Temporal Relationship between Nystagmus and Perception during Bithermal Alternate Caloric Test

Objectives: During caloric irritation, the spinning/rotating sensation is predominant. However, there is no report on the temporal relationship between caloric nystagmus and perception.Methods: Consecutive 57 participants underwent bithermal caloric test in the dizziness clinic of Chungnam National University Hospital from February 2018 to September 2018. For vestibular perception, we asked the subject to report feelings of rotation and/or linear sensation during each warm and cold water irrigation period. Besides routine caloric parameters, the duration of nystagmus and vestibular sensation were analyzed.Results: In most participants, the caloric nystagmus preceded the vestibular sensation (79.6% in right warm, 83.3% in left warm, 88.5% in right cool, and 84.6% in left cool stimuli). The precedence of perception was observed in 5 normal persons and 15 patients with vestibular migraine (n=4), unilateral vestibulopathy (n=3), and Menière’s disease (n=2), multiple systemic atrophy (n=2), cerebellar ataxia (n=2), vertebrobasilar insufficiency (n=1), and post-earthquake dizziness (n=1). The mean latency between nystagmus and perception was 11.7 seconds. And the duration of nystagmus was longer than that of perception in all conditions. Non-spinning sensations during the caloric test were also observed in some participants (26.8% in right warm, 30.3% in left warm, 29.1% in right cool, and 24.1% in left cool stimuli).Conclusions: During the bithemal alternate caloric test, various vestibular perception and temporal relationship between perception and nystagmus suggest the bithermal caloric stimulation does not reflect only the signal originating from the horizontal canal pathway. A further validation study is needed.

Which Is More Important for the Prognosis of Sudden Sensorineural Hearing Loss with Vertigo, Canal Paresis or Benign Paroxysmal Positional Vertigo?

Objectives: This study was performed to determine characteristics and the prognostic values in idiopathic sudden sensorineural hearing loss (SSNHL) with comorbid ipsilateral canal paresis (CP) and/or benign paroxysmal positional vertigo (BPPV). Methods: Of the 338 patients with a diagnosis of idiopathic SSNHL, 29 patients (8.6%) with CP and 24 patients (7.1%) with BPPV were recruited and compared to 23 patients with SSNHL and vertigo but without CP or BPPV. The patients were evaluated for their initial hearing threshold, type of canal involved, response to repositioning maneuvers, and hearing outcome for 6 months. Results: Patients with CP (+) BPPV (‒) showed lower pure-tone averages than those with CP (‒) BPPV (+) on initial and follow-up audiograms. The improvement in pure-tone averages was less in the CP (+) BPPV (‒) group than in the CP (‒) BPPV (+) group. The improvement in speech discrimination scores was less in the CP (+) BPPV (‒) group than in the CP (‒) BPPV (‒) group. BPPV most commonly involved the posterior canal (15 of 24, 62.5%), followed by the horizontal canal (13 of 24, 54.2%). Three of 24 patients (12.5%) had recurrences of BPPV. Conclusions: CP is a more serious sign for hearing recovery than BPPV, although both CP and BPPV are negative prognostic indicators of auditory function in SSNHL. Concurrent CP and/or BPPV in SSNHL suggest combined damage to the vestibule and may indicate severe and widespread labyrinthine damage, leading to a poor prognosis.

Cholesteatoma Causing a Horizontal Semicircular Canal Fistula

Horizontal canal fistulas are not uncommon in patients with cholesteatoma. Patients with canal wall down cavities and exposed horizontal canal fistulas develop significant dizziness with wind or suction exposure. Obliteration of mastoid cavities in patients with exposed fistulas can be challenging. We describe a patient with horizontal canal fistula and chronic dizziness from wind exposure who underwent successful mastoid cavity obliteration with preservation of hearing. Patients with horizontal canal fistulas in a canal wall down cavity can be managed with mastoid obliteration for relief of dizziness.

Treatment Results of Geotropic and Apogeotropic Horizontal Canal Benign Paroxysmal Positional Vertigo in a Tertiary Dizziness Clinic

Purpose: To determine the effectiveness of our treatment protocol for geotropic and apogeotropic horizontal canal benign paroxysmal positional vertigo (h-BPPV).Methods: We retrospectively evaluated patients with newly diagnosed geotropic and apogeotropic h-BPPV who visited our clinic between July 2017 and December 2019. Patients were treated according to our treatment protocol, which was implemented in 2017. Patients with geotropic h-BPPV were preferably treated with the Gufoni maneuver. In patients with apogeotropic h-BPPV we executed the modified Gufoni maneuver to achieve conversion to the geotropic type. We looked at the number of successful treatments and the number of recurrences within 1 year.Results: We included 102 patients with h-BPPV, 62 (61%) of whom were treated for geotropic h-BPPV. The ratio of apogeotropic to geotropic h-BPPV was 0.65. After the first visit, we observed resolution of horizontal canal BPPV in 71 and 63% of the geotropic and the apogeotropic group, respectively. After the second visit, this percentage increased to 92% for geotropic h-BPPV and 78% for apogeotropic h-BPPV. After 1 year of follow-up we determined a recurrence rate of 32 and 24% for the geotropic and apogeotropic group, respectively.Conclusion: With our treatment protocol we managed to achieve high rates of symptom resolution in the geotropic and apogeotropic type of h-BPPV with acceptable recurrence rates. We observed a relatively high ratio of apogeotropic h-BPPV to geotropic h-BPPV.

Skull Vibration-Induced Nystagmus Test in a Human Model of Horizontal Canal Plugging

Background/Aim: the aim of this study was to assess the skull vibration-induced nystagmus test (SVINT) results and vestibular residual function after horizontal semicircular canal (HSCC) plugging. Methods: In this retrospective chart review performed in a tertiary referral center, 11 patients who underwent unilateral horizontal semicircular canal plugging (uHSCCP) for disabling Menière’s disease (MD) were included. The skull vibration-induced nystagmus (SVIN) slow-phase velocity (SPV) was compared with the results of the caloric test (CaT), video head impulse test (VHIT), and cervical vestibular-evoked myogenic potentials (cVEMP) performed on the same day. Results: Overall, 10 patients had a strong SVIN beating toward the intact side (Horizontal SVIN-SPV: 8.8°/s ± 5.6°/s), 10 had a significant or severe ipsilateral CaT hypofunction, 10 had an ipsilateral horizontal VHIT gain impairment, and 3 had altered cVEMP on the operated side. Five had sensorineural hearing worsening. SVIN-positive results were correlated with CaT and horizontal VHIT (HVHIT) results (p < 0.05) but not with cVEMP. SVIN-SPV was correlated with CaT hypofunction in % (p < 0.05). Comparison of pre- and postoperative CaT % hypofunction showed a significant worsening (p = 0.028). Conclusion: SVINT results in a human model of horizontal canal plugging are well correlated with vestibular tests exploring horizontal canal function, but not with cVEMP. SVINT always showed a strong lesional nystagmus beating away from the lesion side. SVIN acts as a good marker of HSCC function. This surgical technique showed invasiveness regarding horizontal canal vestibular function.

Reversible Canalith Jam of the Horizontal Semicircular Canal Mimicking Cupulolithiasis

Objective: To describe a case of benign paroxysmal positional vertigo (BPPV) resulting in reversible horizontal semicircular canalith jam successfully treated with horizontal canal occlusion. A brief literature review of similar cases was performed. Methods: Case report and literature review. Results: A 68-year-old female presented with apogeotropic positional nystagmus, attributed to reversible horizontal canalith jam mimicking cupulolithiasis that was refractory to tailored repositioning maneuvers across months. She was unable to work due to the severity of her symptoms. She underwent surgical occlusion of the affected canal with immediate resolution of her symptoms. A literature review revealed similar cases of canalith jam mimicking cupulolithiasis. Conclusions: Reversible canalith jam, in which particles moving with horizontal head position alternate between obstructing the semicircular canal and resting on the cupula, can mimic signs of cupulolithiasis. This variant of BPPV can be effectively managed with surgical canal occlusion should symptoms fail to resolve after tailored repositioning maneuvers.