•We explored the relationship between event-related potentials, deep grey matter atrophy and cognition in MS.•Cortex volume emerged as the most significant predictor of the P300 amplitude.•The ...amygdala and hippocampal volumes were found to influence P300 latency.•The combination of structural MRI and neurophysiological techniques could improve the understanding of CI in MS.
Event-related potentials (ERPs) have been proposed as a neurophysiological biomarker to capture cognitive dysfunction in multiple sclerosis (MS). Few studies have evaluated the relationships between ERPs and brain atrophy as known marker of structural brain damage related to cognitive impairment (CI).
To explore the relationships of brain atrophy, including of the cortex and deep grey matter, with ERP abnormalities and cognitive function, as defined using the Brief Repeatable Battery of Neuropsychological Tests (BRBN).
Seventy-eight patients with relapsing-remitting MS were enroled, of which 38 (48.7%) had CI. Independent t-test comparisons of the ERP parameters found a significant difference in P300 wave latency, with a latency of 343.7 ± 32.6 ms in the CI group vs. 320.3 ± 16.5 ms in the cognitively preserved (CP) group (p = 0.001). Significant differences in the MRI measurements, including the cortex (p = 0.02) and deep grey matter structures thalamus (p = 0.001), amygdala (p = 0.030), and nucleus accumbens (p = 0.004)) were observed, with lower measurements in the CI group. Regression models were also performed to explore the impact of brain volumes on ERP parameters. This showed a relationship between P300 latency and the lower amygdala (p = 0.02) and hippocampus (p = 0.03) volumes, while the amplitude of the P300 was significantly associated with a lower cortex volume (p = 0.01).
Cortex volume emerged as the most significant predictor of the P300 amplitude. The amygdala and hippocampal volumes were found to influence P300 latency, highlighting the role of deep grey matter atrophy in ERPs for the first time. The combination of structural MRI and neurophysiological techniques, sensitive to diverse aspects of MS pathology, could improve the understanding of CI in MS and its neurodegenerative and inflammatory substrate.
•Several lifestyle risk factors may influence multiple sclerosis (MS) evolution.•Our results showed smoking is associated to higher lesion load already in early MS.•No association was reported with ...vitamin D level, BMI and lipid profile.•Lifestyles interventions to improve health outcomes of people with MS are required.
Some studies have indicated the importance of considering smoking, vitamin D deficiency and obesity as negative prognostic factors for clinical and MRI outcomes in multiple sclerosis (MS). This study aimed to evaluate the possible effects of these modifiable risk factors on brain MRI lesion burden of patients with early MS, also exploring the influence on initial clinical features.
MS patients were enrolled at diagnosis time and examined for smoking, body mass index (BMI), serum level of lipids and 25(OH) vitamin D. Brain MRIs’ were acquired and lesion volume assessed by Jim software. Clinical data (disease course, disease duration, and EDSS score) were also collected.
64 patients were enrolled, of these 4 (6.2%) had a primary progressive course. Mean age was 39.8 ± 11.1 years and mean EDSS 1.5 ± 1.1. Forty (62.5%) patients were smokers and 40 (62.5%) were overweight (BMI>25). Insufficient levels of vitamin D (<20 ng/mL) were reported in 36 (56.2%) patients, while 24 (37.5%) patients had an altered lipid profile with total cholesterol >200 mg/dl and LDL >100 mg/dl. No association between early clinical features and modifiable risk factors were reported. Multiple regression analysis showed an association between lesion burden and smoking status (p 0.003), while no association was reported with BMI, altered lipid profile and vitamin D insufficiency.
Several risk factors may play a role in evolution of MS. Our results show that smoking status, probably due to chronic vascular and neurotoxic effects of the cigarette components, can affect the brain damage from the early stages of MS. No association was observed with the other explored modifiable risk factors, although an effect due to the small sample size cannot be excluded.
