N E W HORIZONS IN N E U R O L O G Y
The Twentieth Century Arthur K. Asbury, MD," and Charles D. Aring, MD?
Neurology in the twentieth century has undergone extraordinary change, particularly in the past 40 years. We trace the major trends, including the growth of the field, the technological advances, the revolution in neuroscience, the emergence of neurology as a free-standing specialty, the rise of child neurology, and the development of neurological subspecialization. Subsequent articles in this series will expand on these subjects. Asbury AK, Aring CD. T h e twentieth century. Ann Neurol 1992;31:669-671
This is the first of an invited series of articles on new horizons in neurology. Subsequent articles will examine current trends and project into the future, but this introductory article examines briefly where the field of American neurology is today and how it came to be so over the past 90 years. Although we are concerned here only with neurology in the twentieth century, two lifetimes nearly span the period back to the earliest pioneer days of academic medicine in this country. O n e of us (C.D.A.) enjoyed a close professional relationship with Dr Philip Zenner, one of the first neuropsychiatrists in southern Ohio. Zenner, who lived to the age of 104, was born in 1852, the year of the death of Dr Daniel Drake, one of the pioneers of American medicine. Drake himself was born in 1785. Neurology i n 1900 In 1900, the American Neurological Association was 25 years old. Although it claimed 125 members, most were neuropsychiatrists and many members were less well trained than their counterparts in internal medicine, even in the care and management of neurological problems. Training in neurology was almost nonexistent, radiographs had just been devised, and the lumbar puncture had not been introduced. Much of the serious illness affecting the nervous system was infectious in origin and was dealt with by general physicians. Neurology and Neuropathology Aside from bacteriological approaches, the only practical ways that the etiology and pathogenesis of neurological diseases could be investigated during the first half of the century was through clinical description or clinical pathological correlation. The latter gained in importance during the last quarter of the nineteenth
From the *Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA; and the tDepartment of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH.
century. As new methods to fuc, stain, and section tissues were devised, the capacity to study disease by microscopy was vastly improved. For the first half of this century, the neuropathological approach remained paramount in the study of neurological diseases and their pathophysiology. Neurology in the Mid-twentieth Century In 1950, neurology was on the threshold of explosive growth. Although the number of neurologists who concentrated on organic disease of the nervous system were relatively few, a new optimism was in the air. During the 1930s and 1940s, it was widely held that neurology was moribund and that one could not make a living practicing neurology without psychiatry. After World War 11, this attitude became far less prevalent. The major clinical tools at hand were the lumbar puncture, the electroencephalogram, plain radiographs, and, most importantly, contrast studies, pneumoencephalography, and ventriculography. These contrast procedures were invasive and dangerous, but they represented major advances in the capacity to diagnose and localize lesions of the central nervous system. Angiography and myelography were just coming into use. With these tools to support their activities, the fields of neurology and neurological surgery were poised in 1950 for major expansion. Neurology Gains Its Independence In 1950 there were 69 training programs in neurology (Table I), but many (we are not sure how many) were sponsored by divisions of neurology existing within departments of either psychiatry or internal medicine. In the 40 years since then, this situation has changed dramatically: There are now more than 100 freestanding departments of neurology. Of the large aca-
Received Feb 18, 1992, and in revised form Mar 3 and Mar 6. Accepted for publication Mar 6,1992. Address correspondence Dr of Neurology, Haspital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104-4283.
Copyright
0 1992 by t h e American N e u r o l o g ~ c a lAssociation
669
Table 1 . Growth of Neurology: 1950-1 990 12
Year
Residency Training Programs
1950 1960 1970 1980 1990
136 107 124 118
69
First-year Residency Positions
Neurologists Certified"
Unknown 186 332 455 427
22 17 119 304 357
11
,o
3
321-
'Certified in neurology in that year by the American Hoard of Psychiatry and Neurology, Inc.
demic health centers, only Tulane University maintains a conjoint Department of Neurology and Psychiatry, and Only a few divisions Of persist within departments of internal medicine (e.g.7 Duke University, University of Washington). Neurology Since 1950 Changes in neurology since 1950 are indicated by the growth in total membership of the American Academy of Neurology (AAN) and by the number of persons certified in neurology in benchmark years at 10-year intervals (Figure). It is also possible to estimate how many neurologists certified by the American Board of Psychiatry and Neurology (ABPN) were active in any given year by looking at those members of AAN who were either Active Members or Fellows. Members of AAN are designated Active at certification, and Fellows are Active Members of 10 years' standing or more. This assumes that all or almost all certified neurologists who are professionally active are members of AAN, which is probably not quite true. The total number of Active Members and Fellows of AAN in 1990 was 6,046, representing approximately three-fourths of the 8,108 individuals in the United States who considered themselves primary neurologists, certified or not 11. The number of first-year residency positions in neurology has also grown, particularly between 1960 and 1980, but may have fallen off slightly in the past 10 years (see Table 1). If an assumption is made that the number of first-year positions is approximately constant at around 430 and will remain so for the next few decades, and if some other arbitrary assumptions are made-that the median duration of a neurological career after training is 35 years; that the overall attrition rate now in training programs, either from failure to fill positions or individuals leaving the field of neurology during training, is approximately 15%,; and that the attrition rate was higher from 1950 to 1980-then one can make a projection (see Figure). This formulation predicts that the number of primary neurologists will achieve equilibrium in the third decade of the next century at approximately 12,500 active certified neu-
r
670
Annals of Neurology Vol 3 1
No 6 J u n e 1902
1950
1960
1970
1980
1990
2000
2010
2020
2030
Membership of American Academy of Neurology IAAN,. Actual figures for 1950 to 1990 and a prediction (dotted line) of ,the growth in number of active certifed neurologi~tslilctizx Menihers and Fellms U N )in the next 40 years, The aJcllmptionson which this projection is made are containedin the text, Note that the number of actioe certified neurologictA i J prediciled to continue t o zncrease steeply for the next two decadeA before leveling OfJ: (Data supplied courtesy of A A N
rologists. This figure suggests that the log phase of growth in neurology will persist for another two clecades before leveling off. The tables and figure oft"er other possibilities for speculation, but they are beyond the scope of this presentation. T h e Rise of Child Neurology The phases of rapid growth in child neurology, mainly in the 1970s and 19SOs, came later than in the field of neurology as a whole (Table 2). If child neurology continues to add to its ranks at thc rate of GO per year, as the present data suggest, that field too should achieve a steady state after the millennium at approximately twice its current size. The reader must understand that these are crude estimates. Specialization in Neurology Specialized approaches to disorders of the nervous system, or subsets thereof, have evolved in two distinct patterns, at least from the standpoint of neurologists. One pattern has been the development of subspecialties by physicians trained in fields other than neurology (e.g., neuroradiology, neuroanesthesia, and, to a lesser extent, neuroophthalmology). The second pattern of neurological specialization has been by subspecialty differentiation within the field of neurology, through the efforts of physicians trained in neurology. Examples include clinical neurophysiology, neuromuscular disorders, epileptology, cerebrovascular disease, movement disorders, neurooncology, and behavioral neurology. These subspecialty fields have developed their own national and international organizations and journals and conduct large and highly successful meetings. The result has been an extraordinary increase in knowledge
Table 2. Growth of Child Neurology: 1970-1 992 ~~
Child
Active Members
Junior Members
Year
CNS"
CNSb
1970 1972 1980 1990 1992
d
d
8
d
e
23 1 446 739 816
117 182 179
Neurologists Certified'
33 44 e
"Child Neurology Society (CNS), formed in 1972. training. 'Certified in that year by the American Board of Psychiatry and Neurology, Inc, as specially qualified in child neurology. dNot applicable. 'Not ascertained.
and understanding of neurological disorders. There are, however, disadvantages, the most important being the balkanization of neurology. Each subspecialty has developed its own vocabulary, assumptions, and points of view. As a result, communication between subspecialties is at times difficult. Despite these drawbacks, patient care and management of disorders of the nervous system have been vastly improved.
The Current State and New Horizons Neurology appears to be in the final phases of a period of rapid growth and will likely enter a phase of maturation. Nonetheless, new horizons in neurology are coming into view. Everyday practice of neurology is inex-
tricably linked to the revolution in neuroscience. New ways are being found to look at old problems, such as neurodegenerative diseases, and new opportunities beckon, such as the many new imaging modes. The article in next month's issue will highlight these and many other changes through a study of the recent neurological literature. Subsequent papers in this series will examine selected aspects of the new vistas and will include analysis of two emerging subspecialties: neurorehabilitation and neurological intensive care. Furthermore, the impact of the revolution in molecular biology and recombinant technology on the field of neurology will be examined, as will the newly emerging capacities to image the nervous system using structural and functional methods. The series will conclude in December 1992 with a consideration of the role of the neurologist in the brave new world we foresee. We wish to thank the following individuals for their timely efforts in collecting the information presented in the tables and figure: Mr Jan W. Kolehmainen, American Academy of Neurology; Ms Sylvia I. Etzel, Department of Information Analysis and Publications, American Medical Association; Ms Jean M. Ferrone, American Board of Psychiatry and Neurology, Inc; Ms Sarah Patsy Knight, Archives of the American Neurological Association; and Dr Peter H. Berman, Child Neurology Society We also thank Ms Mary Holden for secretarial assistance.
Reference 1. Ringel SP. Neurologists-1990. 1866
Neurology 1991;41:1863-
N e w Horizons: Asbury and Aring: T h e Twentieth Century
671
The Twentieth Century Arthur K. Asbury, MD," and Charles D. Aring, MD?
Neurology in the twentieth century has undergone extraordinary change, particularly in the past 40 years. We trace the major trends, including the growth of the field, the technological advances, the revolution in neuroscience, the emergence of neurology as a free-standing specialty, the rise of child neurology, and the development of neurological subspecialization. Subsequent articles in this series will expand on these subjects. Asbury AK, Aring CD. T h e twentieth century. Ann Neurol 1992;31:669-671
This is the first of an invited series of articles on new horizons in neurology. Subsequent articles will examine current trends and project into the future, but this introductory article examines briefly where the field of American neurology is today and how it came to be so over the past 90 years. Although we are concerned here only with neurology in the twentieth century, two lifetimes nearly span the period back to the earliest pioneer days of academic medicine in this country. O n e of us (C.D.A.) enjoyed a close professional relationship with Dr Philip Zenner, one of the first neuropsychiatrists in southern Ohio. Zenner, who lived to the age of 104, was born in 1852, the year of the death of Dr Daniel Drake, one of the pioneers of American medicine. Drake himself was born in 1785. Neurology i n 1900 In 1900, the American Neurological Association was 25 years old. Although it claimed 125 members, most were neuropsychiatrists and many members were less well trained than their counterparts in internal medicine, even in the care and management of neurological problems. Training in neurology was almost nonexistent, radiographs had just been devised, and the lumbar puncture had not been introduced. Much of the serious illness affecting the nervous system was infectious in origin and was dealt with by general physicians. Neurology and Neuropathology Aside from bacteriological approaches, the only practical ways that the etiology and pathogenesis of neurological diseases could be investigated during the first half of the century was through clinical description or clinical pathological correlation. The latter gained in importance during the last quarter of the nineteenth
From the *Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA; and the tDepartment of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH.
century. As new methods to fuc, stain, and section tissues were devised, the capacity to study disease by microscopy was vastly improved. For the first half of this century, the neuropathological approach remained paramount in the study of neurological diseases and their pathophysiology. Neurology in the Mid-twentieth Century In 1950, neurology was on the threshold of explosive growth. Although the number of neurologists who concentrated on organic disease of the nervous system were relatively few, a new optimism was in the air. During the 1930s and 1940s, it was widely held that neurology was moribund and that one could not make a living practicing neurology without psychiatry. After World War 11, this attitude became far less prevalent. The major clinical tools at hand were the lumbar puncture, the electroencephalogram, plain radiographs, and, most importantly, contrast studies, pneumoencephalography, and ventriculography. These contrast procedures were invasive and dangerous, but they represented major advances in the capacity to diagnose and localize lesions of the central nervous system. Angiography and myelography were just coming into use. With these tools to support their activities, the fields of neurology and neurological surgery were poised in 1950 for major expansion. Neurology Gains Its Independence In 1950 there were 69 training programs in neurology (Table I), but many (we are not sure how many) were sponsored by divisions of neurology existing within departments of either psychiatry or internal medicine. In the 40 years since then, this situation has changed dramatically: There are now more than 100 freestanding departments of neurology. Of the large aca-
Received Feb 18, 1992, and in revised form Mar 3 and Mar 6. Accepted for publication Mar 6,1992. Address correspondence Dr of Neurology, Haspital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104-4283.
Copyright
0 1992 by t h e American N e u r o l o g ~ c a lAssociation
669
Table 1 . Growth of Neurology: 1950-1 990 12
Year
Residency Training Programs
1950 1960 1970 1980 1990
136 107 124 118
69
First-year Residency Positions
Neurologists Certified"
Unknown 186 332 455 427
22 17 119 304 357
11
,o
3
321-
'Certified in neurology in that year by the American Hoard of Psychiatry and Neurology, Inc.
demic health centers, only Tulane University maintains a conjoint Department of Neurology and Psychiatry, and Only a few divisions Of persist within departments of internal medicine (e.g.7 Duke University, University of Washington). Neurology Since 1950 Changes in neurology since 1950 are indicated by the growth in total membership of the American Academy of Neurology (AAN) and by the number of persons certified in neurology in benchmark years at 10-year intervals (Figure). It is also possible to estimate how many neurologists certified by the American Board of Psychiatry and Neurology (ABPN) were active in any given year by looking at those members of AAN who were either Active Members or Fellows. Members of AAN are designated Active at certification, and Fellows are Active Members of 10 years' standing or more. This assumes that all or almost all certified neurologists who are professionally active are members of AAN, which is probably not quite true. The total number of Active Members and Fellows of AAN in 1990 was 6,046, representing approximately three-fourths of the 8,108 individuals in the United States who considered themselves primary neurologists, certified or not 11. The number of first-year residency positions in neurology has also grown, particularly between 1960 and 1980, but may have fallen off slightly in the past 10 years (see Table 1). If an assumption is made that the number of first-year positions is approximately constant at around 430 and will remain so for the next few decades, and if some other arbitrary assumptions are made-that the median duration of a neurological career after training is 35 years; that the overall attrition rate now in training programs, either from failure to fill positions or individuals leaving the field of neurology during training, is approximately 15%,; and that the attrition rate was higher from 1950 to 1980-then one can make a projection (see Figure). This formulation predicts that the number of primary neurologists will achieve equilibrium in the third decade of the next century at approximately 12,500 active certified neu-
r
670
Annals of Neurology Vol 3 1
No 6 J u n e 1902
1950
1960
1970
1980
1990
2000
2010
2020
2030
Membership of American Academy of Neurology IAAN,. Actual figures for 1950 to 1990 and a prediction (dotted line) of ,the growth in number of active certifed neurologi~tslilctizx Menihers and Fellms U N )in the next 40 years, The aJcllmptionson which this projection is made are containedin the text, Note that the number of actioe certified neurologictA i J prediciled to continue t o zncrease steeply for the next two decadeA before leveling OfJ: (Data supplied courtesy of A A N
rologists. This figure suggests that the log phase of growth in neurology will persist for another two clecades before leveling off. The tables and figure oft"er other possibilities for speculation, but they are beyond the scope of this presentation. T h e Rise of Child Neurology The phases of rapid growth in child neurology, mainly in the 1970s and 19SOs, came later than in the field of neurology as a whole (Table 2). If child neurology continues to add to its ranks at thc rate of GO per year, as the present data suggest, that field too should achieve a steady state after the millennium at approximately twice its current size. The reader must understand that these are crude estimates. Specialization in Neurology Specialized approaches to disorders of the nervous system, or subsets thereof, have evolved in two distinct patterns, at least from the standpoint of neurologists. One pattern has been the development of subspecialties by physicians trained in fields other than neurology (e.g., neuroradiology, neuroanesthesia, and, to a lesser extent, neuroophthalmology). The second pattern of neurological specialization has been by subspecialty differentiation within the field of neurology, through the efforts of physicians trained in neurology. Examples include clinical neurophysiology, neuromuscular disorders, epileptology, cerebrovascular disease, movement disorders, neurooncology, and behavioral neurology. These subspecialty fields have developed their own national and international organizations and journals and conduct large and highly successful meetings. The result has been an extraordinary increase in knowledge
Table 2. Growth of Child Neurology: 1970-1 992 ~~
Child
Active Members
Junior Members
Year
CNS"
CNSb
1970 1972 1980 1990 1992
d
d
8
d
e
23 1 446 739 816
117 182 179
Neurologists Certified'
33 44 e
"Child Neurology Society (CNS), formed in 1972. training. 'Certified in that year by the American Board of Psychiatry and Neurology, Inc, as specially qualified in child neurology. dNot applicable. 'Not ascertained.
and understanding of neurological disorders. There are, however, disadvantages, the most important being the balkanization of neurology. Each subspecialty has developed its own vocabulary, assumptions, and points of view. As a result, communication between subspecialties is at times difficult. Despite these drawbacks, patient care and management of disorders of the nervous system have been vastly improved.
The Current State and New Horizons Neurology appears to be in the final phases of a period of rapid growth and will likely enter a phase of maturation. Nonetheless, new horizons in neurology are coming into view. Everyday practice of neurology is inex-
tricably linked to the revolution in neuroscience. New ways are being found to look at old problems, such as neurodegenerative diseases, and new opportunities beckon, such as the many new imaging modes. The article in next month's issue will highlight these and many other changes through a study of the recent neurological literature. Subsequent papers in this series will examine selected aspects of the new vistas and will include analysis of two emerging subspecialties: neurorehabilitation and neurological intensive care. Furthermore, the impact of the revolution in molecular biology and recombinant technology on the field of neurology will be examined, as will the newly emerging capacities to image the nervous system using structural and functional methods. The series will conclude in December 1992 with a consideration of the role of the neurologist in the brave new world we foresee. We wish to thank the following individuals for their timely efforts in collecting the information presented in the tables and figure: Mr Jan W. Kolehmainen, American Academy of Neurology; Ms Sylvia I. Etzel, Department of Information Analysis and Publications, American Medical Association; Ms Jean M. Ferrone, American Board of Psychiatry and Neurology, Inc; Ms Sarah Patsy Knight, Archives of the American Neurological Association; and Dr Peter H. Berman, Child Neurology Society We also thank Ms Mary Holden for secretarial assistance.
Reference 1. Ringel SP. Neurologists-1990. 1866
Neurology 1991;41:1863-
N e w Horizons: Asbury and Aring: T h e Twentieth Century
671
