Can active lateral canal benign paroxysmal positional vertigo mimic a false-positive head thrust test?

Area of Science:

• Neurology
• Otolaryngology
• Vestibular Science

Background:

• Benign paroxysmal positional vertigo (BPPV) is a common cause of episodic vertigo.
• The head thrust test (HTT) is a clinical bedside test used to assess vestibular function.
• Lateral semicircular canal (LSCC) BPPV can present with atypical findings.

Observation:

• A patient presented with episodic vertigo and a positive head thrust test (HTT) to the right.
• Video-oculography (VOG) and positional testing revealed active contralateral LSCC BPPV.
• The patient exhibited corrective refixation saccades on HTT, mimicking a false-positive result.

Findings:

• Successful treatment of LSCC BPPV with canalith repositioning maneuvers.
• Immediate resolution of the patient's vertigo following treatment.
• Near-normalization of the head thrust test (HTT) findings post-treatment.

Implications:

• LSCC BPPV can mimic a false-positive head thrust test (HTT), highlighting the importance of comprehensive vestibular assessment.
• Understanding the pathophysiology of LSCC BPPV is crucial for accurate diagnosis and management.
• This case emphasizes the utility of integrating clinical tests like HTT with VOG and positional testing for vestibular disorders.