Can MEG Scans Accurately Assess Cognitive Function in Patients With MS?

Magnetoencephalography (MEG) is a valuable measure of cognitive impairment among patients with multiple sclerosis (MS), according to new data.

“The aim of this study was to demonstrate the value of clinically applicable quantitative MEG measurements in evaluating cognitive impairment in MS,” the researchers wrote. “We found that cognitive impairment in MS is associated with global slowing of the posterior dominant rhythm, resulting, due to the use of relative power bands, in an increase in relative spectral θ and α1 (and reduced α2) power across the brain.”

To conduct their study, the researchers reviewed data from 83 patients with MS and 34 healthy controls from the Amsterdam MS cohort. Results of MEG scans were evaluated to determine peak frequencies and relative power of 6 canonical frequency bands for 78 cortical and 10 deep gray matter areas during patients’ eyes-closed resting-state.

The relationship between cognitive performance and MEG biomarkers was assessed using linear regression models.

Overall, 37 MS patients were classified as cognitively preserved, 18 were mildly cognitively impaired, and 28 were cognitively impaired; and 59 had relapsing-remitting MS, 8 had primary progressive MS, and 16 had secondary progressive MS.

Cognitive impairment was strongly associated with increased α1 and θ power, which differed between patients with cognitive impairment and healthy controls in bilateral parietotemporal cortices.

Compared with healthy controls, patients with cognitive impairment had a lower peak frequency.

The researchers noted that oscillatory slowing was also widespread in the deep gray matter and was most pronounced in the thalamus.

“To conclude, an important step forward has been made in identifying objective measures that can potentially discriminate between cognitive impairment and cognitive preservation in MS,” the researchers wrote. “Additional work needs to be done to assess sensitivity and specificity in a larger patient group as well as to evaluate the prospective value of such measures. Future studies also need to further elucidate the relationship between cortical and thalamic oscillatory slowing and further unravel the complex interplay between different pathological processes that ultimately determine the disease course and burden in MS.”

—Amanda Balbi

Reference:

Schoonhoven DN, Fraschini M, Tewarie P, et al. Resting-state MEG measurement of functional activation as a biomarker for cognitive decline in MS. Mult Scler. 2019;25(14):1896-1906. https://doi.org/10.1177%2F1352458518810260.