News Release

Mayo Clinic study highlights importance of autopsy in Parkinson's disease diagnosis and research

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Mayo Clinic

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Oct. 15, 1999

Jane Jacobs
507-284-2387 (days)
507-284-2511 (evenings)
e-mail: newsbureau@mayo.edu

For Immediate Release

Mayo Clinic Study Highlights Importance of Autopsy
in Parkinson’s Disease Diagnosis and Research

ROCHESTER, MINN. — A Mayo Clinic study, published in the October 12 issue of Neurology, cautions that low autopsy rates and nonrandom autopsy patterns for parkinsonism could call into question the validity of parkinsonism research.

Specifically, the study points out that assessments of diagnostic accuracy, prognosis and survival may be overly pessimistic, and that diagnostic criteria may be skewed toward less typical cases because of the selection factors influencing autopsy. Parkinsonism is a syndrome characterized by slowness, stiffness, tremor and unsteadiness. The most common form of parkinsonism is Parkinson’s disease.

"Autopsy remains the gold standard for the diagnosis of Parkinson’s disease," says Demetrius Maraganore, a Mayo Clinic neurologist and principle author of the study. "However, because autopsy rates are low we’re only getting a highly selective picture of what is happening in the general population."

The study reviewed the medical records of 235 deceased patients who had received a diagnosis of parkinsonism in Olmsted County, Minn. from 1976-1990. Of these patients, only 23 percent had autopsies. Most clinical research studies require at least 70 percent participation for results to be considered valid.

The study found that the certainty of the diagnosis and type of parkinsonism, gender, age at death and location at death were important selection factors for autopsy. Typically, autopsies were performed in cases where there was less certainty in the clinical diagnosis of Parkinson’s disease, or where there were additional symptoms. Also, autopsies were more likely to be performed if the location of death was in a hospital or at home, and if patients were under the age of 70 at the time of their death. Men were more likely to have autopsies than women.

"Autopsy rates in Olmsted County have greatly exceeded the national average in the past, which leads us to believe that the autopsy rates for parkinsonism nationwide may be low," says Dr. Maraganore. "We would encourage people to consider an advance directive to allow an autopsy to be performed. Only by increasing the number of autopsies, not only for parkinsonism but in general, can we get a true picture of how our population is affected by parkinsonism as well as a variety of other diseases that can only be diagnostically confirmed at autopsy."


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