Motor symptoms, including stiffness, tremors, and imbalance, are associated with a significantly increased risk of later Parkinson's disease.
“Subjective complaints related to motor function might indicate a very early phase of not-yet-diagnosable Parkinson's disease during which dopamine loss is not sufficient to produce overt typical PD symptoms but may result in subtle signs that are very mild or only intermittently present and therefore not likely to be detected in routine screening examination,” wrote Dr. Lonneke M. L. de Lau and colleagues (Arch. Neurol. 2006;63:doi:10.1001/archneur.63.3.noc50312).
Dr. de Lau of Erasmus Medical Center, Rotterdam, the Netherlands, prospectively followed 6,038 elderly patients (mean age 69 years) who were free of dementia and parkinsonian signs at baseline.
At baseline, 52% of the subjects reported at least one of the five typical features of the disease: stiffness (32%), tremor (11%), slow movement (21%), feeling of imbalance (11%), and falling (15%).
After a mean of 6 years' follow-up, 56 subjects had developed Parkinson's. Of those, 72% had reported at least one motor symptom during the initial assessment, and 41% had reported at least two symptoms.
Complaints of stiffness and tremor at baseline were each associated with more than a twofold increase in the risk of the disease, while a feeling of imbalance was associated with more than a threefold increased risk. Self-reported falling and slow movement were not significantly associated with an increased risk.
If a preclinical screening tool could be developed, the investigators said, it might be able to identify a window of opportunity where neuroprotective medication could someday slow or arrest the progress of the disease, the authors noted.