Neuro Exam Lecture Flashcards
Components of the Neurologic Exam
1) MENTAL STATUS:
- Level of alertness, appropriateness of responses, orientation to time and place
2) CRANIAL NERVE:
- E.g. pupillary light reflex, facial sensation and strength, gag reflex
3) MOTOR SYSTEM:
- Muscle strength testing, gait and coordination testing
4) SENSORY:
- Pinprick, light touch, vibratory, proprioception
5) REFLEXES:
- Deep tendon reflexes and plantar response (Babinski)
History
- Chief Complaint
- History of Chief Complaint:
a) Family, Developmental, Medical - ONSET and PROGRESSION of SIGN and SYMPTOMS:
A) ABRUPT OR SUDDEN ONSET/ ACUTE ONSET. A sudden onset of symptoms usually followed by gradual improvement is somewhat typical of cerebral hemorrhages, vascular diseases, and infections and head trauma.
B) PROGRESSIVE. Certain neoplasms and degenerative diseases of the nervous system may cause a more linear progression of neurological symptoms and deficits. In some degenerative diseases the patient’s symptoms such as minor memory disturbances, increased irritability or mild personality changes may be unremarkable initially, but quite significant and apparent many years later.
C) INTERMITTENT, RELAPSING EPISODES. Demyelinating diseases such as Multiple Sclerosis and certain vascular diseases often display a gradually deteriorating cycle of remission and symptoms.
Components of Mental Status Exam
- LEVEL OF ALERTNESS: Consciousness of patient (awake, alert, drowsy, lethargic, comatose etc)
- APPROPRIATENESS OF RESPONSE: insight to question and situation and ability to respond concretely to this versus tangential or confused demeanor.
- ORIENTATION: knows date, place, self, situation
Basic Localization of the Cranial Nerves
1) TELENCEPHALON: refers to the cerebral hemispheres (CN I level)
2) DIENCEPHALON: (Rostral part of the brainstem/paired structures on either side of the 3rd ventricle) CN II level
3) MESENCEPHALON: MIDBRAIN (CN III-IV level)
4) METENCEPHALON: PONS (CN V level)
5) MYELENCEPHALON: MEDULLA (CN IX-XII level)
** PONTOMEDULLAR JUNCTION:
(CN VI - VIII)
Examination of the Cranial Nerves
– Optic
– Trigeminal
– Facial
– Cardinal Signs of Gaze (Abducens, Trochlear, Oculomotor)
– Glossopharyngeal
– Vagus
– Hypoglossal
Summary of Cranial Nerves
1) OLFACTORY: Smell
2) OPTIC: Visual acuity, Visual Fields, Optic Fundi, AFFERENT Limb of the PUPILLARY LIGHT REFLEX
3) OCULOMOTOR: Extraocular Movements (Supplies the Medial Rectus, Inferior REctus, and Inferior Oblique Muscles), Supplies the Levator Palpable Muscle (Which lifts the Eyelid) and is the Efferent Limb of the Pupillary Light Reflex
4) TROCHLEAR: Supplies the Superior Oblique Muscle, Extraocular Movements
5) TRIGEMINAL: Facial Sensations (3 Divisions)
i) OPHTHALMIC (V1): Forehead
ii) MAXILLARY (V2): Cheek
iii) MANDIBULAR (V3): Jaw
- Jaw Movements (Motor Portion of Nerve)!!!!!!!
- Corneal Reflex: AFFERENT (Sensor Limb)
6) ABDUCENS: Supplies Lateral Rectus Muscle, Extraocular Movements
7) FACIAL: Facial Movements of Expression, Taste of Anterior 2/3 of Tongue
8) VESTIBULOCOCHLEAR: Hearing (Cochlear Division), Balance by the Vestibular Division
9) GLOSSOPHARYNGEAL: Swallowing, Rise of Palate and GAG Reflex (Along with CN X)
10) VAGUS: Gag Reflex (With CN IX) and Swallowing, Phonation
11) SPINAL ACCESSORY: Innervates the Upper Trapezius and Sternocleidomastoid Muscle (SCM), Shoulder Shrug and Neck Movements (Head Turning to Opposite Side)
12) HYPOGLOSSAL: Innervates the INTRINSIC TONGUE Muscles, Evaluate tongue Symmetry and Position
Olfactory Nerve
- Use non-irritating, familiar odors, i.e., cinnamon, coffee, vanilla
- Have patient compress one nostril and sniff through the other Patient should be able to discern odors on each side
- Loss of smell can occur with Smoking, Chronic Sinus disease, Head Trauma, Aging, Parkinson’s disease and use of cocaine.
- Loss of sense of smell indicates an IPSILATERAL LESION.
Optic Nerve
- Test Visual Acuity with a Snellen eye chart- patient stands 20 feet from chart
- Inspect the FUNDI – locate Optic Disc, check for papilledema, pallor or atrophy. Inspect the retina for hemorrhages or exudates, spontaneous venous pulsations, hypertensive vascular changes, trace the arteries and veins peripherally
- Visual FIELD TEST – patient in front of examiner, one eye covered during testing, patient to count fingers held up testing all 4 quadrants, also test blink response to lateral threat
- Color Vision (usually only done by ophthalmology)
- Pupillary Light Reflex (tests CN II & III)
- Lesions to the Optic Nerve ANTERIOR to the Chiasm cause IPSILATERAL BLINDNESS
Pupillary Light Reflex
• Tests CN II and III (AFFERENT/ Sensory component CNII, EFFERENT/ Motor component CNIII).
- Shine light into the eye and watch for PUPILLARY Constriction
• DIRECT Light Reflex – STIMULATED pupil Constricts
• CONSENSUAL (indirect) Reflex – OPPOSITE Pupil Constricts
(along with the stimulated pupil)
• SUMMARY- light stimulus is given to one eye, CN II sends stimulus to the brainstem (midbrain) where it is transferred to CNIII to produce constriction in both eyes
Oculomotor Nerve
OPTICOKINETIC NYSTAGMUS:
• Normal Physiologic response to FIXATING on a MOVING Target.
• ASYMMETRIC LOSS can be due to a FRONTAL or PARIETAL LESION on the side to which the tape is moving
CN III:
• Check the eyelid for PTOSIS (drooping of the eyelid that does not clear the upper margin of the pupil)
- Check Pupil SHAPE and SYMMETRY
- Reactivity to light (pupillary LIGHT REFLEX) and near reaction
- NEAR REACTION – reaction when gaze shifts from a FAR to a NEAR object – as the object approaches the Pupils CONSTRICT with associated convergence of the eyes (eyes move medially/nasally) and ACCOMMODATION (thickening of the lens by the ciliary muscles). Helps to bring the object into clear focus.
Cardinal Signs of Gaze
- CN III: Adduction, Downward Gaze (aided by CN IV), ELEVATION of eye.
- CN IV: Inward Rotation, DOWNWARD and LATERAL Movement.
- CN VI: LATERAL Movement of the eye
Findings with CN III Lesions
FINDINGS WITH CNIII LESIONS:
a) PTOSIS (drooping of eyelid past the upper margin of the pupil) due to levator palpebral weakness
b) PUPILLARY DILATION OR ASYMMETRY- due to disruption of the PARASYMPATHETIC fibers. If severe will see a fixed/dilated pupil.
c) POSITION CHANGE OF THE EYE -“DOWN AND OUT” pupil due to weakness of the extraocular muscles (MR, IO, IR, SR).
COMPRESSIVE BRAINSTEM LESIONS:
• HEMATOMAS: Subdural Hematomas, epidural hematomas
- LARGE STROKES, ABSCESSES, TUMORS
- SPACE OCCUPYING OR EXPANDING MASSES may cause the brain to herniate through various dural openings in the cranium
- INITIALLY, the Pupilloconstrictor fibers of III nerve causing DILATION and FIXATION of the PUPIL.
- The SECOND EFFECT is on the Somatic Efferent Fibers that supply the extraocular muscles which then cause EXTERNAL STRABISMUS (down and out position of the eye)
• ANEURYSM (areas of weakened arterial blood vessel walls causing dilation of the arterial segment) of the Internal Carotid Artery or the Posterior Communicating Artery generally within the CAVERNOUS SINUS causes SIMILAR FINDINGS as the BRAINSTEM (Uncal) HERNIATION.
- Key difference is LEVEL of CONSCIOUSNESS is PRESERVED WITH ANEURYSMS (prior to rupture) and is abnormal in herniation syndromes.
• DIABETES MELLITUS can cause Extraocular Muscle WEAKNESS but often SPARES the PUPILLOCONSTRICTOR Fibers
Cranial Nerve IV Lesions
***** Due to its long course around the brainstem, CN IV is VULNERABLE to HEAD TRAUMA.
LESIONS of CN IV result in:
• EXTORSION of the eye (eye position Drifts LATERALLY) and - WEAKNESS of DOWNWARD Gaze (due to the weakness of the Superior Oblique muscle)
- VERTICAL DIPLOPIA (Seeing Double)- Increases when looking down.
- HEAD TILTING - To OPPOSITE SIDE of the Lesion. This can be misdiagnosed as idiopathic torticollis.
Cranial Nerve VI Lesions
• MOST COMMON ISOLATED CN palsy due to its LONG PERIPHERAL course. Seen often in patients with SUBARACHNOID HEMORRHAGE, late SYPHILIS and TRAUMA.!!!!!!!!!!!!!!!!!!!!!!
CN VI lesions result in:
• CONVERGENT (Medial) STRABISMUS (Esotropia)- inability to abduct the eye. Due to Lateral Rectus muscle weakness.
• HORIZONTAL DIPLOPIA (Double Vision)- maximal separation of the images when looking toward the paretic lateral rectus muscle.
Trigeminal Nerve CN V
- Check FACIAL SENSATION in forehead (V1), cheek (V2) and chin (V3) to pinprick, light touch, and hot/cold
- Check MOTOR FUNCTION – check Lateral JAW MOVEMENTS (Lateral ptyergoids), JAW CLENCHING (Temporal and Masseter muscles)
- Check CORNEAL REFLEX – (tests CN V & VII) – lightly touch cotton wisp to cornea which should result in contraction of the orbicularis oculi muscle (blink)
Trigeminal Lesions
- DECREASED SENSATION of FACE and MUCOUS membranes
- LOSS of CORNEAL REFLEX
- WEAKNESS of the Muscles of MASTICATION
- JAW DEVIATION TOWARD the WEAK Side (due to unopposed action of the opposite lateral pterygoid muscle
Corneal (Blink) Reflex
PROTECTIVE Reflex involving CN V (Afferent) Limb and CN VII (Efferent limb)
TESTING:
• Ask patient to LOOK UP and AWAY FROM Examiner
• Take a Cotton Wisp and APPROACH from OPPOSITE Side of the patient’s line of vision and touch the cornea. The patient should BLINK IN RESPONSE. Loss of blink reflex indicates a lesion of CN V or CN VII. Can be seen in ACOUSTIC NEUROMAS, BRAINSTEM (pontine) LESIONS etc
Facial Nerve CN VII
- MOTOR – FACIAL Expressions, eye and mouth closure.
- SENSORY – taste for salty, sweet and bitter substances to ANTERIOR 2/3 of tongue
- PARASYMPATHETIC– SECRETION of SALIVA and TEARS
- General SENSATION of EXTERNAL EAR
Lesions of CN VII
- PARALYSIS OF MUSCLES OF FACIAL EXPRESSION (upper and lower portions of the face) seen as a widened palpebral fissure and increased nasolabial fold. ( BELL’S PALSY).
- LOSS of Corneal Reflex – (EFFERENT Limb)
- HYPERACUSIS – (increased Sensitivity to Sound)
- CROCODILE TEARS SYNDROME – due to abberant regeneration of nerve after trauma – Patient SHEDS TEARS WHEN CHEWING
Clinical Notes for CN VII
- BELL’S PALSY (peripheral facial paralysis) can be caused by trauma or infection, but in most cases is Idiopathic (unknown etiology).
- BILATERAL FACIAL PALSY can occur in Miller-Fisher variant of Guillain-Barre Syndrome.
• SUPRANUCLEAR (CENTRAL) FACIAL PALSY spares the upper face and usually is associated with hemiplegia (weakness to one side of the body). This is important in DETERMINING if the WEAKNESS is CENTRAL or
PERIPHERAL in Nature.
Vestibulocochlear Nerve CN VIII
HEARING – (COCHLEAR division):
A) Ceck for loss of hearing by WHISPER Test or FINGER RUB in each ear, if present do Weber and Rinne tests
B) WEBER TEST: Strike a tuning fork and place on the MIDDLE of the Forehead, Diminished TONE in the affected ear indicates SENSORINEURAL LOSS. A LOUDER TONE in the affected ear indicates DEAFNESS (disease in the ossicles in the middle ear).
C) RINNE TEST: CONFIRMS the presence of CONDUCTION Deafness in the affected ear. Strike a tuning fork and place it on the MASTOID Process. When the tone is gone, place it OVER the External Auditory Meatus, the patient should hear the tone again, if not, conduction deafness is present.
BALANCE – (VESTIBULAR division)
Lesions of Cranial Nerve VIII
VESTIBULAR DIVISION LESIONS result in:
• DYSEQUILIBRIUM (imbalance)
• NYSTAGMUS – rapid involuntary and rhythmic movement (or oscillation) of the eye.
COCHLEAR DIVISIONS LESIONS:
• DESTRUCTIVE lesions lead to sensorineural hearing loss. Ex.
acoustic neuroma
• IRRITATIVE lesions can cause Tinnitus (ringing in ears). Ex.
Medications (aspirin, some antibiotics etc)
Weber Test
Performed on patients with UNILATERAL HEARING LOSS
This is a test for LATERALIZATION of SOUND:
1) Place a tuning fork (256Hz or 512Hz) on the VERTEX of the skull or on the forehead after striking the fork between thumb and index finger
2) Ask the patient WHERE the sound can be heard (One or BOTH ears)
3) *In NORMAL individuals the sound is heard EQUALLY in BOTH ears.
RESULTS:
• In CONDUCTIVE Hearing loss seen with occlusion of the ear (cerumen impaction, perforation of the eardrum, otosclerosis) the sound LATERALIZES to the IMPAIRED Ear.
• in SENSORINEURAL hearing loss (Nerve Damage) the sound lateralizes to the GOOD (Unaffected ear)
