Seated Supine Positioning Test

sit to supine (1)

Fundamentals

The Seated Supine Positioning Test (SSPT), also known as “Lying Down Nystagmus,” is used to assist in identifying the affected side of involvement in cases of horizontal canal benign paroxysmal positional vertigo (HC-BPPV).  The test involves transitioning the patient quickly (if possible) from a seated to a supine position with the head flexed approximately 30°, bringing the horizontal semicircular canals into a more vertical orientation (perpendicular to the floor). While the sensitivity of the SSPT is controversial and thus far less studied than the Supine Roll Test (also known as the Pagnini-McClure), the SSPT can provide additional valuable diagnostic information within the context of a full vestibular exam.

History

The SSPT was first described in the early 2000s, as researcher Dr. Asprella-Libonati sought to clarify the cause of nystagmus sometimes seen in supine (BPPV vs. alternative diagnoses causing the nystagmus).

In Koo et al.’s 2006 study of 54 patients, 59.3% diagnosed with horizontal canal BPPV exhibited nystagmus when in supine. This means that even if clinicians don’t see horizontal nystagmus in the supine position, a patient can still have a horizontal canal BPPV case, and we may need other tests to further clarify the affected side.

Around the same time, Han et al. (2006) noted that of 152 patients with horizontal canal BPPV, 38.2% demonstrated nystagmus when lying supine. However, it is possible that this number was lower in this study due to the fact that the researchers did not deliberately move the patients into supine quickly, but rather simply brought them into supine in a standard way.

Instructions

The purpose of the SSPT is to elicit nystagmus which may aid in the identification of the affected side in horizontal canal benign paroxysmal positional vertigo (HC-BPPV).

  1. Start with the patient seated upright on the exam table, legs extended (long sitting), head at midline.
  2. Ask the patient to keep eyes open, then assist the patient (quickly if possible) into a supine position while maintaining 30 deg of cervical flexion.
  3. Observe for nystagmus and ask about symptoms.
  4. Hold for 30 seconds, then return the patient to sitting if no further testing is needed.

Test Interpretation

The Seated Supine Positioning Test is interpreted based on the direction of nystagmus observed after the patient is laid down in supine with their neck flexed 30°.

If horizontal nystagmus is present in supine, the nystagmus will most likely beat toward the affected ear in the apogeotropic type (likely horizontal cupulolithiasis, horizontal canal jam, or short arm horizontal canalithiasis) and away from the affected ear in geotropic type (likely long arm horizontal canalithiasis).

While not described by a separate test name, some researchers have noted nystagmus while bringing the patient from supine to seated, particularly with the head bowed forward into at least 30 degrees of flexion (additional flexion can be gained with a partial forward trunk lean while still in long sitting).

If horizontal nystagmus is present in sitting (particularly with head/trunk bowing forward), the nystagmus will most likely beat toward the affected ear in the geotropic type (likely long arm horizontal canalithiasis) and away from the affected ear in apogeotropic type (likely horizontal cupulolithiasis, horizontal canal jam, or short arm horizontal canalithiasis).

Related Pathology

  • Horizontal Canalithiasis
  • Horizontal Cupulolithiasis

The SSPT Test is best done with infrared video goggles due the risk of otherwise missing about 2/3 of abnormal eye movements when testing in room light or with traditional thickened lens Frenzels. See what you’re missing – access a free virtual demo (on-demand or live with a clinician) today.

 

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