The importance of the neurologic examination in the diagnosis of diseases of the nervous system cannot be overemphasized. In no other branch of medicine is it possible to build up a clinical picture so exact—with regard to localization and pathologic anatomy—as it is in neurology. This requires not only diagnostic acumen but also a thorough knowledge of the underlying anatomy and physiology of the nervous system, vascular supply, neuropathology, psychology, psychiatry, neuropharmacology, and related disciplines. In addition, neurologic practice demands knowledge of neuroradiology, electroencephalography, electromyography, neurochemistry, microbiology, genetics, neuroendocrinology, neurotransmitters, immunology, oncology, epidemiology, and an understanding of the neuromuscular system.
Neurologic diagnosis is a correlation of data in the study of the human nervous system in health and disease—a synthesis of all the details obtained from the history, examination, and ancillary studies. Nervous tissue makes up about 2% of the human body, and yet it is supplied to all portions of the body. Should the rest of the body tissues be dissolved, there remains an immense network of fibers in addition to the brain, brainstem, and spinal cord. This network is the great receptor, effector, and correlating mechanism of the body. It acts in response to stimuli, acclimates the individual to the environment, and aids in defense against pathologic changes. To understand man, one must first understand the nervous system. Because the nervous system governs the mind and mental operations, one cannot study psychology without knowledge of it. Because the nervous system regulates and controls all bodily functions, one cannot study disease of any organ or system of the body without a comprehension of neural function. We are interested, however, not in studying the nervous system and related disease alone but in studying the person whose nervous system is diseased. The formulation of a case in terms of the relationship of the individual to the disease and the relationship of the patient to his or her associates and the environment is as important as providing a precise diagnosis. If we bear this in mind, we can most effectively aid our patients, treat their illnesses, restore them to health, and aid them in regaining their place in society.
Neurologic diagnosis is often considered difficult by the physician who does not specialize in clinical neurology. Most parts of the nervous system are inaccessible to direct examination. Gowers observed “The nervous system is almost entirely inaccessible to direct examination. The exceptions to this are trifling.” Many practitioners feel that all neurologic matters belong to the realm of the specialist and make little attempt at neurologic diagnosis. However, many neurologic disorders come within the everyday experience of most practitioners; they should know how to examine the nervous system, when additional studies might be helpful, and how to use the data collected. Furthermore, neurologic dysfunction is the first manifestation of many systemic diseases. Medical diagnosis cannot be made without some knowledge of neurologic diagnosis. True, there are certain rare conditions and diagnostic problems that require long experience in the field of diseases of the nervous system for adequate appraisal. Neurophobia has been prevalent among medical students and nonneurologists for decades, and the explosion of knowledge in neuroscience has if anything made it worse. However, the majority of the more common neurologic entities could and should be diagnosed and treated by the primary care physician.
The neurologic examination requires skill, intelligence, and patience. It requires accurate and trained observation, performed—in most instances—with the help and cooperation of the patient. The examination should be carried out in an orderly manner, and adequate time and attention are necessary to appreciate the details. Each clinician eventually works out a personal method based on experience, but the trainee should follow a fixed and systematic routine until he or she is very familiar with the subject. Premature attempts to abbreviate the examination may result in costly errors of omission. A systematic approach is more essential in neurology than in any other field of medicine, because the multiplicity of signs and variations in interpretation may prove confusing. The specific order that is followed in the examination is not as important as the persistence with which one adheres to this order.
It may be necessary on occasion to vary the routine or to modify the examination according to the state of the patient and the nature of his or her illness. O’Brien emphasized a focused examination driven by the history. If the investigation is long, the patient’s interest may flag. Or, he or she may fail to understand the significance of the diagnostic procedures and the need to cooperate. The purpose of the procedures may not be apparent, and he or she may view them as unrelated to his or her presenting complaints. It may help to explain the significance of the tests or their results or to use other means to stimulate interest and cooperation. If fatigue and lack of attention interfere with testing, it may be advisable to change the order of the examination or to complete it at a later date. It is important to bear in mind that slight deviations from the normal may be as significant as more pronounced changes and that the absence of certain signs may be as significant as their presence. On occasion, clues may be obtained merely by watching the patient perform normal, routine, or “casual” actions—such as dressing or undressing, tying shoelaces, looking about the room, or walking into the examining room. Abnormalities in carrying out these actions may point to disorders that might be missed in the more formal examination. The patient’s attitude, facial expression, mode of reaction to questions, motor activity, and speech should all be noted.
Interpretation and judgment are important. The ability to interpret neurologic signs can be gained only by carrying out repeated, thorough, and detailed examinations, as well as through keen and accurate observation. In the interpretation of a reflex, for instance—or in the appraisal of tone or of changes in sensation—there may be differences of opinion. The only way the observer may become sure of his or her judgment is through experience. However, the personal equation may enter into any situation, and conclusions may vary. The important factor is not a seemingly quantitative evaluation of the findings but an interpretation or appraisal of the situation as a whole.
The use of a printed outline or form with a checklist for recording the essentials of both the history and the neurologic examination is advocated by some authorities and in some clinics. With such an outline, various items can be underlined, circled, or checked as being either positive or negative. Numerical designations can be used to record such factors as reflex activity or motor strength. Such forms may serve as teaching exercises for the student or novice and as time-saving devices for the clinician, but they cannot replace a careful narrative description of the results of the examination. An outline of the major divisions of the neurologic examination is given in Chapter 5.
No other branch of medicine lends itself so well to the correlation of signs and symptoms with diseased structure as neurology does. However, it is only by means of a systematic examination and an accurate appraisal that one can elicit and properly interpret the findings. Some individuals have a keen intuitive diagnostic sense and can reach correct conclusions by shorter routes, but in most instances, the recognition of disease states can be accomplished only through a scientific discipline based on repeated practical examinations. Diagnosis alone should not be considered the ultimate objective of the examination, but the first step toward treatment and attempts to help the patient. The old saw that neurology is long on diagnosis and short on therapy is outdated. The currently available spectrum of neurologic therapeutics is overwhelming. In cerebrovascular disease, for example, we have gone from “if he can swallow, send him home” to the intra-arterial injection of tissue plasminogen activator. So many agents are now available for the treatment of Parkinson’s disease and multiple sclerosis that it almost requires subspecialist expertise to optimally manage these common disorders. There is now even reason for optimism in such previously hopeless situations as spinal muscular atrophy and amyotrophic lateral sclerosis.
This revision of Dr. DeJong’s classic text begins with an overview of neuroanatomy, including some of the underlying neuroembryology. The overview provides broad perspective and an opportunity to cover certain topics that do not conveniently fit into other sections. Chapters 3 to 44 are organized as the neurologic clinical encounter typically evolves: history and the general physical examination, followed by the elements of the neurologic examination as commonly performed—including mental status, cranial nerves, motor, sensory, reflexes, cerebellar function, and gait. Early editions covered the sensory examination first, Dr. DeJong’s argument being that it required the most attentiveness and cooperation from the patient and should be done early in the encounter. The countervailing argument is that the sensory examination is the most subjective and usually the least helpful part of the examination, and it should be done last. We are more inclined toward the latter view and hope Dr. DeJong would forgive the demotion of the sensory examination. The neuroscientific underpinnings of the neurologic examination are discussed before the clinical aspects. Dr. DeJong’s original concept for his textbook was to incorporate the fundamentals of neuroanatomy and neurophysiology and to highlight pertinent relationships to the examination. With the explosion in basic neuroscience knowledge, these efforts, continued in this edition, appear increasingly inadequate. The bibliography lists several excellent textbooks that cover basic neuroscience in the kind of exhaustive detail not possible here. Chapter 53 consists of a discussion of neurologic epistemology, diagnostic reasoning, and differential diagnosis.
There are a number of other textbooks on the neurologic examination. These range from the very brief The Four-Minute Neurologic Examination to more comprehensive works intended for neurologic trainees and practitioners. Dr. William DeMyer’s textbook is unfailingly entertaining and informative. Mayo Clinic Examinations in Neurology continues to be a standard in the field. Dr. Sid Gilman’s Clinical Examination of the Nervous System includes a discussion of the underlying neuroanatomy. Dr. Robert Laureno’s Foundations for Clinical Neurology provides unique perspective on the clinical encounter. Dr. Robert Schwartzman’s Neurologic Examination is excellent; likewise the short textbooks by Ross and Fuller. Bickerstaff’s Neurological Examination in Clinical Practice was recently revised. The Neurologic Examination: Scientific Basis for Clinical Diagnosis by Shibasaki and Hallett examines the scientific underpinnings of the examination. Dr. DeJong’s text has long been the most encyclopedic; the tradition is continued in this edition. In this revision, we have included more illustrations, and now, there are embedded videos as well as links to relevant outside videos.
There is a wealth of online information about the neurologic examination. Neurosciences on the Internet (Web Link 1.1) is a valuable resource and includes an excellent demonstration of the cutaneous fields of the peripheral nerves. The site Neuroexam.com (Web Link 1.2) has numerous videos and is by the author of the popular Neuroanatomy Through Clinical Cases. There are numerous links throughout the text to Neurosigns (Web Link 1.3), a collection of photos and videos of neurologic examination findings; there is an associated youtube channel, (Web Link 1.4). The library at the University of Utah houses a rich repository of neurologic examination videos (Web Link 1.5). The Neuro-ophthalmology Virtual Education Library, NOVEL, also at the University of Utah, has an amazing collection of videos (Web Link 1.6). NOVEL includes collections by such luminaries as David Cogan, Robert Daroff, William Hoyt, J. Lawton Smith, and Shirley Wray. The Canadian Neuro-Ophthalmology Group maintains an extensive collection of videos, fundus photos and other resources (Web Link 1.7). A series of examination videos is available on the EMG on DVD Series: Volume XIII, Practical Neurologic Examination, by Nandedkar Productions, LLC (Web Link 1.8).
Ancillary diagnostic techniques have, through the years, played important roles in neurologic diagnosis. The original electrodiagnostic techniques of Duchenne, Erb, and others were introduced in the latter part of the 19th century. Later, neurologic diagnosis was aided by the introduction of pneumoencephalography, ventriculography, myelography, electroencephalography, ultrasonography, angiography, electromyography, evoked potential studies, nerve conduction studies, radioisotope scanning, computed tomography, magnetic resonance imaging (MRI), blood flow studies by single photon emission computed tomography and inhalation methods, positron emission tomography (PET), and others. In previous editions, space was devoted to many of these topics. Some of these techniques have been abandoned. The modern neurodiagnostic armamentarium has become complex and highly specialized. We have moved from the era of air studies to an era of functional MRI, diffusion weighted imaging, and PET. There can only be conjecture about what new technologies may be in use before this textbook is next revised. The reader is referred to the many excellent textbooks and other sources that cover ancillary neurodiagnostic techniques. The focus of this book is on neuroanatomy and neurophysiology, the clinical neurologic examination, clinical reasoning, and differential diagnosis. Current techniques of imaging, electrodiagnosis, and other laboratory studies have revolutionized the practice of neurology. However, their use must be integrated with the findings of the history and neurologic examination. The practice of “shotgunning” with multiple tests is to be discouraged. Such studies do not replace the examination. Not only is it poor clinical practice but also the resource consumption is enormous.
The development of ever more sophisticated imaging studies of the nervous system along with many other sensitive laboratory techniques has raised questions about the continued need and utility of the neurologic examination. In a provocative paper, I’ve stopped examining patients!, Hawkes pointed out that the examination adds little in some common conditions, such as migraine and epilepsy. A flurry of correspondence followed. But in many other common conditions, the examination is indispensable. In such common conditions as Parkinson’s disease and amyotrophic lateral sclerosis, the physical examination is essential to the diagnosis. In many other common conditions, the examination is the key to proper diagnosis and management, such as optic neuropathy, benign positional vertigo, Bell’s palsy, Alzheimer’s disease, and virtually all neuromuscular disorders. In a recent case, extensive evaluations for gait difficulties by a family physician, including lumbosacral MRI and CSF examination, were unrevealing. Only when examination disclosed, spasticity was the problem solved by imaging the neck. The examination determines where to point the scanner. Just as a normal EKG does not exclude myocardial infarction, normal imaging does not necessarily exclude neurologic disease. The clinician relinquishes examination skills at his/her peril.
The neurologic examination will not become obsolete. It will not be replaced by mechanical evaluations; rather, a more precise and more directed neurologic examination will be needed in the future. The neurologic history and examination will remain to hold important in clinical evaluation. Neurodiagnostic technology should supplement clinical evaluation, not replace it. Nicholl and Appleton recently reviewed the role of the clinical examination in neurologic evaluation and emphasized that investigation should follow clinical assessment, not precede it. Aminoff reminds us that it is important the art of the clinical examination is not lost in the era of precision medicine. The neurologist will have to be the final judge of the significance of his or her own findings and those of special studies.
Web Link 1.1. Neurosciences on the Internet. http://www.neuroguide.com
Web Link 1.2. Neuroexam.com. http://www.neuroexam.com/neuroexam/
Web Link 1.3. Neurosigns. www.neurosigns.org
Web Link 1.4. Neurosigns on YouTube. https://www.youtube.com/channel/UC7JOrAlJruTYA-aZdSeK7bQ
Web Link 1.5. NeuroLogic Exam at The University of Utah. https://library.med.utah.edu/neurologicexam/html/home_exam.html
Web Link 1.6. The Neuro-ophthalmology Virtual Education Library, NOVEL. https://novel.utah.edu/
Web Link 1.7. The Canadian Neuro-Ophthalmology Group. http://www.neuroophthalmology.ca/
Web Link 1.8. EMG on DVD Series: Volume XIII, Practical Neurologic Examination, by Nandedkar Productions, LLC. https://www.nandedkarproductions.com/productdetail.php?id=21
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