Longitudinal investigation on the feature-binding working memory after subcortical infarction

Abstract

Objective To investigate the cognitive behavioral characteristic longitudinally of the patients after subcortical infarction engaged in feature and binding working memory tasks. Methods The behavioral performances were recorded from 28 patients after subcortical infarction at the 1st week(W1), 3rd moth(M3) and 6th month(M6) while performing color, location, and color-location binding delayed match-to-sample working memory task.25 healthy volunteers(controls) were investigated once using the same task protocol during the study period.Computer recorded the behavior reaction time and accuracy.Single factor variant analysis of repeated measurement was adopted. Results The accuracy of three memory tasks of M3( (64.92±5.47)%; (92.88±2.98)%; (82.35±7.44)%) was improved than that of W1 ((61.06±7.78)%; (90.59±2.95)%; (77.06±5.58)%) and the difference had statistically significant (P<0.05). But the reaction time of M3 ((868.31±118.91)ms; (833.37±120.99)ms; (918.72±101.28)ms) was shortened than that of W1 ((914.02±110.53)ms; (859.89±139.94)ms; (1150.17±92.02)ms) and the difference also had statistically significant (P<0.05). In the location-memory task, the correct rate of M6((93.91±2.86)%) was improved than that of M3((92.88±2.98)%) and the reaction time of M6 ((813.24±119.54)ms) was shortened than M3 ((833.37±120.99)ms). M6 and M3 to be compared in the color memory task, the correct rate ((64.50±4.49)%; (64.92±5.47)%)and the reaction time ((866.47±123.87)ms; (868.31±118.91)ms) had no significant difference (P<0.05). But in the color-location binding task, the correct rate of M6((78.49±7.85)%) and M3 ((82.35±7.44)%) to be compared had significant decreased nearly the level((77.06±5.58)%) of the stroke beginning.All behavioral performances of patients were worse than that of control subjects except the compare result of location-memory task in M6((93.91±2.86)%; (813.24±119.54)ms). Conclusion Feature memory and binding memory had been damaged in different degrees in the patient after subcortical infarction.The binding memory had the secondary damage what might be related to the secondary nerve fiber degeneration after infarction. Key words: Subcortical infarction; Secondary degeneration; Binding memory; Working memory