Our oldest showed evidence of nerve damage on every nerve tested. Her arms, wrists, legs and ankles were all tested. Not good at only 9 years old but things could be worse. She appears to be functioning normally right now and her only recent issue was very mild. She woke up with one arm much weaker than the other. She could move everything as she should but it took a lot more effort. Thankfully this problem was gone by the end of the day. We have her sleeping on a memory foam mattress to reduce pressure while she sleeps but it is not a guarantee.
This disease is so hard to monitor. Nerves can and are being injured during normal daily activity but you don't know until enough of the nerves in the bundle get damaged that the others can no longer compensate for the difference. Then we see it, when normal function is effected. She had a period of over a year where she was incontinent. Her bladder muscles were very weak. Very unusual in young children who are well beyond toilet training. It only made sense to me that it was HNPP related. Muscle weakness onset with no apparent injury and then the eventual "healing" on its own. We went to several doctors about this problem too and none could agree on a cause or found something that would help. Some thought it might be related, some said it wasn't, and no one said it was for sure due to HNPP. Another trial in having a rare, lesser studied and lesser known disease.
Our second child's results were that she did have some nerve damage in her wrists. Similar to carpal tunnel at six years old. Not normal but not a confirmation that she has it, probably does in my opinion.
In My Opinion: It seems to be difficult for doctors to accept unusual symptoms from HNPP patients being due to HNPP. Not only is it rare, it is also rarely diagnosed due to its hugely varied symptomatology, varied degree of severity and lack of knowledge among the medical community. My husband visited several doctors over the years for various problems that were considered "mysterious" in some way and not only was the condition HNPP not considered, it was completely unknown to them. He was never led to a neurologist and there are many others with mild enough symptoms that they never mention them to a doctor. We were only led to the knowledge of it in our family through our daughter's problems, and even then I feel we were lucky we received the correct diagnosis despite it taking a year. Her neurologist was familiar with it. Even with this knowledge we hit stumbling blocks with doctors who just don't know enough about it to accept what we say. They still want to eliminate all other possibilities for having the trouble they do before reaching the conclusion that the only thing you can do is leave it alone until it starts to heal and then mild occupational or physical therapy to regain as much movement as you can. I appreciate doctors and all they are able to do but they are also part of a frustrating cycle at times. Hopefully in years to come it will get better as more information becomes available to all of us.