What Is Horizontal Canal BPPV?

Update: 6/15/25 – Some More Insight

Whenever I have motion-activated symptoms triggered by reading, driving, and rolling onto one or both side sides in bed, I screen myself very carefully for horizontal canal BPPV.

I refer to the jittery feeling in my eyes as “typewriter eyes.” My patients with horizontal canal BPPV seem to relate to that concept. One of my patients even wrote a song about his typewriter eyes!

——-

Horizontal canal BPPV is more common than researchers originally thought. This type of BPPV is more common in children than adults and more common after head trauma in patients of any age.

Some patients experience horizontal canal BPPV spontaneously with no known cause. In these cases, they usually feel it at night or in the morning when lying down or rolling over in bed.

Horizontal canal BPPV can also occur after Epley maneuvers, which is a BPPV treatment complication called a “canal conversion.” This can occur when patients with posterior canal BPPV attempt self-Epleys on their own without proper skills or supervision from a professional. It can also possibly occur during posterior canal BPPV treatment by a vestibular professional.

Two Types of Horizontal Canal BPPV

BPPV crystals displaced into the horizontal canal can be free-floating called “canalithiasis.”

If the crystals are stuck on the sensory apparatus within horizontal canal, that is called “cupulolithiasis.”

Patients with horizontal canal cupulolithiasis often go to the emergency room due to the severe intensity of their unrelenting vertigo symptoms. For those patients, sitting straight upright may be the only position of relief they can find until it is treated. Sometimes these patients can also get relief by lying on the affected side, but not always.

I have personally experienced horizontal canal BPPV about seven times in my life, both canalithiasis and cupulolithiasis types. In comparison to posterior and anterior canal BPPV, I have noticed more severe nausea with onset and more disequilibrium with walking.

What Tests are Used to Assess for Horizontal Canal BPPV?

Many of my patients with recurrent episodes of BPPV eventually ask about the test position for the horizontal canal.

The traditional test position for horizontal canal BPPV is the “roll test.” The roll test is performed by using one pillow under your head to do any of these movements:

1. Lying on your back then rolling your whole body to lie on your side

2. Sitting on the edge of the bed then lying down directly onto your side

3. Lying on your back with your head on a pillow then turning your head to the side 90 degrees.

You have to hold the test for at least 30 seconds, usually one minute is ideal. This is called the “roll test” and it is the gold standard in testing for horizontal canal BPPV. The vestibular clinician may perform the roll test with or without camera goggles.

The second main test used to assess for horizontal canal BPPV is called the Bow & Lean Test. The patient sits in a chair to:

1. Lean back to look up

2. Bow forward to look down

You have to hold the test for at least 30 seconds, usually at least a one-minute hold is ideal. The vestibular clinician may perform the bow & lean test with or without camera goggles. Even though this is thought to be a “secondary” test, I’ve had many cases that only showed nystagmus during this test.

The roll test is optimized to induce horizontal canal BPPV, but you can also experience dizziness or vertigo while lying on your side from posterior canal BPPV. Likewise, the bow & lean test can reveal posterior or anterior canal BPPV.

Then how can you tell which canal is involved?

That’s an excellent question!

Horizontal Canal Assessment

For assessing horizontal canal BPPV, the roll test is used as the gold standard. Therefore, the primary test position for horizontal canal BPPV is lying on your side.

Contrary to an assessment for posterior canal BPPV, the clinician has to assess both sides with a roll test before starting horizontal canal BPPV treatment.

To assess the horizontal canal, the clinician must compare any vertigo or nystagmus on either side in the roll test position. This comparison and analysis determines which side to treat, what type of BPPV is present, and indicates which maneuver may be needed.

Horizontal canal BPPV can also be assessed or confirmed by having the patient lie flat, bend over, or look up. All these positions typically elicit nystagmus in patients with horizontal canal BPPV.

Most clinicians are taught to only perform a bow & lean test “if needed,” but I have decided to test it for every patient just in case it shows something important on my infrared camera goggles. The bow & lean test is especially important if the patient’s primary complaint is symptoms while looking down.

It’s Complicated!

A confounding variable for assessing the horizontal canal with the roll test is that posterior canal BPPV can also show up in those test positions.

For that reason, interpretation of any nystagmus is the key to differentiating between the canals involved, the type of BPPV, and the side that needs treatment.

A clinician will observe any nystagmus present. Of importance are the direction and duration of any nystagmus observed with BPPV testing.

Clinical Practice for Horizontal Canal BPPV

Off the top of my head, I can count six different maneuvers I use regularly to treat horizontal canal BPPV. Even if the maneuvers are successful, this type of BPPV has a high rate of causing nausea during or after treatment.

In contrast with many vestibular providers, I rarely do maneuvers at an accelerated speed. Almost all of my patients remark that the maneuvers I do are much more gentle than their past vestibular providers.

I think it’s because I’ve had vertigo myself, so I know how awful it can be!

Horizontal canal cupulolithiasis is the most common cause of vertigo I see that causes vomiting at my office.

For that reason, most patients with horizontal canal cupulolithiasis need to premedicate with ondansetron prior to the treatment. After the treatment is completed, many of them bring more medications to take right away such as meclizine and/or alprazolam as soon as we finish.

For example, I just had two patients today with horizontal canal cupulolithiasis. One patient took meclizine after we finished and drove himself home after resting for about 20 minutes. The other patient took ondansetron beforehand plus took meclizine and alprazolam after we finished. Her symptoms were so severe that she had to get a ride both ways.

Should I Try to Treat BPPV by Myself?

My recommendation for anyone with vertigo is to consult a professional to assess for any new BPPV recurrence or other causes of vertigo.

BPPV testing is complicated! That is why I recommend finding an expert who specializes in BPPV assessment and treatment.

You can use this article to search for a local provider.

I generally do not recommend treating yourself with BPPV treatment maneuvers you learned in the past. Research shows that past episodes of BPPV have limited predictive value for the ear or canal that might be involved in a future episode of BPPV.

Also, complications can arise during BPPV treatment that require a professional to assess. The treatment plan may need to change on the spot!

For seven examples of BPPV complications, click here.

Clinical Pearl

For patients who have lingering dizziness after Epley maneuvers, I suggest finding a vestibular clinician to test you for horizontal canal BPPV.

If that does not help, you may want to get checked for upper cervical dizziness, which can also occur as a side effect of Epley maneuvers.

Learn More

Click here to discover five reasons why the Epley maneuver does not help.

For eight common pitfalls of attempting to treat yourself for BPPV, click here.