Hello,
As this symptoms sound to be of the brain
stroke since you mentioned about one side of the body weakness. You mentioned the scan has tuned to be negative, was the scan taken for the brain? If the brain scan is negative then we need to check for the
cervical spine MRI to see if the major portion of the
nerve root is getting compression due to which there is a sudden loss of movements on one side of the body.
Based on the clinical examination, laboratory tests we should be able to figure out what could be the cause and treat accordingly. Also as you said doctors don't know why are these symptoms then we have to treat Symptomatically for now like undergoing
physiotherapy management which will help the muscles to be active on the proper state of their well being and get some muscle activation by a passive and active-assisted range of motion exercises.
Wait for the body to get some response. In many cases post having a sudden onset of weakness are helped by physiotherapy management.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Jay Indravadan Patel, Physical Therapist or Physiotherapist