EFFECT OF TESTING PROCEDURE ON CORSIS BLOCK-TAPPING TASK IN NORMAL SUBJECTS AND ALZHEIMER-TYPE DEMENTIA

Corsi's block-tapping task was given to 30 normal subjects and 38 Alzh eimer-type demented patients following two different procedures. The f irst is the most widely standardized (scoring criterion: 3 correct rep roductions out of 5 sequences), while the second is more lenient since it does not require subjects to replicate a certain performance three times. Demented patients' scores were lower than those of controls in both conditions, and scores on the two tasks were significantly corre lated for patients and controls. However, the requirement of replicati ng the visuospatial memory performances was more detrimental for demen ted patients than for controls so the two procedures cannot be conside red equivalent.