Differential characteristics of the aging process and the vascular cognitive impairment in the organization of memory retrieval.

Early identification of cognitive impairment in patients with chronic cerebral vascular disorders can allow for evaluating the time course of the disease up to the phase of conversion to dementia. The specific indicators of pathological cognitive decline should be identifiable vs. the concurrent age-associated changes in memory which accompany the aging process. We propose a method which evaluates memory dysfunctions in vascular cognitive impairment (VCI) as distinct from age-associated memory changes. This method is based on a serial learning task of concrete frequent words and it consists in controlling the effects of age and cerebral pathology on various characteristics of immediate recall, including serial effect and productivity. Ninety participants underwent a between group examination: younger adults vs. older adults vs. VCI patients who were outpatients with a positive history for chronic cerebral vascular disorder, positive neuroimaging examination, a Hachinski ischemic score ≥ 5 and a mild to moderate cognitive impairment. VCI patients show a reduced efficiency of retrieval and recall organization while, age-associated cognitive changes consist of a modification of the serial position effects. In particular, VCI patients, as distinct from same-age normal cases, can perform an only partial utilization of the inherent structure of the memory task with a very limited efficiency of relearning which is not sufficiently supported by the facilitating factors due to task repetition.