Hello Shahul, and welcome to the forum.

There are a lot of well informed people here, but I guess your post is in the middles of a thread about an issue that isn't quite what you are asking about. Diagnosis of Pd is quite difficult which is why people on this thread are talking about bio-markers.

Some of your dad's problems do have things that are similar to PD, but some of them are not usually found in early PD. There are however a number of conditions that are similar to Pd and have sometimes been included under the PD label. Not everybody with PD has a tremor, some figures reckon that as many as 30% do not have it. Some people with no visible tremor have an internal vibration sensation that is often called an internal tremor. Others have intermittent shakiness that is not the same as the classic PD tremor. So as you can see nothing is clear cut.

You do not say how old your dad is, or how long he has had symptoms, or what medications he is on and how they have/have not helped him. I suggest that you start a new thread, to ask the question again, and outline some of these things. For instance if your dad is responsive to PD meds that might be an indication. If he is not perhaps he might have another PD related condition. Or he may have something else altogether. If he is elderly then you are likely to want some kind of resolution of what is wrong fairly soon, and his condition sounds difficult. Ask again and maybe others will have more suggestions.

You also do not say where your dad lives. If he is in the US a neurologist who is a movement disorder specialist will be the best to ascertain if he has PD, in the UK and elsewhere a neurologist who specializes in PD may be able to help.

Best wishes as you try to find out what you are dealing with, and please ask any questions you think are relevant.

Lindy