DISORDERS OF VERBAL MEMORY AND LEARNING IN PATIENTS WITH CEREBROVASCULAR DISEASE

The main goal of the study was to assess overall memory impairment in patients with dyscirculatory encephalopathy (DE) stage I or II and in patients with stroke using our modification A.R. Luria free-recall memory test. Our modification of this test included 1) use 16 words, taken from four semantic categories: vegetables, animals, ways of traveling, and furniture, 2) use six lists of words that allows avoiding «item-specific» practice during retesting of each patient, 3) use six trials during each test, and 4) modeling the learning curve with an exponential function Y = B3xexp(—B2x(X—1))+B4x(1—exp(—B2x(X—1))), where Y is the number of correct recalled words, X is the trial number. The parameters are: B2 — the learning rate; B3 is an estimator of the general functional state of a participant before starting the test and is called «readiness to learn»; B4 is an estimator of general ability to learn and is called «ability to learn». The software SPSS and Mathematica were used for modeling the learning curves. Memory assessment with the ’Mini Mental State Examination’ method revealed no memory impairment. On the other hand, the modified free-recall memory test revealed moderate, but significant (p<0,01) impairment of readiness to learn (short-term memory) and ability to learn (long-tern memory) in the DE group as well as in the group of patients after stroke in comparison with the control group. At that, the learning curve did not differ between the DE and the stroke group (p>0,20) for each coefficient. Thus, the modified Luria’s verbal learning test might be used for estimation of initial memory impairment in patients with cerebrovascular diseases and effects of pharmacotherapy in the rehabilitation of these patients.

memory, learning curve, mathematical model, cerebrovascular diseases, discircular encephalopathy, ischemic insult