Charles-bonnet Syndrome: Hallucinations are in the Eye of the Beholder

Abstract

Introduction

Charles-Bonnet Syndrome (CBS) is a clinical entity characterized for visual hallucinations in patients with severe vision impairment and preserved cognitive state. Its pathogeny is still unknown, limiting management options. For diagnosis neurological and psychiatric disorders must be discarded. Treatment is based in three pillars: explaining to the patient the origin and nature of the symptoms, treating the visual deficit when possible, and pharmacotherapy with anti-psychotics.

Objectives and aims

To outline the main characteristics and etiopathogenic theories of the CBS, so as to improve diagnosis and treatment.

Methods

Basing on a case followed in mental health consults, we made a systematic review of the articles published in Medline (PubMed) in the last 5 years, with the following keywords, Charles-Bonnet Syndrome, hallucinations, deafferentation, visual impairment.

Results

We found that all our case and the reported ones had in common the nature and characteristics of the hallucinations, the presence of a trigger, usually a new medicament, and the functional MRI patrons of activity; those patrons located the loss of input prior to the association cortex, which appeared hyper-excitable in functional MRI.

Conclusions

Although the aetiology and pathogeny of CBS is still unclear, present data suggests that the key mechanism may be a dysregulation in the homeostatic adaptation of the neural pathway when it is left without external input, traducing a hyper-function of a physiological process, probably mediated by acetylcholine, as opposed with other neuropsychiatric pathologies, in which the cortex is the primary affected area.

Disclosure of interest

The authors have not supplied their declaration of competing interest.