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

Abstract

The aim of this paper was to evaluate prospectively, in a group of patients affected by VN, a diagnostic protocol employing C-VEMPs, O-VEMPs and vHIT together. The diagnosis of vestibular neurolabyrinthitis was based on the clinical history, absence of associated auditory or neurological symptoms, and a neuro-otological examination with an evaluation of lateral semicircular canal function using the Fitzgerald-Hallpike caloric vestibular test and ice test. Our series revealed an incidence of 55% of superior and inferior vestibular neurolabyrinthitis, 40% of superior vestibular neurolabyrinthitis and 5% of inferior vestibular neurolabyrinthitis. These data, however, comprised different degrees of vestibular involvement considering the evaluation of each single vestibular end-organ with potential different prognosis. Four patients had only deficits of the horizontal and superior semicircular canals or their ampullary nerves. The implementation of C-VEMPs, O-VEMPs and vHIT in a vestibular diagnostic protocol has made possible to observe patients with ampullary VN, unidentifiable with other types of vestibular exams. The effect of age seems to have some impact on the recovery. When recovery firstly involves the utricular and saccular nerves and subsequently the ampullary nerves, it may be reasonable to expect a more favorable and successful outcome.

Neuro-otology- some recent clinical advances

“…Here, an absent ipsilateral ocular VEMP in the contralateral eye confirms that the patient had superior vestibular neuritis [102–104, 106, 109]. Similarly, if the patient has only an impaired posterior canal vHIT, then an absent ipsilateral cervical VEMP supports the diagnosis of inferior vestibular neuritis [101, 106]. VEMPs can also help decide if a radiologically suspected superior canal dehiscence is likely to be symptomatic [155]: if the air-conducted oVEMP from that side has a low threshold and a large amplitude, then it probably is [156–158].…”

“…Consider the patient who has recovered from an acute vestibular syndrome with no impairment of vHIT, but with a canal paresis on a caloric test. Here, an absent ipsilateral ocular VEMP in the contralateral eye confirms that the patient had superior vestibular neuritis [102–104, 106, 109]. Similarly, if the patient has only an impaired posterior canal vHIT, then an absent ipsilateral cervical VEMP supports the diagnosis of inferior vestibular neuritis [101, 106].…”

“…Also, in patients with recovered vestibular neuritis, the recovery might be less obvious on caloric testing than on vHIT. This means that a patient seen some time after an acute vestibular syndrome who now has a normal vHIT should have a caloric test—as it might still show a canal paresis [106, 108], indicating that it really was vestibular neuritis and there is no need for MRI.…”

About the pathophysiology of acute unilateral vestibular deficit – vestibular neuritis (VN) or peripheral vestibulopathy (PVP)?

“…A recent study by Magliulo et al [29] looked at 1-year follow-up results of UVD patients in their oVEMP, cVEMP and vHIT measurements showing acute-phase findings similar to ours: Half of their patients had incomplete involvement of vestibular receptors of their superior and/or inferior vestibular nerve. However, the authors remained true to the NH and argue for the existence of even more subgroups of vestibular neuritis than the two (three) described so far, superior and inferior vestibular neuritis (or the combination thereof).…”

Experiencia con Video Head Impulse Testing (vHIT)

“…Pese a su sensibilidad y especificidad, los aná-lisis comparativos demuestran que la prueba del impulso cefálico videoasistido es equivalente a la «Bobina de Búsqueda Escleral en Campo Magnético» en la identificación de dé-ficit vestibulares periféricos, con la diferencia de que es mucho más sencilla de utilizar y mejor tolerada por los pacientes [18].…”