Thanks for the good question. Lymphatic system is indeed important in clearing metabolic waste from the brain. Aging comes with less effective lymphatic clearance, also contributes to the development of dementia (https://pubmed.ncbi.nlm.nih.gov/25861024/).

So, it makes sense that our lymphatic system may not be able to clear toxins and waste as effectively when we get older. The abundance of environmental toxins probably make this worse, assuming they manage to get into the brain. Mold, for instance, has also been linked to the development of neurodegenerative diseases, including multiple sclerosis (MS) (https://www.imrpress.com/journal/JIN/22/6/10.31083/j.jin2206137/htm).

Neurodegenerative diseases have multifactorial risk factors, so stress is also a contributing factor. And I hope you can manage your health well despite having MS.