Hello Dr Faisal here. I have read and understood your query. The demyelination is the removal of myelin sheath, a protective cover on nerves. As there are billion of nerves placed together in brain. Any disease may lead to demyelination. Even a fast change in your sodium levels from a very low level to high levels or from high level of lowered immediately over a few hours may also lead to demyelination. Bacterial, viral, infections and autoimmune disease just like small vessel disease can lead to demyelination. This complex phenomenon needs to be treated at its root cause. Inflammatory or autoimmune disease will respond to steroids and disease.modifying drugs. Like wise electrolytes to be regulated strictly and replaced slowly to a good demyelination . If cause is long standing atheroaclerosis , answer is control of sugar levels , blood pressure , smoking, weight control , exercise and healthy diet . Demyelination of what ever site manifests in decreased or no functioning of that specific part of brain. Small vessel disease is a generalized term and this usually leads to dementia. (Gnenenalized mental sluggishness) I hope I have answered your query and if you need any further assistance please feel free to contact me again . Regards Dr Faisal Bacha. MBBS;FCPS.(MEDICINE)