Atypical parkinsonian tremor

My husband is 40 years old and has devoloped a rapid on-set tremor in his right arm.  We are having difficulties getting any answers from the Doctors we have seen so far.  The latest is that it is not Parkinson's, go have a sleep study and after that is done we'll look at it again in 3 months.  There is no eye or handwriting involvement at this time and the tremor appeared 2 months ago.  These are the main reasons being stated for it not being Parkinson's.  He fails the Rhomberg test even with his eyes open but he has not yet experienced any falls.  Prior to the onset of the tremor he did not have any balance issues.  Also since the onset of the tremor he has begun to move excessively in his sleep.  Sometimes just like he is trying to get comfortable and other times it is full body jerks, they occur at all times of night, the worst night I counted more than 65 individual events over a 2 hour period immediately after going to bed.  He has had difficulties maintaining sleep for approximately 10 years but if the movements were there previously they were minimal compared with what is currently going on.  Initially there was involvement of the right leg in the tremor as well but that has subsided and we both feel that tha may have been more of a nervous issue due to the stress of the situation because he is an individual who has always had issues with "jumping" his leg when he is nervous.  Unfortunately, when this stopped it has not helped with the muscle weakness, limping and decreased sensation in that leg.  Approximately 12 years ago he had what was believed to have been a pinched nerve that caused a period of more severe sensation loss in that leg.  By the time testing was done the situation was resolving and nothing showed up on the MRI of his spine other than his scholiosis which is severe.  Since that time he has had brief periods (5-30 minutes) of sensation loss on occaision but we have always attributed this to some form of minor damage done when the nerve was pinched and had never sought treatment.  Since the tremor started the lack of sensation has become almost constant but is still not as severe as the initial event.  He has had MRIs with and without contrast on his brain and cervical spine within the last month and nothing of significance showed up.  The only notations were a Chiari type 1 with 3-4mm herniation and some mild disk degeneration at C4-C5.  His ability to sustain movement seems to be preserved but initiating standing from sitting is impaired at times.  It is not all the time but there are times when he has to sit and tell  his body to get up rather than just standing and moving.  Similarly when he needs to write there is difficulty with initiating the action but there is no evidence of micrographia at this point in time.  The oringinal nurse practitioner that he saw first told him that she belives there is strong evidence that this could be psycogenic in nature because the tremor is distractable and his gait disturbance is not ataxic but more anatonic and sometimes with concentration he can acheive an almost normal (for him--he has a distinct gait due to the 17 degree curvature of his spine) gait.  At this time he is more bothered by the balance and gait issues but the movement specialist has said that these are not an issue at all and is focussing solely on treating the tremor.  He has trialed both Proprananol and Sinemet and neither have had any effect on the tremor.  When given vallium for the MRI there was a slight decrease in the tremor.  Currently the tremor is much improved in the evenings and on weekends when he is at home even just watching tv but especailly when engaged in an activity with myself or our 5 and 9 year-old boys.

The only information given to us by the movement specialist so far is that she does not believe this is Parkinson's and the tremor is not entirely Parkinsonian but that is the closest classification she can give.  At this point it will be early next year before she will see him again.  He is being evaluated to determine what type of sleep study another neurologist feels is necessary next week.  Right now we are frustrated because the movement specialist he has been assigned to is very difficult to engage in any type of dialog and we are deperate for more information than well we know it isn't MS and it may not be Parkinson's.  We were told that she believes she knows what it is but she would not even discuss possiblities or what she hopes to find in the sleep study other than she stated that she does not care if he has obstructive sleep apnea or not as that would not affect his condition (my thought is that since stress exacerbates the situation it might not be the cause but since not sleeping makes it more difficult to handle stressful situations I would think that anything to imrove his sleep would surely help to lessen the disability, but I am not a physician).  In the future it is very likely that we will be looking for a different neurologist because neither of us were comfortable with the lack of empathy and concern for the situation but for the moment we are trying to deal with what we have so that we don't have to start over at square one.  What we are looking for at this point information regarding the possiblities as to what this is, clinically speaking it is not Parkinson's at this time and there are no lessions in the brain so MS has been ruled out for now.  I know there are lots of really nasty things out there and he does have some evidence of minor orthostatic hypotension if he bends or kneels with his head down for an extended period he will "grey out" upon standing.  At this point it does not happen upon sitting up from lying down or standing from sitting and it is not consistent.  As of right now he has no problems with constipation but has been experiencing increased bloating and gas (a problem for years but more pronounced) that he attributes to being stressed over the situation.  There is no current evidence of urinary issues or impotence at this point either.  I think the only other relevant point here is that he does have a positive family history for Parkinson's in his maternal grandfather.

What we are really looking for is possiblities.  We know the biggies out there MSA, PSP, CBGD, Parkinson's Plus, and Parkinson's.  It sounds funny but I would love it at this point if the issue were that he is suffering from a functional but severe mental illness because at least he will likely be around for a while for our boys then.  But I keep being told that there are other less devastating neurological options as well, yet I have not encountered anything in the research I have done.  I would like to feel like there is some hope that this can be stopped where it is or at least slowed down so that we might have some time, I understand that there is really no way to regain what has been lost even with a psycogenic cause but to think that maybe we can keep it from progressing would be a big relief for our stress levels for the moment even if later we discover it is one of the major life-limiting situations.  Currently this is consuming our thoughts and creating major stress in our family so any insight that can be given would be helpful.