Charles Bonnet syndrome
(CBS)
   The eponym Charles Bonnet syndrome (CBS) refers to the Swiss naturalist and philosopher Charles Bonnet (1720-1792). It was introduced in 1936 by the Swiss neurologist Georges de Mor-sier (1894-1982) to denote a hallucinatory state or syndrome characterized by *visual hallucinations occurring in "senile syndromes with ocular lesions", or, as de Morsier rephrased it in 1938, "in the elderly with intact cognition". Historically, the eponym CBS has variously been used to denote (1) visual hallucinations occurring in the cognitive intact elderly, (2) visual hallucinations occurring in the context of eye disease, and (3) visual hallucinations occurring in the presence of preserved insight. The syndrome that was later to be named CBS was first described in 1760 by Bonnet, whose grandfather Charles Lullin suffered from this type of hallucinations. As rendered by Bonnet in his book Essai Analytique sur les Facultés de ï Ame, Lullin had suffered from loss of visual acuity due to a bilateral cataract. Eight years after a first cataract operation (and 1 year after a second operation, after which his visual acuity had become even worse), Lullin reported seeing vivid images of scaffolding and brickwork patterns, a multitude of particles ("atoms") whirling about, clover patterns covering the walls and furniture, as well as people, birds, carriages, buildings, and other objects. According to Bonnet these images were not accompanied by hallucinations in any of the other sensory modalities. Nor did Lullin, a retired magistrate, show any signs of cognitive impairment. Reportedly, Lullin was well aware that his visions were "fictions" of his brain, and showed himself intrigued and amused by them. Near the end ofhis life, Bonnet's own visual acuity deteriorated as well, after which he, too, began to experience visual hallucinations. The hallucinations occurring in CBS have also been referred to as * ophthalmopathic hallucinations, and as * positive spontaneous visual phenomena (PSVP). Their complexity can range from * simple or * geometric to * complex, although the operational definition of CBS, as issued by the psychiatrists Jorge Manuel Ribeiro Damas-Mora et al. in 1982, requires the presence of complex visual hallucinations. Due to their *xenopathic character, hallucinations occurring in the context of CBS tend to have a highly realistic appearance. However, individuals in possession of proper reality monitoring strategies usually recognize the hallucinations at hand as non-sensory percepts. Their onset can be at any age, although CBS has been found to be most prevalent at old age. Estimates as to the prevalence of CBS among elderly individuals with impaired visual acuity range from 10 to 30%. Risk factors for the development of CBS include such conditions as poor visual acuity due to corneal degeneration, age-related mac-ular degeneration, glaucoma, and cataract, as well as solitude, fatigue, poor general physical health, and the use ofbeta blockers. CBS can also occur in association with partial disturbances of vision such as *hemianopia, *quadrantanopsia, central scotoma, and *amblyopia, as well as in temporary disturbances of vision (i.e. * amaurosis fugax). Visual hallucinations occurring in the context of hemianopia or quadrantanopsia tend to manifest themselves in the impaired visual field, but they can also present in the intact field of vision. Pathophysiologically, the hallucinations concomitant to CBS tend to be regarded as falling into the class of * release hallucinations, i.e. hallucinations mediated by spontaneous electrophysiological activity originating from subcortical brain areas such as the thalamus, the pedunculus cerebri, and the limbic system. A competing explanatory model, known as the * deafferentiation hypothesis, attributes the mediation of hallucinations in CBS to the increased excitability of the visual pathways and/or the visual cortex, due to a lack of inhibitory afferent impulses. Brain regions considered capable of mediating spontaneous visual percepts include the retina, the lateral genicu-late nucleus, the primary visual cortex, and the visual association cortex. Conceptually as well as phenomenologically (and perhaps pathophysio-logically as well), visual hallucinations occurring in the context of CBS appear to display some overlap with * bereavement hallucinations and * phantom vision. A variant of Charles Bonnet syndrome was reported in 1953 by the American neurologist and psychiatrist Walter Jackson Freeman (1895-1972) and his colleague Jonathan M. Williams, which involved visual * hallucinations in braille experienced by a virtually blind woman. In occultism and mysticism, individuals suffering from CBS are sometimes referred to as 'Bonnet people', and their capacity to hallucinate as 'a portal to a parallel reality'.
   References
   Bonnet, Ch. (1760). Essai analytique sur les facultés de l'âme. Copenhague: Frères Cl. & Ant. Philibert.
   De Morsier, G. (1936). Les automatismes visuels (Hallucinations visuelles rétro-chiasmatiques). Schweizerische Medizinische Wochenschrift, 66, 700-703.
   ffytche, D.H. (2005). Visual hallucinations and the Charles Bonnet syndrome. Current Psychiatry Reports, 7, 168-179.
   Menon, G.J., Rahman, I., Menon, S.J., Dutton, G.N. (2003). Complex visual hallucinations in the visually impaired: The Charles Bonnet syndrome. Survey of Ophthalmology, 48, 58-72.
   Teunisse, R.J., Cruysberg, J.R., Hoefnagels, W.H., Verbeek, A.L., Zitman, F.G. (1996). Visual hallucinations in psychologically normal people: Charles Bonnet's syndrome. Lancet, 347, 794-797.

Dictionary of Hallucinations. . 2010.

Look at other dictionaries:

  • Charles Bonnet syndrome — Classification and external resources DiseasesDB 2349 Charles Bonnet syndrome (CBS) is a condition that causes patients with visual loss to have complex visual hallucinations, first described by Charles Bonnet in 1760[1 …   Wikipedia

  • auditory charles bonnet syndrome —    Atermusedtodenote musical hallucinations occurring in association with moderate or severe hearing loss. By analogy with the pathophysi ology of Charles Bonnet syndrome in individuals with diminished visual acuity, it has been suggested that… …   Dictionary of Hallucinations

  • Syndrome de charles bonnet — Le Syndrome de Charles Bonnet doit son nom au naturaliste genevois Charles Bonnet qui en donna la description en 1760.[1] Il s agit d hallucinations visuelles complexes survenant chez des sujets âgés ne présentant pas de troubles mentaux. Ces… …   Wikipédia en Français

  • Charles Bonnet — Born March 13, 1720 Geneva Died …   Wikipedia

  • Charles Bonnet — (naturaliste) Pour les articles homonymes, voir Bonnet. Portrait de Charles Bonnet (1720 1793) Charles Bonnet, né le …   Wikipédia en Français

  • Charles Bonnet (Naturaliste) — Pour les articles homonymes, voir Bonnet. Portrait de Charles Bonnet (1720 1793) Charles Bonnet, né le …   Wikipédia en Français

  • Charles bonnet (naturaliste) — Pour les articles homonymes, voir Bonnet. Portrait de Charles Bonnet (1720 1793) Charles Bonnet, né le …   Wikipédia en Français

  • Charles-Bonnet-Syndrom — Klassifikation nach ICD 10 F06.0 Organische Halluzinose …   Deutsch Wikipedia

  • Syndrome de Charles Bonnet — Le Syndrome de Charles Bonnet doit son nom au naturaliste genevois Charles Bonnet qui en donna la description en 1760[1]. Il s agit d hallucinations visuelles complexes survenant chez des sujets âgés ne présentant pas de troubles mentaux. Ces… …   Wikipédia en Français

  • Charles Bonnet (naturaliste) — Pour les articles homonymes, voir Bonnet. Portrait de Charles Bonnet (1720 1793) Charles Bonnet, né le 13 mars 17 …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”