Aim: To define the patterns of cognitive impairment in a homogeneous group of secondary progressive multiple sclerosis (SPMS) patients.
Patients and methods: Forty-two SPMS patients were included with a similar degree of disability; all had been treated with interferon beta-1b for a minimum of 3 months. They voluntarily complimented a battery of 10 neuropsychological tests selected for this study, distributed in two sessions of one hour. In addition, the emotional state was evaluated with the Beck Depression Inventory and the Hamilton Anxiety Scale. We considered cognitive impairment as more than two tests altered, according with previously reported studies.
Results: 73.8% of patients were women; mean age was 45 years (range: 25-62); mean EDSS was 5.4 (range: 3.0-7.5); mean evolution time was 34.5 months (range: 24-80); mean treatment duration was 13.5 months (range: 3-38). Cognitive impairment was present in 78.5% of patients. The most frequently impaired functions were: attentional capacity, visuospatial perception, verbal fluency, short-term and long-term logic memory and abstract reasoning. The presence of cognitive impairment was related to the time of evolution of the disease (r = 0.31; p < 0.05) but not with the age, the degree of disability or the treatment duration.
Conclusion: Cognitive impairment in the SPMS patients is a frequent finding, being the alteration in the speed for the acquisition and processing of new information, and the abstract reasoning the most frequent and severe altered functions. The also frequent impairment of visuospatial information was a differential finding in our study that could contribute to diagnosis of clinical progression.