NEURODEGENERATION IN MULTIPLE SCLEROSIS: COMPARISON BETWEEN CLINICAL, NEUROPSYCHOLOGICAL, MRI,AND OPTICAL COHERENCE TOMOGRAPHY PARAMETERS

Abstract

BACKGROUND AND OBJECTIVE Optical Coherence Tomography (OCT) enables rapid, non-invasive in vivo measurement of retinal nerve fiber layer (RNFL) thickness, reflecting axonal density within the optic nerve. There is still lack of concordance about the use of OCT in clinical routine as a surrogate measure of brain atrophy. Objective: To investigate the role of OCT as possible predictor of disability, cognitive impairment and neurodegeneration in Multiple Sclerosis (MS). MATERIAL AND METHODS We recruited patients affected by MS according to validated criteria at the Neurological Department of the University of Palermo. Patients performed Stratus OCT- 3 Zeiss to assess RNFL and GCS measurements. Nearly 18 months later, the same patients were re-evaluated. Clinical and cognitive status was assessed also using an extensive neuropsychological battery exploring attention, executive functions and working memory, verbal and visuo-spatial memory, visuospatial functions and language and BICAMS (Brief International Cognitive Assessment for Multiple Sclerosis). Patients performed all subtests of the Italian standardized version. Subjects underwent a single-time-point brain scan using a 1.5T MRI unit; an isotropic 3D-FSPGR T1w sequence was used for brain tissue volume estimation (normalized for subject head size) with tissue-type segmentation by the use of FSL’s package SIENAX. We collected information about disease status, EDSS, relapse rate and current and former therapies. RESULTS Thirty patients (20 women; 27 RR, 2 SP) were recruited for the study. Patients were divided into two groups considering if they were affected by a previous optic neuritis (ON yes) or not (ON no). Ten patients performed the MRI scan. Twenty-two patients were on therapy (5 Interferon beta 1 a, 8 Natalizumab, 8 Fingolimod and 1 azathioprine) and 8 patients don’t take any specific therapy.DISCUSSION AND CONCLUSION.The present study confirms previous data indicating an association between a previous optic neuritis and RFNL thickening. We didn’t observe a significant association with cognitive performances. We observed a significant association also between RFNL thickness and grey matter atrophy independent by neuropsychological performances .There is a need to increase the sample of the study and for longitudinal studies to further clarify the role of OCT as a surrogate marker of degeneration.