Thalamic atrophy predicts cognitive impairment in relapsing remitting multiple sclerosis. Effect on instrumental activities of daily living and employment status.

INTRODUCTION: Cognitive impairment is an important predictor of quality of life at all stages of MS. Magnetic Resonance Imaging (MRI) markers have been used to associate tissue damage with cognitive dysfunction. OBJECTIVE: The aim of the study was to designate the MRI marker that predicts cognitive decline and explore its effect on every day activities and employment status. METHODS: 50 RRMS patients and 31 healthy participants underwent neuropsychological assessment using the Trail Making Test (TMT) parts A and B, semantic and phonological verbal fluency task and a computerized cognitive screening battery (Central Nervous System Vital Signs). Everyday activities were evaluated with the instrumental activities of daily living (IADL) scale and employment status. Brain MRI was performed in all participants. We measured total lesion volume, third ventricle width, corpus callosum and thalamic atrophy. RESULTS: The frequency of cognitive dysfunction for our RRMS patients was 38%. RRMS patients differed significantly from controls on the TMTA, TMTB, phonological verbal fluency task, memory, psychomotor speed, reaction time and cognitive flexibility. Neuropsychological measures had a strong correlation with all MRI atrophy measures and a weak or moderate correlation with lesion volume. Psychomotor speed was the most sensitive marker for IADL, while memory and TMTB for employment status. Thalamic area was the most sensitive MRI marker for memory, psychomotor speed and TMTB.. CONCLUSION: Thalamic atrophy predicts the clinically meaningful cognitive decline in our RRMS patients.