title: The computer-based Symbol Digit Modalities Test: establishing age-expected performance in healthy controls and evaluation of pediatric MS patients.
abstract: Decreased information processing speed (IPS) is frequently reported in pediatric multiple sclerosis (MS) patients. The computerized version of the Symbol Digit Modalities Test (c-SDMT) measures IPS over eight consecutive trials per session and additionally captures changes in performance within the session. Here, we establish normative c-SDMT performance and test-retest reliability in healthy children (HC) and explore differences in the overall c-SDMT-performance between HC and MS patients. This cross-sectional study included 478 HC (237 female, 49.5%) divided into five age groups (2 years each), and 27 MS patients (22 female, 81.5%) aged 8-18 years. The average time to complete the c-SDMT increased with age (|r| 0.70, 95% CI -0.74, -0.64). Test-retest reliability was high (ICC = 0.91) in HC. The total time to complete the c-SDMT did not differ between children with MS and sex- and age- matched HC (p = 0.23). However, MS patients were less likely to show faster performance across all the successive eight trials compared to HC (p = 0.0001). Healthy children demonstrate faster IPS with increasing age, as well as during successive trials of the c-SDMT. The inability of pediatric MS patients to maintain the increase in processing speed over successive trials suggests a reduced capacity for procedural learning, possibly resulting from cognitive fatigue.
authors.affiliation: Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada. Sandra.Bigi@insel.ch.|Division of Child Neurology, Department of Pediatrics, The University Children's Hospital, University of Bern, Freiburgstrasse 15, 3010, Bern, Switzerland. Sandra.Bigi@insel.ch.
authors.forename: Sandra
authors.initials: S
authors.lastname: Bigi
authors.affiliation: Departments of Internal Medicine and Community Health Sciences, University of Manitoba, Winnipeg, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: Department of Psychology, York University, Toronto, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Till
authors.affiliation: Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada.
authors.forename: E A
authors.initials: EA
authors.lastname: Yeh
authors.affiliation: Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Akbar
authors.affiliation: Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Feinstein
authors.affiliation: The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Philadelphia, Philadelphia, PA, USA.
authors.forename: B L
authors.initials: BL
authors.lastname: Banwell
mesh_terms: D000293:Adolescent; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology; D003201:Computers; D003430:Cross-Sectional Studies; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000150:complications / Q000523:psychology*; D009483:Neuropsychological Tests; D002666:Psychology, Child; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors
keywords: Neurocognition; Pediatric MS; Processing speed; Symbol Digit Modalities Test