Diagnosing and phenotyping visual synaesthesia: a preliminary evaluation of the revised test of genuineness (TOG-R).

Full Abstract

Synaesthesia, a neurological condition affecting approximately .05% of the population, is characterised by anomalous sensory perception:
a stimulus in one sensory modality triggers an automatic, instantaneous, consistent response in another modality (e.g., sound evokes colour) or in a different aspect of the same modality (e.g., black text evokes colour). As evidence was limited to case studies based on self-report, the existence of synaesthesia was regarded with scepticism until the development of the Test of Genuineness (TOG) in 1987, which measures the consistency of stimulus-response linkage:
synaesthetes typically score between 70-90% range, whereas controls typically score between 20-38%. However, the TOG had only limited ability to quantify the characteristics of visual synaesthesia. In this study, the revised Test of Genuineness (TOG-R), utilising the Pantone-based Cambridge Synaesthesia Charts, was given to 26 synaesthetes and 23 controls. Results confirmed that the TOG-R is equally accurate in the diagnosis of synaesthesia; synaesthetes scored significantly (t47 = 16.01, p < .001) higher (mean = 71.3%, SEM = 1.4%) than controls (mean = 33%, SEM = 2.0%). The TOG-R provides greater precision in quantifying the closeness of colour matches and enables a more detailed analysis of visual synaesthesia. Synaesthetes were phenotyped into broad- and narrowband based on their overall responsiveness to auditory stimuli, with bandwidth determined primarily by responsiveness to non-word stimuli. They were further sub-phenotyped based on responses to sub-groups of stimuli into word-colour (WC) and music-colour (MC). Development of this instrument has important implications for the diagnosis and phenotyping of visual synaesthesia.

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Author information

Author/s: Asher, Julian E (JE); Aitken, Michael R F (MR); Farooqi, Nasr (N); Kurmani, Sameer (S); Baron-Cohen, Simon (S);

Affiliation: Department of Psychiatry, University of Cambridge, Cambridge, UK. jea41(-atsign-)cam.ac.uk

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Cortex; a journal devoted to the study of the nervous system and behavior (Cortex), published in Italy. (Language: eng)

Reference: 2006-Feb; vol 42 (issue 2) : pp 137-46

Dates: Created 2006/05/10; Completed 2006/09/07; Revised 2006/11/15;

PMID: 16683486, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Male
Middle Aged
Neuropsychological Tests - statistics & numerical data
Psychometrics
Reading
Reproducibility of Results
Visual Perception

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