The Predictive Role of Processing Speed deficit in Verbal and Visual Memory in Multiple Sclerosis

Gómez, A. 1 , Rilo, O. 1 , Ibarretxe, N. 1 , Peña, J. 1 , Mendibe, M. 2 , Antigüedad, A. 3 & Ojeda, N. 1

1 Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Basque Country, Spain
2 Neurology service, Cruces University Hospital, Bilbao, Basque Country, Spain
3 Neurology service, Basurto University Hospital, Bilbao, Basque Country, Spain

Introduction:
Multiple sclerosis (MS) patients suffer from impairment in several cognitive functions including attention (At), working memory (WM), processing speed (PS), verbal memory (VM) and visual memory (ViM). Previous studies have found an association between At, WM or PS and memory. The aim of this study was to investigate the predictive role of At, WM and PS in VM and ViM in MS and healthy controls (HC).

Methods:
Twenty-seven patients with MS and 27 matched HC underwent an extensive neuropsychological battery. Simple and multiple stepwise regression analyses were performed to examine the predictive relationship between At, PS and WM and VM as well as ViM.

Results:
Simple regressions showed that a significant percentage of the variance of VM was predicted by At (21.5%, p<0.05) and PS (30.6%, p<0.01) among patients with MS. For ViM, only PS predicted a significant percentage of the variance (25.3%, p<0.01). Finally, multiple stepwise regression showed that the unique cognitive function which explains a percentage of VM (30.6%, p<0.01) and ViM (25.3%, p<0.01) variance was PS. No significant regressions were found in HC.

Conclusion:
In conclusion, taking into account the interaction of the three cognitive domains the unique function that predicts the performance in MS on VM or ViM is PS. These results emphasize the need of include PS training in cognitive rehabilitation programs to improve VM and ViM performance in MS.