Active Head Auto-Rotations in Patients With Benign Paroxysmal Positional Vertigo

Area of Science:

• Neuroscience
• Ophthalmology
• Vestibular System

Background:

• Benign paroxysmal positional vertigo (BPPV) is linked to utricular degeneration and otoconia displacement.
• The precise pathology underlying BPPV remains unclear.
• Increasing reports suggest associations between BPPV and other inner ear conditions.

Purpose of the Study:

• To investigate the vestibulo-ocular reflex (VOR) during sudden head accelerations in BPPV patients.
• To determine if head auto-rotation testing can identify functional differences in VOR related to the affected side.

Main Methods:

• A prospective controlled study involving 34 BPPV patients (13 lateral, 21 posterior canal) and 15 healthy controls.
• Testing VOR response to impulsive head rotations at various frequencies (1-5 Hz).
• Measuring VOR gain (head and eye velocity ratio) during horizontal and vertical head movements.

Main Results:

• All participants exhibited normal VOR gain (≥0.9) at 1 and 2 Hz, with gain decreasing at higher frequencies.
• No statistically significant differences in VOR gain were found between horizontal rotations toward the pathologic versus normal side in BPPV patients.
• No significant differences were observed in VOR gain between upward and downward vertical head rotations.

Conclusions:

• VOR gain reduction was noted in some BPPV patients, particularly at higher frequencies.
• The head auto-rotation test (HART) did not demonstrate functional VOR abnormalities during head rotations toward the affected side.
• HART is not recommended as a screening test for diagnosing BPPV.