The term incomplete hallucination is used to denote a hallucination that lacks one or more of the formal characteristics of the full-blown perceptual phenomenon. For example, the term is used to denote a " visual hallucination that lacks the saturation of colour of ordinary sense perceptions or the spatial qualities of an object in the extracorporeal world. It is also used to denote an " auditory hallucination perceived 'inside' the head (i.e. an " internal auditory hallucination) or one with a 'fake' or artificial sound quality. The French psychiatrist Pierre Lelong conceptualizes incomplete hallucinations as dissociated or depersonalized mental elements that have not - or not yet - been turned into fully ego-alien or ego-dystonic percepts. Lelong divides the developmental process of these mental elements into three stages or degrees, which he designates as obsession (characterized by self-consciousness and anxiety), "psychic hallucination (characterized by depersonalization and "automatisms), and "sensorial hallucination (characterized by its subconscious nature and an apparent objectivity). The issue of phe-nomenological incompleteness has traditionally been considered a favourable sign, in the sense that a 'desensorialization' of hallucinations tends to be interpreted as a sign of recovery, whereas their 're-concretization' tends to be seen as a sign of relapse. The fact that not all the formal characteristics of " hallucinations proper are present has led some authors to designate incomplete hallucinations as "pseudohallucinations. The term incomplete hallucination is used in opposition to the term "complete hallucination.
References
Lelong, P. (1928). Le problème des hallucinations. Paris: Librairie J.-B. Baillière et Fils.
Dictionary of Hallucinations. J.D. Blom. 2010.