Up to 70% of MS patients suffer from cognitive decline, which often has a profound impact on an individual’s quality of life. It is little surprise that MS researchers are racing to identify methods to accurately predict that cognitive decline and to develop therapeutic measures to counteract its effects. At the recent ECTRIMS 2018 Congress in Berlin, Germany, we attended an exciting scientific session on the latest advances in monitoring and treating cognitive impairment in MS.
Cognitive impairment is associated with MS disease activity
Early focal inflammatory activity in the brain and spinal cord has been identified as one of the causes for cognitive impairment in MS. In his overview of a 15-year study with 104 patients showing early signs of MS, Dr Wallace Brownlee (London, UK) explained that early inflammatory disease activity, visible on the MRI scans as specific types of lesions at baseline, was predictive for lower performance of all of the cognitive faculties tested 15 years later. Especially, new, early occurring inflammatory lesions in the supratentorial area of the brain were associated with a decline in information processing speed and memory after 15 years.
The impact of inflammatory lesions on cognitive impairment may also depend on which types of neuronal connections are affected. We heard from Kim A. Meijer (Amsterdam, The Netherlands) that the longest distance neural connections appeared to be most vulnerable to inflammatory damage. Lesions in these long-range neuronal connections had the largest impact on cognitive function. This intriguing finding was made by studying the functional integrity of the brain’s neural network through imaging approaches in 133 MS patients and 48 healthy volunteers, the authors found.
Interestingly, psychiatric factors may be associated with disability worsening. Dr Stephanie Binzer (Stockholm, Sweden) reported on a cohort study which included 15,541 patients, and assessed correlations between psychiatric disorders and disability progression. Patients diagnosed with depression or bipolar disorder, and those who had received at least one prescription for anti-depressants, were at significantly greater risk of reaching disability milestones earlier. Dr Binzer concluded highlighted the importance of recognising and managing mood disorders early to help reduce MS disability worsening and associated cognitive impairment.
How monitoring of cognitive impairment may help guide treatment decisions
Given that cognitive impairment appears to be strongly associated with other MS symptoms, regular monitoring of cognitive status may help physicians to identify high-risk patients early on, which in turn could lead to selecting better therapies for this patient group. Dr Kunio Nakamura (Cleveland Clinic, Ohio, USA) presented a novel iPad-based test, called CogEval, (Biogen). This method assesses cognition by measuring information processing speed.
Dr Nakamura showed us that the scores for cognitive status measured in 850 patients through the app significantly correlated with MS lesion volume, brain atrophy, as well as social and psychiatric measures of well-being. Dr Nakamura believes the CogEval could prove very useful in both clinical trials and in routine clinical practice because it allows to save precious time and helps reduce the workload of administering cognitive testing.
For further information about iPad-based monitoring of cognition, check out our recent article dedicated to the topic.
Therapies to combat cognitive decline
Beyond pharmacological treatments with disease-modifying therapies (DMTs), there are targeted approaches that are applied to reduce cognitive impairment. Dr John Deluca (Kessler Foundation, New Jersey, USA) led the audience through the data of several recent publications (e.g. Dardiotis et al. 2018, Prosperini et al. 2015, Ernst et al. 2018) showing that computer-based cognitive rehabilitation is effective in improving memory and adaptability of the neural network. The positive effect of computer-based training on cognitive performance also seems to correlate with MRI-detected changes in brain function. Is there sufficient evidence to recommend ‘video games’ to all patients with MS? According to Dr Deluca, the evidence is still preliminary, although a program called RehaCom delivers very promising results.
We also heard from Prof Iris-Katharina Penner that exercise can improve cognitive function. An ongoing study with 44 patients, who either exercised on a treadmill, performed computer-based cognitive rehabilitation, or were subjected to a combination of both training methods, show that treadmill walking – alone or in combination with computer-based cognitive rehabilitation – significantly improves information processing speed and self-reported cognitive function.
All told, the take-home message from this session was that performing conventional MRI measurements are crucial for an early identification of patients who are at high risk for later cognitive decline. Clinicians should consider to regularly monitor their patients’ cognitive function, and apply therapeutic measures where appropriate. With the consequent application of such measures and ongoing research, the MS community is on the path to help further improve the quality of life of patients with deteriorating cognitive function.