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Open Access Research article

Cognitive performance in relapsing remitting multiple sclerosis: A longitudinal study in daily practice using a brief computerized cognitive battery

Chris Edgar1, Peter J Jongen2*, Evert Sanders3, Christian Sindic4, Sophie Goffette4, Michel Dupuis5, Philippe Jacquerye5, Daniel Guillaume6, Regine Reznik6 and Keith Wesnes1

Author Affiliations

1 United BioSource Corporation, 9 Gatehampton Road, Goring-on-Thames, RG8 0EN, UK

2 MS4 Research Institute, Ubbergseweg 34, 6522 KJ Nijmegen, the Netherlands

3 Amphia Ziekenhuis, Molengracht 21, 4818 CK Breda, the Netherlands

4 Cliniques Universitaires St. Luc, Université catholique de Louvain, Avenue Hippocrate 10, 1200 Brussels, Belgium

5 Clinique Saint-Pierre, Avenue Reine Fabiola 9, 1340 Ottignies, Belgium

6 Centre Neurologique et de Readaptation Fonctionnelle, 30 rue Champs des Alouettes, 4557 Fraiture-en-Condroz, Belgium

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BMC Neurology 2011, 11:68  doi:10.1186/1471-2377-11-68

Published: 7 June 2011



There is need for a cognitive test battery that can be easily used in clinical practice to detect or monitor cognitive performance in patients with multiple sclerosis (MS). In order to conduct, in this patient group, a preliminary investigation of the validity and utility of a brief computerized battery, the Cognitive Drug Research (CDR) battery, we longitudinally assessed cognition in patients with relapsing remitting (RR) MS.


Forty-three mildly disabled, clinically active RRMS patients were repeatedly assessed with the Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) and five composite scores derived from the CDR computerized cognitive test system (CDR System): Power of Attention, Continuity of Attention, Quality of Working Memory, Quality of Episodic Memory and Speed of Memory. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) measured disability.


The composite scores from the CDR battery generally showed excellent test-retest reliability over the repeated assessments, though was low on occasions for the Quality of Working Memory and Quality of Episodic Memory measures. The CDR measures tended to be highly correlated with other measures of cognition (DSST and PASAT) and were also strongly related to disability (EDSS and MSFC). Baseline scores indicated large impairments to visual information processing speed and attention (DSST, Cohen's d 1.1; Power of Attention d 1.4 [reaction time on tasks of focussed and sustained attention]), and a moderate impairment both to sustained attention (Continuity of Attention d 0.6) and complex information processing speed (Speed of memory d 0.7 [reaction time on tasks of working and episodic Memory]), when compared to normative data derived from healthy volunteers enrolled in a series of separate, prior clinical trials. Working memory (Quality of Working Memory) and episodic memory (Quality of Episodic Memory) were unimpaired.


Preliminary validation of the CDR System indicated that for most, but not all measures psychometric properties were adequate and the measures were related to disability (EDSS and MSFC) and other measures of cognition.