Optic Neuritis: From Magnocellular to Cognitive Residual Dysfunction

Anne-Claire Viret,Céline Cavézian,Sylvie Chokron,Netta Levin,Vivien Vasseur,Olivier Gout,Catherine Vignal,Noa Raz,Olivier Coubard

doi:10.1155/2013/142680

Abstract

Optic Neuritis (ON) has been associated to both parvocellular dysfunction and to an alteration of the magnocellular pathway. After objective visual field and acuity recovery, ON patients may complain about their vision suggesting a residual subclinical deficit. To better characterize visual abnormalities, 8 patients recovering from a first ON episode as well as 16 healthy controls performed a simple detection task and a more complex categorization task of images presented in low spatial frequencies (to target the magnocellular system) or in high spatial frequencies (to target the parvocellular system) or of non-filtered images. When completing the tasks with their (previously) pathologic eye, optic neuritis patients showed lower accuracy compared to controls or to their healthy eye for low spatial frequency images only. Conjointly, the longest reaction times were observed with the previously pathologic eye regardless the type of images and to a greater extent in the categorization task than in the detection task. Such data suggest two distinct, although associated, types of residual dysfunction in ON: a magnocellular pathway alteration and a more general (magno and parvocellular) visual dysfunction that could implicate the cognitive levels of visual processing.

Highlights

Optic neuritis (ON) is an acute inflammatory disease of the optic nerve that affects young women [1, 2]
The only significant effect revealed by the analyses of variance (ANOVA) for three groups, two tasks and three image types was the group by image type interaction (F(4,58) = 2.6; p = 0.046)
The three groups did not differ in the detection task, the Pathologic Eye group showed longer response times (RTs) than did the Control Eye group in the categorization task (p = 0.014; note that the Healthy Eye group showed intermediate RTs, as it did not differ from either of the other two groups) (Fig. 3)

Summary

Introduction

Optic neuritis (ON) is an acute inflammatory disease of the optic nerve that affects young women [1, 2]. Visual loss is often unilateral and rapid, can be partial or complete, and may be associated with retrobulbar pain [3]. The degree of visual loss is apparently unrelated to age, gender, or abnormalities on fundus examination [1]. Whilst optic neuritis has multiple causes, the most common etiology is multiple sclerosis (MS), a nervous system disease that affects the brain and the spinal cord; in 20% of MS patients, an episode of ON is the presenting sign of the disease. Recovery usually begins 2 weeks after the acute phase and is complete within 1 to 3 months in most patients following their first episode of ON [4,5]. The degree of recovery is apparently unrelated to age, gender, ethnicity, concurrent presence of MS, or mor-

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