The Neurologic Examination

James M. Noble

INTRODUCTION

Of all the chapters presented in this book, the one most likely to remain nearly 100% relevant, if not also accurate, decades from now is that of the neurologic examination. Clearly new handheld and bedside examination tools continue to and will make implementation and interpretation of the exam different over time, but the general principles and approach have not substantially changed for decades and are unlikely to substantially differ over a trainee’s career. This chapter should be used in close conjunction with the guidelines for developing the neurologic history that are presented in Chapter 2.

One must recognize that an exhaustively comprehensive neurologic examination cannot be defined within the scope of this chapter. Instead, this chapter provides a set of guiding principles on which the neurologic examination can be built to support, augment, or refute findings suggested by the neurologic history.

A thorough neurologic history and examination are designed to accurately localize neurologic dysfunction and develop a differential diagnosis of the most likely disease processes. The history and physical should be used in a complementary manner rather than as stand-alone devices. With the patient or family members as informants and physician as historian, the neurologic history should be a logical, linear story told such that the history leads sensibly into the examination, without many surprises to the examiner or another physician hearing about the encounter.

SETTING GOALS OF EXAMINATION VERSUS NEUROLOGIC TESTS

As is the case in many professions, there are likely as many ways to accomplish an examination as there are examiners performing the examination itself. However, some approaches may be far more efficient, understandable, and sensible than others. There are numerous neurologic examination techniques known, sufficient to comprise a substantial book, let alone a single chapter.

The approach presented here is intended to demystify the reasons and the methods by which a comprehensive neurologic examination is accomplished. It is well recognized that most trainees in neurology will not go on to become professionals or practitioners in advanced neurology. However, it must be the case that every graduate of any medical training program has a sufficient confidence, skill level, and knowledge base to begin to develop a proficient neurologic examination for each context it requires.

This chapter attempts to strike a balance between the comprehensive examination that neurologist can accomplish, with the base expectation of all practitioners being able to approach a neurologic patient without trepidation, concern, misdiagnosis, or more importantly, a missed urgent neurologic diagnosis. A comprehensive neurologic examination is one typically done in the context of a focused neurologic assessment. All physicians should be familiar with how to accomplish each of these tests in the appropriate context. However, it is likely good practice to perform a screening neurologic examination in any patient encounter seen in a general medical inpatient or outpatient assessment, as major neurologic diseases can likely be identified through such an approach or alternatively provide a good point of reference should the patient subsequently develop neurologic problems. Elements suggested to be included in comprehensive and screening neurologic examinations are provided in Table 3.1. An in-depth review of the coma examination is provided in Chapter 18.

A TOP-DOWN APPROACH

The manner in which the neurologic examination should be presented follows a structured approach that facilitates a complete and comprehensive neurologic examination. Anatomically and generally speaking, this follows a “top-down” approach, which begins with the mental status examination and cranial nerve examination at the top with the head, followed by the body including motor and deep tendon reflex examinations, followed by sensory and coordination exams, and finally gait. The neurologic examination can be temptingly approached in an excitedly, symptom-focused manner, but this method introduces the risk of unintentionally forgoing an essential element of the neurologic examination. This approach is also designed to improve efficiency during the first pass assessment, to be followed by more focused and detailed examination based on relevant initial findings.

HELPING YOUR PATIENT THROUGH THE NEUROLOGIC EXAMINATION

There is a good chance that a neurologic examination performed on a patient may be perceived the most comprehensive medical examination the patient has experienced, with many elements even seemingly strange during the exam. Accordingly, some patients may unintentionally embellish the examination or even provide nonsensical physical exam responses, in an effort to impress their physician during demonstration of their neurologic system. In some cases, it may be helpful to tell the patient very specifically what is going to be done, as well as the expected outcome or finding, particularly when a normal examination is expected based on a benign relevant history. On the other hand, it may be more worthwhile to provide no instructions to patients with psychogenic disorders who are also prone to purposeful embellishment or feigned signs. It is certainly allowable for an unexpected neurologic examination finding to be repeated on a patient after coaching for expected findings has been given.

SOFT VERSUS HARD NEUROLOGIC EXAMINATION FINDINGS

In some cases, the examiner may be inclined to search unnecessarily for an abnormality on neurologic examination based on history provided or alternatively identify a subtle unexpected finding referred to as a “soft” neurologic sign. Commonly, faces may be asymmetric, strabismus persists into adulthood, memory may be imperfect, or
balance may be less than pristine especially with advancing age. Slight asymmetries, particularly in the face, are commonly found during neurologic examination in normal individuals and likely do not hold much clinical relevance. Some reviews have suggested that soft neurologic signs including poor motor coordination, sensory perception, and motor sequencing may occur in as much as half of all healthy individuals. Understanding when to strongly consider finding, simply record it, or to discard it altogether often takes a very skilled examiner cautiously interpreting each finding. However, this need not take a fully refined neurologist to make such decisions, particularly if one approaches the neurologic examination with a clear sense of the likely localization as suggested by a fully developed history. When findings are found in isolation, particularly without a clear connection to the history that has just been developed, it may be justifiable to recognize and record the finding but not necessarily dwell on it. A neurologist typically will take these findings into consideration and tailor, repeat, or perform additional elements of the neurologic examination to assure that the finding is simply an isolated finding (and perhaps even a normal variation) or a relevant new finding. In addition, it is certainly acceptable upon discovery of a subtle neurologic finding to reask a newly relevant history, which may not have otherwise been apparent despite a seemingly comprehensive initial history.

TABLE 3.1 The Neurologic Exam

Comprehensive	Screening
Mental Status
Level of alertness	Level of alertness
Language function (fluency, comprehension, repetition, and naming)	Appropriateness of responses
Memory (short-term and long-term)	Orientation to date and place
Calculation	—
Visuospatial processing	—
Abstract reasoning	—
Cranial Nerves
Vision (visual fields, visual acuity, and funduscopic examination)	Visual acuity
Pupillary light reflex	Pupillary light reflex
Eye movements	Eye movements
Facial sensation	—
Facial strength (muscles of facial expression and muscles of facial expression)	Facial strength (smile, eye closure)
Hearing	Hearing
Palatal movement	—
Speech	—
Neck movements (head rotation, shoulder elevation)	—
Tongue movement	—
Motor Function
Gait (casual, on toes, on heels, and tandem gait)	Gait (casual, tandem)
Coordination (fine finger movements, rapid alternating movements, finger-to-nose, and heel-to-shin)	Coordination (fine finger movements, finger-to-nose)
Involuntary movements	—
Pronator drift	—
Tone (resistance to passive manipulation)	—
Bulk	—
Strength (shoulder abduction, elbow flexion/extension, wrist flexion/extension, finger flexion/extension/abduction, hip flexion/extension, knee flexion/extension, ankle dorsiflexion/plantar flexion)	Strength (shoulder abduction, elbow extension, wrist extension, finger abduction, hip flexion, knee flexion, ankle dorsiflexion)
Reflexes
Deep tendon reflexes (biceps, triceps, brachioradialis, patellar, Achilles)	Deep tendon reflexes (biceps, patellar, Achilles)
Plantar responses	Plantar responses
Sensation
Light touch	One modality at toes—can be light touch, pain/temperature, or proprioception
Pain or temperature	—
Proprioception	—
Vibration	—
From Gelb DJ, Gunderson CH, Henry KA, et al. The neurology clerkship core curriculum. Neurology. 2002;58(6):849-852.

DESCRIPTIONS VERSUS IMPRESSIONS

Whenever possible, a description of neurologic findings should be included in the examination rather than the synthesis of the findings themselves. Changes in the neurologic examination day to day can be remarkably subtle and only a descriptive neurologic examination may reveal such changes and sometimes only in retrospect. For example, a patient may be described on a series of examinations by different examiners to be lethargic, yet substantially different levels of stimulus are required to result in the same response from the patient, ranging from light tactile to verbal stimuli to other more rigorous stimuli applied yet inadequately described. Such a failure to accurately describe patient, particularly in an era increasingly reliant on effective care transitions, can jeopardize true understanding of neurologic disease progression in both inpatient and outpatient practices.

POSITIONING THE PATIENT (AND EXAMINER)

Appropriately positioning the patient and examiner is an important first step in many aspects of the neurologic examination and is described in each of the relevant sections. Positioning of the patient and examiner is important throughout the patient encounter, including initial moments of a patient encounter when developing patient trust and rapport. At the bedside, correct position with each component of the neurologic examination is essential in both effective and efficient performance and interpretation of the neurologic examination. Positioning is most relevant not only to assessment of visual fields, funduscopy, strength, and deep tendon reflexes but also during times of potential injury during provocative or potentially risky elements of the exam, such as pull testing for assessing postural stability, or even when standing a patient affected by frailty or imbalance suggested in the history or during gross inspection.

REPEATED EXAMINATIONS ARE THE KEY TO IMPROVE SKILL

Skill and ability in any medical field, or in any field involving adult learners, likely relates to the prior volume of experience had in that field. A well-described cognitive heuristic suggests that adult learners transition from a hypothetical deductive approach in learning to a more automated approach through progressive experience.

A set of rich and deeply understood normative values can be determined for simple yet essential components of the neurologic examination, including determining the relatively normalcy of interpersonal interactions, conversations, or even walking. With this set of normal findings, an examiner can begin to dissect a subtly abnormal neurologic examination into its principal components. By the same measure, one cannot know how an abnormal funduscopic examination or tandem gait may appear until having seen normal findings in many patients. Although a specific diagnosis, particularly among patients with complicated history, may remain elusive even in the hands of an accomplished neurologist, an accomplished dissection of abnormal findings on the neurologic examination, used in conjunction with the history, can facilitate localization and diagnostic approach.

THE PATIENT EXAMINATION

GENERAL MEDICAL EXAMINATION

All neurologists participate in substantial training in internal medicine, whether in the adult or pediatric setting. Thus, it is expected that any patient with a neurologic disease should have a comprehensive general medical examination performed on them at least once in the course of their initial neurologic assessment. However, it is typically the case that a relatively brief overview of the general medical examination will be included in any neurologic case presentation with only the elements most germane to the neurologic diagnosis presented. For example, description of cardiac and carotid auscultation should be described for a patient presenting with stroke, and a rash should be described in a patient presenting with proximal myopathy.

However, each patient should have a complete and accurate description of the general impression—the essence of the strong first impression each patient may have provided to the examiner. Specific points to mention may include general appearing of wellness, nourishment, habitus, manner of dress, or other related elements. Some of these elements may be reinforced in the mental status examination.

MENTAL STATUS EXAMINATION

In contrast to other elements of the neurologic examination, the mental status examination is composed of a potentially variable set of tasks tailored to each patient. Rather than beginning with the prespecified set of neurologic examination tasks, a far preferable approach is one that aims to develop a description of the function of the cognitive domains based on a set of often interdependent tests. It is difficult, if not impossible, to find any single test that can comprise and completely describe an entire neuropsychological cognitive domain. Instead, many tests map to several cognitive domains and vice versa. In graphical or mathematical terms, the brain expresses its cognitive functions in a series of overlapping domains, conceptually representable as Venn diagrams (Fig. 3.1), which can broadly be broken down into domains of language, memory, attention and executive function, visuospatial function, and processing speed. Predicated on each of these is that the patient has a sufficient level of consciousness in order to participate in the examination.

The neurologic examination should include a standardized assessment of mental status for several reasons. First, any
standardized cognitive screening examination will often have been developed in the context of hundreds, if not thousands, of applications and multiple social economic and cultural contexts, making its interpretation more generalizable. Second, at the level of the examiner, use of the same examination repeatedly may give the examiner greater confidence in examination skill and interpretation based on a learned experience of typical or expected responses developed over the course of giving the same test in multiple clinical contexts. Third, most standardized mental status examinations allow for a hierarchical approach to understanding someone’s cognitive abilities. For instance, for a task of delayed recall, it is important to understand not only what a patient can freely recall but also what the patient may recognize either through the contextual or categorical clue given for recognition tasks or subsequently through list of forced choices. Using a sequential, hierarchical approach to assessing memory abilities allows for determination of free word retrieval (presumably a harder response) versus recognition (by choices), which are thought to be independent of registration tasks. Finally, serial assessments of an individual patient may require adjustment of exam techniques to avoid the potential effects of learning or practice.

Many caveats apply to interpreting the mental status examination and thus require understanding and how it is devised for each patient, particularly how it is tailored to each cultural context. For instance, education and lifetime cognitive abilities play a strong role in one’s ability to interpret both normal and abnormal mental status examination findings. Prior to each mental status examination, developed within social history must be a clear sense of someone’s educational history, literacy, and thus likely expected performance on mental status testing. As a point of comparison, more formal neuropsychological testing will take into consideration two norms: the person’s premorbid intellectual capacity as determined by intelligence quotient as well as comparison to normative values based on peer performance matched to age, education, and potentially primary language.

FIGURE 3.1 Conceptual framework for the mental status examination and interpretation. Each of the five principal cognitive domains (language, memory, visuospatial, processing speed, and executive function) are drawn from a series of tests comprising the mental status examination. Relative strengths and weaknesses in each domain may be inferred based on a series of related tests which map potentially to several domains but relatively consistently identify a domain of impairment. The interpretation of each abnormality must be considered within the context of each test, including normative information if known. The relative function of each domain is likely influenced by and superimposed on crystallized knowledge, which conceptually summarizes education, life experiences, and cognitive reserve.

It is important during the mental status examination not only to record whether or not the patient correctly answers the question but also the actual response itself. Much can be learned through some elements of the mental status examination which can, to some degree, be influenced by complex factors including mood. For instance, a patient may be considered to be disoriented to time and place through simple scoring, but when review of the actual answers suggest an exactly wrong response to every single question (including nonsensical dates, often in the future), it might suggest an element of feigned or embellished neurologic examination.

Determining Alertness

The entirety of the formal mental status testing is predicated on a patient being fully awake, alert, and able to engage the examiner. Presuming this is the case, neurologic examination as described in the following section is relevant in such patient. Determining a depressed level of alertness is described in Chapter 18 as relates to the examination of coma and brain stem examination.

Tasks of Attention and Concentration

Typical tasks of attention and concentration relate to the ability of a patient to attend and focus any specific, often narrow set of tasks in real time. Typical bedside techniques in assessing concentration include serial subtraction, spelling a five-letter common word backward, or more simply involving stating the months of the year in reverse, days of the week in reverse, or counting from 20 down to 1, always beginning with the most difficult task first. Elements of these examinations are often appropriately interpreted in the context of related domains such as executive function. For instance, the ability of a patient to count down from 20 may reflect the ability to attend to the task, whereas subtracting a series of changing answers may suggest intact or impaired executive or calculation abilities. Other more practical tasks may involve simple addition and subtraction, presuming appropriate levels of literacy and numeracy. Tasks such as making monetary change may not only give one a sense of the patient’s calculation abilities but also any degree of functional impairment should a clear impairment emerge. For a patient residing in a major metropolitan area, the ability to appropriately make change at a hypothetical street-side food vendor can be such an example.

Additional tasks of attention and concentration may be more conventionally thought of in conjunction with other cognitive tests, such having a patient register several words to be later recalled, following a three-step command, or drawing a complex figure. As detailed earlier, it is not the performance on a single test that draws concern but rather an overall pattern that may emerge across the sequence of several tests.

Memory Testing

Differing definitions of working, short-, and long-term memory exist, are often used inappropriately in colloquial examination and
presentations, and may have differing meanings depending on the person reviewing the examination described by others. A formal description of various forms of memory is provided in summary in Table 30.2. Working memory is generally considered to be the online or in-the-moment memory, such as what may be used when repeating a series of unrelated words or number sequence. Short-term memory involves testing a set of ideas registered with the patient and specifically queried by the examiner after a delay of several minutes. Items not freely recalled but instead recognized from a list (recognition) can be additionally informative. Long-term memory can either represent a more prolonged delay in testing responses to the task of recollection, or in some other tasks may instead represent long-term general or autobiographical knowledge. It is important to document the content asked to be remembered and the duration of time until asking for retrieval of information. Recall is entirely predicated on the patient’s ability to register several items to be recalled, and this begins with preparing patient for this task in a minimally distracting environment.

In its simplest form, memory testing involves having a patient remember several items in the context of an examination to be recalled several minutes later. Certainly, this is an important element of memory testing but is just one method of assessing memory among many. This manner of testing memory, in conjunction with several other tests, such as time and place orientation, may be highly specific in screening out major cognitive disorders, which may adversely affect health care such as medication compliance. However, it largely serves to only test verbal memory of three unrelated words, and does not take into account nondominant hippocampal function such as visuospatial memory or implicit memory associated with programmed motor tasks.

Ideally, a test of three to five unrelated words, or a brief contextually related phrase (name and address of a fictional person), should be given to a patient to register and subsequently recall. It is most important for the examiner to use a series of words that have been rigorously studied to understand their cultural and socioeconomic norms, can be understandably and simply chosen from categorical clues, which may be given to help with recognition after-the-fact (e.g., “the first word was a color”), can be recognizable from a list of similar words, and is also easily memorable to the examiner who may be giving such an examination many times over the course today.

Verbal memory can also be tested through repetition and recall of a simple story. This can be particularly effective in identifying the patient with a confabulatory amnestic syndrome (i.e., Korsakoff syndrome) rather than anterograde amnesia (i.e., Alzheimer disease). For example, a patient may be given a brief story to recall such as “Johnny had a red tricycle. Billy liked Johnny’s red tricycle and stole it one day. Billy broke Johnny’s red tricycle after he took it. When Johnny found out Billy had stolen the tricycle, he got very upset.” A patient with a typical amnestic disorder may respond to this task by providing a few or a restricted set of elements germane to the story with the remainder unrecalled. In contrast, a patient with a confabulatory amnestic disorder may provide the initial basic elements of the story correctly but then provide an idiosyncratic thread far beyond the initial details provided in the story. Moreover, such a patient may begin with the same thread when testing the story on a follow-up examination, only to give a remarkably different yet linear story thereafter.

Nonverbal short-term memory is thought to be localizable to the nondominant hippocampus or most typically the right side in right-handed individuals. Testing visuospatial memory in the office can be somewhat difficult but can be accomplished. For instance, one can hide three objects within a room telling the examinee each time where each object is placed, to be registered and recounted several minutes later. A hospital corridor can be used as a visuospatial memory task by having a patient and examiner pass through a specific path, to be led by the patient immediately to demonstrate registration, and again several minutes later to demonstrate recollection.

Long-term memory likely engages separate circuits, widespread across the cerebrum, and is better categorized as public or autobiographical memory rather than a true function of working or recent memory. This memory type can also be easily conflated and is dependent on knowledge of worldly events and life experiences. Testing long-term memory can be approached by using a standardized set of questions which should be well known to the individual, such as sequential ordering of recent presidents. However, this can be easily tailored to a patient who may lack such conventional knowledge. For example, an elderly sports enthusiast can be tested for his knowledge of recent sports events important to him and hierarchically working back to biographical events which must be corroborated by an informant. A test of recent worldly events likely more reflects function of the same recent memory circuits being tested by recollecting three unrelated words, given the need to both register and recall worldly information gathered through the news.

Language

Language is composed of seven principal components: (1) fluency, (2) prosody, (3) repetition, (4) naming, (5) comprehension, (6) reading, and (7) writing. A language examination is not complete without each of the seven elements. The pattern of dysfunction related to these seven components allows the neurologist to diagnose and classify all types of aphasia (Table 3.2).

Fluency and prosody can often be determined through development of the neurologic history before turning to formal examination. Prosody is the musical component of language, the singsong nature, and cadence that allows one to understand the nature of a stated expression. For example, prosody allows one to discern when a declarative sentence is stated versus a question. In contrast to normal prosody, aprosodic patients may be identified among those with major neuropsychiatric disorders including schizophrenia or in patients with advanced or untreated Parkinson disease. Fluency is a quality of speech pertaining to the ability of a patient to express him- or herself without hesitation or disruption spontaneously as well as during formal testing. Dysfluent speech may have hallmarks of patient frustration or an unexpected halting pattern, such as that seen in a suddenly acquired Broca area stroke, or progressively developed in a patient with progressive nonfluent aphasia form of frontotemporal dementia. Dysfluent speech is distinct from thought blocking, which is described within the elements of psychiatric examination.

Repetition may be assessed by asking a patient to repeat a simple, understandable phrase and further tested by a longer more complex sentence if the history and examination warrant further exploration. When such a phrase cannot be repeated, repetition of single words should be attempted.

Naming also should be approached in a hierarchical manner when testing knowledge of names of presented objects and virtual pictures. Standard images/figures comprise most neurologic screening examinations but differ among each exam. Objects to be named should be ubiquitous, well-known to the patient, and have elements that offer an opportunity to test parts and not just the sum of the object. This approach may reveal difficulty in describing
low-frequency relative to high-frequency words, as is often seen in disorders like Alzheimer disease. In addition, the naming examination may be tailored to the patient for objects well-known in the context of their life experience or profession, such as images of a set of carpenter’s tools. A number of forms of specific categorical dysnomic aphasias are known to exist, such as color dysnomia, and should be tested in the appropriate clinical context.

TABLE 3.2 Types of Aphasia Types of Aphasia

Aphasia Subtype	Fluency	Comprehension	Repetition	Localization
Expressive (motor, Broca)	Effortful speech with paraphasic errors^a and agrammatism^b; mutism in severe cases	Normal	Impaired^c	Frontal opercular region of inferior frontal gyrus (Broca area) in the dominant hemisphere
Receptive (sensory, Wernicke)	Fluent speech, mostly nonsensical in content; frequent paraphasic errors	Impaired	Impaired^c	Posterior-superior temporal region (Wernicke area) in the dominant hemisphere
Global aphasia (combination of expressive and receptive)	Effortful speech with paraphasic errors^a and agrammatism^b; mutism in severe cases	Impaired	Impaired^c	Both inferior frontal gyrus and posterior-superior temporal region in the dominant hemisphere
Conduction aphasia	Normal	Normal	Impaired	Due to lesions of the arcuate fasciculus connecting Broca and Wernicke areas in the dominant hemisphere
^aLiteral (phonemic) paraphasic error: an error made by substituting a similar-sounding word for another (i.e., “pat” substituted for “cat”). Verbal (semantic) paraphasic error: an error made by substituting words with similar meaning (i.e., “cup” for “bottle”). ^bAgrammatism or telegraphic speech: Language content of spontaneously uttered sentences is condensed, missing many filler words, such as definite articles and sometimes verbs. ^cNormal repetition in the setting of expressive, receptive, or global aphasia denotes transcortical expressive, transcortical receptive, and transcortical mixed aphasia subtypes.