Diabetes Mellitus and Cognition: A Pathway Analysis in the MEMENTO Cohort

OBJECTIVE:To assess the role of biomarkers of Alzheimer’s Disease (AD), neurodegeneration and small vessel disease (SVD) as mediators in the association between diabetes mellitus and cognition.METHODS:The study sample was derived from MEMENTO, a cohort of French adults recruited in memory clinics and screened for either isolated subjective cognitive complaints or mild cognitive impairment. Diabetes was defined based on blood glucose assessment, use of antidiabetic agent or self-report. We used structural equation modelling to assess whether latent variables of AD pathology (PET mean amyloid uptake, Aβ42/Aβ40 ratio and CSF phosphorylated tau), SVD (white matter hyperintensities volume and visual grading), and neurodegeneration (mean cortical thickness, brain parenchymal fraction, hippocampal volume, and mean fluorodeoxyglucose uptake) mediate the association between diabetes and a latent variable of cognition (five neuropsychological tests), adjusting for potential confounders.RESULTS:There were 254 (11.1%) participants with diabetes among 2,288 participants (median age 71.6 years; 61.8% women). The association between diabetes and lower cognition was significantly mediated by higher neurodegeneration (standardized indirect effect: -0.061, 95% confidence interval: -0.089; -0.032), but not mediated by SVD and AD markers. Results were similar when considering latent variables of memory or executive functioning.CONCLUSION:In a large clinical cohort in the elderly, diabetes is associated with lower cognition through neurodegeneration, independently of SVD and AD biomarkers.

Abstract P73: Imaging Markers of Brain Frailty and Outcome in Patients With Acute Ischemic Stroke

Background and purpose: Functional outcome after stroke may be related to preexisting brain health. Several imaging markers of brain frailty have been described including brain atrophy and markers of small vessel disease. We investigated the association of these imaging markers with functional outcome after acute ischemic stroke. Methods: We retrospectively studied patients with acute ischemic stroke enrolled in the AXIS-2 trial, an international, multicenter, randomized controlled clinical trial of Granulocyte Colony Stimulating Factor versus placebo. We assessed the ratio of brain parenchymal volume to total intracerebral volumes (i.e., the brain parenchymal fraction [BPF]) and total brain volumes from routine baseline MRI data obtained within 9 hours of symptom onset using the unified segmentation algorithm in SPM12. Enlarged perivascular spaces (EPVS), white matter hyperintensities (WMH), lacunes as well as a small vessel disease (SVD) burden were rated visually. Functional outcomes (modified Rankin Scale [mRS] score) at day 90 were determined. Logistic regression was used to test associations between brain imaging features and functional outcomes. As there was no significant effect of G-CSF on any outcomes in AXIS-2, placebo and active groups were combined for these analyses. Results: We enrolled 259 patients with a mean age of 69±12 years and 46 % were female. Increased BPF was associated with higher odds of excellent outcome (OR per percent increase: 1.081, 95%CI: 1.012-1.155). Total brain volumes and SVD burden were not associated with functional outcome. An interaction between BPF and large vessel occlusion on excellent outcome was not observed. Conclusions: Global brain health, as assessed by brain parenchymal fraction on magnetic resonance imaging, is associated with excellent functional outcome after ischemic stroke. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT00927836.

Imaging Markers of Brain Frailty and Outcome in Patients With Acute Ischemic Stroke

Background and Purpose: Functional outcome after stroke may be related to preexisting brain health. Several imaging markers of brain frailty have been described including brain atrophy and markers of small vessel disease. We investigated the association of these imaging markers with functional outcome after acute ischemic stroke. Methods: We retrospectively studied patients with acute ischemic stroke enrolled in the AXIS-2 trial (AX200 in Ischemic Stroke Trial), a randomized controlled clinical trial of granulocyte colony-stimulating factor versus placebo. We assessed the ratio of brain parenchymal volume to total intracerebral volumes (ie, the brain parenchymal fraction) and total brain volumes from routine baseline magnetic resonance imaging data obtained within 9 hours of symptom onset using the unified segmentation algorithm in SPM12. Enlarged perivascular spaces, white matter hyperintensities, lacunes, as well as a small vessel disease burden, were rated visually. Functional outcomes (modified Rankin Scale score) at day 90 were determined. Logistic regression was used to test associations between brain imaging features and functional outcomes. Results: We enrolled 259 patients with a mean age of 69±12 years and 46 % were female. Increased brain parenchymal fraction was associated with higher odds of excellent outcome (odds ratio per percent increase, 1.078 [95% CI, 1.008–1.153]). Total brain volumes and small vessel disease burden were not associated with functional outcome. An interaction between brain parenchymal fraction and large vessel occlusion on excellent outcome was not observed. Conclusions: Global brain health, as assessed by brain parenchymal fraction on magnetic resonance imaging, is associated with excellent functional outcome after ischemic stroke. REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00927836.

Smartphone-Based Symbol-Digit Modalities Test Reliably Measures Cognitive Function in Multiple Sclerosis Patients

Limited time for patient encounters prevents reliable evaluation of all neurological functions in routine clinical practice. Quantifying neurological disability in a patient-autonomous manner via smartphones may remedy this problem, if such tests provide reliable, disease-relevant information.We developed a smartphone version of the cognitive processing speed test, the Symbol-Digit Modalities Test (SDMT), and assessed its clinical utility. The traditional SDMT uses identical symbol-number codes, allowing memorization after repeated trials. In the phone app, the symbol-number codes are randomly generated.In 154 multiple sclerosis (MS) patients and 39 healthy volunteers (HV), traditional and smartphone SDMT have good agreement (Lin’s coefficient of concordance [CCC] = 0.84) and comparable test-retest variance. In subjects with available volumetric MRI and digitalized neurological examinations (112 MS, 12 HV), the SDMT scores were highly associated with T2 lesion load and brain parenchymal fraction, when controlled for relevant clinical characteristics. The smartphone SDMT association with clinical/imaging features was stronger (R2 = 0.75, p < 0.0001) than traditional SDMT (R2 = 0.65, p < 0.0001). In the longitudinal subcohort, improvements from testing repetition (learning effects), were identifiable using non-linear regression in 14/16 subjects and, on average, peaked after 8 trials. Averaging several post-learning SDMT results significantly lowers the threshold for detecting true decline in test performance.In conclusion, smartphone, self-administered SDMT is a reliable substitute of the traditional SDMT for measuring processing speed in MS patients. Granular measurements at home increase sensitivity to detect true performance decline in comparison to sporadic assessments in the clinic.

A novel classification of fatigue in multiple sclerosis based on longitudinal assessments

Background: Magnetic resonance imaging (MRI) studies of multiple sclerosis–related fatigue had limited reproducibility. Temporal fatigue fluctuations have not been considered. Objective: To investigate whether a novel group allocation that reflects temporal dynamics of fatigue improves our ability to detect fatigue-associated structural brain abnormalities. Methods: Patient stratification based on biennial fatigue assessments: sustained fatigue (SF, n = 29, fatigued at the latest ⩾2 assessments), one time-point fatigue (1F, n = 15, fatigued at the latest, but non-fatigued at the penultimate assessment), reversible fatigue (RF, n = 31, non-fatigued at the latest assessment, but reported fatigue previously), and never fatigued (NF, n = 54). Brain parenchymal fraction (BPF) and T2 lesion volume (T2LV) were compared between these groups and were derived using a conventional, single time-point fatigued versus non-fatigued stratification. Results: The SF versus NF stratification yielded improved power. SF ( p = 0.005) and RF ( p = 0.043) showed significantly higher T2LV than NF. T2LV showed no significant differences in SF versus 1F, SF versus RF, or 1F versus RF. Fatigued versus non-fatigued patients showed significantly higher T2LV ( p = 0.030). We found no significant differences in BPF between the groups. Conclusion: Taking into account temporal fatigue dynamics increases the statistical power with respect to T2LV and may improve characterization of brain pathological correlates of MS-related fatigue.

Neurofilament light levels are associated with long-term outcomes in multiple sclerosis

Background: Neurofilament light chain (NfL) is a promising marker of disease activity/treatment response in multiple sclerosis (MS), although its predictive value for long-term clinical outcomes remains unclear. Objective: We measured NfL from a phase 3 trial in relapsing-remitting MS and investigated its association with outcomes after 8 and 15 years. Methods: NfL concentrations were measured by single molecule array assay in cerebrospinal fluid (CSF) from MS patients ( n = 235) in a 2-year randomized clinical trial (RCT) of intramuscular interferon β-1a, and in serum ( n = 164) from the extension study. Results: Year 2 CSF and Year 3 serum NfL were associated with brain parenchymal fraction (BPF) change over 8 years ( p < 0.0001, r = −0.46; p < 0.05. r = −0.36, respectively) and were predictive of reaching Expanded Disability Status Scale (EDSS) ⩾ 6.0 at Year 8 (odds ratio (OR) (upper vs lower tertile) = 3.4; 95% confidence interval (CI) = 1.2–9.9, p < 0.05; OR = 11.0, 95% CI = 2.0–114.6; p < 0.01, respectively). Serum NfL concentration (Year 4) was predictive of reaching EDSS score ⩾6.0 at 15 years (OR (upper vs lower tertile) = 4.9; 95% CI = 1.4–20.4; p < 0.05). NfL concentrations were complementary to 2-year BPF change in predicting long-term outcomes. Conclusion: Serum and CSF NfL concentrations were associated with long-term clinical outcomes in MS patients and are promising biomarkers for disease severity stratification supporting treatment decisions.

Periventricular magnetisation transfer ratio abnormalities in multiple sclerosis improve after alemtuzumab

Background: In multiple sclerosis (MS), disease effects on magnetisation transfer ratio (MTR) increase towards the ventricles. This periventricular gradient is evident shortly after first symptoms and is independent of white matter lesions. Objective: To explore if alemtuzumab, a peripherally acting disease-modifying treatment, modifies the gradient’s evolution, and whether baseline gradients predict on-treatment relapses. Methods: Thirty-four people with relapsing-remitting MS underwent annual magnetic resonance imaging (MRI) scanning (19 receiving alemtuzumab (four scans each), 15 untreated (three scans each)). The normal-appearing white matter was segmented into concentric bands. Gradients were measured over the three bands nearest the ventricles. Mixed-effects models adjusted for age, gender, relapse rate, lesion number and brain parenchymal fraction compared the groups’ baseline gradients and evolution. Results: Untreated, the mean MTR gradient increased (+0.030 pu/band/year) but decreased following alemtuzumab (−0.045 pu/band/year, p = 0.037). Within the alemtuzumab group, there were no significant differences in baseline lesion number ( p = 0.568) nor brain parenchymal fraction ( p = 0.187) between those who relapsed within 4 years ( n = 4) and those who did not ( n = 15). However, the baseline gradient was significantly different ( p = 0.020). Conclusion: Untreated, abnormal periventricular gradients worsen with time, but appear reversible with peripheral immunotherapy. Baseline gradients – but not lesion loads or brain volumes – may predict on-treatment relapses. Larger confirmatory studies are required.

A.03 Durable clinical and MRI efficacy of alemtuzumab over 6 years in CARE-MS II patients with RRMS who relapsed between Courses 1 and 2

Background: In RRMS patients with inadequate response to prior therapy, 2 alemtuzumab courses (12 mg/day; baseline: 5 days; 12 months later: 3 days) significantly improved outcomes over 2 years (y) versus SC IFNB-1a (CARE-MS II [NCT00548405]), with durable efficacy over a 4-y extension (NCT00930553). We present 6-y efficacy (2-y core study plus 4-y extension) in patients with relapse (relapsers) between Courses (C) 1 and 2. Methods: Annualized relapse rate (ARR); 6-month confirmed disability worsening (CDW); MRI disease activity (Gd-enhancing lesions; new/enlarging T2 hyperintense lesions); brain volume loss (BVL; derived by relative change in brain parenchymal fraction). Results: 105/435 (24%) patients relapsed between C1 and C2; 33% (relapsers) versus 55% without relapse (non-relapsers) received neither alemtuzumab retreatment nor another disease-modifying therapy through Y6. ARR (Y1: 1.2) declined post-C2 (0.5), remaining low through Y6 (0.2 [0.1, non-relapsers]; 10/105 [10%] relapsed). Through Y6, patients remained CDW-free (60% [relapsers]; 75% [non-relapsers]), Gd-enhancing lesion-free (94% [relapsers]; 90% [non-relapsers]), new/enlarging T2 hyperintense lesion-free (68% [relapsers]; 69% [non-relapsers]), and MRI disease activity-free (68% [relapsers]; 69% [non-relapsers]). Alemtuzumab slowed median percent yearly BVL (Y6: -0.13% [relapsers]; -0.10% [non-relapsers]). Conclusions: Patients relapsing between C1 and C2 improved post-C2 through Y6. These findings support administering 2 alemtuzumab courses to achieve optimal and durable benefit.

A 24-month advanced magnetic resonance imaging study of multiple sclerosis patients treated with alemtuzumab

Background: Tissue damage in both multiple sclerosis (MS) lesions and normal-appearing white matter (NAWM) are important contributors to disability and progression. Specific aspects of MS pathology can be measured using advanced imaging. Alemtuzumab is a humanised monoclonal antibody targeting CD52 developed for MS treatment. Objective: To investigate changes over 2 years of advanced magnetic resonance (MR) metrics in lesions and NAWM of MS patients treated with alemtuzumab. Methods: A total of 42 relapsing–remitting alemtuzumab-treated MS subjects were scanned for 2 years at 3 T. T1 relaxation, T2 relaxation, diffusion tensor, MR spectroscopy and volumetric sequences were performed. Mean T1 and myelin water fraction (MWF) were determined for stable lesions, new lesions and NAWM. Fractional anisotropy was calculated for the corpus callosum (CC) and N-acetylaspartate (NAA) concentration was determined from a large NAWM voxel. Brain parenchymal fraction (BPF), cortical thickness and CC area were also calculated. Results: No change in any MR measurement was found in lesions or NAWM over 24 months. BPF, cortical thickness and CC area all showed decreases in the first year followed by stability in the second year. Conclusion: Advanced MR biomarkers of myelin (MWF) and neuron/axons (NAA) show no change in NAWM over 24 months in alemtuzumab-treated MS participants.