TUESDAY, Sept. 13 (HealthDay News) -- Intranasal administration of insulin may delay or improve cognitive decline, functional ability, and cerebral glucose metabolism in adults with amnestic mild cognitive impairment (aMCI) or Alzheimer's disease, according to research published online Sept. 12 in the Archives of Neurology.
Suzanne Craft, Ph.D., of the University of Washington School of Medicine in Seattle, and colleagues assigned 64 adults with aMCI and 40 adults with mild to moderate Alzheimer's disease to placebo, 20 IU of insulin, or 40 IU of insulin, administered intranasally, over four months. The authors sought to examine the effect of the insulin therapy on cognition, function, cerebral glucose metabolism, and cerebrospinal fluid biomarkers in the two patient populations.
The researchers found that 20 IU of insulin improved delayed memory. Functional ability was preserved in recipients of the 20 and 40 IU insulin doses, both of which also preserved general cognition. Although cerebrospinal fluid markers remained unchanged in the treatment recipients as a group, exploratory analysis showed an association between memory and function changes with changes in the Aβ42 level and the tau protein-to-Aβ42 ratio.
"These results support longer trials of intranasal insulin therapy for patients with amnestic mild cognitive impairment and patients with Alzheimer's disease," the authors write.