DTI data ties cognitive impairment in MS patients to signs of brain damage

A diffusion tensor imaging (DTI) study has shown that multiple sclerosis (MS) patients with cognitive problems have more damage to areas of the brain involved with cognitive processes compared with MS patients who don’t suffer from cognitive problems, according to the results of the study published online March 6 in Neurology.

The results confirmed that cognitive symptoms in MS have a biological basis, explained authors Hanneke E. Hulst, MSc, of VU University Medical Center in Amsterdam, and colleagues.

Problems with memory, attention and concentration affect up to 65 percent of people with MS. To investigate whether the extent and severity of white matter damage on DTI could distinguish cognitively impaired patients from those with preserved cognitive function, conventional and DTI data were acquired from 55 MS patients and 30 healthy controls. Fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity were analyzed.  

Decreased fractional anisotropy was found in 49 percent of cognitively preserved patients, compared with 76 percent of cognitively impaired patients. The corpus callosum, superior and inferior longitudinal fasciculus, corticospinal tracts forceps major, cingulum and fornices all demonstrated reduced fractional anisotropy in both groups of patients, but the reduction was significantly worse in impaired patients. These patients also showed white matter integrity damage in cortical brain areas, thalamus, uncinate fasciculus, brainstem and cerebellum.

“These findings were independent of lesion location and regional gray matter volume, since no differences were found between the groups,” wrote the authors.

Since white matter integrity changes were found in brain areas involved in cognition in impaired patients but not in cognitively preserved patients, these changes are likely related to the cognitive deficits, according to the authors. DTI could become useful in monitoring cognitive impairment in MS patients, they noted.

“The consequence of this discovery is that imaging can now be used to capture a wider spectrum of changes in the brains of people with MS, and will therefore help determine more accurately whether new treatments are helping with all aspects of the disease,” Hulst said in a release.