Chorea-acanthocytosis (ChAc) is a form of neuroacanthocytosis (see this term) and is characterized clinically by a Huntington disease-like phenotype with progressive neurological symptoms including movement disorders, psychiatric manifestations and cognitive disturbances.

Perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space.