I was writing to Mr. Lehmann-Horn about two years ago. He let me fill in a form of 20 pages and then diagnosed a hyperPP with Myotonia, but he was not 100% sure. He didn't offer a free testing. He send me an estimate of costs and it was too much for me to pay.
Yes, I do have problems with the diaphragma ( in the water I cant breathe at all and after coughing a lot or singing I suffer from respiratory depression) and with my eye muscles (the inner ones) and a bit with my face (masticatory muscle), but my tongue and throat are not really affected. But when I speak for a longer time, I fell a kind of pain and my voice gets raucous, so I have to stop using my voice and be quiet for a cuple of hours or a day.
My EMG was positive. It cannot be Becker because my doughter has the same.