A term used to denote a phenomenologically rich and often well-organized type of hallucination that is confined to a single sensory modality. Theoretically, complex hallucinations may present in any of the sensory modalities. It is customary, however, to reserve the term for hallucinations experienced in the *visual or * auditory modalities. In the auditory modality, complex hallucinations typically take the form of well-articulated speech, elaborate and realistic environmental sounds, or music. In the visual modality, they typically take the shape of a person, a face, an animal, a landscape, a scene, or a composite image of fantasy elements. When a complex hallucination replaces the entire sensory input picture, it is referred to as a * scenic or * panoramic hallucination.Pathophysiologically, complex hallucinations are traditionally associated with aberrant neurophysiological activity in higher-level cortical regions, such as those in the temporal lobe. It has been suggested, however, that the initial impulse for the mediation ofcom-plex hallucinations may stem from other cerebral structures, such as the limbic system (rendering a * reperceptive hallucination), the pedunculus cerebri (rendering a * peduncular hallucination), or the speech areas (rendering a * verbal auditory hallucination). Moreover, complex hallucinations have been described in individuals suffering from lesions affecting the primary sensory cortex, and from lesions affecting the peripheral sense organs. It is unlikely that lesions in such early sensory structures can be held responsible for mediating complex hallucinations. Instead, it has been suggested that such lesions act via the *deafferentiation of higher-level cortical areas, which are in turn responsible for mediating the hallucinations at hand. The term complex hallucination derives from a classification of hallucinations governed by the guiding principle of complexity. It is used in opposition to the terms * simple (or * elementary) hallucination and *geometric hallucination. When hallucinations are experienced in more than one sensory modality at a time, they are referred to as * compound hallucinations.
References
Beniczky, S., Kéri, S., Vörös, E., Ungureân, A., Benedek, G., Janka, Z., Vécsei, L. (2002). Complex hallucinations following occipital lobe damage. European Journal of Neurology, 9, 175-176.
ffytche, D.H. (2007). Visual hallucinatory syndromes: Past, present, and future. Dialogues in Clinical Neuroscience, 9, 173-189.
Jaspers, K. (1963). Gesammelte Schriften zur Psychopathologie. Berlin: Springer-Verlag.
Parish, E. (1897). Hallucinations and illusions. A study ofthe fallacies ofperception. London: Walter Scott.