AB094. Development and validation of a screening questionnaire for the Charles Bonnet syndrome
Visual Impairment and Rehabilitation

AB094. Development and validation of a screening questionnaire for the Charles Bonnet syndrome

Sylvie Cantin1,2, Josée Duquette1,2, François Dutrisac1,2, Lise Ponton1,2, Marie Courchesne1,2, Roger Dufour1, Walter de Abreu Cybis1,2, Kassandre Montisci1,2, Walter Wittich1,2,3, Marie-Chantal Wanet-Defalque1,2,3

1Institut Nazareth et Louis-Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada; 2Centre de recherche interdisciplinaire en réadaptation du Montréal Métropolitain, QC, Canada; 3École d’optométrie, Université de Montréal, École d’optométrie, Montréal, QC, Canada

Background: The purpose of this study is to develop a screening questionnaire for the Charles Bonnet syndrome (CBS) that is valid, particularly in terms of specificity and sensitivity, and that allows to examine certain dimensions of these hallucinatory manifestations, to better assess the needs of people who live with the CBS.

Methods: Interviews with clients of the Institut Nazareth et Louis-Braille who experienced visual hallucinations, supported by scientific literature and expert experience, guided the development of the questionnaire. Its content was first validated by six experts who assessed the questions developed, organized in seven subscales: (I) unusual perceptions; (II) contact with reality; (III) discriminatory screening; (IV) adaptation strategies; (V) psychological impact; (VI) description of the context of occurrence and (VII) characteristics. In a second step, a clinical study involving 76 people with visual impairment made it possible to determine the sensitivity and specificity of the instrument according to a criterion validity methodology, namely the clinical impression of a psychologist and/or an optometrist specialized in visual impairment, based on specific examinations and clinical tests. Subjects who appeared to have a CBS following the scouting done by subscale 1 (Unusual Perceptions) completed the rest of the questionnaire.

Results: (I) The analyzes revealed a sensitivity of 1.00 and a specificity that varies from of 0.42 to 0.77 for the identification of CBS with the “Unusual Perceptions” subscale; (II) the administration of the questionnaire to the 76 study participants revealed that the wording of some questions needs to be improved; (III) the responses to the other 6 subscales of the questionnaire given by the 21 participants with SCB, show among others that most have simple rather than complex hallucinations and that these occur daily for 50% of them. Hallucinations do not negatively affect their mood, although they are experienced as disturbing by half of the participants with CBS. Only 11 participants with CBS have already talked about their hallucinations to a relative or a health professional, and only 5 have heard about CBS before.

Conclusions: The CBS screening questionnaire has an excellent sensitivity, and an acceptable specificity. The CBS “Unusual Perceptions” subscale should include additional items. Further studies are needed for this purpose. In addition, the rest of the questionnaire reveals clinically important information about various aspects of these individuals’ hallucinations, such as the fact that many are disturbed by their hallucinations and have never heard of CBS. This questionnaire will help to better assess their needs and better plan interventions.

Keywords: Charles Bonnet syndrome (CBS); questionnaire; screening

doi: 10.21037/aes.2018.AB094
Cite this abstract as: Cantin S, Duquette J, Dutrisac F, Ponton L, Courchesne M, Dufour R, Cybis Wd, Montisci K, Wittich W, Wanet-Defalque MC. Development and validation of a screening questionnaire for the Charles Bonnet syndrome. Ann Eye Sci 2018;3:AB094.