Effects on Amyloid Deposition?
Amyloid imaging was not performed at baseline, but at 12 to 18 months into the study. At that point, the combination intervention group had the lowest percentage of amyloid-positive subjects (22%). The rate of amyloid positivity was 34% in the training-program-alone group, 46% in the DHA-alone group, and 51% in the placebo group.
It is not possible to determine whether the intervention altered the trajectory of amyloid deposition, Dr. Vellas said. That question will be explored in a different study.
PET imaging showed striking between-group differences in glucose metabolism. Patients in the training-alone group had a transient metabolic increase in the right and left temporal regions, which, compared with placebo, was significant at six months, but not at 12 months.
In the DHA-only group, there was no difference in glucose metabolism at six months, compared with placebo. At 12 months, there was significantly more activity in the left supplementary motor area.
The combination group showed significant increases in metabolism in several regions, including the right hemisphere cluster (ie, insula/putamen/amygdala/superior and middle temporal region), the left middle temporal pole fusiform gyrus and anterior temporal region, the right middle and inferior frontal region, and the right rolandic opercula.
—Michele G. Sullivan