Abstract Details

Title Temporal Reorganization To Overcome Monocular Demyelination

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) IN4 - (-)

Poster/Presentation
Number 005

Objective

Background Following unilateral ON, input to the visual cortex is delayed via the affected eye (AE) as manifested by prolonged visual evoked potential [VEP] latencies. Prolonged VEP latencies are also commonly found in the clinically unaffected fellow eye (FE). These are commonly interpreted as evidence for sub-clinical demyelination in the fellow nerve.

Design/Methods 18 patients 1-2 years following an ON attack & 18 aged-matched controls were studied. All subjects underwent VEP test. Latencies of the start, peak and end of VEP wave (corresponding to N75 P100 & N135) were measured. Additionally, high resolution and diffusion MRI were obtained and post-chiasmal visual pathways were delineated. T2 and FLAIR sequences were used to identify demyelinated lesions in these pathways. Behaviorally, novel motion perception test and stereopsis test in which the stimuli are presented for a limited time interval were conducted.

Results P100 was significantly prolonged in both AEs (127ms ±6) and FEs (117ms ±8). FEs exhibited normal visual functions (versus sustained motion perception deficits in AEs). The prolonged VEP latencies were not explained by demyelinative lesions along the visual pathways. The FEs' VEP wave revealed a delayed peak, but an early start (N75 latency was similar to controls, 75ms ±7.6, versus 88ms ±10 in AEs, p=0.002). Thus FEs exhibit a widened VEP wave, approximating its peak with that of the AE. Significant correlation was found between the proximity of VEP peaks among the eyes and 3D perception, for stimuli presented during a limited time interval (r=-0.69, p=0.02).

Conclusions Delayed latencies in the FE may reflect an adaptive cortical process aiming at binocular integration in time, and restoration of binocular visual functions. This provides a unique example of reorganization in the temporal domain.

Authors/Disclosures
Netta Levin, MD, PhD (Hadassah Hebrew University Hospital) PRESENTER	Dr. Levin has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file

��ɫ��

��ɫ��