Cupulolithiasis, Canalithiasis and Vestibulithiasis

Timothy C. Hain, MD • Page last modified: March 9, 2021

BPPV (benign paroxysmal positional vertigo) is presently generally accepted to be due to dislodged particles from the utricle.The utricle is one of the two otolith organs. There are several possible sites within the inner ear where particles can accumulate. The purpose of this page is to explain these terms and give some general orienting information. More detail can be found in Squires et al, 2004, and in Hain et al, 2005.

Canalithiasis

This is thought to be the cause of most BPPV. Debris is loose within the fluid filled pathways of the inner ear. When the head is repositioned with respect to gravity, the particles move to the new lowest portion of the inner ear.

This causes a "nystagmus", or jumping of the eyes with the following features: Here we are discussing debris in the posterior canal.

• A latency between 5-30 seconds. Particles move out of the ampulla (dilated part of inner ear at bottom of picture above). While they are moving through the ampulla, there is no nystagmus. After the particles finish moving through the ampulla and into the duct, the nystagmus begins. Other explanations for the latency are offered here.
• A "burst" of nystagmus, typically lasting 10 seconds.
• The direction of the burst is about the axis of the canal containing the debris (i.e. upbeating and torsional for the posterior canal).
• A reversal of nystagmus on sitting
• Fatigueability (i.e. less nystagmus when the maneuver is repeated, within a short period of time). This is thought to be due to margination.

In theory, there might be canalithiasis involving any of the semicircular canals (or several at once). Each canal produces a different vector of nystagmus --

• Posterior canal -- upbeating and twisting towards the ground (called "geotropic" or "geotrophic").
• Anterior canal -- downbeating, with variable twisting (torsion)
• Lateral canal - -side-beating, either always downward (geotropic), or always upward (ageotropic).

Cupulolithiasis

This is thought to be unusual (less than 5%). In our "dizzy" practice database of about 25,000 patients, as of 2019 only 8 are diagnosed as cupulolithiasis. So it is probably exceedingly rare.

In cupulolithiasis, debris is attached to the cupula of one of the canals. When the cupula is horizontal, there is no nystagmus or dizziness. When the cupula is non-horizontal (most of the time), there is a constant input from the inner ear and dizziness.

The typical nystagmus of cupulolithiasis is thought to have the following features:

• No latency
• Permanent nystagmus, that persists as long as the head is positioned so that the canal being stimulated is not horizontal.
  • Posterior canal -- upbeating (excitatory) in dix-hallpike position, should be downbeating with head forward. Torsion should reverse-- with the fast phase towards the bad ear supine, and fast phase towards the good ear prone.
  • Anterior canal -- upbeating upright, downbeating upside down. Both 90 deg forward and backward are "neutral" positions for the anterior canal cupula.
  • Lateral canal -- small nystagmus that beats to the opposite side that is down ("ageotrophic").
• Weak nystagmus (less than 5 deg/sec), directed about the axis of the canal being stimulated.
• Reversibility when the head is positioned such that canal is flipped 180 degrees. This is called "direction changing", and is most commonly observed in persons in whom lateral canal BPPV is diagnosed. The author has occasionally observed this in presumed PC cupulolithiasis as well.

Cupulolithiasis was found on pathology of autopsy specimens made by Schuknecht and Ruby in three patients who had BPPV during their lives (Schuknecht 1969; Schuknecht et al. 1973). Moriarty and colleagues found similar deposits in 28% of 566 temporal bones (Moriarty et al. 1992).

If cupulolithiasis is suspected, it seems logical to treat with either the Epley with vibration, or alternatively, use the Semont maneuver, perhaps also with vibration. We are not aware of any studies using the Foster maneuver with vibration, but one would think this might be equally productive (or unproductive). There are no studies of cupulolithiasis to indicate which strategy is the most effective. Experimental models in frogs suggest that vibration is more effective than using gravity (Otsuka et al, 2013). In other words, the Epley, Gufoni or Semont without vibration are unlikely to be as effective as any procedure including vibration.

One would expect that cupulolithiais (which is very rare), might be more common in persons who have gone untreated for long periods of time, giving the debris more time to adhere to the cupula.

Vestibulolithiasis

The prevalence of this condition is unknown. The conjecture is that debris is on the "vestibule" side of the labyrinth, rather than within or on the canal side. Debris might be either attached or loose. If attached, the pattern is identical to cupulolithiasis.

Pathologic studies of BPPV have found roughly equal amounts of fixed debris on either side of the cupula (Moriarty et al. 1992), suggesting that loose debris might also be found on either side. If loose, then there should be a mixture of cupulolithiasis and canalithisis (see below). Very little is written on this condition, although Buki published a paper suggesting that there was a prominent trunkal movement (2014).

Loose variant pattern vestibulolithiasis features

For head position where gravity is directed away from vestibule (and towards cupula). Only the posterior canal is likely to have much of an incidence of this, as for the other canals, the canals are normally higher than the vestibule.

• No latency
• Permanent nystagmus, that persists as long as the head is positioned so that the canal being stimulated is not horizontal AND direction of gravity is towards cupula rather than towards vestibule.
  • PC -- UBN
  • AC -- no possibility of loose variant because debris would fall off of cupula.
  • LC -- unlikely to have permanent nystagmus for same reason.
• Weak nystagmus (about 5 deg/sec), directed about the axis of the canal being stimulated.
• For the lateral canal, the nystagmus is "ageotrophic", meaning that it beats upward with respect to the head position.
• Asymmetrical nystagmus
  • When head is positioned so that debris is pulled off of the cupula, nystagmus dies away very quickly because the debris does not have hydrodynamic advantage.

References:

• Buki, B. (2014). "Benign paroxysmal positional vertigo--toward new definitions." Otol Neurotol 35(2): 323-328.
• Hain, T. C., T. M. Squires and H. A. Stone (2005). "Clinical implications of a mathematical model of benign paroxysmal positional vertigo." Ann N Y Acad Sci1039: 384-94.
• Moriarty, B., et al. (1992). "The incidence and distribution of cupular deposits in the labyrinth." Laryngoscope 102(1): 56-9.
• Otsuka K, Suzuki M, Negishi M, Shimizu S, Inagaki T, Konomi U, Kondo T, Ogawa Y.Efficacy of physical therapy for intractable cupulolithiasis in an experimental model. J Laryngol Otol. 2013 May;127(5):463-7. doi: 10.1017/S0022215113000698. Epub 2013 Apr 10.
• Schuknecht, H. F. (1969). "Cupulolithiasis." Arch Otolaryngol 90(6): 765-78.
• Schuknecht, H. F., et al. (1973). "Cupulolithiasis." Adv Otorhinolaryngol 20: 434-43.
• Squires TM, Weidman MS, Hain TC, Stone HA. A mathematical model for top-shelf vertigo: the role of sedimenting otoconia in BPPV. J Biomech, 2004. 37(8): p. 1137-46.