The High Yield Neurologic Examination

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1 The High Yield Neurologic Examination John Engstrom, M.D. April 2017 Overview The Neurologic Examination Mental status-brief review Cranial nerves common/urgent patterns Motor exam common/urgent patterns Sensory exam common/urgent patterns Selective demonstrations Screening Mental Status Orientation-time, place, person Attention-Digit span forward (nl > 6-7) Language-repetition, naming, comprehension Memory-Recall of 3 common objects at 5 minutes; if misses an answer give a prompt Abstractions-Similarities and differences (e.g.-apple vs. orange; lake vs. river) Q1: Which statement regarding the mental status exam is false? 1) Attention span (immediate recall) is not abnormal in patients with dementia 2) Language testing is a screen for aphasia 3) If recent memory testing is abnormal, then attention is probably also abnormal 4) Abstractions are often abnormal in the setting of dementia 5) Attention span is often abnormal in late dementia 1

2 Assessment of Vision Measure acuity with glasses on/contacts in Establishing a visual field cut establishes a structural lesion (eye vs. brain) The pupils always react in cortical blindness Afferent-retina, optic nerve/tract, brainstem Efferent-midbrain, third nerve, ciliary muscle Screening for Visual Field Deficits Allows you to test function of broad areas of brain Lobes-occipital, temporal, parietal Optic nerves, chiasm, thalamus Clinical Importance An anatomic sedimentation rate of the brain Detect abnormalities that require brain imaging Localize the deficit (right vs. left brain) Screening for Visual Field Deficits- Ambulatory, Cooperative Patient Imagine visual field cut in four equal pieces Move examiner finger in the center of each quadrant with patient gaze fixed Test each eye by covering the opposite eye, present stimulus in center of all 4 quadrants Describe the deficit in terms of the portion of the visual field affected 2

3 Q2: What causes sustained dilation of a pupil in response to a light? 1) Afferent pupillary defect 2) Hippus 3) Efferent pupillary defect 4) Stroke affecting the parietal lobe 5) Stroke affecting the occipital lobe Cranial Nerve Exam-Pupils Anatomic pathways-afferent CN II, midbrain, efferent bilat parasymp in CN III Best tested dim light; Est size before/after light Assess baseline symmetry of shape and size Assess direct and consensual response No other part of the nervous system affected! Abnormalities may be in CN II or III Common Pupillary Exam Patterns Common False Positives Mydriatic drugs (unilateral if topical); child Inadequacy of light stimulus (use bright light against a dim background) Post surgical-cataracts, prosthetic eye Afferent pupil defect-light stimulus doesn t reach brainstem due to diseased CN II Pupil dilates despite constant light stimulus Examples-multiple sclerosis, meningioma 3

4 Urgent Outpatient Pupillary Exam Pattern Exclude false positives History/exam suggest intracranial process? Efferent pupil dilated unilaterally (6-9 mm) Accompanied by CN III palsy (eye down/out) Greater than 1 mm asymmetry Compression of CN III by temporal lobe brain tissue displaced from a mass Consider urgent brain MRI or head CT What Cranial Nerves Have in Common Brainstem portion-many other brainstem findings present (e.g.-ms, tumor) Subarachnoid space-cn and nerve roots pass through the CSF after exit cord Often multiple CN involved Example-infectious/carcinomatous meningitis, Skull base-inside/outside skull to target tissue innervated (e.g.-motor/sensory) Cranial Nerves III, IV, and VI Movements-eye out is VI, eye down and in is IV, everything else is III Move finger in horizontal and vertical planes Move finger in and down bilaterally-ivth Monocular diplopia Pt cover one eye; is only one image remaining? Strongly consider ordering brain MRI to cover brainstem, skull base, and orbit 4

5 Q3: What facial movement is normal in upper motor neuron weakness? 1) Smile 2) Eye closure 3) Eyebrow furrowing 4) Lower 2/3 of face 5) Upper 2/3 of face Cranial Nerve VII-Muscles of Facial Expression Upper 1/3-Furrowing the eyebrows Middle 1/3-Eye closure-can test power by forcing eyes open against resistance Lower 1/3-Smile All three affected-lower motor neuron facial paresis (e.g.-bell s palsy) Lower 2/3 affected-upper motor neuron (brain or upper brainstem) CN VII-Examination Upper 1/3-furrowing brow, symmetry Middle 1/3-degree eye closure, symmetry Power testing-force eyelids open using thumbsone each at upper and lower orbit With effort, globe rotates upward-see sclera Lack of effort, globe motionless-see iris + pupil Lower 1/3-excursion of smile, symmetry CN VII-Utility of Testing Lower 2/3 face-mri of brain Entire face-bell s palsy LMN VII only finding Acute onset; stabilize/improve over days-weeks Apparent Bell s but CNS location (e.g.-ms, brain tumor) Other neurol symptoms/signs Coincident medical illness (e.g.-meningitis) 5

6 CN V, VIII, X, XI CN V-test three divisions of face with pin or light touch CN VIII-finger rub next to each ear; audiogram if questionable CN X-uvula elevation in the midline CN XI-symmetry/power of shoulder shrug CN XII-Tongue Two muscles fused midline; separate CNs Bulk-smooth lateral contour, symmetry Power screen-tongue protrusion midline nl Grading power-hold tongue-in-cheek vs. resistance Dysarthria-slurred speech due to weakness Lips (labial dysarthria) Tongue (lingual dysarthria) Palate (nasal dysarthria) Motor Exam Bulk-place the contour of the muscle on a perpendicular to your line of vision Tone-move limb passively across a joint slowly and rapidly Power-grade 1-5 on the MRC scale Reflexes-grade 0-4 Gaits-Demonstration at the end of talk 6

7 The Symptom of Weakness Patients mean a functional limitation of motor activity Confused with: fatigue depression ( neurasthenia ) decreased sensation decreased force moving a painful limb The Weak Patient: Pertinent History Temporal sequence Functional activities SOB Ambulation-independent vs. cane vs. walker vs. wheelchair Stand up/reach overhead-proximal muscles Stand on toes; use pen/spoon-distal muscles Complete motor exam-not power alone Examination Signs of True Weakness Reduced but constant resistance when testing the power a muscle on clinical examination There are only two types of true weakness: Central: brain, brainstem, cord Peripheral: anterior horn cell, root, plexus, nerve, neuromuscular junction, muscle Breakaway Weakness is Not True Weakness DEFINITION: Variable resistance by the patient during muscle power testing ASSOCIATED WITH PAIN: Cannot determine if underlying weakness present UNASSOCIATED WITH PAIN: Poor effort or attention 7

8 Weak Patient: History and Examination Q4: Which statement is FALSE re/ clinical utility of distinguishing UMN from LMN weakness on exam? UPPER MOTOR NEURON NEUROLOGIC LOWER MOTOR NEURON NON-NEUROLOGIC FATIGUE BREAKAWAY POOR EFFORT PAIN 1) Informs decision to obtain imaging 2) Informs the decision of what part of the nervous system to image 3) Determines need for neuromuscular referral 4) Helps determine differential diagnosis 5) None of the above statements is false Weak Patient: Central Weakness I Weak Patient: Central Weakness II Power - distal > proximal in limbs extensors > flexors in arms dorsiflexors > plantar flexors in legs lower 2/3 of face (if from brain injury) Bulk - Normal Tone - spastic; Babinski sign(s) present Reflexes - Spasticity-velocity-dependent increase in tone to passive stretch of a limb that is greatest in the flexors of the arms and extensors of the legs -Rapid, repetitive movements are slow in the fingers and feet; dominant side normally faster -Pronator drift-pronation the essential finding; may also flex the fingers and drop the arm 8

9 Motor Exam-Grading Power SCORE RESPONSE 5 Full power 4+/5- Minimal weakness 4 Mild weakness 4- Moderate weakness 3 Severely weak; able to move vs. gravity 2 Moves, but not against gravity 1 Flicker of contraction 0 No muscle contraction Motor Exam-The Challenge of Grading Power Most weakness is between 4 and 5 Inter-examiner variability What do you do with the weight-lifter? Qualitative scale: mild, moderate, severe? Pattern weakness usually more informative than attempt to exactly quantify weakness Motor Examination-Common Traps Focal atrophy from disuse or pain with use Tongue fasciculations-all tongues twitch Apparent increased tone from patient inability to relax during the exam Nocturnal headaches can be caused by CO2 retention during sleep in NM resp failure Motor Exam-Grading Reflexes SCORE RESPONSE 4 Clonus 3 Hyperactive 2 Normoactive 1 Hypoactive Trace Present with reinforcement only 0 Absent 9

10 Q5: Which answer is an inadequate explanation for an absent DTR? 1) Inadequate stretch on tendon being struck 2) Contracture of the tendon 3) Vinca alkaloid use (e.g.-vincristine) 4) Muscle weakness 5) Absence of muscle tissue attached to the tendon being struck Weak Patient-Lower Motor Neuron Weakness All features of true weakness on exam Patterns of weakness and other findings determine the differential diagnosis Distal polyneuropathy-weakness first in distal legs with sensory loss and absent ankle reflexes Myopathy-proximal weakness in arms and legs without sensory loss or reflex changes Global new areflexia-always needs explanation CNS Sensory Loss (2 Cs) and PNS Sensory Loss (2 Ps) Central-Circumferential limb/trunk distrib. Distribution belong to many nerves/nerve roots Cord, brainstem, brain Peripheral-Patchy distribution over a limb In nerve or root distribution Distribution belongs to single nerve/nerve root Exception: stocking-glove sensory loss of a distal sensory polyneuropathy Sensory Examination Light touch-tests primarily large diameter nerve fibers and CNS sensory pathways Easy to test with finger or Q-tip Can use over entire body Can use VAS (0-10) for semi-quantitation Change in quantity or quality of light touch? Pin sensation tests small diameter nerve fibers and CNS pain pathways-sharp or dull 10

11 Demonstrations-A Volunteer? CNs-facial strength, tongue Motor exam Tone-normal, rigidity, spasticity Power-proximal and distal limb muscles Reflexes-triceps, finger flexors, ankles Gait-What is wrong with my walking? Gait-Hemiparetic Affected leg is stiff and circumducts during walking Affected arm is partially flexed in a spastic position Gait-Parkinsonian Short small shuffling steps bilaterally En-bloc turning-multiple steps to turn around instead of the normal two steps Reduced arm wing-unilateral or bilateral Retropulsion-tendency to fall backwards when standing still and given a minor push Gait-Alcoholic Cerebellar Degeneration Affects the truncal balance center in the midline cerebellum Limb coordination is fine Typical gait is wide-based Cannot tandem walk Classic presentation-no distal sensory loss 11

12 Gait-Steppage Due to foot drop of any cause To avoid tripping over the toes during the foot drop, the patient compensates by lifting the proximal leg high in the air High risk of falls; socially embarrassing Correctable with ankle-foot orthosis (brace) Gait-Sensory Ataxia Lack to sensation in the feet of any cause Nearly all patients have a Romberg sign Inability to tell position of feet in space results in imbalance Visual compensation is gone in darkness (washing hair with eyes closed while standing) Wide-based gait accompanied by sensory loss Conclusions A good screening neurologic exam can be performed in 10 minutes Additional neurologic examination will be dictated by the history and initial examination findings The disease context and pattern of neurologic findings is most helpful, not a single finding 12

13 + John Engstrom, M.D. April 2017 The HNeurological Examination Mental Status Examination Before beginning the mental status examination, assess education level and native language of the patient. The results of the exam must be interpreted in the context of these factors. 1. Orientation You will have an excellent indicator of orientation simply by interviewing the patient. To test formally, ask for the patient's name, the date (as day, month, year), and where the patient is located now. 2. Attention span Test attention span (immediate recall) by having the patient repeat a numerical sequence. A patient should be able normally to recall 7-8 digits forward; The likelihood of normal recent recall at 5 minutes is low if attention span is impaired. Almost everyone must remember a numerical sequence (e.g.-telephone number). 3. Recent recall Ask the patient to remember 3 items and repeat them back after 5 minutes. This test is best performed if the objects to be remembered are familiar to the patient. For example, one might ask a carpenter to remember a hammer, a board, and a house. You should always ask the patient to repeat all 3 items immediately back to you first to make sure the patient understands each item. 4. Repetition, naming, and comprehension The inability to produce language (aphasia) can be tested efficiently. A sentence can be repeated such as, Today is a sunny day. Naming can be performed with 3 common objects such as a pencil, tie, shoe, or belt. Objects should be easily identifiable and appropriate to the cultural background and educational level of the patient. Comprehension is tested throughout the examination history and by the ability of the patient to follow directions and answer questions. 5. Abstractions Abstractions are complex, difficult tasks for a cognitively impaired patient. Examples: What is the difference between a cat and a dog? How would you distinguish between a lake and a river? or How are a lake and river alike? The answers may be abnormal in patients with either delerium or dementia. 6. Speech Speech can be placed under the mental status or cranial nerve examinations. Abnormalities of speech (dysarthria) can be related to cranial nerve abnormalities including VII (labial dysarthria), X (palatal dysarthria), or XII (lingual dysarthria). 7. Neglect- Can the patient distinguish between the right and left side of the body or pay attention to the left and right side of the room (name objects to the right or left) 8. The above guidelines are for a screening mental status examination. There are many different formats for the mental status examination that can be adapted to specific circumstances. Cranial Nerve Examination If in doubt about whether or not a cranial nerve finding is abnormal, check for symmetry between the two sides. II Vision Screen corrected (i.e.- with glasses) visual acuity with a vision card. Allow the patient to hold the card. Screen for major visual field deficits by having the patient cover one eye and identify an object (often a finger) in the center of each visual quadrant of each eye. II, III Pupillary examination Normal size in moderate light for adults is 3-4 mm. Normally larger in children and smaller in the elderly ( senile miosis ). Acceptable asymmetry is 1 mm. Page 1

14 Check both direct and consensual reactions. For patients with a dark pigmented iris, try using a second flashlight held from below or above the face to illuminate the pupils without causing constriction. III, IV, VI Extraocular movements. Check horizontal, vertical, and inferonasal (down and in) eye movements. Can the patient move the eyes from side-to-side fully so as to eliminate the sclera from view? Nystagmus is a rapid, beating movement of the eyes (usually in a horizontal plane) that is triggered by eye movement. Remember that VI controls abduction and IV controls inferonasal movement. III controls all other eye movements. V Corneal response, facial sensation. Use a wisp of cotton and lightly touch the cotton to the surface of each cornea. Note if both the direct and consensual corneal responses are present. Check pin and light touch sensation on each cheek. VII Facial expression Test the muscles of facial expression by having the patient raise the eyebrows, close the eyes tightly, and smile. Note any asymmetry in the extent of facial movement and speed of movement on the two sides of the face. VIII Hearing Rub the fingers together by each ear so that the fingers can normally be heard, but no movement of the fingers or arms seen by the patient. Vestibular function is screened during testing of the extraocular movements by noting the presence or absence of nystagmus. A few beats of nystagmus at the extremes of horizontal eye movement is normal. Direction of the nystagmus (by convention) named for fast component of the beating eye movements. Vertical gaze nystagmus is almost always due to a posterior fossa (cerebellum or brainstem) lesion IX, X Soft palate function Gag reflex, nasal voice, elevation of the palate. Elevation of the palate is the best screening test. The uvula normally elevates in the midline when the patient says 'Ahhhhhhhl" A nasal voice is an indication of soft palate dysfunction. Gag reflex is helpful when asymmetric, but uncomfortable for patients; may be bilaterally absent in some normal or elderly patients. XI Trapezius If you need to test this cranial nerve, do so with the trapezius muscles (bilateral shoulder shrug against resistance-both sides tested simultaneously). XII Tongue Note the bulk of the two sides of the tongue when protruded. If the tongue is weak from a XIIth nerve lesion, it will protrude toward the side of the lesion. Strength can be tested by having the patient push the tongue against the inside of each cheek. In the presence of facial weakness, one can think tongue appears tomprotrude to one side. Line up position of the tongue with tip of the nose and middle of chin to determine if tongue protrudes to one side. The Motor Examination 1. If in doubt about whether or not a finding (bulk, power, reflexes) is abnormal, check for symmetry between the two limbs. 2. A screening examination will include sampling of the proximal and distal muscles of the arms and legs. In otherwise healthy patients, the ability to perform a deep-knee bend is a good screen of proximal leg power. 3. You cannot perform an adequate muscle examination unless you can see the muscles! The patient must be positioned and dressed appropriately. 4. You will not remember the innervation and action of all the muscles. You may want to get a portable book with diagrams that can serve as an instant resource (i.e.-aids to the Examination of the Peripheral Nervous System). Page 2

15 Bulk Check the bulk of the deltoid, abductor pollicis brevis (APB), and quadriceps muscles. Visually compare the same muscles on the right with the left limbs. Tone Move the limbs slowly and quickly through their range of motion with the patient relaxed and supine. Increased tone consists of abnormal resistance to passive movement of the limbs, despite adequate relaxation and the absence of pain during the movement. Spasticity is a velocity-dependant increase in resistance that is greatest in the flexors of the arms and extensors of the legs. Power For a screening exam, check one proximal and one distal arm muscle (biceps and first dorsal interosseus muscles are good choices in the arms). Check one proximal and one distal leg muscle: iliopsoas and tibialis anterior are good choices. Alternatively, screen the proximal muscles of the legs by having the patient perform a deep-knee bend. Coordination Check finger-to-nose and heel-knee-shin on both sides. Check tandem gait by having the patient walk while placing the toe of one foot to the heel of the opposite foot repetitively. Tell the patient that it is an accuracy test, not a speed test! The patient can use laterally outstretched arms for balance while walking and should keep their eyes open. Correct results for patient age; tandem gait normally begins to normally deteriorate over age 60. Check for fast finger movements by having the patient tap the first finger and thumb in a rhythmic and rapid fashion. Asymmetric, slow, but rhythmic fast finger movements or foot tapping is a sensitive test for an upper motor neuron lesion. Check for pronator drift by having the patient extend outstretched arms fully forward with the palms up and close the eyes. The patient is instructed to hold the arms steady. The hand of a weak arm in an upper motor neuron lesion (i.e. a stroke) will pronate, flex, and tend to drift downward. Gait Many neurologic problems may be subtle until a patient attempts to walk. Walking can be difficult for the hospitalized patient due to pain, instrumentation, or extreme fatigue. Can the patient independently bear weight on both legs? Can the patient independently maintain balance while standing? Do the legs move symmetrically when walking? These questions can be answered when a patient stands and takes just a few steps at the bedside. Specific gait disorders (i.e. spastic, parkinsonian, steppage, and elaboration) for inpatents able to ambulate will be demonstrated. Reflexes The limbs to be tested should be relaxed and in a comparable position bilaterally if interpretation of the results is to be valid. Always check for symmetry. The most common cause of an unobtainable ankle reflex is improper positioning of the foot! Your reflex screen should include the biceps, triceps, finger flexors, quadriceps, and ankle reflexes. For the neuroanatomy of each reflex, consult your handout. Check for a Babinski response by first lightly stroking the lateral aspect and ball of the foot from back to front with the stick of a Q-tip. You can use a more vigorous stimulus if a response is initially absent. A normal response is plantar flexion of the toes. A Babinski response consists of dorsiflexion of the great toe. The Sensory Examination The sensory examination almost kept me out of the field of neurology Robert A. Fishman, MD, former Professor and Chairman, UCSF Neurology. The sensory examination should ideally include small fiber modalities (pain or temperature) and large fiber (light touch, vibration, position) modalities because disease may selectively involve one or the other. When neuropathy is present, both are most commonly inovled. Light touch Use a cotton swab or fingertip to check for asymmetry of touch sensation or a proximal-to-distal gradient below the knees. If the patient has a subjective complaint of diminished sensation, compare sensation on the affected patch of skin with an analogous patch of skin on the opposite limb. Define normal touch as 10 (on a scale of 0-10) and complete absence of touch as 0. Ask the patient to assign a number to the amount of touch always Page 3

16 beginning with demonstration of normal sensation as 10. Reduction of touch sensation below 7 strongly suggests decreased sensation. Pin Use a safety pin and lightly touch the patient asking if a sharp sensation can be felt. Check one spot on each hand and foot. Check from proximal-to-distal below the knees to see if perception of the sharpness declines. An increase in sensitivity from proximal to distal can be normal, but a decrease is abnormal. Romberg The patient stands with the feet together as closely as possible. First verify that balance is maintained with the eyes open, then ask the patient to close the eyes. The most common cause of a false positive test is failure to perform this first step. If the patient cannot maintain balance when the eyes are closed, then a Romberg sign is present. The Romberg sign is a sensory test of large fiber sensation, not a cerebellar test of coordination. Page 4

17 Neurologic Examination-References John Engstrom, MD April Ropper AH, Samuels, MA, Kline JP. Principles of Neurology, 10 th ed. New York: McGraw Hill, Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology, 7 th ed. Philadelphia:Wolters-Kluwer, Lin VW, Cardenas DD, Cutter NC et al. Spinal Cord Medicine. New York: Demos, Daroff RB, Mazziotta JC, Pomeroy SL, and Jankovic J. Neurology in Clinical Practice. Philadelphia:Elsevier, Stewart JD. Focal Peripheral Neuropathies, 3 rd ed. Philadelphia: Lippincott Williams and Wilkins, O Brien M. Aids to the Examination of the Peripheral Nervous System, 5 th ed. New York: Saunders-Elsevier, My favorites above are in bold Q1-selection 1 Q2-selection 1 Q3-selection 3 Q4-selection 5 Q5-selection 4 Question Answer Key Page 5