Brief Answer:
Read below.

Detailed Answer:
I read your question carefully and I am sorry about the symptoms you are experiencing.

The answer to your question is rather difficult though. Polyneuropathy can have many different causes, at times the cause remains unknown despite extensive testing. Management and prognosis can vary according to the origin. Since no cause was found it is difficult to predict a pattern, can have a progressive pattern, recurrent flares subsequently returning to baseline or leaving behind increasingly more damage.
Perhaps if you have reports from the tests you have had, like nerve conduction testing, imaging, lab reports etc, you could upload some of them in order to know what were you tested for and what type and extent of damage there was. That might help in making a more accurate prediction. Otherwise simply having polyneuropathy and some brain lesions involves a vast range of diagnoses.

I remain at your disposal for further questions.

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