Long-term Cognitive Outcomes and Socioprofessional Attainment in People With Multiple Sclerosis With Childhood Onset.

BACKGROUND AND OBJECTIVES: Patients with pediatric-onset multiple sclerosis (MS) can be especially vulnerable to cognitive impairment (CI) due to the onset of MS during a critical period for CNS development and maturation. The objective of this longitudinal study was to assess long-term cognitive functioning and socioprofessional attainment in the Italian pediatric MS cohort, previously assessed at baseline and 2 and 5 years. METHODS: The 48 patients evaluated at the 5-year assessment were screened for inclusion. All participants were assessed with a cognitive test battery exploring 4 different cognitive abilities. Depression, fatigue, and socioprofessional attainment were also assessed. Mean cognitive z scores were calculated for the whole cohort, and their evolution over time was analyzed with an analysis of variance for repeated measurements test. Predictors of cognitive worsening or improvement were assessed with a linear mixed-model analysis. RESULTS: Thirty-three participants were included (mean follow-up 12.8 ± 0.8 years). The global cognitive performance worsened at year 2 and improved at year 5, although the z score remained significantly lower than at baseline (-0.9 ± 1.2 vs -0.3 ± 0.9, p = 0.002). There was no significant variation between years 5 and 12 (-0.7 ± 1.1, p = 0.452). Higher IQ (>90) at baseline (effect 0.3, 95% CI 0.1-0.5, p = 0.017) and lower number of relapses in the 2 years before baseline (effect -0.1, 95% CI -0.1 to 0.1, p = 0.025) predicted better cognitive performances. Eighteen (54.5%) patients failed at least 2 tests compared with healthy controls and were defined as cognitively impaired. The presence of CI predicted worse socioprofessional attainment (ß = 4.8, 95% CI 1.4-8.2, p = 0.008). DISCUSSION: The longitudinal cognitive trajectory in pediatric-onset MS has a heterogeneous course over time, with a decline in the first years followed by a partial recovery over the long term. However, at the last follow-up evaluation, the proportion of impaired patients was more than double compared with baseline, with a negative impact on the individual's socioprofessional attainment in adulthood. This study underscores how cognitive reserve may partially mitigate the negative effects of brain damage, highlighting the critical importance of intellectual enrichment early during the disease course.

MRI substrates of sustained attention system and cognitive impairment in pediatric MS patients.

OBJECTIVE: To explore the structural and functional integrity of the sustained attention system in patients with pediatric multiple sclerosis (MS) and its effect on cognitive impairment. METHODS: We enrolled 57 patients with pediatric MS and 14 age- and sex-matched healthy controls (HCs). Patients with >3 abnormal tests at neuropsychological evaluation were classified as cognitively impaired (CI). Sustained attention system activity was studied with fMRI during the Conners Continuous Performance Test (CCPT). Structural integrity of attention network connections was quantified with diffusion tensor (DT) MRI. RESULTS: Within-group analysis showed similar patterns of recruitment of the attention network in HCs and patients with pediatric MS. Diffuse network DT MRI structural abnormalities were found in patients with MS. During CCPT, with increasing task demand, patients with pediatric MS showed increased activation of the left thalamus, anterior insula, and anterior cingulate cortex (ACC) and decreased recruitment of the right precuneus compared to HCs. Thirteen patients (23%) were classified as CI. Compared to cognitively preserved patients, CI patients with pediatric MS had decreased recruitment of several areas located mainly in parietal and occipital lobes and cerebellum and increased deactivation of the ACC, combined with more severe structural damage of white matter tracts connecting these regions. CONCLUSIONS: Our results suggest that the age-expected level of sustained attention system functional competence is achieved in patients with pediatric MS. Inefficient regulation of the functional interaction between different areas of this system, due to abnormal white matter integrity, may result in global cognitive impairment in these patients.

Regional hippocampal involvement and cognitive impairment in pediatric multiple sclerosis.

OBJECTIVES: We assessed global and regional hippocampal volume abnormalities in pediatric multiple sclerosis (MS) patients and their correlations with clinical, neuropsychological and magnetic resonance imaging metrics. METHODS: From 53 pediatric MS patients and 18 healthy controls, global hippocampal volume was computed using a manual tracing procedure. Regional hippocampal volume modifications were assessed using a radial mapping analysis. MS patients with abnormal performance in three or more tests of a neuropsychological battery for children were classified as cognitively impaired. RESULTS: Global hippocampal volume was reduced in MS patients compared with controls, but did not correlate with clinical, neuropsychological and magnetic resonance imaging measures. Compared to controls, MS patients experienced bilateral radial atrophy of the cornu ammonis, subiculum and dentate gyrus subfields as well as radial hypertrophy of the dentate gyrus subfield. Regional hippocampal volume modifications correlated with brain T2 lesion volume as well as attention and language abilities. Global hippocampal volume did not differ between cognitively impaired (n=12) and cognitively preserved MS patients. Compared to cognitively preserved, cognitively impaired MS patients had atrophy of the subiculum and dentate gyrus subfields of the right hippocampus. CONCLUSIONS: Hippocampal subregions have different vulnerability to damage in pediatric MS. Regional rather than global hippocampal involvement contributes to global cognitive impairment as well as to deficits of selected cognitive tests.

A comparison of the brief international cognitive assessment for multiple sclerosis and the brief repeatable battery in multiple sclerosis patients.

BACKGROUND: Recently, a Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) has been developed as an international and standardized brief cognitive test, which is easily performed in everyday clinical practice for neuropsychological assessment in multiple sclerosis (MS). However, we need to gather more information about this tool compared to other neuropsychological batteries. The aim of our study is to compare the performance of BICAMS and Brief Repeatable Battery (BRB) in MS subjects. METHODS: Tests of the BRB and BICAMS were administered to MS patients recruited from 11 Italian MS centres. Cognitive impairment (CI) was defined as the failure on at least two tests (scores below the fifth percentile) on the BRB and as the failure on at least one test of the BICAMS. The agreement between the performances on the two batteries was assessed through Cohen's K statistic. Finally we calculated the effects sizes for each test of the two batteries using Cohen's d. RESULTS: The two batteries were administered to 192 MS patients (142 women, 50 men; mean age 41.4 ± 10.8 years, mean education 12.3 ± 3.5 years). Mean scores of patients were lower compared to those of healthy subjects in all the cognitive measures examined. Forty-six MS patients were identified as impaired and 48 as unimpaired on both of the batteries, when the Symbol Digit Modalities Test (SDMT) was included in the analysis. Cohen's K statistic was 0.46 which corresponds to a moderate accord. If the SDMT was excluded from the BRB, 37 MS patients were identified as impaired and 57 as unimpaired on both of the batteries. Cohen's K statistic was 0.3 which corresponds to a poor accord. The SDMT, the Paced Auditory Serial Addition Test (PASAT) 3 and 2 yielded higher d values (SDMT 0.83, PASAT 3 0.65, PASAT 2 0.84). CONCLUSIONS: This study confirms the feasibility of BICAMS in everyday clinical practice for the identification of CI and highlights the good psychometric properties of the SDMT.

Cognitive impairment in paediatric multiple sclerosis patients is not related to cortical lesions.

We investigated the contribution of cortical lesions to cognitive impairment in 41 paediatric MS patients. Thirteen (32%) paediatric MS patients were considered as cognitively impaired. T2-hyperintense and T1-hypointense white matter lesion volumes did not differ between cognitively impaired and cognitively preserved MS patients. Cortical lesions number, cortical lesions volume and grey matter volume did not differ between cognitively impaired and cognitively preserved patients, whereas white matter volume was significantly lower in cognitively impaired versus cognitively preserved MS patients (p=0.01). Contrary to adult MS, cortical lesions do not seem to contribute to cognitive impairment in paediatric MS patients, which is likely driven by white matter damage.

Posterior brain damage and cognitive impairment in pediatric multiple sclerosis.

OBJECTIVE: We combined structural and functional MRI to better understand the mechanisms responsible for cognitive impairment in pediatric patients with multiple sclerosis (MS). METHODS: Brain dual-echo, diffusion tensor, 3D T1-weighted, and resting-state (RS) fMRI scans were acquired from 35 consecutive pediatric patients with MS and 16 sex- and age-matched healthy controls. Patients with abnormalities in ≥2 neuropsychological tests were classified as cognitively impaired. The regional distribution of white matter (WM) and gray matter (GM) damage was assessed using voxel-wise analyses. Default mode network (DMN) RS functional connectivity (FC) was also measured. RESULTS: Sixteen patients (45%) were classified as cognitively impaired. Compared to cognitively preserved (CP) patients, cognitively impaired patients with MS had higher occurrence of T2 lesions as well as more severe damage to the WM and GM, as measured by atrophy and diffusivity abnormalities, in the posterior regions of the parietal lobes close to the midline (precuneus, posterior cingulum, and corpus callosum). Compared to the other study groups, they also showed reduced RS FC of the precuneus, whereas CP patients experienced an increased RS FC of the anterior cingulate cortex. A multivariable model identified diffusivity abnormalities of the cingulum and corpus callosum and RS FC of the precuneus as the covariates more strongly associated with cognitive impairment (C-index = 0.99). CONCLUSIONS: In pediatric patients with MS, cognitive dysfunction is associated with structural and functional abnormalities of the posterior core regions of the DMN. WM structural abnormalities co-occurring at this level are likely to be the substrate of such modifications.