Neuroplasticity Linked to Cognitive Performance in Patients With Multiple Sclerosis

In patients with relapsing-remitting multiple sclerosis, cognitive performance correlated with the degree of cortical plasticity induced by quadripulse stimulation of the motor cortex, according to a study published in Brain Stimulation.

“Cortical reorganization and plasticity may compensate for structural damage in multiple sclerosis,” wrote researchers. “It is important to establish sensitive methods to measure these compensatory mechanisms, as they may be of prognostic value.”

To gauge plasticity, researchers used amplitudes of the motor evoked potential before and after quadripulse stimulation applied over the contralateral motor cortex in 63 patients with relapsing-remitting multiple sclerosis and 55 matched healthy controls.

In patients with multiple sclerosis, performance on the Symbol Digit Modalities Test and Brief Visuospatial Memory Test-Revised correlated with quadripulse stimulation-induced cortical plasticity, according to the study. Patients with cognitive impairment had significantly reduced plasticity compared with patients with preserved cognitive function. Furthermore, the degree of plasticity differentiated between patients with and without cognitive impairment.

Interestingly, patients did not demonstrate reduced plasticity compared with healthy controls. Symptoms in the overall patient group, however, were mild, researchers noted.

“Together with our finding of reduced plasticity in cognitively impaired patients, this implies that promotion of synaptic plasticity may be a promising tool to prevent clinical deterioration and cognitive impairment specifically,” they wrote. “Further, promotion of synaptic plasticity could be used as a rehabilitation effort.”

For the time being, more research is necessary.

“We provide first evidence that quadripulse stimulation-induced plasticity may inform about the global synaptic plasticity in relapsing-remitting multiple sclerosis, which correlates with cognitive performance as well as clinical disability,” concluded authors of the study. “Larger longitudinal studies on patients with multiple sclerosis are needed to investigate the relevance and prognostic value of this measure for disease progression and recovery.”

Reference:
Balloff C, Penner IK, Ma M, et al. The degree of cortical plasticity correlates with cognitive performance in patients with multiple sclerosis. Brain Stimul. 2022;15(2):403-413. doi:10.1016/j.brs.2022.02.007