7
Table 6. Selected Methods to Determine the Affected Ear in
Lateral Canal BPPV
Technique or Circumstance Conclusion regarding the affected ear
Supine roll testing (Figure 2) reveals
a direction changing nystagmus that
is either geotropic (beating toward
the ground) or apogeotropic (beating
away from the ground) and is distinctly
stronger on one side than the other.
• Geotropic form: the side with the
strongest nystagmus is the affected ear
• Apogeotropic form: the side opposite the
strongest nystagmus is the affected ear.
Posterior canal BPPV torsional
upbeating nystagmus converts to
strongly horizontal nystagmus (lateral
canal BPPV) during positioning.
• Same ear as was affected by the posterior
semicircular canal BPPV
Patient is moved from sitting to
straight supine facing up results in
transient horizontal nystagmus (lying-
down nystagmus
a
).
• Geotropic: Nystagmus beats away from
the affected ear
• Apogeotropic: Nystagmus beats toward
the affected ear
With the patient in the straight supine
position, the patient then sits up, and
the head bends down as a "Head Pitch
Test" (head-bending nystagmus).
• Geotropic: Nystagmus usually beats
toward the affected ear
• Apogeotropic: Nystagmus beats away
from the affected ear (opposite of lying-
down nystagmus. )
Bow and lean test (BLT)
a
in which the
direction of nystagmus is noted when
the patient bends the head forward
facing down (bowing ) and when facing
upward (leaning ).
• Geotropic:
bowing position (face down):
nystagmus toward the affected ear
leaning position (face up):
nystagmus beats away from the affected
ear
• Apogeotropic: (reverse of geotropic type)
bowing position (face down):
nystagmus beats away from the affected
ear
leaning position (face up):
nystagmus beats toward the affected ear.
a
e supine head roll test will still be needed to determine if there is a pattern of geotropic or
apogeotropic direction-changing nystagmus.
