The disease comes on gradually

 With the growth of age, disease comes gradually and some of them become dominant. Family history and lifestyle are important. 

This is a genetic condition that most often occurs after an accident or trauma to the head, especially when someone has died from this type of stroke. This can also happen if you are pregnant or suffering from traumatic damage such as your baby's birth. The symptoms can include difficulty seeing, hearing, or thinking clearly, along with involuntary muscle spasms and mental confusion.