Neuropsychiatry of complex visual hallucinations

Authors

  • Ramon Mocellin,

  • Mark Walterfang,

  • Dennis Velakoulis


Mark Walterfang, Consultant Psychiatrist of Neuropsychiatry Unit, Royal Melbourne Hospital, and Research Fellow of Melbourne Neuropsychiatry Centre, University of Melbourne (Correspondence); Ramon Mocellin, Consultant Psychiatrist of Neuropsychiatry Unit, Royal Melbourne Hospital, and Northwest Aged Persons’ Mental Health Program, Bundoora; Dennis Velakoulis, Director of Neuropsychiatry Unit, Royal Melbourne Hospital, and Clinical Director of Melbourne Neuropsychiatry Centre, University of Melbourne
Neuropsychiatry Unit, Level 2, John Cade Building, Royal Melbourne Hospital, Melbourne, Victoria 3050, Australia. Email: mark.walterfang@mh.org.au

Abstract

Objective:  To describe the phenomenology and pathophysiology of complex visual hallucinations (CVH) in various organic states, in particular Charles Bonnet syndrome and peduncular hallucinosis.

Method:  Three cases of CVH in the setting of pontine infarction, thalamic infarction and temporoparietal epileptiform activity are presented and the available psychiatric, neurological and biological literature on the structures of the central nervous system involved in producing hallucinatory states is reviewed.

Results:  Complex visual hallucinations can arise from a variety of processes involving the retinogeniculocalcarine tract, or ascending brainstem modulatory structures. The cortical activity responsible for hallucinations results from altered or reduced input into these regions, or a loss of ascending inhibition of their afferent pathways.

Conclusions:  A significant degree of overlaps exists between the concepts of Charles Bonnet syndrome and peduncular hallucinosis. The fluidity of these eponymous syndromes reduces their validity and meaning, and may result in an inappropriate attribution of the underlying pathology. An understanding of how differing pathologies may produce CVH allows for the appropriate tailoring of treatment, depending on the site and nature of the lesion and content of perceptual disturbance.

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