title: Information processing speed in multiple sclerosis: Past, present, and future.
abstract: Information processing speed (IPS) is a prevalent cognitive impairment in multiple sclerosis (MS).
  
  
  
  This review aims to summarize the methods applied to assess IPS in MS and its theoretical conceptualization. A PubMed search was performed to select articles published between 1 January 2004 and 31 December 2013, resulting in 157 articles included.
  
  
  
  The majority (54%) of studies assessed IPS with heterogeneous samples (several disease courses). Studies often report controlling for presence of other neurological disorders (60.5%), age (58.6%), education (51.6%), alcohol history (47.8%), or use of steroids (39.5%). Potential confounding variables, such as recent relapses (50.3%), history of developmental disorders (19.1%), and visual problems (29.9%), were often neglected. Assessments used to study IPS were heterogeneous (ranging from simple to complex tasks) among the studies under review, with 62 different tasks used. Only 9.6% of articles defined the construct of IPS and 22.3% discussed IPS in relation to a theoretical model.
  
  
  
  The challenges for the upcoming decade include clarification of the definition of IPS as well as its theoretical conceptualization and a consensus on assessment. Based on the results obtained, we propose a new theoretical model, the tri-factor model of IPS.
authors.affiliation: Neuropsychology & Neuroscience Laboratory, Kessler Foundation, West Orange, NJ, USA/Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA.
authors.forename: Silvana L
authors.initials: SL
authors.lastname: Costa
authors.affiliation: Neuropsychology & Neuroscience Laboratory, Kessler Foundation, West Orange, NJ, USA/Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Genova
authors.affiliation: Neuropsychology & Neuroscience Laboratory, Kessler Foundation, West Orange, NJ, USA/Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA/Department of Neurology, Rutgers New Jersey Medical School, Newark, NJ, USA.
authors.forename: John
authors.initials: J
authors.lastname: DeLuca
authors.affiliation: Neuropsychology & Neuroscience Laboratory, Kessler Foundation, West Orange, NJ, USA/Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA.
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Chiaravalloti
mesh_terms: D060825:Cognitive Dysfunction / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008606:Mental Processes / Q000502:physiology*; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology*
keywords: Multiple sclerosis; cognitive assessment; processing speed; working memory