The patient is asked to look at your nose and when you uncover the right eye, notice that the eye is skewed and moves medially and diagonally upward, to look at your nose. Here's a video of the test of skew being performed on a patient.
is about 98% specific for a central cause of vertigo, so abnormal vertical correction is bad.
Do this for both eyes, looking at each eye. Look to see if there's any vertical movement or diagonal or slanted movement, as the eye is uncovered. your nose and cover one eye and then move your hand quickly to cover the other eye. The last component of the HINTS exam, is the test of skew. Most patients with a central cause of their vertigo do not demonstrate this finding, but if it's seen, it's highly specific for a central cause and a stroke. When the patient is asked to look to her right, the fast phase is towards the right and when the patient looks to the left, the fast phase changes direction towards the left. This is a pathologic bidirectional nystagmus. This patient has a unidirectional nystagmus and was diagnosed with vestibular neuritis, as the other components of the HINTS exam were also reassuring. Notice that the fast phase of the beating is always towards the left, no matter which direction the patient is asked to look. unidirectional nystagmus, which is reassuring. Presence of this type of nystagmus points to a central cause of vertigo, meaning stroke. Look for bidirectional or vertical nystagmus. When evaluating nystagmus, the fast component of the beating, is what determines the direction. The key here is not to have your patient focus on your finger because that can suppress the nystagmus. slightly to the right and look for direction-changing nystagmus. Ask your patient to look slightly to the left and then The second component of the HINTS exam, is evaluation for nystagmus.
Also, be very careful in elderly patients, who may have severe neck arthritis because the rapid head movement could lead to vertebral or arterial injury. A very important thing to remember is that the brain can learn to compensate for this corrective saccade and so it's important to perform the test randomly to avoid a false negative result. Here is one more example of a patient with corrective saccade and, therefore, a peripheral cause of vertigo. Notice that when the patient's head is moved quickly towards his left side, you see a corrective saccade but you don't see it in the other direction. Here's an example of a patient with vestibular neuritis and, therefore, the head impulse test showing a corrective saccade. Again, please note you should not apply this test to patients who have episodic vertigo or are no longer symptomatic However, if the reflex is not working and you observe a corrective saccade, then you are reassured that the cause of the vertigo is likely peripheral, but you still must continue with the two other components of the HINTS exam, to be 100% sure. is not affected and your exam is very concerning for a central cause of vertigo. If there is a normal vestibulo-ocular reflex, then the eighth cranial nerve This is called the corrective saccade and will only happen in one direction, so be sure to test both sides. If the vestibulo-ocular reflex is affected by a virus, the eyes will keep moving in the direction of movement and then quickly jerk back to looking at your eyes. This method is preferred because it will avoid potentially over-rotating the neck and causing spine or artery damage. To perform this test, ask the patient to stare at your nose, hold their head in your hands and move ahead 30 degrees to the side and rapidly bring it to the midline, You're trying to see if the eighth cranial nerve, the vestibulocochlear nerve, has been affected by a virus. This test is only performed on a patient who has active and persistent vertigo and nystagmus. The caveman would surely not survive if he couldn't focus on the direction he was going, while bouncing up and down, running through the jungle. As you can imagine, this reflex came in very handy for a caveman running away from a saber-toothed tiger. Your eyes will be able to read the words without any trouble. Shake your head quickly from left to right, up and down, and look at the center of the screen. This reflex allows your eyes to stay focused on an object, despite head movement. peripheral or central in patients with ongoing, constant vertigo and nystagmus. This test uses the vestibulo-ocular reflex to predict whether the vertigo is First, the head impulse test second, the test of skew and third, the nystagmus assessment. The HINTS exam helps to differentiate central and potentially life-threatening causes of vertigo from vestibular neuritis, which is benign.
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