[Tupelo3]

Never has it been more evident that we need reliable PD biomarkers.

About three-quarters of patients suspected to have early Parkinson’s disease (PD) eventually prove to have other conditions, a study shows.

“This inaccuracy was present despite that all cases were examined by a small group of movement disorder specialists as opposed to many neurologists and geriatricians who examined the cases in other studies”, say lead researcher Charles Adler (Mayo Clinic, Scottsdale, Arizona, USA) and colleagues.

All of the 89 patients in the study had at least two out of three cardinal signs of PD: resting tremor, bradykinesia and cogwheel rigidity. Of these patients, 34 were classified as having possible PD, because they were untreated or had been treated for too short a time to assess their response to dopaminergic medications.

But just nine of these patients with possible PD ultimately had the disease confirmed on autopsy, giving a positive predictive value (PPV) of just 26%.

A further 97 patients were considered to have probable PD because they responded to dopaminergic medications. Among these patients, the PPV was 53% for those with a disease duration of less than 5 years at first visit, but 88% for those with a longer disease duration.

http://www.medwirenews.com/454/10570...s_disease.html

[johnt]

Interesting findings.

Unfortunately the original paper is behind a paywall, but an accompanying editorial is available [1].

Rajput and Rajput describe the implications of the findings on clinical trials:

"A sobering observation made by Adler et al. ... is
that only 20% to 26% of the untreated cases who
would be candidates for drug trials had accurate
clinical diagnosis of PD."

In my view the finding that diagnostic accuracy is substantially higher after 5 or more years of symptoms makes it harder to justify early DBS.

Reference:

[1] "Accuracy of Parkinson disease diagnosis unchanged in 2 decades"
Rajput A. H., Rajput A.
http://www.neurology.org/content/sup...0000000653.pdf

John

[anagirl]

Would be interesting to know what illness all the non-Pd people ended up having

[Tupelo3]

Originally Posted by anagirl

Would be interesting to know what illness all the non-Pd people ended up having

Great point, Ana. I would suspect other forms of Parkinsonism in many of the cases.

[GerryW]

Is response to levodopa diagnostic for PD? Do any other conditions respond?

[Tupelo3]

Originally Posted by GerryW

Is response to levodopa diagnostic for PD? Do any other conditions respond?

LD is used for several other forms of Parkinsonism and dopamine responsive dystonia (DRD). As Ana stated, it would be nice to read the actual study and see what other conditions were mistaken for PD.