SDAT patients: Measurements of rCBF and memory performance

Abstract

Cognitive processes, and especially disorders of memory in elderly normal and senile individuals are very actively investigated. Our interest was to study metabolic correlates of memory processes in both groups, and we were also interested in the effects that a drug (pyritinol) could have at such processes.All the subjects were selected from our Memory Center in an Old Peoples' Nursing Home in Zagreb, and those who satisfied DSM III criteria for senile dementia formed one group (N --26), while the elderly normals who did not show a particular cognitive disorder were the other group. Regional cerebral blood flow (rCBF) measured by the Xenon inhalation technique was used as a correlate of cortical metabolic function, rCBF was always measured in rest and after an activation procedure which consisted of a memory test. Placebo and pyritinol were administered in a double blind cross over randomized clinical trial in all SDAT patients.A cortical activation pattern of rCBF after the activation procedure was determined for normal elderly and it was compared with the SDAT patients. At the same time the memory performance for the two groups was compared. The results show that the normal elderly have a much better memory performance, while at the same time they increase their rCBF in a much smaller, and quite distinct region of the cortex, as opposed to the SDAT patients in whom the cortical activation rCBF pattern was widespread. When the SDAT patients were given a placebo their memory performance improved, and simultaneously their rCBF activation pattern improved from the one seen in the same group without any medication. After therapy with pyritinol the memory performance improved significantly, and the rCBF pattern of activation approached the pattern seen in normal elderly.It is possible to determine the rCBF activation patterns of memory processes in elderly normals and SDAT patients. They are distinctly different, but after treatment with placebo and especially after treatment with pyritinol a significant improvement can be seen in both the rCBF pattern and in their performance. Pyritinol significantly improves both the memory performance and the pattern of metabolic activation.