he would acknowledge the possibility that the shunt malfunctioning could have caused these concerns....I am not a doctor, I am a parent of a 3-1/2 year old son with hydrocephalus. Trust your instincts, ask questions and refuse to be ingnored. Read as much as you can and talk about it. You are your child's advocate.