CHAPTER 5

General Outline of the Neurologic Examination

The neurologic examination, as commonly done, includes the major categories listed in Table 5.1. The examination does not have to be performed in any particular sequence, and every physician develops his own routine for the examination. It is customary to record the neurologic examination in the general format outlined in Table 5.1 or with minor modifications.

TABLE 5.1 Major Sections of the Neurologic Examination

The complete neurologic examination can be a complex and arduous undertaking. In fact, few neurologists do a truly complete exam on every patient. As with the general physical examination, the history focuses the neurologic examination so that certain aspects are emphasized in a given clinical situation. The exam done on a typical patient with headache is not the same as that done on a patient with low back pain, or dementia, or cerebrovascular disease. The examination should also be adapted for the circumstances. If the patient is in pain or feels apprehensive, it may initially focus on the area of complaint, followed later by a more thorough assessment. Only a brief examination may be possible for unstable or severely ill persons until their condition stabilizes. With comatose, combative, or uncooperative patients, a compulsively complete examination is an impossibility. However, in each of these situations, at least some maneuvers are employed to screen for neurologic dysfunction that is not necessarily suggested by the history. A rapid screening or mini neurologic examination may initially be adequate for persons with minor or intermittent symptoms. Every patient does not require every conceivable test, but all require a screening examination. The findings on such a screening examination determine the emphasis of a more searching subsequent examination. There are a number of ways to perform a screening examination. Table 5.2 details such an abbreviated examination from previous editions of this book.

TABLE 5.2 Components of a Screening Initial Neurologic Examination (Abnormalities or Specific Symptoms Should Lead to More Complete Evaluations)

There are two basic ways to do a traditional neurologic examination—regional and systemic. A system approach evaluates the motor system, then the sensory system, and so on. A regional approach evaluates all the systems in a given region, such as the upper extremities and then the lower extremities. The screening exam outlined in Table 5.3 is an amalgam of the regional and system approaches geared for speed and efficiency. The concept is an examination that requires the nervous system to perform at a high level, relying heavily on sensitive signs, especially the flawless execution of complex functions. If the nervous system can perform a complex task perfectly, it is very unlikely there is significant pathology present, and going through a more extensive evaluation is not likely to prove productive. A neurologic examination that assesses complex functions and seeks signs that are sensitive indicators of pathology is efficient and not overly time consuming.

TABLE 5.3 Steps in a Screening Neurologic Examination

Modified from Campbell WW, Pridgeon RP. Practical Primer of Clinical Neurology. Philadelphia: Lippincott Williams & Wilkins, 2002.

Educators have proposed a third type of exam, especially for teaching: the hypothesis-driven examination. This approach evolves naturally with experience but has not been used previously in teaching the exam. Teaching a hypothesis-driven neurologic exam evolved from a similar approach to the general physical exam. Examination maneuvers were focused by the history. Using the hypothesis-driven approach produced greater sensitivity but lower specificity and was performed in less time. Learning to develop a hypothesis from the history and how to test it is of course a paramount challenge in neurology.

The examination begins with taking the medical history, which serves as a fair barometer of the mental status. Patients who can relate a logical, coherent, pertinent, and sensible narrative of their problem will seldom have abnormalities on more formal bedside mental status testing. On the other hand, a rambling, Table 5.1 disjointed, incomplete history may be a clue to the presence of some cognitive impairment, even though there is no direct complaint of thinking or memory problems from the patient or the family. Similarly, psychiatric disease is sometimes betrayed by the patient’s demeanor and style of history giving. If there is any suggestion of abnormality from the interaction with the patient during the history-taking phase of the encounter, then a more detailed mental status examination should be carried out. Other reasons to do a formal mental status examination are discussed in Chapter 8. Simple observation is often useful. The patient’s gait, voice, mannerisms, ability to dress and undress, and even handshake (grip myotonia) may suggest the diagnosis.

Functions requiring the use of the penlight having been completed, observe the nasolabial folds for depth and symmetry and compare the forehead wrinkles on both sides. Then have the patient grimace, vigorously baring the teeth, while closing the eyes tightly. Note the symmetry of the grimace, how many teeth are seen on each side, and the relative amplitude and velocity of the lower facial contraction, as well as the symmetry of the upper facial contraction (see Chapter 16). How completely the patient buries the eyelashes on the two sides is a sensitive indicator of orbicularis oculi strength.

If the patient has no complaints of hearing loss, tinnitus, vertigo, facial numbness, or weakness and there is no specific reason suggested by the history to do so, routine examination of hearing is seldom productive. Examination of hearing is discussed further in Chapter 17. Complete the cranial nerve examination by checking the visual fields and fundi (see Chapter 13).

The screening examination detailed in Table 5.3 continues by doing everything that requires use of a penlight. Begin by noting the position of the eyelids and the width of the palpebral fissures bilaterally. Check the pupils for light reaction with the patient fixing at distance. If the pupillary light reaction is normal and equal in both eyes, checking the pupillary near reaction is not necessary. Continue by assessing extraocular movements in the six cardinal positions of gaze, having the patient follow the penlight. Be sure that the patient has no diplopia or limitation of movement and that ocular pursuit movements are smooth and fluid. With the eyes in primary and eccentric positions, look for any nystagmus. The eye examination is discussed in more detail in Chapter 14. With the light still in hand, prepare to examine the pharynx and oral cavity. Examination of the trigeminal motor function is accomplished merely by watching the patient’s jaw drop open prior to examining the mouth and throat. When the pterygoids are unilaterally weak, the jaw invariably deviates toward the weak side on opening. This deviation, while subtle, is a sensitive indicator of trigeminal motor root pathology (see Chapter 15). Observe the tongue for atrophy or fasciculations (see Chapter 20). Have the patient phonate, and be sure the median raphe of the palate elevates in the midline (see Chapter 18). There is little to be gained by checking the gag reflex if the patient has no complaints of dysphagia or dysarthria and if there is no reason from the history to suspect a brainstem or cranial nerve lesion. Routine elicitation of the gag reflex is rarely informative and is unpleasant for the patient. Have the patient protrude the tongue and move it from side to side.

Screening examination of motor function, sensory function, and coordination in the upper extremities can be completed as one compound, multifaceted maneuver. In most clinical situations in which a screening examination is appropriate, the primary concern is to detect a lesion involving the corticospinal tract (CST). The CST preferentially innervates certain muscle groups, and these are the groups most likely to be weak because of an upper motor neuron lesion. In the upper extremity, the CST-innervated muscles are the finger extensors, wrist extensors, forearm supinators, external rotators of the shoulder, triceps, and deltoid. The cardinal CST muscles in the lower extremity are the hip flexors, the hamstrings, and the dorsiflexors of the foot and toes. In addition, one of the most important functions of the CST is to provide fine motor control to distal muscles. Fine motor control, including rapid alternating movements, would furthermore be impossible without normal cerebellar function. The screening examination focuses on detecting weakness in the CST distribution and impaired distal fine motor control. In the upper extremity, the best muscles for strength testing are the deltoid, triceps, wrist and finger extensors, and intrinsic hand muscles, especially the interossei. Although commonly done, it is very poor technique to use grip power to assess strength. The finger and wrist flexors are not corticospinal innervated, and they are not likely to be weak with a mild CST lesion. In addition, grip is a complex function with many different muscles involved, so it is insensitive to peripheral pathology as well. Although strength is the primary focus of the motor examination, it is important to note any changes in muscle bulk, for example, atrophy, hypertrophy, or pseudohypertrophy; or muscle tone, for example, rigidity, spasticity, or hypotonia; and to note any abnormal involuntary movements, for example, tremor, fasciculations, or chorea.

When patients with mild CST lesions retain normal strength, ancillary maneuvers may detect the deficit. The most important of these is the examination for pronator drift (see Chapter 27). With the patient’s upper extremities outstretched to the front, palms up, and with the eyes closed, observe the position of each extremity. Normally, the palms will remain flat, the elbows straight, and the limbs horizontal. With a CST lesion, the strong muscles are the pronators, the biceps, and the internal rotators of the shoulder. As these overcome the weakened CST-innervated muscles, the hand pronates, the elbow flexes, and the arm drifts downward.

A screening sensory examination assesses sensory function by tasking the nervous system with performing a complex and difficult function. If this function is executed flawlessly, the likelihood of finding clinically significant sensory loss through a more detailed examination is low. Testing for stereognosis and performing double simultaneous stimulation are efficient and sensitive screening tools. The period of time waiting for pronator drift to occur is a convenient time to begin examining upper extremity sensory functions. While the patient is still in “drift position”—arms outstretched in front, palms up, and eyes closed—ask him to indicate which side is touched. Then lightly touch first one hand, then the other, and then both, using minimal finger pressure, a cotton wisp, or a tissue. A set of stimuli to the lower extremities is also convenient at this point. Continue by testing for stereognosis. Place an object, such as a coin, a key, a safety pin, or a paper clip, into one of the patient’s still upturned palms, and ask him to feel and identify it. Stereognosis is the ability to recognize and identify an object by feel; the inability to do so is astereognosis. Stereognosis can only be normal when all the peripheral sensory pathways and the parietal lobe association areas are intact; only when the primary sensory modalities are normal does astereognosis indicate a parietal lobe lesion. A patient with severe carpal tunnel syndrome and numb fingers may not be able to identify a small object by feel; this finding is NOT astereognosis. As a screening test, stereognosis is an excellent modality because it tests the entire sensory pathway, from the fingertips to the parietal lobe. If stereognosis is rapid and accurate, then all the sensory pathways must be functioning normally, and detailed examination is not likely to be productive. If a deficit is found on this preliminary assessment, a detailed examination of sensory function is necessary to localize the site of the abnormality. Additional useful information can be gained by dropping the small stereognosis object more or less in the center of the palm. A patient with normal fine motor control will adroitly manipulate the object, move it to the fingertips, rub it between the thumb and opposed fingers, and announce the result. A patient with a mild corticospinal lesion, producing relatively subtle clinical signs without major weakness, may be clumsy in manipulating the object and will occasionally drop it. The sensory examination is discussed further in Chapters 31 to 36.

After testing double simultaneous stimulation and stereognosis, with the patient’s eyes still closed, the hand and arm position is examined to determine if any drift has occurred. Then, eyes still closed, the patient is instructed to spread the fingers and touch first one index finger and then the other to the tip of the nose. This is the finger-to-nose (FTN) test, which is used to look for intention tremor, incoordination, and past-pointing. Ordinarily, the FTN test is carried out with the patient’s eyes open. For purposes of the screening exam, the more difficult maneuver of eyes closed FTN is performed first. If it is done perfectly, then neither cerebellar nor vestibular disease is likely. Complete the upper extremity examination by examining forearm roll, finger roll, and rapid alternating movements (see Chapter 27).

After completing examination of motor, sensory, and cerebellar function in the upper extremities, attention is turned to strength assessment of the lower extremities. The important muscles to examine are the CST-innervated groups: hip flexors, knee flexors, and the dorsiflexors of the foot. Further sensory testing is convenient at this point, comparing primary modality sensibility on the two sides; comparing proximal to distal in the lower extremities if peripheral neuropathy is a diagnostic consideration; and examining vibratory sensation over the great toes.

Continue by eliciting the biceps, triceps, brachioradialis, knee, and ankle reflexes; then assess the plantar responses. Conclude the examination by checking station and gait. Excellent tests for gait and balance functions are tandem walking with eyes closed and hopping on either foot (see Chapter 44).

The rest of this book is devoted to the detailed assessment of the functions touched on in the screening examination.

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