Categorization and learning in multiple sclerosis patients. New neuropsychological assessment instrument

VANOTTI, S; CORES, V; ORELLANO, A; TABULLO, A; GALEANO, PABLO; YORIO, A; FERNÁNDEZ LIGUORI, N; SANDOVAL, G; VILLA, A; GARCEA, O

Madrid

Congreso; 22nd Congress of the European Committee for Treatment and Research in Multiple Sclerosis; 2006

European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS)

Cognitive Impairment (CI) occurs in 40-60% of patients with MS. Categorization is a cognitive process that has been associated with executive function and memory, functions of the prefrontal and temporal cortices. Categorization consists of distributing elements into classes (class formation). It also implies a hierarchical order of classes. This allows subjects to use abstraction abilities favouring the thinking process. Objectives: 1) To compare MS patients with normal control, at the performance of the categorization 2) To correlate the results with another cognitive domains, such as executive function, memory and attention. 3) To correlate the conceptualization concepts formation results with other scales such as Expanded Disability Status Scale (EDSS) and Beck Depression Inventory. Methods: 12 (7 females) MS patients with relapsing-remitting pattern and 72 healthy controls were evaluated and compared regarding age and education level. Age: 40.97 ± 11.20; Disease evolution: 7.15 ± 6.53; Instruction level: 13.7 ± 3.1 (years). Cognitive performance was evaluated using the Brief Repeatable Battery Neuropsychology (BRB-N), California Verbal Learning Test, WMS-R, Trail Making A y B, Wisconsin Card and Boston Test. EDSS and Beck Inventory were other outcome measures. In order to evaluate the categorization ability a computerized test was used: Two series of conditional discriminations were trained and the untrained relations (reflexivity, symmetry and transitivity) between the stimuli were evaluated. This is a conventional test of equivalent relations that is considered a model of symbolic behaviour. Results: 9/12 patients (75%) reached trained criteria and 7/12 (58%) reached test condition criteria. Thus, 42% of patients did not pass the test phase vs. 57 (80%) controls that passed both phases. There was a significantly high correlation, r=0.7 (p=.05), in tests measuring executive functions (PASAT and Wisconsin) and verbal and visual memory (California and 7-24 Spatial recall). Other significant correlations were observed regarding Digit Span (r=0.78), and Phonological Verbal Fluency (r=0.74). Conclusion: MS patients showed categorization deficits associated with impairment of the executive function, verbal and visual memory. Due to the high correlation between the cognitive tests evaluated in our study, we achieved a higher level of validity. These tests include a neuropsychological assessment that has not been considered in previous studies.