Optical Coherence Tomography Is Associated With Cognitive Impairment in Multiple Sclerosis.

BACKGROUND: Optical coherence tomography (OCT) is a sensitive method for quantifying retinal neuronal and axonal structures. Reductions in retinal nerve fiber layer (RNFL) and ganglion cell inner plexiform layer (GCIPL) thicknesses have a reported association with white and grey matter atrophy in multiple sclerosis (MS). We hypothesized that the thinning of intraretinal layer measurements associates with cognitive decline in MS patients with no prior event of optic neuritis (ON). METHODS: OCT and NeuroTrax computerized cognitive assessments were performed in 204 relapsing remitting MS patients with no history of ON or other conditions affecting the eye. Data were collected between 2010 and 2020 and retrospectively analyzed. Correlations were examined between cognitive performance and a lower RNFL or GCIPL thickness. A multilinear regression model was generated to assess the significance of these correlations regarding the disability score and disease duration. RESULTS: The 204 study participants had a mean age of 40.52 ± 11.8 years (mean ± SD) and disease duration of 9.80 ± 9.40 years. The mean RNFL thickness in this whole cohort was 82.22 ± 10.85 µm and the global cognitive score was 95.32 ± 12.32. The mean GCIPL thickness measured in a subgroup of 104 patients was 74.27 ± 10.37 µm. The RNFL and GCIPL both correlated with the global cognitive score (r = 0.174, P = 0.013 and r = 0.29, P = 0.03, respectively), and with various cognitive domains. However, the GCIPL showed stronger correlations than RNFL, particularly with executive function (r = 0.29, P = 0.003), attention (r = 0.332, P = 0.001), and the information processing speed (r = 0.25, P = 0.012). These correlations remained significant after correcting for confounders. CONCLUSION: OCT measurements correlate with cognitive performance in MS patients. OCT can thus be used to evaluate central nervous system neurodegeneration in MS, as reflected by cognitive decline.

Residual disability after severe relapse in people with multiple sclerosis treated with disease-modifying therapy.

BACKGROUND: The rate of post-relapse residual disability in patients with relapsing-remitting multiple sclerosis (RRMS) treated with disease-modifying drugs (DMD) has not been studied. OBJECTIVE: To assess relapse residual disability in DMD-treated RRMS patients. METHODS: We followed DMD-treated RRMS patients presenting with acute relapse who received high-dose steroids. Increases in Expanded Disability Status Scale (EDSS) of at least 2.0, 1.0-1.5 or 0.5 were defined as severe, moderate or mild relapses, respectively. The proportions of patients with post-relapse residual disability defined as the failure to regain pre-relapse neurological status at 1, 4 and 12 months were evaluated. RESULTS: Out of 1672 relapses in DMD-treated RRMS patients, 17% were severe. In patients who presented with a severe relapse, we observed post-relapse residual disability of at least 1.0 EDSS point in 60.1%, 55.9% and 48.2% of patients at 1, 2 and 12 months of follow-up, respectively. Post-relapse residual disability of at least 2.0 EDSS points was observed in 37.4%, 30.7% and 20.7% of patients after 1, 2 and 12 months, respectively. CONCLUSION: A high rate of incomplete recovery was seen 12 months following severe relapse among RRMS patients and may contribute to the accumulation of long-term disability.