Maturational Trajectory of Processing Speed Performance in Pediatric Multiple Sclerosis

Neuropsychological performances, quality of life, and psychological issues in pediatric onset multiple sclerosis: a narrative review

Multiple sclerosis (MS) is primarily a disease diagnosed in young and middle-aged adults. Although MS is a rare condition in pediatric age, an increasing rate of patients is diagnosed under the age of 18. The disabling nature of the disease cannot be reduced only to physical symptoms. Several additional symptoms such as cognitive impairment, fatigue, and psychological symptoms are common features of pediatric MS. The reviewed literature suggests that, despite the lower physical disability, children and adolescents diagnosed with MS are vulnerable to cognitive impairment even in the early stage of the disease. The neuropsychological profile of pediatric MS may resemble that of adult MS, including an impairment in attention/information processing speed, learning, verbal, and visuospatial memory. However, cognitive difficulties in children and adolescents are more likely to involve also general intelligence and linguistic abilities, presumably due to patients' younger age and cognitive growth stage. Cognitive difficulties, beyond physical disability and relapses, may have a considerable impact on learning and school achievement. Depression and fatigue are other highly prevalent disturbances in pediatric MS and may contribute to patients' low functional outcomes. Overall, these manifestations may cause considerable functional impairment on daily activities and quality of life that may require individualized rehabilitative treatment and extensive psychosocial care. Additional neuropsychological research evaluating larger samples, using more homogenous methods, and exploring the role of MS treatment on cognitive and psychological development is required.

Pediatric Multiple Sclerosis Severity Score in a large US cohort

OBJECTIVE

To characterize disease severity and distribution of disability in pediatric-onset multiple sclerosis (POMS) and to develop an optimized modeling scale for measuring disability, we performed a multicenter retrospective analysis of disability scores in 873 persons with POMS over time and compared this to previously published data in adults with multiple sclerosis (MS).

METHODS

This was a retrospective analysis of prospectively collected data collected from 12 centers of the US Network of Pediatric MS Centers. Patients were stratified by the number of years from first symptoms of MS to Expanded Disability Status Scale (EDSS) assessment and an MS severity score (Pediatric Multiple Sclerosis Severity Score [Ped-MSSS]) was calculated per criteria developed by Roxburgh et al. in 2005.

RESULTS

In total, 873 patients were evaluated. In our cohort, 52%, 19.4%, and 1.5% of all patients at any time point reached an EDSS of 2.0, 3.0, and 6.0. Comparison of our Ped-MSSS scores and previously published adult Multiple Sclerosis Severity Scores (MSSS) showed slower progression of Ped-MSSS with increasing gaps between higher EDSS score and years after diagnosis. Decile scores in our POMS cohort for EDSS of 2.0, 3.0, and 6.0 were 8.00/9.46/9.94, 7.86/9.39/9.91, and 7.32/9.01/9.86 at 2, 5, and 10 years, respectively. Notable predictors of disease progression in both EDSS and Ped-MSSS models were ever having a motor relapse and EDSS at year 1. Symbol Digit Modalities Test (SDMT) scores were inversely correlated with duration of disease activity and cerebral functional score.

CONCLUSIONS

Persons with POMS exhibit lower EDSS scores compared to persons with adult-onset MS. Use of a Ped-MSSS model may provide an alternative to EDSS scoring in clinical assessment of disease severity and disability accrual.

Cognitive processing speed in pediatric-onset multiple sclerosis: Baseline characteristics of impairment and prediction of decline

BACKGROUND

Cognitive impairment occurs in approximately one-third of pediatric-onset multiple sclerosis (POMS) patients. The Symbol Digit Modalities Test (SDMT), a widely used cognitive screen in adults, has yet to be incorporated early into the standard care of POMS.

OBJECTIVE

To screen for cognitive impairment early in the course of POMS and analyze predictive factors.

METHODS

Of the 955 POMS or clinically isolated syndrome (CIS) patients prospectively assessed from March 2014 to July 2018, 500 POMS and 116 CIS patients met inclusion criteria (disease onset before the age of 18, one or more SDMTs, and 8 years or older at the time of testing). Those with relapse were analyzed separately from those who were relapse-free.

RESULTS

At initial assessment, the mean (interquartile range (IQR)) age at symptom onset was 13.5 years (12.0, 15.9) and the mean (±SD) disease duration was 3.0 ± 2.9 years. Impaired processing speed occurred in 23.4% of POMS and in 16.4% of CIS. On serial testing (n = 383, mean follow-up: 1.8 years), 14.1% had clinically meaningful decline predicted by older age of multiple sclerosis (MS) onset and male gender. Disease relapse or steroid use led to transient worsening on the SDMT.

CONCLUSION

Early in the disease, some POMS and CIS patients are at risk for cognitive impairment and subsequent decline.

The Multiple Sclerosis Functional Composite and Symbol Digit Modalities Test as outcome measures in pediatric multiple sclerosis

Background

There is an increasing number of pediatric multiple sclerosis (MS) clinical trials occurring; however, data validating outcome metrics that accurately capture functional disability within pediatric cohorts are limited.

Objective

The aim of this study was to investigate the ability of the MS Functional Composite (MSFC) and Symbol Digit Modalities Test (SDMT) to distinguish functional disability in pediatric MS patients.

Methods

A total of 20 pediatric MS patients and 40 age and sex-matched controls completed the SDMT and MSFC components: a timed 25-foot walk (T25FW); 9-hole peg test (9HPT); and paced auditory serial addition test (PASAT). Z scores for MS patients were created for each test based on control means. MS patients underwent Expanded Disability Status Scale (EDSS) examination.

Results

Pediatric MS patients exhibited low levels of disability on EDSS, median [range]: 1.5 [1.0–3.0]. Compared with controls, MS patients performed significantly lower on SDMT (p = 0.0002) and all MSFC components: T25FW (p = 0.001), 9HPT (p = 0.01), and PASAT (p = 0.004). SDMT and MSFC performance were not correlated with EDSS.

Conclusions

Despite low levels of neurologic disability as measured by EDSS, pediatric patients with MS exhibit impaired performance in leg function, upper limb fine motor function, and auditory/visuospatial processing speeds, supporting the value of the MSFC and SDMT in this population. Longitudinal studies are needed to further validate their utility.