Background

In 2017, a revision of the 2010 McDonald criteria for multiple sclerosis (MS) diagnosis in clinically isolated syndrome (CIS) patients has been proposed. However, its validation in a large multicenter cohort of CIS patients is still needed.

Objectives

To compare the performance of 2017 and 2010 revisions of the McDonald criteria with respect to MS development in a large multicentric cohort of CIS suggestive of MS.

Methods

Brain and spinal cord magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) examination obtained ≤5 months from CIS onset and a follow-up brain MRI acquired ≤15 months from CIS onset were assessed in 626 CIS patients from 9 European MS centres. The occurrence of a second clinical attack (clinically definite [CD] MS) was recorded. Performances of the 2017 and 2010 revisions of McDonald criteria for dissemination in space (DIS), time (DIT) and DIS plus DIT, also including OCB assessment, were evaluated with a time-dependent receiver operating characteristic curve analysis. Median time to MS diagnosis for the different sets of criteria was estimated through Kaplan-Meier curves.

Results

At the last evaluation (median=61.9 months [IQR=39.1-102.5]), 319 (51%) of 626 patients had CDMS. At 36 months, for DIS, the 2017 MRI criteria had higher sensitivity (0.84 [95% CI=0.79-0.88] vs 0.77 [0.72-0.82]), lower specificity (0.33 [0.28-0.39] vs 0.40 [0.35-0.46]), and similar area under the curve values (AUC, 0.59 [0.55-0.62] for both). The 2017 DIS plus DIT MRI criteria had higher sensitivity (0.68 [0.63-0.74] vs 0.62 [0.56-0.68]), lower specificity (0.55 [0.49-0.61] vs 0.62 [0.56-0.68]), and similar AUC values (0.62 [0.58-0.66] for both). CSF-specific OCB assessment as part of the 2017 criteria revision, increased the sensitivity (0.81 [0.75-0.85]), decreased specificity (0.40 [0.34-0.46]) and preserved AUC values (0.60 [0.56-0.64]). Median time to MS diagnosis was earlier with the 2017 revision compared to the 2010 or CDMS criteria, especially with OCB assessment (2017 revision with OCBs=3.6 months [3.1-4.0], 2017 revision without OCB=11.6 months [7.8-13.5], 2010 revision=13.9 months [12.4-15.3], CDMS=56.3 months [43.8-76.0]).

Conclusions

The 2017 revision of the McDonald criteria showed overall similar accuracy to the 2010 McDonald criteria in predicting CDMS development. The suggested modifications are expected to simplify the clinical use of MRI criteria without reducing accuracy and allow an earlier diagnosis of MS.

Background

Cognitive deterioration affects a large proportion of multiple sclerosis (MS) patients, but it occurs also with healthy aging. The effects of aging on cognitive performance in MS have not been fully investigated yet.

Objectives

By evaluating a large multicentric cohort of healthy controls (HC) and MS patients, we compared the age-related decline of cognitive functions occurring in HC and MS patients.

Methods

Brief Repeatable Battery of Neuropsychological Tests (BRB-N) was evaluated in 301 healthy controls (HC) (150 females, age 18-76 years, mean education=14.9 years) and 664 MS patients (421 females; age 18-77 years; mean education=13.3 years; 536 relapsing-remitting and 128 progressive MS) recruited from 3 centers of the Italian Neuroimaging Network Initiative (INNI, www.inni-ms.org). BRB-N allowed to assess verbal memory (Selective Reminding Test [SRT]), visuospatial memory (10/36 Spatial Recall Test [SPART] and delayed-recall), information processing speed (Symbol Digit Modalities Test [SDMT], Paced Auditory Serial Addition Test [PASAT] 3” and 2”) and verbal fluency (Word List Generation [WLG]). Raw scores of each test were converted to Z-scores, based on HC’s cohort by running linear models to regress out the effects of sex, age, education and center. The residuals for both HC and MS patients were then divided by the HC’s error term. Linear models were built for investigating the association of standardized scores with age in MS patients.

Results

In HC, scores of all the BRB-N tests except PASAT 3” and WLG declined significantly with aging (p from <0.0001 to 0.003). Compared to HC, MS patients showed significant worse estimated mean performances already from the age of 20 years in all BRB-N tests (p from <0.0001 to 0.003), except for SPART, SPART delayed-recall and PASAT 3”, whose estimated mean scores significantly worsened later in age (p from 0.03 to 0.04). MS patients showed also a steeper age-related decline of SPART, SPART delayed-recall, SDMT, PASAT 3”, PASAT 2” performances compared to HC (p from <0.0001 to 0.008). No differential effect of age compared to HC was detected in MS patients for WLG and SRT.

Conclusions

Cognitive deficits already affect young adult MS patients and progress faster during patients’ lifespan compared to healthy aging. A different susceptibility to age-effect exists in the cognitive tests currently used to assess cognition in MS patients. The accumulation of MS-related damage combined with brain aging may have synergic detrimental effects on cognitive performances of MS patients.

Funding. This project has been supported by a research grant from the Fondazione Italiana Sclerosi Multipla (FISM2018/S/3), and financed or co-financed with the ‘5 per mille’ public funding.

Background

The functional substrates of deficits of executive function (EF), a relevant disabling symptom in MS patients, have been scarcely investigated.

Objectives

To investigate changes of resting state (RS) functional connectivity (FC) in patients with MS and their correlation with neuropsychological measures related to EF.

Methods

High-resolution T1-weighted and RS functional MRI (fMRI) scans were acquired from 116 MS patients and 65 matched healthy controls (HC). All subjects underwent a neuropsychological evaluation, including the computerized version of the Wisconsin Card Sorting Test (WCST), a multidimensional EF assessment. MS patients also underwent a clinical evaluation, including the expanded disability status scale (EDSS). RS FC was assessed using a seed-voxel correlation analysis. Seed regions relevant for EF were derived from the literature: left (L) inferior parietal sulcus (IPS), L frontal pole (FP) and right (R) cerebellum (Crus I and II). We used SPM and voxel-wise models to compare RS FC between MS patients and HC within the identified networks. Then, associations between RS FC and age- and education-corrected WCST scores and EDSS were evaluated.

Results

Twenty-five (21.5%) MS patients failed the WCST. Compared to HC, MS patients showed significantly decreased RS FC of the L IPS with bilateral middle frontal, L middle temporal and L cerebellar regions, as well as increased RS FC of the L IPS with bilateral thalami. MS patients also exhibited decreased RS FC between the L FP and superior parietal regions. A widespread RS FC decrease was found in MS vs HC between the R Crus I/II and bilateral cerebellar regions and fronto-parietal cortices. Significantly increased RS FC was finally detected between the R Crus I/II and the bilateral orbitofrontal cortex. In MS patients, significantly increased RS FC between the R Crus I/II regions and the orbitofrontal cortex was associated with better performance at the WCST (r=range 0.19-0.27, p=range 0.03-0.003). Conversely, decreased fronto-cerebellar and parieto-cerebellar RS FC was correlated with higher EDSS score (r=range -0.19 to -0.35, p=range 0.03-<0.001).

Conclusions

In an MS group relatively spared by relevant EF deficits, increased RS FC strength in EF-related functional networks was detected. The association between increased RS FC and better WCST scores suggests a compensatory role of detected RS FC abnormalities in these patients.

Background

Cognitive impairment (CI) affects up to 70% of multiple sclerosis (MS) patients. Although several magnetic resonance imaging (MRI) correlates of CI have been suggested, their relative contribution to explain CI requires further investigation.

Objectives

To evaluate the combined contribution of white matter (WM) lesions, gray matter (GM) atrophy and resting state (RS) functional (f) MRI abnormalities in explaining CI in a large cohort of MS patients.

Methods

Brain 3T dual-echo, 3D T1-weighted and RS fMRI scans were acquired from 100 healthy controls (HC) and 276 MS patients. All MS patients underwent the Rao’s battery. CI was defined by ≥2 tests with a z-score<-1.5. Distribution of brain WM lesions, GM atrophy and RS functional connectivity (FC) abnormalities within the default mode (DMN) and salience (SN) networks were compared between HC and MS patients at a voxel level. Using sex-, age- and phenotype-adjusted stepwise logistic regression models, the role of WM lesions (model 1), GM atrophy (model 2), RS FC (model 3) and their combination (model 4) in explaining CI was investigated. Model performances were assessed by the area under the curve (AUC).

Results

Eighty-three MS patients had CI. In model 1, lesions in left (L) superior longitudinal fasciculus (SLF) (odds ratio [OR]=1.84), L medial lemniscus (OR=1.79) and L inferior longitudinal fasciculus (OR=1.57) predicted CI (p≤0.009). In model 2, L precuneus (OR=0.52) and L caudate (OR=0.56) volumes predicted CI (p≤0.007). In model 3, increased RS FC in L caudate (DMN) (OR=1.77) and decreased RS FC in right (R) thalamus (DMN) (OR=0.66) and L inferior frontal gyrus (IFG) (SN) (OR=0.68) predicted CI (p≤0.02). In model 4, R middle cerebellar peduncle (OR=2.05) and L SLF (OR=1.84) lesions, L precuneus atrophy (OR=0.46), increased RS FC in L caudate (DMN) (OR=1.64), and decreased RS FC in L IFG (SN) (OR=0.64) predicted CI (p≤0.02). Compared to demographic and clinical variables only (AUC=0.73), the separate models performed significantly better (AUC=0.82, 0.81 and 0.80, respectively, p≤0.003), with model 4 having the best performance (AUC=0.86, p<0.001).

Conclusions

The combination of multiparametric MRI techniques contributes to better understand the structural and functional substrates of cognitive dysfunction in MS patients. The accumulation of focal WM lesions and GM atrophy in strategic brain regions together with maladaptive functional mechanisms explains CI in MS.

Background

Cladribine significantly reduces disease activity and disability progression in relapsing-remitting multiple sclerosis (RRMS) through a selective but transient depletion of lymphocyte subsets. The SARS-COV-2 outbreak has raised several concerns regarding cladribine use for RRMS patients.

Objectives

To evaluate the prevalence and clinical features of COVID-19 disease among cladribine-treated relapsing-remitting MS patients.

Methods

Fifty-six RRMS patients treated with cladribine in our centre (female=39; mean age=33.8 years [y]; median Expanded Disability Status Scale [EDSS]=1.5, disease duration [DD]=5.2 y, treatment duration=1.15 y) were asked if they had developed manifestations suggestive of SARS-COV-2 infection up to June 30^th 2020. Their detailed characteristics were collected.

Results

At June 30^th 2020, nasal/pharyngeal swabs have been found positive in 0.94% of the Lombardy population. Since the pandemic start, 2/56 (3.6%) cladribine-treated RRMS complained a symptomatology suggestive of COVID-19 disease, with a prevalence similar to that of the whole MS population of our centre (84/2950, 2.8%). The first patient was a 30-year-old male with RRMS (DD=1.2 y, EDSS=1.5) and no comorbidities. He started cladribine on January 10^th 2020. One week later, he developed fever (<37.5°), ageusia, cough, fatigue, sputum production, sore throat, nasal congestion, shortness of breath without desaturation and conjunctivitis.

The second patient is a 39-year-old female with RRMS (DD=13.2 y, EDSS=3.5), and no comorbidities. She started cladribine on February 13^th 2020 and underwent the second week of the first treatment course from March 5^th 2020. On March 30^th, she developed fever (<37.8°), anosmia, ageusia, cough, fatigue, and bone/joint pain. Serology for SARS-COV-2 was positive in May 2020. For both patients, blood examinations performed before and after COVID-19 disease were within normal limits. Both patients were telephone-monitored at home and completely recovered within 15 days.

Conclusions

Only a minority of cladribine-treated RRMS patients developed a mild and self-limiting COVID-19 disease. In our cohort, this occurred in two RRMS patients within a few weeks from treatment course and the possible nadir of selective immunosuppression. Both patients recovered completely. Cladribine administration seems to be safe also in the setting of the COVID-19 pandemic.

Background

Cortical damage is clinically relevant in multiple sclerosis (MS), however reliable MRI markers for its monitoring are still an unmet need. Ratio of T1-weighted (T1w) and T2-weighted (T2w) sequences (i.e., T1w/T2w-ratio) has been suggested as a feasible MRI measure to assess cortical abnormalities in patients with MS (PwMS), but its histopathological substrate has yet to be definitively elucidated.

Objectives

To define the histopathological substrate of T1w/T2w-ratio in normal-appearing and demyelinated cortices of PwMS by performing a combined post-mortem MRI/histopathology study.

Methods

Fifteen PwMS and ten age- and sex-matched non-neurological controls (nNC) underwent post-mortem in situ 3T MRI with 3D T1w and T2w sequences, followed by brain dissection.

One hundred and five paraffin embedded tissue blocks (49 from PwMS, 56 from nNC) were collected. Tissue regions were matched to T1w/T2w-ratio maps to obtain regional cortical T1w/T2w-ratio. Using immunohistochemistry and silver staining, cortical density of myelin, microglia, neurons, glial cells and neurites were evaluated. Correlates of T1w/T2w-ratio alterations with histological markers were assessed through linear mixed-effects models.

Results

Twenty-six cortical lesions (85% subpial) were found in 24/49 (51%) cortical regions from PwMS. Compared to nNC’s cortex, both PwMS’ normal-appearing and demyelinated cortices had a significantly lower T1w/T2w-ratio (p=0.045 and 0.001). In PwMS, demyelinated cortex showed a significant lower T1w/T2w-ratio compared to normal-appearing cortex (p=0.007). In PwMS, neurite density was significantly lower in both normal-appearing and demyelinated cortices compared to nNC (p=0.041 and 0.001), and in demyelinated vs. normal-appearing cortex (p=0.048). Demyelinated cortex showed also significant lower myelin density compared to normal-appearing cortex in both nNC and PwMS (p<0.001). Regarding the pathological substrate, T1w/T2w-ratio was positively associated with neurite density (β=3.464×10^-2, p=0.004), whereas only a trend for myelin density was found (p=0.082).

Conclusions

Both demyelination and neurite loss were found in the cortex of PwMS. By evaluating several histopathological markers in nNC and PwMS (in normal-appearing and demyelinated cortices), T1w/T2w-ratio was found to be sensitive to MS cortical damage and more specific to neurite than myelin density. T1w/T2w-ratio could be useful to investigate cortical damage in MS.

Background

In multiple sclerosis (MS), cortical damage is a relevant predictor of clinical disability, but MRI measures more specific to cortical pathology are needed. Neurite orientation dispersion and density imaging (NODDI) model is a multi-compartment diffusion model to better evaluate the complexity of brain microarchitecture.

Objectives

To characterize, using NODDI, the microstructural abnormalities of normal-appearing cortex (NA-cortex) and cortical lesions (CLs) and their relations with disease phenotypes and clinical disability in a relatively large cohort of MS patients.

Methods

Brain 3D T1-weighted, FLAIR, double inversion recovery (DIR) and diffusion-weighted (DW) sequences were acquired from 164 MS patients (94 relapsing-remitting [RR], 70 progressive [P] MS) and 51 healthy controls (HC). The cortex was segmented from 3D T1-weighted sequence, whereas CLs were quantified on DIR. CLs and NA-cortex masks were then transformed into DW space. Using NODDI, intracellular volume fraction (ICV_f), representing neurite density, extracellular volume fraction (ECV_f) and orientation dispersion index (ODI), reflecting neurite orientation variability, were assessed in NA-cortex and CLs. Between-group comparisons and correlations with clinical and structural MRI measures were investigated.

Results

One hundred and twelve (68.3%) MS patients had ≥1 CL. MS NA-cortex had a significant lower ICV_f vs HC NA-cortex (p=0.001). CLs showed a significant increased ECV_f (p<0.001) and decreased ICV_f and ODI compared to NA-cortex of HC (p<0.001) and MS (p=0.035 and <0.001). Compared to RRMS, PMS had a significant decreased NA-cortex ICV_f (p=0.024). Higher burden of CLs (p<0.001) were found in PMS vs RRMS, without microstructural differences. In MS patients, NA-cortex ICV_f, ECV_f and ODI were significantly correlated with disease duration, EDSS, white matter lesion volumes, CL volumes and whole brain and gray matter atrophy (r from -0.37 to 0.71, p from <0.001 to 0.048).

Conclusions

A significant neurite loss occurs in MS NA-cortex, being more severe with longer disease duration, higher disability and PMS. CLs show a further reduction of neurite density, together with an increased extracellular space, possibly due to inflammation and gliosis, and a reduced ODI suggestive of increased tissue coherence and simplification of neurite complexity. NODDI is reliable and clinically relevant to investigate in vivo the heterogeneous pathological processes affecting MS cortex.

Funding. This study is supported by a senior research fellowship FISM – Fondazione Italiana Sclerosi Multipla – cod. 2019/BS/009 and financed or co-financed with the ‘5 per mille’ public funding.