Selective Vestibular Neurolabyrinthitis of the Lateral and Superior Semicircular Canal Ampulla and Ampullary Nerves

Abstract

To our knowledge, these are the first reported cases in which selective damage to the lateral and superior semicircular canals and their nerves caused by neurolabyrinthitis was demonstrated clinically. Our clinical results indicate that the damage can be selective for specific vestibular end organs.

A 1-year follow-up study with C-VEMPs, O-VEMPs and video head impulse testing in vestibular neuritis

“…Few investigations combined these tools in the evaluation of the VN. In a small series, Magliulo et al [6] using a battery test including VEMPs and vHIT together reported the clinical suspicion of selective damage of the lateral semicircular canal receptor or superior semicircular canal receptor and the respective ampullary nerves in patients affected by VN. In 2013, Walther and Blödow [7] using the same diagnostic protocol in twenty patients were able to clinically differentiate a fourth type of VN, the ampullary VN, over the classic total, superior and inferior types.…”

“…Since the first small case series of Magliulo et al [6] in 2012, Walther and Blödow [7] were able to differentiate four types of VN, i.e., entire VN, superior VN, inferior VN and ampullary VN employing these new diagnostic tools. Magliulo et al [8] contemporary proposed a 6-class system of classification to categorize the various pathological findings with regard to the location of vestibular damage and the number of vestibular end-organs involved in a group of forty patients with unilateral acute VN followed up for 6 months.…”

Retinitis Pigmentosa

“…The criteria adopted for assessing abnormality of C-VEMPs comprised the absence of p1-n1, the so-called p13-n23 complex, or the increase of latency and the decrease of the amplitude of p1-n1 more than 2 standard deviations with reference to our agerelated normative reference range (15,20) A handheld Mini-shaker (4810; Bruel and Kjaer, Naerum, Denmark) was used to measure O-VEMPs through boneconducted vibration with the patient lying in the supine position and shown a target placed approximately 15 to 30 degrees backwards at a distance of 2 m. The two exploring electrodes were positioned below the center of the lower eyelids with the two reference electrodes placed 1 to 2 cm below the active ones and a ground electrode was positioned on the forehead. Recorded signals were amplified and band-pass-filtered from 20 to 500 Hz (15Y19).…”

“…O-VEMPs were evaluated using the same criteria for the C-VEMPs: the absence of n10 wave or increase of latency and the decrease of the amplitude of the n10 wave more than 2 standard deviations with reference to our age-related normative range (15,20) (N10 wave latency normal value, 10.29 T 0.6 ms; N10 wave amplitude normal value, 6.57 T 2.01 KV).…”

Clinical Utility of Ocular Vestibular-Evoked Myogenic Potentials (oVEMPs)

“…The deficits were often patchy, suggesting that the disease can be restricted to isolated parts of the inner ear. For example, selective VN affecting the lateral and superior semicircular canals has been described, based on the video head impulse test, absent calorics, but preserved oVEMPs and cVEMPs [55]. In the rare cases of VN where only the inferior division was involved, a reversed pattern of spared oVEMPs and affected cVEMPs was found [50].…”