Information Processing Speed Assessed with Letter Digit Substitution Test in Croatian Sample of Multiple Sclerosis Patients
Ana Jerković,
Meri Matijaca,
Ana Proroković,
Anđela Šikić,
Vana Košta,
Ana Ćurković Katić,
Krešimir Dolić,
Klaudia Duka Glavor,
Joško Šoda,
Zoran Đogaš,
Maja Rogić Vidaković
Affiliations
Ana Jerković
Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, School of Medicine, University of Split, Šoltanska 2, 21000 Split, Croatia
Meri Matijaca
Department of Neurology, University Hospital of Split, Spinčićeva 1, 21000 Split, Croatia
Ana Proroković
Department of Psychology, University of Zadar, Ul. Mihovila Pavlinovića, 23000 Zadar, Croatia
Anđela Šikić
Department of Psychology, University of Zadar, Ul. Mihovila Pavlinovića, 23000 Zadar, Croatia
Vana Košta
Department of Neurology, University Hospital of Split, Spinčićeva 1, 21000 Split, Croatia
Ana Ćurković Katić
Department of Neurology, University Hospital of Split, Spinčićeva 1, 21000 Split, Croatia
Krešimir Dolić
Department of Radiology, University Hospital of Split, Spinčićeva 1, 21000 Split, Croatia
Klaudia Duka Glavor
General Hospital Zadar, Neurology, Ul. Bože Peričića 5, 23000 Zadar, Croatia
Joško Šoda
Signal Processing, Analysis, Advanced Diagnostics Research and Education Laboratory (SPAADREL), Faculty of Maritime Studies, University of Split, Ul. Ruđera Boškovića 37, 21000 Split, Croatia
Zoran Đogaš
Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, School of Medicine, University of Split, Šoltanska 2, 21000 Split, Croatia
Maja Rogić Vidaković
Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, School of Medicine, University of Split, Šoltanska 2, 21000 Split, Croatia
Cognitive impairment is a common complaint in people with multiple sclerosis (pwMS). The study objective was to determine the psychometric properties of the letter digit substitution test (LDST) that measures information processing speed and to investigate the impact of relevant predictors of LDST achievement in pwMS. The design was cross-sectional. The study included 87 pwMS and 154 control subjects. The validity of LDST was examined, and a hierarchical regression model was used to explore relevant predictors of LDST success. The LDST had excellent construct validity, as expressed by differences between pwMS and control subjects. Convergent validity of the LDST was supported by a significant moderate correlation with the expanded disability status scale (EDSS) (ρ = −0.36; p p < 0.01). The LDTS score well differentiated the pwMS considering age, education, EDSS, disease duration, comorbidity, and medication therapy. Using the LDST as a criterion variable in pwMS results showed consistent evidence for the age, education, and EDSS impact on LDST performance. The best cut-off score of ≤35 discriminated the control and MS group. LDST proved to be a valid test for assessing information processing speed in pwMS.
