Cranial Nerve Exam Flashcards
What is anosmia?
loss of the sense of smell
What are some causes of anosmia?
Parkinson’s, lesions in CN I, tumor at the base of the skull
What three things do you want to check for regarding sight?
can someone see distance, up close, and color
Ask the patient if they wear glasses and what for
How far should a Snellen chart be held from the patient?
20 ft. Do it for each eye in glass, and for corrected and uncorrected setting
How do you test near vision?
Jaegar plates
How do you test color vision?
Ishihara plates. Test plate is usually 12. sets are typically 13 or 17 plates
What is an optic eye test?
This is referred to as visual field testing by confrontation. You are comparing your visual field (which you assume is normal) with the patient’s. You each maintain focus on the other’s pupil, cover or close opposite eyes (e.g., patient’s right and your left) and compare when you each first see your finger move into the field of vision. This should be simultaneously. Be sure you keep your fingers in a plane half way between you and the patient
Are central visual field tests typically done for all patients?
No. Central visual field testing is usually done only in specialty practice (e.g., ophthalmology and neurology). In such cases, this may be done more precisely using a large device called a Goldmann perimeter.
Where are the nuclei of CN 3 and 4 located?
in the midbrain
Where is the nuclei of CN 5 located?
runs through the brainstem
Where are the nuclei of CN 6 and 7 located?
pans
Where are the other nuclei of CNs located?
the medulla (bulbar nuclei)
What is a cover test?
ask patient to focus on a near object
cover, then uncover one eye
observe if there is adjustment in alignment or readjustment of the eyes in response
normally done in children to diagnose strabismus (squint)
How is a pursuit eye movement test performed?
ask patient to follow the motion of an object while keeping their head still. First move to the left and look for nystagmus.
Ask the patient if they have diplopia
What is diplopia?
double vision
If the patient says he/she does not have diplopia during a left movement pursuit test, what does that tell you?
the left lateral rectus (innervated by CN VI, nucleus in the pans) is intact, as is the right medial rectus (CN III, nucleus in the midbrain)
continue the test for the right side, and if everything is normal you know that the the right lateral rectus (innervated by CN VI, nucleus in the pans) is intact, as is the left medial rectus (CN III, nucleus in the midbrain)