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The human brain is the most complicated biological system; Ramón y Cajal referred to it as the “masterpiece of life.” Not surprisingly, neurological disease produces very diverse symptoms and signs. (Symptoms are what a patient experiences; signs are what an examiner observes.) To assess a patient’s “chief complaint,” a clinician elicits a neurological history and performs a neurological examination addressing three basic questions: (1) Do the symptoms and signs signify neurological disease or injury? (2) What part of the nervous system is affected? (3) What is the disease process?

Neurological illness can be direct—from primary disease of the nervous system such as glial tumors or multiple sclerosis—or indirect—secondary to disease outside the nervous system, such as renal failure, which can cause altered mentation, or cardiac disease, which can result in embolic stroke. The terms organic and functional, used to distinguish neurological from psychiatric symptoms, are well entrenched but misleading; psychiatric illness is as organic as neurological illness. Indeed, psychiatry has been described as “neurology without signs.” Certain symptoms—particularly headache and dizziness—often have a psychiatric origin, usually anxiety or depression. Psychiatric illness also directly produces neurobehavioral symptoms, for example, schizophrenic hallucinations. Sometimes symptoms turn out to be fabricated by patients for secondary gain (malingering).

Whether direct or indirect, symptomatic nervous system lesions can be diffuse or focal, can be single or multiple, and can involve the peripheral nervous system (muscle, neuromuscular junction, peripheral or cranial nerve, nerve plexus, and nerve root) or the central nervous system (spinal cord, brain stem, cerebellum, diencephalon, and cerebrum). A competent neurological history and examination thus require a basic understanding of the anatomy and physiology of the nervous system.

Fortunately, such an undertaking is less daunting than might be supposed. For all its complexity, the nervous system is highly organized; different combinations of regions subserve different functions, allowing a clinician to localize lesions with considerable accuracy. Moreover, in the great majority of cases, the history and examination not only will define the problem as neurological and localize it accurately within the nervous system but also will generate a reasonable hypothesis as to the underlying disease process (Table 1–1). Laboratory or imaging studies are then selected to confirm or exclude the tentative working diagnosis.

Table 1–1.Major categories of disease.


History-taking should allow patients to describe symptoms in their own words. The clinician’s questions should not lead the patient, yet should be sufficiently directed to determine precisely what the patient means. Many terms are used differently by different people. For example, dizziness might refer to near-syncope, vertigo, imbalance, or simply a hard-to-describe subjective feeling. Numbness ...

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