Intranasal insulin improves memory, thinking, and functioning in people with mild cognitive impairment and Alzheimer's disease, a small pilot trial indicates.
Intranasal insulin improves memory, cognitive skills, and functional ability in people with mild cognitive impairment and Alzheimer’s disease (AD), a small pilot trial indicates. The trial results were published online this week in Archives of Neurology.
Earlier research had found that insulin levels and insulin activity in the central nervous system are reduced in AD. To see whether restoring normal insulin function in the brain would counter AD, researchers tested the effects of a nasal spray that delivers insulin rapidly and directly to the brain
The trial included 104 adults with amnestic mild cognitive impairment (aMCI), which involves memory loss and may proceed to AD, or mild to moderate AD. Participants received a daily dose of 20 international units (IU) of insulin, 40 IU of insulin, or a saline placebo, for four months.
Compared with the placebo group, those receiving 20 IU of insulin were better able to recall details of a story they had heard previously, while those receiving 40 IU were no better at recalling the story than those in the placebo group. Scores on the Dementia Severity Rating Scale (DSRS) were preserved for both groups taking insulin compared with the placebo group.
Both insulin levels also appeared to preserve cognition for younger participants as measured by the Alzheimer’s Disease Assessment Scale cognitive subscale (ADAS-cog) score as well as functional abilities in adults with AD as measured by scores on the Alzheimer's Disease Cooperative Study activities of daily living (ADCS-ADL) scale. In addition, participants with AD who received either dose of insulin had preserved function compared with participants in the placebo group, who showed a slight decline. (Participants with aMCI demonstrated no change regardless of treatment.)
The trial results indicate that intranasal insulin has the ability to stabilize or improve cognition and function for adults with aMCI or AD, providing an impetus for future clinical trials and study of insulin’s role in the development of AD.
Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment [Archives of Neurology]