Demyelination affects temporal aspects of perception: An optic neuritis study

Abstract

Conduction velocity in the visual pathways correlated closely with dynamic visual functions, implicating the need for rapid transmission of visual input to perceive motion. Motion perception level may serve as a tool to assess the magnitude of myelination in the visual pathways. The constancy across patients may serve as a baseline to assess the efficacy of currently developing neuroprotective and regenerative therapeutic strategies, targeting myelination in the central nervous system.

Optic Neuritis: From Magnocellular to Cognitive Residual Dysfunction

“…The present data are also consistent with previous findings showing impaired motion [19,30,31] or achromatic stimuli [20] processing, thus also suggesting a magnocellular deficit among ON patients that appeared to have full ophthalmologic recovery. Magnocellular deficits have been proposed to represent a behavioural correlate of demyelination in ON patients [31,32].…”

“…Magnocellular deficits have been proposed to represent a behavioural correlate of demyelination in ON patients [31,32]. However, it is interesting to note that in ON patients, the deficit in processing LSF only occurs in terms of error rate and not in terms of reaction time.…”

Dynamic Visual Tests to Identify and Quantify Visual Damage and Repair Following Demyelination in Optic Neuritis Patients

“…Using the OFM protocol, we have demonstrated a sustained deficit in the affected eyes of ON patients, evident even 12 months following the optic neuritis attack, while standard visual functions had recovered 8 . Furthermore, impaired performance was associated with delayed conductions (delayed P100, reflecting demyelination) and improvement in motion perception was correlated with shortening of conduction rates (reflecting remyelination; linear least squares regression with calculation of the correlation coefficient F=27.3; p=0.0005; r=-0.87) 9 .…”

“…The correlation between OFM scores and VEP (P100) latency values indicate that OFM may not only identify, but also quantify the demyelinative damage. The correlation between improvement in the OFM protocol and shortening of VEP latencies along time 9 suggest that the OFM protocol may also sensitively quantify remyelination.…”

The second face of blindness: Processing speed deficits in the intact visual field after pre- and post-chiasmatic lesions

“…Despite exhibiting normal detection abilities in their visual field, patients with optic neuritis are impaired in motion detection and temporal processing tasks [19][20][21]. Longitudinal studies showed that perception of stationary stimuli, as presented in perimetry, recovers fast after the optic neuritis episode, but deficits in dynamical aspects of perception persist [20,21].…”