Background and purpose: The aim of this study was to assess cognitive impairment in patients with relapsing-remitting multiple sclerosis (RR-MS) and to evaluate the correlation of cognitive impairment with physical disability and MRI lesion volume.
Material and methods: Sixty patients with RR-MS and 50 healthy controls were assessed using neuropsychological tests. All the patients were subjected to MRI examination using PD/T2 and T1 sequences, and clinical evaluation with the EDSS scale was applied.
Results: Selective cognitive impairment was found in 40% of the RR-MS group, and broad, overall cognitive dysfunction was found in 15% of patients. A correlation was found between neurological signs and memory deficits and psychomotor speed. The mean total lesion volume (TLV) was significantly higher in patients with selective and overall cognitive impairment than in those without (8060 vs. 3183 mm3, p=0.001; 7234 vs. 3138 mm3, p=0.004, respectively). There was no difference in TLV between RR-MS patients with selective or overall cognitive impairment (8060 vs. 7234 mm3, p=0.134). Moderate correlations were found between nonverbal memory, verbal fluency and abstract reasoning tests and TLV.
Conclusions: Cognitive impairment is present in more than 50% of patients with RR-MS, and they are mainly selective deficits. The correlation between physical disability and cognitive impairment was not significant, except for memory deficits and psychomotor speed. There is a correlation between TLV and presence of cognitive impairment, but no correlation between TLV and pattern of cognitive impairment.