Correspondence

Parkinsonism and Parkinson's Disease

N Engl J Med 1996; 334:1611-1612June 13, 1996

Article

To the Editor:

Bennett et al. (Jan. 11 issue)1 further document the increasing prevalence of parkinsonism as people age. However, parkinsonism is not Parkinson's disease, and we fear that the two may be confused.

Although the diagnosis of Parkinson's disease is a clinical judgment with no confirming laboratory tests, the presence of typical resting tremor in a patient with other signs of parkinsonism is diagnostically extremely important.2 In fact, of all the signs of parkinsonism studied by Bennett et al.,1 resting tremor is most specific for the diagnosis of Parkinson's disease. They demonstrate that the prevalence of resting tremor does not increase with age. This supports previous observations that the incidence of Parkinson's disease peaks between the ages of 60 and 69 and that older patients may be resistant to the etiologic factors that produce Parkinson's disease.3 In fact, the presentation of parkinsonism after the age of 75 (the middle age range studied by Bennett et al.) is not likely to represent levodopa-responsive Parkinson's disease.4 Parkinson's disease may not be a disease of aging, and other specific causes need to be considered.

One of the conclusions of the study is that parkinsonism is associated with a twofold increase in the risk of death, and this conclusion may have an important role in determining insurance risks, not only for patients with parkinsonism but also for those with Parkinson's disease. Since there is considerable evidence that Parkinson's disease has only a modest effect on longevity, people with Parkinson's disease may have increased difficulty obtaining insurance of all types as a result of this article.

W.J. Weiner, M.D.
C. Singer, M.D.
L.M. Shulman, M.D.
University of Miami School of Medicine, Miami, FL 33136

4 References

1. 1

   Bennett DA, Beckett LA, Murray AM, et al. Prevalence of parkinsonian signs and associated mortality in a community population of older people. N Engl J Med 1996;334:71-76
   Full Text | Web of Science | Medline

2. 2

   Rajput AH. Clinical features and natural history of Parkinson's disease (special consideration of aging). In: Calne DB, ed. Neurodegenerative diseases. Philadelphia: W.B. Saunders, 1994:555-71.
   

3. 3

   Koller W, O'Hara R, Weiner W, et al. Relationship of aging to Parkinson's disease. Adv Neurol 1987;45:317-321
   Medline

4. 4

   Singer C, Shulman LM, Weiner WJ. Late-onset parkinsonism. Ann Neurol 1995;38:329-330 abstract.
   Web of Science

Author/Editor Response

The authors reply:

To the Editor: We agree that it is important to differentiate Parkinson's disease from the many other conditions that can cause parkinsonian signs among older persons. Because our paper specifically dealt with the prevalence of parkinsonism and its association with the risk of death, we did not estimate the incidence or prevalence of Parkinson's disease in this community. However, reports regarding the relation between the occurrence of Parkinson's disease and age are conflicting. The position of Weiner and colleagues, that the incidence and prevalence of Parkinson's disease decline among very old persons, is supported by some studies based on persons coming to medical attention. By contrast, most population-based studies in which the illness is diagnosed independently of the health care system report that the prevalence of Parkinson's disease continues to increase in the oldest age groups.1-5 Since it appears that only a fraction of older people with Parkinson's disease come to medical attention, longitudinal population-based studies are necessary to estimate its incidence and prevalence.

David A. Bennett, M.D.
Christopher G. Goetz, M.D.
Denis A. Evans, M.D.
Rush–Presbyterian–St. Luke's Medical Center, Chicago, IL 60612

5 References

1. 1

   Bharucha NE, Bharucha EP, Bharucha AE, Bhise AV, Schoenberg BS. Prevalence of Parkinson's disease in the Parsi community of Bombay, India. Arch Neurol 1988;45:1321-1323
   Web of Science | Medline

2. 2

   de Rijk MC, Breteler MMB, Graveland GA, et al. Prevalence of Parkinson's disease in the elderly: the Rotterdam Study. Neurology 1995;45:2143-2146
   Web of Science | Medline

3. 3

   Mayeux R, Denaro J, Hemenegildo N, et al. A population-based investigation of Parkinson's disease with and without dementia: relationship to age and gender. Arch Neurol 1992;49:492-497
   Web of Science | Medline

4. 4

   Morgante L, Rocca WA, Di Rosa AE, et al. Prevalence of Parkinson's disease and other types of parkinsonism: a door-to-door survey in three Sicilian municipalities. Neurology 1992;42:1901-1907
   Web of Science | Medline

5. 5

   Mutch WJ, Dingwall-Fordyce I, Downie AW, Paterson JG, Roy SK. Parkinson's disease in a Scottish city. BMJ 1986;292:534-536
   CrossRef | Web of Science | Medline