Comparison of Lateral Semicircular Canal Dysfunction in Chronic Otitis Media Patients using Air Caloric Test and Video Head Impulse Test

Abstract

In developing nations like India, chronic otitis media (COM) is a common middle ear ailment that has serious ramifications for both hearing and quality of life. Long-term inflammation of middle ear cavity and tympanic membrane are the hallmarks of COM, which can result in consequences like facial paralysis, labyrinthitis, hearing loss, and potentially fatal cerebral abscesses. The effect of COM on vestibular function is still unknown. Studies reveal a positive correlation between the severity of COM and vestibular impairment, which may point to a cause-and-effect link. Using air caloric testing and video head impulse testing (VHIT), this study seeks to explore the link between vestibular symptoms, particularly lateral semicircular involvement with COM. To quantify the involvement of lateral semicircular canal using air caloric test and video head impulse test, compare the results of both tests in patients with chronic otitis media and to detect early labyrinthine dysfunction using air caloric test and Video head impulse test. A cross-sectional study was conducted over a period of 2 years to investigate the involvement of the lateral semicircular canal in patients aged 18 years and above with symptoms suggestive of chronic otitis media. All patients underwent air caloric and video head impulse tests, to evaluate canal paresis and horizontal vestibulo-ocular reflex (VOR). The outcomes of both tests were compared to investigate their correlation and diagnostic value. A total of 145 patients were enrolled in this study, with a median age range of 30–39 years and the gender distribution was nearly equal. The majority of patients (85.5%) presented with mucosal type chronic otitis media (COM), while 14.5% had squamosal type COM.Video head impulse test (VHIT) revealed abnormalities in 45.5% of patients, whereas the air caloric test (ACT) showed abnormalities in 21%. A positive head impulse test was observed in 11 patients (14.5%). Patients with medium and large-sized central perforations were more prone to giddiness. Labyrinthine fistula was detected in one patient with active squamosal disease. 56.1% of patients with abnormal VHIT had normal canal paresis and only 29 patients (43.9%) showed both abnormal VHIT and Air caloric test. VHIT is found to be more sensitive compared to air caloric test. The study highlights the significance of utilising both VHIT and ACT in the comprehensive evaluation of vestibular function in patients with COM. For individuals with vestibular deficits due to COM, a combined approach can improve diagnostic accuracy and guide targeted therapy and rehabilitation options.

Introduction

Chronic suppurative otitis media (CSOM) is a chronic inflammatory condition of the middle ear and mastoid cavity, characterized by persistent or recurrent ear discharge through a perforated tympanic membrane [1]. The clinical spectrum of chronic otitis media (COM) is broad, encompassing mild to severe manifestations, including tympanic membrane perforations, hearing loss, otorrhea, sclerosis, effusion, cholesteatoma formation, mucosal hyperplasia, and ossicular and bony erosion [2].

If left untreated, COM can lead to severe complications, such as intracranial abscesses, meningitis, facial paralysis, labyrinthine fistula, and permanent sensorineural hearing loss (SNHL) due to labyrinthitis [3].

Research has identified a correlation between vestibular impairment and the severity and duration of COM, suggesting a potential causal relationship [4]. Moreover, a significant link exists between SNHL and vestibular symptoms, indicating shared underlying damage to both cochlear and vestibular systems, likely resulting from COM [5]. Collectively, these findings imply that COM may cause progressive and irreversible vestibular impairment, highlighting the need for prompt diagnosis and treatment to mitigate this risk.

Hence in this study both air caloric test and video head impulse test were used to analyse the lateral semicircular canal dysfunction in patients with chronic otitis media. VHIT and Air Caloric Test are advantageous as they are less influenced by middle-ear status, providing a more reliable evaluation of vestibular function. Additionally, VHIT offers high sensitivity, quantifiable results, and better patient comfort, while Air Caloric Test is more comfortable and faster than traditional caloric tests.

Aim

This study aimed to determine lateral semicircular canal involvement using air caloric test and video head impulse test (VHIT) in patients with chronic otitis media, compare the air caloric test and video head impulse test results and analyse the lateral semicircular canal dysfunction.

Inclusion Criteria

• Both sexes

• Age group from 18 years to 65 years

• Patients diagnosed with unilateral chronic otitis media with or without giddiness

Exclusion Criteria

• Age below 18 years and above 65 years

• Patient with central cause of vestibular dysfunction

• History of previous ear surgery

• Neurological or psychiatric disease

• Patient with history of ototoxic drug intake

• Individuals suffering from chronic otitis media with intracranial complications

• Patients presenting with bilateral disease

• Patients refusing to participate

Methodology

Upon obtaining ethical approval and written, informed consent from each patient, our cross-sectional study included 145 individuals aged above 18 years who sought treatment at a tertiary healthcare facility in Tamil Nadu, India, with a clinical diagnosis of chronic otitis media for a study period of 2 years from March 2022 to April 2024.

All patients with history suggestive of chronic otitis media and within the inclusion criteria, underwent routine otological examination, vestibular function test and audiological examination followed by Air caloric testing and video head impulse test which was done in the ENT OPD on an outpatient basis.

Air Caloric Testing

Patient was placed in supine position with 30 degree head end elevation. Using the NeuroEqulibrium Caloric irrigator (Fig. 1) and ergonomically designed delivery head each ear was irrigated alternatively with a continuous flow of air at 50 °C and 24 °C for a duration of 60 s. The bilateral ear stimulation involved the sequential delivery of warm and cold air, initiating with the right ear receiving warm air, then the left ear, subsequent to which the right ear received cold air, and finally the left ear received cold air. Nystagmus following irrigation was monitored using frenzel glass and the duration of nystagmus was noted. Canal paresis was measured using air caloric test.

$$\text{Canal paresis}-\frac{\left(\text{RW}+\text{RC}\right)-\left(\text{LW}+\text{LC}\right)}{\text{RW}+\text{RC}+\text{LW}+\text{LC}}\times 100\%$$

RW—Right warm air, RC—Right cold air, LW—Left warm air, LC—Left cold air.

Fig. 1.

NeuroEqulibrium air caloric irrigator with frenzel glass

Difference between the 2 ears of more than 25% was considered abnormal.

Video Head Impulse Test

This was performed using the NeuroEquilibrium cutting edge technology and recorded using NeuroEquilibrium software in our department. The participant was made to comfortably wear the goggles, which had a clean face cushion attached to it. The apparatus was calibrated.

The head was rotated about the vertical plane to the left and right. The patient's direct line of sight is a dot at eye height that is situated 1.2 m distant from them. The horizontal VOR gain was evaluated, Fig. 2. On both the left and right sides, at least 15 sufficient impulses were applied.

Fig. 2.

The Graph showing abnormal VOR gain values in right lateral canal

When the VOR value was greater than 1.2 or less than 0.8, the test was deemed abnormal. The test results of both were compared at the end of the study.

Results

This study enrolled 145 patients with chronic otitis media, with the majority (24.1%) aged between 30 and 39 years. The gender distribution was nearly equal, with 49% female and 51% male participants. Mucosal type chronic otitis media accounted for 86% of cases, while squamosal type accounted for 15%. Most patients (71%) had inactive disease, with 98 having mucosal and 5 having squamosal disease. Only 12% of patients reported giddiness during the trial, and one patient with active squamosal disease had a positive fistula test.

Disease duration varied, with 34% of patients having a duration of 1–5 years, followed by those with a duration of over 10 years. A positive head impulse test result was observed in only 11 patients.

The prevalence of hearing loss types in the study group was: conductive hearing loss (52%), mixed hearing loss (39%), and sensorineural hearing loss (SNHL) (9%). Otoscopic examination revealed various tympanic membrane abnormalities, with medium central perforation being the most common (34%) in mucosal disease, and attic erosion (6%) and attic retraction more common in squamosal disease.

The size of the central perforation was significantly linked to both vestibular-ocular reflex (VOR) gain and canal paresis. Video head impulse testing (VHIT) was abnormal in 66 (45.5%) patients, while air caloric testing showed abnormal canal paresis in 31 (21%) patients. But out of the 66 patients with abnormal VHIT only 29 patients showed abnormal air caloric test, remaining 37 patients with abnormal labyrinthine function were not detected by air caloric test.

Discussion

Chronic otitis media (COM) patients require vestibular function assessment to mitigate potential balance and spatial orientation risks. This analysis compares the diagnostic accuracy and effectiveness of air caloric test (ACT) and video head impulse test (VHIT) in identifying lateral semicircular canal dysfunction in COM patients. Our research revealed a peak prevalence in the 40–59 age range, accounting for 36% of patients, with a mean age of 41.90 ± 14.30 years, aligning with the findings of Andreza Tomaz et al. [5, 6] We observed a balanced gender distribution, with 71 Female (49%) and 74 Male (51%) participants, differing from the male-dominated results reported by Eldin Mostafa et al. [7]. Conversely, Rout et al.[8] noted a slight female preponderance. It is to be noted that, our study showed a low incidence of giddiness, reported by only 12% of patients, contrasting sharply with the 53.5% incidence reported in a previous study. Furthermore, our results indicated a predilection for right ear involvement in 78 patients (53.7%) over left ear involvement in 67 patients (46.2%), contradicting the left ear predominance observed by Ananthula et al.[9].

This study also showed predominance of mucosal disease (85.5%) over squamosal disease (14.5%), consistent with the findings of Eldin Mostafa et al. [7]. However, a notable disparity emerged in the disease activity, with a higher proportion of active cases among patients with squamosal disease (16 out of 20) compared to those with mucosal disease (26 out of 125). This contrasts with the study by Bijan Basak et al. [10, 11], which found aural discharge to be the most common presenting symptom in mucosal chronic otitis media (COM) (84.4%) and universally present in squamous COM (100%). Furthermore, our study’s perforation pattern analysis showed a preponderance of medium and large central perforations, followed by subtotal perforations, mirroring the findings of Memon et al. [12] and Nagle SK et al. [13].We found a correlation between the duration of illness and the presentation of giddiness, similar to the findings of Mostafa et al. Additionally, giddiness was more prevalent in patients with medium and large-sized central perforations. One patient with active squamosal disease had a positive fistula test, suggesting a possible labyrinthine fistula complication. Romberg’s and Unterberger’s tests were negative for all patients, while the head impulse test was positive in 11 patients (7.5%).

Our investigation revealed a distribution of hearing loss types, with conductive hearing loss (CHL) being the most prevalent (52%), followed by mixed hearing loss (MHL) (39%), and sensorineural hearing loss (SNHL) (9%). This diverges from the findings of Vijayalakshmi Subramaniam et al.[14], who reported a significantly higher incidence of SNHL (71.4%) in cases of chronic suppurative otitis media (CSOM).Interestingly, our study showed that patients with medium and large central perforations primarily presented with CHL, followed by MHL. In contrast, all patients with an automastoid cavity exhibited MHL, highlighting a distinct correlation between perforation type and hearing loss pattern. This study suggests that prolonged duration of disease leads to extended exposure of the inner ear to toxins, which diffuse through the round window membrane, causing sensorineural hearing loss (SNHL). Additionally, pars flaccida perforations were more commonly linked to cholesteatoma, and active middle ear disease was associated with lower pH levels around the round window membrane, allowing microtoxins to enter the inner ear more easily. As the perforation size increases, greater amounts of microtoxins penetrate the inner ear, damaging hair cells, particularly in the basal turn of the cochlea, leading to SNHL development. In this study, 66 patients (45.5% of the total population) exhibited abnormal video head impulse test (VHIT) results, which is a higher percentage compared to the study by Sandhu et al.[15], where 35% of the population showed abnormal vestibulo-ocular reflex (VOR) gain. Additionally, 21% of our study population demonstrated abnormal canal paresis, similar to the findings of Lee et al. [16], which reported 25% of their study population with abnormal canal paresis. The air caloric test (ACT) is a long-standing technique for assessing lateral semicircular canal function by inducing endolymphatic flow through thermal stimulation. In this study, ACT results revealed a significant presence of canal paresis in patients with chronic otitis media (COM), with 42.5% of those with mucosal-type COM and 13.3% with squamosal-type COM showing abnormal results. These findings underscore substantial impairment of the lateral semicircular canal (LSCC) in patients with COM, particularly those with the mucosal subtype. The air caloric test (ACT) measures vestibulo-ocular reflex (VOR) by inducing nystagmus through temperature changes. However, ACT has limitations, including patient discomfort, requirement for patient cooperation, and potential inaccuracies in cases with external or middle ear pathologies. In contrast, the video head impulse test (VHIT) is a more recent advancement that directly assesses all six semicircular canals by recording eye movements in response to rapid head rotations. VHIT offers advantages like non-invasiveness, quick administration, and ability to test high frequency VOR ranges not assessed by ACT. Studies have shown that VHIT is generally more sensitive than ACT in detecting vestibular dysfunctions across various otoscopic findings, particularly in cases with auto mastoid cavities, medium central perforations, and subtotal perforations. In our study out of 145 patients with chronic otitis media we found that 66 had abnormal results in the Video Head Impulse Test (VHIT), while 31 had abnormal results in the air caloric test. Notably, only 29 of the 66 patients with abnormal VHIT results also had abnormal air caloric test results, leaving 37 patients with labyrinthine dysfunction undetected by the air caloric test. This suggests that VHIT is a more sensitive test than the air caloric test for detecting labyrinthine dysfunction. But both ACT and VHIT are considered valuable tools for diagnosing vestibular dysfunction in COM patients, with studies like Singh et al. [17] and Kim et al. [18] highlighting their complementary diagnostic information. A combined approach using both VHIT and ACT can enhance diagnosis accuracy and informs targeted treatment and rehabilitation strategies for patients with COM-related vestibular impairments.

Strength and Limitation

Employing these tests as a screening tool enables early detection of labyrinthine involvement, even in asymptomatic patients, facilitating timely intervention and potentially preventing complications. Limitations noticed in this study were the subjective nature of air caloric testing, technical difficulties associated with VHIT and the study's reliance on operator expertise and patient cooperation during the study. While this single-center study yields promising results, future multicenter studies with a larger sample size and diverse population would likely provide more favourable outcomes.

Conclusion

Assessing vestibular function is crucial for lowering the likelihood of balance issues and difficulties with spatial orientation in patients with chronic otitis media (COM). Chronic otitis media is associated with an increased risk of labyrinthine dysfunction even in patients who present with absent giddiness. The higher sensitivity of VHIT in certain conditions and ACT’s effectiveness in others highlight the need for a tailored approach in clinical practice. Based on our study VHIT is considered to be more sensitive in detecting labyrinthine dysfunction compared to air caloric test. The use of VHIT (Video Head Impulse Test) and air caloric testing offers the advantages of minimized observer bias and improved data documentation, leading to more reliable and objective results.

Declarations

Ethical approval

Institutional Ethical clearance number—ST0323-392.

Informed consent

Informed and written consent obtained from all patients included in the study.