Which is not a perceptional disorder

Imagery: awareness of a percept that has been generated within the mind, can be terminated by an effo of will. It is a pa of a normal phenomenon Hallucination: False sensory perception occurring in the absence of any relevant stimulation of the sensory modality involved. Types: auditory, Visual, tactile, gustatory, smell Illusion: Perceptual misinterpretation of a real external stimulus. Synesthesia: Condition in which the stimulation of one sensory modality is perceived as a sensation in a different modality, as when a sound produces a sensation of colour. Reference: P. 924 ,925, 928 chap 7.3 Signs and Symptoms in Psychiatry(Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 9th Edition)