Interesting ..mmm
Imad

Olfaction testing in patients with tremor-dominant Parkinson's disease: is this a distinct condition?
Ondo WG, Lai D.

Department of Neurology, Baylor College of Medicine, Houston, Texas 77030, USA. wondo@bcm.tmc.edu

There is considerable controversy regarding the relationship between essential tremor (ET) and Parkinson's disease (PD), especially when tremor is the dominant feature of PD or there is a family history of tremor. Reduced olfaction function is one of the initial signs of PD. In contrast, ET has relatively preserved olfaction. To infer whether the tremor-dominant subgroup of PD is intrinsically different from mainstream PD, we tested olfaction using the University of Pennsylvania Smell Identification Test-40 (UPSIT) in this group and compared the findings with those of patients with non-tremor-dominant "regular" PD. We then evaluated predictors of reduced UPSIT scores within the tremor-dominant group. Overall, olfaction did not differ between tremor-dominant PD and regular PD; however, the subgroup of tremor-dominant PD with a family history of tremor had less olfaction loss than those without a family history (P = 0.0007) or those with regular PD (P = 0.0350). Other clinical features of this tremor-dominant PD with a family history of tremor group mostly resembled those without a family history. This finding suggests that patients with a family history of tremor may represent a different disease process even though, aside from differences in olfaction, they are clinically similar to other patients with tremor-dominant parkinsonism. It additionally suggests phenotypic overlap between PD and ET. Copyright 2004 Movement Disorder Society.

PMID: 15597336 [PubMed - indexed for MEDLINE]

Hi Imad,


Wow! This really hits home! Like you, I am tremor dominant, but I also have a family history of tremor (father and grandfather). Do you find that you have atypical PD things going on as well? I do not have many of the targeted biomarkers like loss of smell or REM Sleep Disorder. I also have atypical PD tremor. I was diagnosed with ET for six years before my tremor even remotely looked like PD.

How about you? Where do things look different or atypical for you? I have read that people who initiially present with ET are 4-5 times more likely to end up with a PD diagnosis later on. This NY Times article, while not scientific, gives a good overview of the similarities and likely ties between ET and PD. I think all this says is that PD is really a syndrome or spectrum disorder and I wonder if ET is a more benign expression of tremor dominant PD. Keep in mind there is also something identified as Benign Tremulous Parkinsonsism too.

In the final analysis, I find this all so frustrating because I think people like us hold answers but not many researchers want to study us. It's too bad because we may hold answers for both medical conditions.

Laura

Laura,
In my case, I have no family history of tremor. I think my PD is not atypical although my main complain (after 3 and half years of diagnosis) is a mild tremor, loss of short term memory and small handwriting).
I think the other typical symptoms are a bit delayed by my severe exercise routine which I follow.
Having said this, it is still my belief that PD includes a spectrum of diseases caused by degrees of damage in many parts of the brain and it is much more than Dopamine loss.
I sincerely hope that in your case, it is a mild version of PD or ET and I am sorry for myself for not qualifying to the above research criterion for being atypical PD. Good luck.

Imad