The High Yield Neurologic Examination Mental status-brief review - - PDF document

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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

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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
• f the visual field affected

3 Q2: What causes sustained dilation

• f 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

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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

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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 thumbs-

• ne 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)

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CN V, VIII, X, XI

• CN V-test three divisions of face with pin
• r 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

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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
• r attention

8 Weak Patient: History and Examination

NEUROLOGIC NON-NEUROLOGIC

UPPER MOTOR NEURON LOWER MOTOR NEURON BREAKAWAY FATIGUE POOR EFFORT PAIN

Q4: Which statement is FALSE re/ clinical utility of distinguishing UMN from LMN weakness on exam? 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

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 - 

Weak Patient: Central Weakness II

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

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 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 Absent

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

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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

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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

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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.

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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

• f 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).

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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

• ne 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

• f 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

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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.

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John Engstrom, MD April 2017

Neurologic Examination-References

• 1. Ropper AH, Samuels, MA, Kline JP. Principles of Neurology, 10th ed. New York:

McGraw Hill, 2014.

• 2. Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology, 7th ed.

Philadelphia:Wolters-Kluwer, 2017.

• 3. Lin VW, Cardenas DD, Cutter NC et al. Spinal Cord Medicine. New York: Demos, 2003.
• 4. Daroff RB, Mazziotta JC, Pomeroy SL, and Jankovic J. Neurology in Clinical
• Practice. Philadelphia:Elsevier, 2015.
• 5. Stewart JD. Focal Peripheral Neuropathies, 3rd ed. Philadelphia: Lippincott Williams and

Wilkins, 2013.

• 6. O’Brien M. Aids to the Examination of the Peripheral Nervous System, 5th ed. New

York: Saunders-Elsevier, 2010. My favorites above are in bold

Question Answer Key

Q1-selection 1 Q2-selection 1 Q3-selection 3 Q4-selection 5 Q5-selection 4