San Raffaele Hospital - Vita-Salute San Raffaele University
Neurology

Author Of 1 Presentation

Neuro-Ophthalmology Oral Presentation

PS15.05 - Retinal neuro-axonal loss reflects disability accrual in progressive multiple sclerosis independently from disease activity

Speakers
Presentation Number
PS15.05
Presentation Topic
Neuro-Ophthalmology
Lecture Time
13:39 - 13:51

Abstract

Background

The visual pathway has emerged as an elective platform to study the interaction between demyelination and neurodegeneration in multiple sclerosis (MS)

Objectives

We specifically assessed neural damage at this level in progressive MS (PMS), also exploring the evolution over time of functional (trough visual evoked potentials - VEPs) and structural (trough optical coherence tomography - OCT) parameters, as well as their relations with disease course and clinical disability.

Methods

We performed a prospective longitudinal study enrolling 350 PMS patients (228 secondary progressive MS - SPMS, 122 primary progressive MS - PPMS) who underwent a cross-sectional evaluation comprehensive of Expanded Disability Statur Scale (EDSS) assessment, high (HCVA)- and low-contrast (LCLA) visual acuity test, full-field (ff-VEPs) as well as multifocal (mf-VEPs) VEPs, and OCT. We performed a follow-up assessment (mean interval 2.0±0.9 years) in 147 patients (52 PPMS and 95 SPMS); a parallel collection of clinical records (including reports MRI scans, performed as per clinical practice) has been also obtained.

Results

Independently from previous optic neuritis (ON), we found visual conduction to be slower among SPMS compared to PPMS patients, particularly for mf-VEPs: mean latency 168.9 ms (95% CI 166.2-171.1) vs 163.8 ms (95% CI 160.7-166.9) respectively, p=0.019. Retinal Nerve Fiber Layer (RNFL) was also found to be thinner among SPMS in comparison to PPMS patients: mean 83.4 μm (95% CI 81.4-85.4) vs 87.0 μm (95% CI 84.4-89.6), p=0.040, with similar results for Ganglion Cell-Inner Plexiform Layer (GCIPL). Considering the evolution over time of functional and structural parameters, we found no significant differences comparing PPMS and SPMS patients. Reclassifying our cohort according to EDSS status (“stable” vs “worsened”) we found a significant between-groups difference in terms of RNFL evolution: mean annualized percent change -0.163 %/year (95% CI -0.467 - -0.141) vs -0.854 %/year (95% CI -1.188 - -0.521) respectively, p=0.003. Similar findings were obtained for GCIPL change. In both cases, these observations were independent from the evidence of MRI activity during follow-up.

Conclusions

our results suggest the presence of a greater functional and structural involvement of the visual system among SPMS compared to PPMS patients, independently from previous ON history; follow-up data suggest however neurodegeneration accrual over time to be similar between these two clinical subgroups. The longitudinal relation between RNFL - GCIPL thinning and EDSS worsening, even in the absence of overt MRI activity and/or clinical relapses, suggests OCT to represent a useful tool to monitor disease progression and to assess neuroprotection in PMS.

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