Cranial Nerve Testing Flashcards
test sense of smell on each side( close off nostril) use common nonirrittaing
possible abnormal findings:
anosmia inability to detect smells, seen with frontal lobe lesions
function: olfaction smell
CN I Olfactory
what nerve is vision
Test: visual acuity test- uses snellen eye chart; test each eye separately covering other eye test at 20ft
visual field test: test temporal and vertical peripheral vision by confrontation
abnormal findings: blindness, myopia (imparied far vision)
persbyopia impaired near vision
fields defects are homonymous hemianopsia
CN II Vision
Function:
pupillary reflex
accommodation
convergence
test:
shine light in eye and eye constricts
eye accommodates to light
pupils move medially when viewing objects at close range
abnormal finding :
absence of pupillary constrictions
lateral strabisums (eexotropia)
anisocoria ( unequal pupils)
horneys syndrome, CNIII paralysis
CN III Oculomotor
Function:
Extraocular movements CN III: turns eye up, down, in; elevates eyelid CN IV: turns eye down when adducted CN VI: turns eye out
test:
-Test saccadic movements: ask patient to look up, down, medial, and lateral
-Test pursuit eye movements: ask patient to follow moving finger
-Test one eye at a time; other eye occluded
Possible abnormal findings?
Lateral strabismus: eyeball turns lateral; can cause diplopia or nystagmus
Impaired eye movements Ptosis
Medial strabismus: eyeball turns inward; can cause diplopia or nystagmus
III, IV, VI Oculomotor, trochlear, and abducens
Function:
-Face
-cornea
-motor function: muscles of mastication
Test:
pain, light touch sensations: forehead, cheeks, inner oral cavity (occlude vision).
test corneal reflex: touch lightly with wisp of cotton.
Palpate temporal and masseter muscles. Observe spontaneous movements.
Have patient open mouth, move jaw side to side. Bite down on tongue depressor, hold against resistance
Possible abnormal findings:
Weakness, wasting of muscles
When opened, deviation of jaw to ipsilateral side Asymmetry of jaw movement
Asymmetry of jaw strength
V Trigeminal: ophthalmic, maxillary, mandibular divisions
Motor function: facial muscles
Sensory function: taste to anterior two thirds of tongue
Test strength and symmetry of facial muscles: have patient elevate eyebrows and forehead; wrinkle forehead, smile, frown, and pucker lips, close eyes tightly, puff out both cheeks.
pply sweet, salty, and sour solutions to outer and lateral portions of anterior tongue using a
cotton swab (occlude vision).
Paralysis:
Inability to close eye, drooping corner of mouth, difficulty with speech articulation
Unilateral LMN: Bell’s palsy (PNI) Bilateral LMN: Guillain-Barré Unilateral UMN: stroke
Incorrectly identifies solution Decreased taste
VII Facial
Vestibular function
Test balance and protective functions: vestibulospinal function (VSR)
Test eye–head coordination: vestibular ocular reflex (VOR)
Vertigo, decreased balance, decreased protective responses (disequilibrium)
Gaze instability with head rotations, nystagmus (constant, involuntary cyclical movement of the eyeball)
Cochlear function
Test auditory acuity
Weber test for lateralization: place vibrating tuning fork on top of head, mid-position; check if sound heard in one ear, or equally in both
Rinne test: Compares air and bone conduction, place vibrating tuning fork on mastoid bone, then close to ear canal; sound heard longer through air than bone
abnormal
Deafness, impaired hearing, tinnitus
Unilateral conductive loss: sound lateralized to impaired ear Sensorineural loss: sound heard in good ear
Conductive loss: sound heard through bone is equal to or longer than air
Sensorineural loss: sound heard longer through air
VIII Vestibulocochlear
Sensory function: posterior one-third of tongue, pharynx, middle ear
Apply sweet, salty, and sour solutions to posterior tongue
Incorrectly identifies solution, loss of taste on posterior tongue
X Glossopharyngeal
(1) Phonation, Listen to voice quality, Dysphonia: hoarse voice; denotes vocal cord weakness; nasal quality denotes palatal weakness
(2) Swallowing, Examine for difficulty in swallowing: glass of water, different consistencies of food, Dysphagia: difficulty swallowing; loss of swallowing reflexes
(3) Palatal, pharynx control, Have patient say “ah”; observe motion of soft palate (elevates) and position of uvula (remains midline).,
Dysarthria: difficulty articulating words clearly, slurs words
Palate fails to elevate, (lesion of CN X); asymmetrical elevation with unilateral paralysis
(4) Gag reflex, Stimulate back of throat lightly on each side., Loss of gag reflex: lesion of CN IX; possibly CN X
IX, X Glossopharyngeal and Vagus (tested simultaneously)
Motor function: Spinal nerve root Trapezius muscle
examine bulk, strength.
In sitting, ask patient to elevate the shoulder upward against resistance applied in the direction of depression.
LMN: atrophy, fasciculations, weakness
Weakness, inability to approximate the acromion and the occiput
sternocleidomastoid
-In supine, ask patient to flex head anterolaterally and rotate head to opposite side; resistance is applied in an obliquely posterior direction.
-Weakness, inability to flex head laterally and forward, rotate head to contralateral side
Cranial nerve root:
Examine laryngeal elevation by placing index and middle fingers over patient’s Adam’s apple (laryngeal muscles); ask patient to swallow
Dysphagia due to decreased laryngeal elevation
XI Accessory
Motor function: tongue movements
Listen to patient’s articulation. Examine resting position of tongue.
Ask patient to protrude tongue, move tongue side to side
-dysarthria (seen with lesions of CN X or CN XII, also V, VII)
-Atrophy or fasciculations of tongue (LMN, ALS)
-Impaired movements with deviation of tongue to weak side
-UMN lesion: tongue deviates away from side of cortical lesion
-Check for tongue tremors or involuntary tongue movements
