Formed image perseveration Formed image perseveration refers to a single, stationary object that remains fixed in one's visual field. These pathological afterimages look realistic and have the same color and clarity as the original stimulus. The palinopsia lasts at least 15 seconds, but may persist for hours or days. For example, a patient sees a cat, and an identical copy of the cat remains fixed in the field of view for 30 minutes. A patient commonly complains of the perseverated fingers of an examiner. These afterimages often occur in visual field deficits but may occur anywhere in the visual field, regardless of the location of the original stimulus. The generation of the afterimages is not affected by external conditions such as the length of fixation, brightness of the stimulus, contrast, or motion. The palinoptic image can appear immediately after seeing the original image or may be delayed in time. Scene perseveration Scene perseveration refers to seeing a previously-viewed, short stereotyped scene that continuously replays for several minutes. For example, a patient might view a person throwing a ball, and then an hour later, perceives the same action sequence repeated many times. The palinoptic scene usually has the same color and clarity as the original. Our understanding of visual memory considers a short scene as a unit of memory, similar to an image, thus scene perseveration is probably mechanistically related to formed image perseveration. Categorical incorporation Categorical incorporation refers to seeing an object or feature and superimposing it onto comparable objects or people. For example, after seeing a person wearing a hat, that same hat is seen on each subsequent person seen. Or a person sees the spire of a building and then incorporates it to the top of other structures seen. The palinoptic images have the same characteristics as the original stimulus, and episodes of categorical incorporation usually last a few minutes. Categorical incorporation highlights the brain's use of constructs to process stimuli. Patterned visual spread Patterned visual spread describes the spread of a pattern in a field of view. For example, a patient sees a checkered pattern on a lamp, which then contiguously spreads to objects such as the floor or a desk. Contextual clues do not influence patterned visual spread, distinguishing it from categorical incorporation.
Hallucinatory palinopsia
Lexical–gustatory synesthesia
Illusory palinopsia
Agraphesthesia
Homonymous hemianopsia
Hemifacial spasm
Facial toning
Binocular dysphoria