Olfaction testing in patients with tremor-dominant Parkinson's disease
 

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]

Explains some things
 

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

you qualify but I don't
 

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