CP06
Assessment of Information Processing Speed in Multiple Sclerosis: Past and Future
Objectives: The present review aims to summarize how IPS has been assessed during the last decade.
Methods: A PubMed search with key words “Processing Speed” AND “MS” for articles published from 1/1/04-12/31/13 and 2 inclusion screens resulted in 157 articles.
Results: IPS has been mostly assessed with heterogeneous samples (combined disease course) (53.5%). Fewer studies focused on 1 disease course (33.8%), and as few as 9.6% examined differences between disease course. Studies often controlled for: presence of other neurological disorders (61.54%), age (58.60%), education (51.59%), alcohol (47.77%) or use of steroids (39.49%). Although relapses are known to impact functioning, only 50.32% of studies report controlling time since last exacerbation. Although studies assess cognitive functions, only 19.11% controlled for history of developmental disorders. Visual problems are a common symptoms in MS, yet just 29.30% of studies report visual function evaluation. This is important since the majority of tests used to assess IPS are visual. Longitudinal studies are scarce (10%) and none examined the efficacy of rehabilitation interventions.
Tests were grouped into 7 categories to understand frequency of usage. The most popular tests to assess IPS in MS were symbol/digit substitution tests (132 times), followed by tests designed to measure working memory(111). Reaction time tests were used 44 times to assess IPS, with tests designed to measure executive functioning being used 42 times. Less often utilized were tests designed to measure attention (13), verbal fluency (6), or other domains (12). While the use of symbol/digit modalities tests increased 23.71% between the first 5 years and second 5 years of the decade, tests designed to measure WM/executive functions decreased 10.79% in the same time period. This observation might be related to the recognition of the cognitive complexity inherent in the PASAT, and the emotional burden. Additionally, accumulating evidence over the last decade has built support for the sensitivity of the SDMT to IPS deficits in persons with MS.
Conclusions: Our understanding of IPS deficits in MS has advanced notably during the last decade. Our future goal should be to increase our understanding of the variability of IPS between the different disease courses, with a focus on the impact of IPS deficits on everyday functional abilities. When selecting participants, attention should be paid to pre-morbid pathologies that impact cognitive performance (e.g. developmental disorders), disease progression (e.g. last exacerbation) and sensorial function (visual and motor). More longitudinal and rehabilitation studies will be essential to further our understanding of IPS deficits in MS and their impact on daily functioning and quality of life.