MG is a strange disease. If one sits down and rests the muscles will then work again for a short while. I don't think the doctor would notice anything abnormal about IS on a visit to the surgery if he was taking the appropriate medication. Problems arise, depending on how severe one suffers the disease, when it is necessary to walk anywhere or repeatedly use a group of muscles etc. I can tell you my GP was useless but most GP's never see the disease because it is so rare. It took me several years to get a diagnosis and in the end it was I who insisted I saw a neurologist who diagnosed it immediately.
What happens is that the receptor sites that "trigger" muscles into action are destroyed by antibodies and therefore cannot work. This normally happens over a period of time, meaning that fewer and fewer receptor sites are available to allow the muscle to be activated. This is where the fatigues sets in.
I don't really want to talk too much about me, only to give some insight into what a nasty disease this is. I have a feeling he had a thymectomy, as I did, which eventually meant I could reduce the drugs. I was one of the lucky ones because thymectomy does not always work. It is not a cure in that the damaged receptor sites, after a period of time, will never work properly again. If he is still taking drugs he should, if he gets the timing right, be able to behave reasonably normally for 2 hours out of 4. His GP has confirmed he does have MG and he will have a repeat prescription for the drugs he needs.
I have to be honest and say I think he does have a real problem but if medicated properly it should enable him to function fairly normally for at least part of the day. I think it is in his interest not to take his medicine as and when he should whilst he is in the witness box because he will wish to appear a bit on the weak side. I have assumed he will be sitting down to give evidence although nobody has actually confirmed this. Tiredness may show in his speech and an inability to hold his head up. I did wonder when the Pros and Def decided he was getting too tired whether his speech was deteriorating. The other problem is stress. As with everyone stress can cause fatigue. With a myasthenic this can exacerbate the symptoms of the disease.
Please don't think I am making any excuses for him. I have no doubt he is guilty. He is an unfettered liar. He was perfectly able to murder Helen and probably chose the drugging method because it would not require any physical effort on his part. Poor Helen probably was nearly comotose and it would not be too difficult to overcome someone in that state, either with an arm lock or by simply placing a pillow over her face or a polythene bag over her head. There is a point, however, I do not understand. With suffocation eyes would normally be bloodshot and the eyes would normally bulge. I don't recall anything we have heard in the PM report that describes this. Therefore I do wonder whether, like his first wife, she had a fit of some sort. Unfortunately there would be no indication in the brain three months on as I think the brain deteriorates quite quickly after death.
This link describes the process of the disease and how it affect people.
https://medicine.yale.edu/neurology/patients/neuromuscular/mg.aspx