Non-invasive MEG scan can predict cognitive therapy outcomes in MS
MEG could help personalize treatment recommendations for MS patients
A non-invasive scan that measures network activity across the brain was able to predict the outcomes of behavioral therapies designed to improve cognitive function in people with multiple sclerosis (MS), a study demonstrates.
Brain network function, as assessed by the test, called magnetoencephalography (MEG), “could play an important role in predicting treatment response and personalized treatment recommendations,” researchers concluded.
The study, “Neurophysiological brain function predicts response to cognitive rehabilitation and mindfulness in multiple sclerosis: a randomized trial,” was published in the Journal of Neurology.
MS is marked by an abnormal inflammatory response that leads to brain and spinal cord damage. Beyond the hallmark physical disabilities, people with MS can experience cognitive difficulties, which can affect daily function and quality of life.
REMIND-MS study evaluated 2 behavioral therapies
To help MS patients with their cognitive challenges, the recent REMIND-MS study evaluated two alternative behavioral therapies: cognitive rehabilitation therapy (CRT) and mindfulness-based cognitive therapy (MBCT).
Cognitive rehabilitation therapy includes interventions to enhance an individual’s cognitive performance following a brain injury. Individuals in MBCT are instructed to practice mindfulness, which refers to focused attention on the present moment without passing judgment.
REMIND-MS data showed CRT helped patients achieve cognitive goals. At the same time, mindfulness-based therapy improved cognitive performance via enhanced information processing speed (IPS), the most commonly affected cognitive function in MS. Benefits appeared to favor those with fewer cognitive problems before treatment.
Scientists have now investigated whether brain network function, as measured by MEG, can predict responses to cognitive rehab and mindfulness-based therapies.
MEG measures fluctuating magnetic fields produced in brain by nerve cells
MEG is a non-invasive technique that measures oscillating (fluctuating) magnetic fields produced in the brain by nerve cell electrical activity. MEG can detect six clinically relevant frequency bands, each associated with different brain activities: delta, theta, alpha1, alpha2, beta, and gamma.
Of the 110 REMIND-MS participants, 105 (mean age of 48.6, 75% female) had usable MEG data at baseline, or before the interventions, with 59 experiencing cognitive impairment. Among the participants, 32 were assigned CRT, 31 received MBCT, and 33 had “enhanced” treatment as usual, which means usual care and meeting with an MS nurse. MEG data from 56 individuals without MS served as controls.
Data showed differences in MEG measures at baseline between MS patients with and without cognitive impairment as well as controls. For example, compared with patients with normal cognition, those with cognitive impairment had lower delta and gamma power levels, and an elevated beta phase lag index (PLI), which measures the functional connectivity between different brain regions.
Patient-reported cognitive complaints were examined using the Cognitive Failures Questionnaire, and executive functioning was assessed using the Behavior Rating Inventory of Executive Function-Adult version.
None of the patient-reported cognitive complaints at baseline were associated with any MEG measures.
However, worse memory performance was related to lower delta and gamma and higher alpha1 power. Worse memory and executive function were associated with higher theta PLI connectivity as related to the strength of the default mode network, which are brain regions that are active during wakeful rest, such as when daydreaming.
For MEG predictability, patients with higher beta PLI connectivity, both globally and in the default mode network, showed greater benefits six months after cognitive rehab therapy.
Likewise, those with higher theta PLI benefited significantly more on personalized goals immediately following mindfulness-based therapy. Six months after the therapy, patients with lower gamma power and higher theta PLI connectivity related to the default mode network benefited more in information processing speed.
Certain MEG predictors indicate worse brain function in MS patients
MEG measures that predicted treatment response — higher theta and beta connectivity and lower gamma power — were also abnormal in cognitively impaired patients at baseline. Overall, these MEG predictors indicated worse brain function in MS patients than in the controls.
Additional analysis confirmed worse cognition and disability, as assessed with the Expanded Disability Status Scale, at baseline also predicted improved information processing speed after the mindfulness-based therapy but not after cognitive rehabilitation therapy.
“Brain network function predicted better cognitive goal achievement after MBCT and CRT, and IPS improvements after MBCT,” the researchers concluded.
MS patients with “neuronal slowing and hyperconnectivity were most prone to show treatment response, making network function a promising tool for personalized treatment recommendations.”
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