Explain why retained insight into the unreality of the added structure is described as typical in paraschemazia.

Paraschemazia is a felt, subjective distortion of body structure rather than a fixed false belief, so the person is generally able to recognise that the felt extra or altered structure does not correspond to physical reality, even though the sensation itself persists. This retained insight is part of what places paraschemazia among the experiential body-image distortions, alongside phenomena such as schemazia distortion, rather than among the more severe, conviction-based disturbances such as somatoparaphrenia or a delusion of body alteration, where the false belief is held with full conviction and insight is characteristically absent. Recognising which pattern, retained insight or fixed conviction, is present therefore carries useful information about where a presentation sits along this spectrum of body-image disturbance.