Role of Video Head Impulse Test to Assess Noise Exposure

Abstract

Noise exposure has been reported to exert numerous detrimental effects on the human population, although most research has centred around hearing damage. Vestibular and balance loss have been demonstrated among industrial workers, although reports on this are still scarce. Vestibular loss increases the risk of falls, especially among industrial workers who are at constant risk. Nonetheless, the ideal investigation tool to investigate vestibular function remains unknown. We aim to review the available literature to elucidate the effect of noise exposure on semicircular canals using a video head impulse test (vHIT). A literature search identified only three studies involving 137 patients (mean age: 44.4). Semicircular canal deficit was found in 50.4% of the included participants, with lateral canal predominantly affected (71%). We highlight the importance of assessing the effect of noise exposure on vestibular function, especially among those prone to occupation-related vestibular loss.

Introduction

The vestibular response following noise exposure has been reported widely, albeit the exact pathophysiology remains unexplored. Evidence has shown that chronic noise exposure causes a damaging effect on the vestibular end-organ [1]. The otoliths, notably the saccule, have been demonstrated as the most sound-sensitive peripheral vestibular organ, hence susceptible to the damaging impacts following noise exposure, as shown in numerous animal and human studies [1]. Yet, the exact rate of impact of noise exposure on the semicircular canal (SCC) remains obscure. Stewart et al. demonstrated using an animal model that high-intensity noise exposure significantly reduces stereocilia hair bundle density in the anterior and lateral SCC, sparing the posterior SCC [2].

Nonetheless, earlier investigations revealed that chronic noise exposure has harmful effects on the lateral SCC using a caloric test [1]. Recently, the development of the video head impulse test (VHIT), a fast, safe test that assesses each SCC function individually, has enabled objective quantification of each canal individually and the presence of covert and overt saccade.

Methods

A literature search was conducted on 1st April 2023 using articles published in PubMed, Scopus, Embase, Web of Science and Google Scholar according to PRISMA guidelines to elucidate the effect of noise exposure on individual semicircular canals. The inclusion criteria were studies investigating the impact of noise exposure on semicircular canals using vHIT. The keywords used for the article search include vestibular test, video head impulse test, Halmagyi head impulse, head thrust test, semicircular canal, noise exposure, and occupational and recreational noise exposure. To our best knowledge, this is the first article that aims to investigate the effect of noise exposure on individual semicircular canals using VHIT.

Results

Our search yielded 3 articles [3–5], all of which were observational case-control studies. (Summary of the characteristics and the main findings: Table 1) A total of 137 patients were pooled from this review, with a mean age of 44.4 years. All three studies included participants exposed to occupational-related noise from industry (100%). Only 1 study included a female participant, n = 1 (2.7%). The mean of noise exposure was ten years. 32.1% of the participants had normal hearing, whereas the rest had varying degrees of hearing loss. Vertigo was reported in only one study involving 3.7% of the participants.

Table 1.

Summary of the characteristics and main findings

Author, Year Country	Type of study	Total patients	Age	Gender	Noise exposure types	Hearing	Subjective vestibular assessment	VHIT type	Result	Abnormal VOR gain	Outcome
Yilmaz [3], 2018 Turkey	Case-control	36	44.4 ± 6.1	36 M	Occupation Steel and metal industrial exposure (4 years)	13 normal 21 mild HL 2 moderate HL	None reported vertigo	SYNAPSYS vHIT (Ulmer, France)	Canal deficit in 20 (55.5%) e covert saccades in 19 patients and an overt saccade in 1 patient	Abnormal mean gains LC (> 0.80) PC & AC (> 0.75)	Left LC:8 Right LC: 4 Bilateral LC: 5 Left AC: 1 Multicanal: 2
Yilmaz [4], 2019 Turkey	Case-control	84	41.97 ± 6.45 (range 26–55	84 M	Occupational Machinery area of heavy industry (4 yrs of exposure)	53 NIHL 41 Normal hearing	NR	SynapsysVR (Marseilles, France) VHIT Ulmer system	(41/84 patients) 48.80% had canal deficit	Abnormal mean gains LC (> 0.80) PC & AC (> 0.75)	Left LC:18 Right LC: 8 Right AC: 1 Multicanal: 14
Elewa [5], 2022 Egypt	Case-control observational study	17	46.7 ± 7.9	16 M 1 F	Occupation Industry Textile factory Mean 22.1 ± 8.8 yrs of exposure	Bilateral SNHL (Mild to moderately severe)	5	EYE SEECAM vHIT from Interacoustics	Canal deficit in 8 (47%) 8 patients (47%) with refixation saccade (6 patients with covert saccade and 2 patients with overt saccade)	Abnormal mean gains LC (> 0.80) PC & AC (> 0.75)	Left LC:3 Right LC: 2 Bilateral LC: 3 Left PC:1

M: Male; F: Female; VHIT: Video head impulse test; NR: Not reported; SNHL: sensorineural hearing loss; NIHL: noise-induced hearing loss; LC: lateral canal; AC: anterior canal; PC: postreior canal

VHIT was performed using the SYNAPSYS vHIT (Ulmer, France) system in two studies [3, 4], whereas Elewa et al. used the EYE SEECAM vHIT from Interacoustics [5]. The parameter response for canal deficit used in all three studies was similar, whereby mean VOR gain less than 0.80 for the horizontal SCCs, and VOR gain less than 0.75 for the posterior and anterior SCCs was considered abnormal.

In our review, sixty-nine of the included participants were found to have a canal deficit (50.4%), whilst 28 participants were noted to have saccade (18%), notably covert saccade (25/28). Furthermore, the lateral canal was found to be a predominantly affected canal following noise exposure (49/69) either unilaterally or bilaterally (8/49), followed by the anterior canal (3/69) and the posterior canal (1). On the other hand, multicanal involvement was reported in 15 participants (15/69).

Discussion

This mini-review corroborates that chronic noise exposure leads to SCC deficit, as evidenced in 50.4% of the included participants in this study, of which only 5 participants complained of vertigo. Previous studies have shown that industrial workers are prone to suffer from vestibular and balance symptoms such as spinning sensation, nystagmus and postural instability, which may be life-threatening since they are more susceptible to falls [1]. Parallel to that, the small number of vestibular complaints is attributed to the compensation by the central nervous system. It is axiomatic to note that the increased reactive oxygen species and glutamate excitotoxicity have been postulated as the primary culprit in labyrinth damage from noise exposure [6].

From this study, we can posit that lateral and anterior SCC are more susceptible to noise-induced damage than posterior SCC. This finding echoes the report by Zhu et al. that the posterior SCC afferents are less sensitive to sound stimulation [7].

Interestingly, vestibular damage may precede cochlear damage, as shown by Raghunath et al. [8]. Akin to that, 7 out of the 13 participants with normal hearing in this review demonstrated canal deficit, with all 7 participants demonstrating covert saccade [3].

Looking ahead, our knowledge of the effect of noise exposure on SCC has laid a foundation to further research on the exact pathomechanism of damage and the susceptibility of each SCC to noise exposure. We recommend the use of VHIT as a part of a screening tool to assess vestibular function among those exposed to occupation as well as recreation-related noise. We acknowledge that the quality of evidence is inadequate to recommend the widespread use of the VHIT until a better-quality study has been completed. Future randomised controlled studies with a large sample size are warranted to determine the efficacy of VHIT in assessing noise-induced vestibular damage.

Author Contributions

Jeyasakthy Saniasiaya: Conceptualization, Drafting, data analysis, writing, editing, literature review.

Funding

None.

Declarations

Conflict of Interest

All authors have no conflict of interest.

Ethical Approval

No ethical approval was required as no patients were involved.