Ishihara color plates utilized as an assessment for simultanagnosia in posterior cortical atrophy: A case report

Abstract

BACKGROUND

Simultanagnosia is a neurological disorder that impairs an individual's ability to perceive more than one object at a time visually. While the individual may acknowledge the presence of multiple objects in his field of view, he cannot generally summarize the overall percept.

CASE SUMMARY

We describe a case of simultanagnosia in Posterior Cortical Atrophy, evidenced by the Ishihara color test. A 54-year-old woman complained of reading problems despite normal visual acuity and a structural eye exam. The patient failed to identify any of the Ishihara color plates in either eye despite adequate naming of colors. Automated visual field testing showed a homonymous hemianopia. Structural and functional neuroimaging and cerebrospinal fluid analysis were consistent with posterior cortical atrophy.

CONCLUSION

Simultanagnosia can be tested with the Ishihara pseudoisochromatic plates because the recognition of embedded number patterns in the test requires appreciation of a collection of individual stimuli.

Keywords: Simultanagnosia; Posterior cortical atrophy; Color vision; Benson syndrome; Ishihara color plates; Case report

Core Tip: The Isihara pseudoisochromatic plate is a commonly available non-invasive, subjective test for color vision. The diagnosis of simultanagnosia relies on the subjective responses of the likely sufferer to visual stimuli. Therefore, the Isihara test plates offer a novel way of diagnosing this condition. A knowledge of the response of simultanagnostic patients can potentially guide diagnosis when performing standard color vision testing using Isihara test plates.