Many of us have them in our brain,eyes, and all over.
You can be asymptomatic and/or have just a few symptoms for parasites or any health condition can be atypical.
You don't have to have diarrhoea, I have never had it and I have 4 parasites to battle.

For eye twitching..use warm water and Epsom Salt mix applied to the eye lid and see if this helps.
Also it will stop after the para's diminish.
Most people complain paragone is not very effective.
Fresh herbs are better.
Also some use organic coconut oil warmed to room temp and dropped in each eye to get parasites out. Do this right before bed or else you will be bumping into things.
It is harmless make sure everything is sterile and your hands are very clean.
If you have parasiteds in the head you willknow without a doubt they are very noisy.
The brain actually has no feeling but the external part between the skull and the skin..those you can feel and hear.
Ask Mendomaid

Doctors have not generally been trained at all regarding parasites & are walking around clueless that they are inhabited by them. (Maybe tell the doc to take the cayenne pepper challenge test - ditto his or her family members.) I don't know where he got his informal "test" for parasites but it is just not true at all.

I agree that Paragone is often said to not be very effective. If you were using two zappers and more effective herbals I think you would have way too much die off.

There really is no way to know for sure if your symptoms are caused by parasites directly and/or indirectly. Hulda Clark 's ozonated olive oil & mega coQ10 dosing reportedly kills at least some types of parasites no matter where they are.

I would personally have been zapping for a month before trying that, without adding in any other paracides, so that you don't get any overwhelming die off. Die off ain't fun though kind of inevitable. In fact if there is no die off probably you are not killing very many bugs.

An approach to (per Hulda Clark universal) tapeworms, also ascaris:
//www.curezone.org/clark/ascaris.asp