Plenty of measures of brain structure and function have been shown to correlate with Alzheimer’s disease, if you look at people who already have it or even at those who have mild cognitive impairment (MCI) and who may be on their way to developing the disease. There was a handy review about all this in Clinical Pharmacology & Therapeutics last year (subscription required).
But that comes second to being able to predict Alzheimer’s disease before there are any clinically noticeable changes – the idea being that only if we start early might we manage to pre-emptively treat this condition.
Reporting at a session on the uses of neuroimaging in neurology here at the AAN, Bradford Dickerson said that he and his group at Harvard Medical School are wrapping up a ten-year study of people with and without MCI who either remained healthy for the duration of the study or went on to develop Alzheimer’s. In as-yet-unpublished results, they’ve been able to show that even individuals who started off asymptomatic but who subsequently got Alzheimer’s have differences in certain aspects of brain structure to those who didn’t.
They’ve been using a brain imaging technique called quantitative MRI to look at the thickness of various areas of the brain’s cortex. It was a thinning of the cortex in a region called the medial temporal lobe that seemed to predict whether someone would develop Alzheimer’s disease: those who developed it showed a thinning of the cortex in this area by about 0.2mm.
Before this can become part of a battery of tests for pre-symptomatic Alzheimer’s, says Dickerson, it will need to be subjected to clinical trials. The most likely form these will take are trials for drugs or other treatments for Alzheimer’s which will incorporate measures of cortical thickness as measures of success. It’ll also be necessary to think about the ethics of predicting future susceptibility to this disease.
Dickerson predicts that the first results of such clinical trials – in people with MCI, rather than asymptomatic, healthy people – will start to emerge at conferences as early as this summer.