Using MRI to measure the impact of subjective cognitive decline on the brain

Patients suffering from subjective cognitive decline (SCD) have measurable increased activity in certain areas of the brain on resting-state MRI, a characteristic that may be used to predict the development of Alzheimer’s disease and other diseases associated with diminished cognitive capacities, according to results of a study published in the journal Radiology.

Many elderly patients are believed to have SCD, which occurs when patients suffer from self-reported and persistent declines in their own cognitive abilities but do not exhibit measurable cognitive impairment according to standard assessments.

But up until now, research into how SCD affects the brain both structurally and functionally has been limited, said Yu Sun, MS, of Capital Medical University in Beijing, China, and his colleagues.

“Increasing evidence has suggested that individuals with SCD exhibit a trend toward a greater risk of cognitive decline and the development of mild cognitive impairment and Alzheimer disease,” they wrote. “Therefore, SCD may serve as a clinical indicator for early detection of Alzheimer disease and may arouse growing research interests.”

Sun and his team sought to assess individuals with SCD and determine whether they exhibit functional and structural brain alterations following neuroimaging examinations.

To do so, they used resting-state functional and structural MRI to measure the amplitude of low-frequency fluctuations and regional gray matter volume in 25 patients with SCD as well as 61 control subjects.

They found that patients with SCD exhibited higher levels of brain activity in the bilateral inferior parietal lobule, right inferior and middle occipital gyrus, right superior temporal gyrus, and right cerebellum posterior lobe, with no significant group differences found in gray matter volume.

“Higher intrinsic or spontaneous brain activity measured by means of resting-state functional MR imaging was observed in individuals with subjective cognitive decline,” the authors concluded, “indicating that there might be a compensatory mechanism in the early stage of Alzheimer disease and that resting-state functional MR imaging is an important technique for detecting brain alterations in individuals with subjective cognitive decline.”