Changes

** Idiopathic

** Idiopathic

** Symptomatic

** Symptomatic

*** Due to intracranial disease e.g. neoplasia, storgae diseases etc.

*** Due to intracranial disease e.g. neoplasia, storage diseases etc.

** Cryptogenic

** Cryptogenic

*** There is probably an underlying cause but it cannot be identified by the diagnostic tests available.

*** There is probably an underlying cause but it cannot be identified by the diagnostic tests available.