Home Email this page Print this page Bookmark this page Decrease font size Default font size Increase font size
Noise & Health  
 CURRENT ISSUE    PAST ISSUES    AHEAD OF PRINT    SEARCH   GET E-ALERTS    
 
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Email Alert *
Add to My List *
* Registration required (free)  
 


 
   Abstract
   Introduction
   Materials and Me...
   Results
   Discussion
   Conclusion
   References
   Article Figures
   Article Tables
 

 Article Access Statistics
    Viewed6551    
    Printed323    
    Emailed6    
    PDF Downloaded28    
    Comments [Add]    
    Cited by others 7    

Recommend this journal

 


 
ARTICLE Table of Contents   
Year : 2010  |  Volume : 12  |  Issue : 48  |  Page : 191-194
Vestibular evoked myogenic potential in noise-induced hearing loss

Department of Audiology and Speech Language Pathology, KMC (Unit of Manipal University) Mangalore - 575 001, Karnataka, India

Click here for correspondence address and email
Date of Web Publication30-Jun-2010
 
  Abstract 

Noise affects one's hearing as well as balance mechanism. The hearing mechanism of the noise-exposed individuals has been extensively studied. However, in view of the poor research focus on the sacculo-collic reflexes, especially in this study area, the present study was undertaken to examine the vestibular evoked myogenic potentials (VEMP) in subjects with noise-induced hearing loss (NIHL). A total of 30 subjects (55 ears) with NIHL participated in the present study within the age range of 30-40 years. VEMP recordings were done at 99 dBnHL using IHS instrument. The results indicated that as the average pure tone hearing threshold increased, the VEMP latencies were prolonged and peak to peak amplitude was reduced in NIHL subjects. Out of the 55 ears, VEMP was absent in 16 (29.0%) ears. The latency was prolonged and the peak to peak amplitude was reduced in 19 (34.6%) ears. VEMP results were normal in 20 (36.4%) ears. Therefore, VEMP was abnormal or absent in 67% of NIHL subjects in the present study. Hence it can be concluded that the possibility of vestibular dysfunction, specially the saccular pathway, is high in individuals with NIHL. VEMP, a non-invasive and user friendly procedure, can be employed in these individuals to assess sacculo-collic reflex.

Keywords: Noise-induced hearing loss, sacculo-collic reflex, vestibular system

How to cite this article:
Kumar K, Vivarthini CJ, Bhat JS. Vestibular evoked myogenic potential in noise-induced hearing loss. Noise Health 2010;12:191-4

How to cite this URL:
Kumar K, Vivarthini CJ, Bhat JS. Vestibular evoked myogenic potential in noise-induced hearing loss. Noise Health [serial online] 2010 [cited 2020 Nov 30];12:191-4. Available from: https://www.noiseandhealth.org/text.asp?2010/12/48/191/64973

  Introduction Top


Unlike the situation with hearing, noise is not generally recognized as a common cause of vestibular disturbances. This is likely a result from the difference in "tuning" between the hair cells of the cochlea and the vestibular labyrinth. Cochlear hair cells are "tuned" to respond to frequencies between 20 and 20 000 Hz, while vestibular hair cells are "tuned" to respond for inputs between 0 and 10 Hz. [1]

It is known that noise affects hearing as well as vestibular system. There are numerous studies indicating noise as a cause of vestibular damage. Golz et al. had reported that noise results in asymmetrical or symmetrical hearing loss with abnormal vestibular functions. [2],[3],[4] Exposure to industrial solvents and noise can have an adverse effect on hearing and balance mechanisms in humans and animals. [5],[6] Body sway increases in patients with noise-induced hearing loss (NIHL) suggesting sub-clinical disturbances of the vestibular system. [7] On the contrary, Sohmer et al. [8] reported that at higher intensity levels (113dB SPL), there was a clear effect on cochlea but not on vestibular end organs. Although loud noise clearly shifts temporary and permanent hearing thresholds, vestibular changes are less clearly understood, possibly because the vestibulo-occular reflex is less sensitive to impulse noise even at maximum intensities unless the labyrinth is opened (eg., Superior semicircular canal dehiscence). In this case, the so-called Tullio phenomenon occurs. [9],[10]

The neurophysiological and clinical data indicate that the vestibular evoked myogenic potentials (VEMPs) are mediated by a pathway that includes the saccular macula, the inferior vestibular nerve, the lateral vestibular nucleus, the lateral vestibulospinal tract, and the motorneurons of the ipsilateral sternocleidomastoid (SCM) muscle. [11] VEMP is a reliable clinical test of saccular or inferior vestibular nerve function. [12] There is initially a positive peak P1 at 13 ms, followed by a negative peak N1 at 23 ms recorded from the averaged surface electromyography (EMG) which occurs at short latency and ipsilateral to the stimulated ear. [13] Wang et al. [14] reported abnormal Caloric and VEMP responses in 45 and 50%, respectively, in individuals exposed to chronic noise.

Need of the study

The vestibular functioning, especially sacculo-collic reflexes, on the noise-exposed individuals are not well understood especially in this area of study. Hence the present study was taken up with an aim of assessing the VEMP in noise-induced hearing loss subjects. It was also aimed to check the correlation between the hearing thresholds and the VEMP responses in NIHL subjects.


  Materials and Methods Top


Subjects

A total of 30 NIHL subjects (28 males and two females) were involved in the present study within the age range of 30 to 40 years in the experimental group (55 ears). Five ears were excluded from the test due to middle ear pathology. Control group comprised of age and sex matched 30 normal hearing subjects (60 ears). The following subject selection criteria were adopted for the study.

Control group: (Normal subjects)

  • All the ears with hearing sensitivity within 15 dBHL for frequencies from 250 to 8000 Hz, having 'A' type tympanogram with normal acoustic reflexes.
  • None of the subjects had recent history or presence of any otological problem (like ear discharge, ear ache etc) or any neurological symptoms.
  • Uncomfortable levels (UCL) for speech were greater than 105 dBHL in all the subjects.
Experimental group (NIHL subjects)

  • All the ears were having sensory neural hearing loss ranging from mild to moderately severe degree (pure tone average ranging from 25dB to 70dB).
  • Subjects were having exposure to noise greater than 90dBA daily for 8 hours.
  • Subjects were working in an industrial setup for 10 years or more.
  • None of the subjects had recent history or presence of any otologic problem (like ear discharge, ear ache etc.) or neurological symptoms.
Instrumentation

GSI 61 Diagnostic Audiometer was used to obtain pure tone audiometry and UCL. GSI-Tympstar was used for middle ear analysis. IHS Smart EP version: 3140 (Intelligent hearing systems, Florida, USA) was utilized for VEMP recording.

Procedure

Initially each subject was subjected to pure tone audiometry across octave frequencies from 250 to 8000 Hz for air conduction and from 250 to 4000 Hz for bone conduction. Using the same instrument, uncomfortable level for speech was obtained using ascending method in 5dB steps. Subjects were asked to indicate when the loudness of the speech was not tolerable. Subsequently tympanogram and acoustic reflexes were established using 226 Hz probe tone. Finally for the VEMP recording, the subjects were seated in an upright position and were instructed to turn their head to opposite side of the test ear to activate the ipsilateral SCM muscle. Surface EMG was monitored between 50 and 100 ΅v using VEMP software. The electrode montage that was used was Non-inverting electrode (+) to mid point of the SCM muscle of the side being stimulated, Inverting electrode (-) to sternoclavicular junction and ground electrode to the forehead. Inverting and non-inverting electrodes record the VEMP response with reference to ground. All the electrodes were connected with an amplifier box. VEMP was recorded at 99 dBnHL. Total of 250 sweeps were taken for the recording. Rarefaction click stimulus was used with repetition rate of 5/s. It was ensured that the electrode impedance at each electrode site was less than 5 KΩ and the inter electrode impedance was within 3 KΩ.

The positive/negative polarity of biphasic waveforms were termed as waves P1 and N1 on the basis of their respective latencies. Consecutive runs were performed to confirm reproducibility of peaks P1 and N1 and thus VEMP responses were considered to be present. Conversely, VEMP responses were absent, when reproducibility of biphasic P1-N1 waveform was lacking. A VEMP response was considered as normal if it was within mean+ 2SD. VEMP latency (P1-N1) and amplitude were noted. Independent t test was employed to measure the statistical difference between control group and clinical group. Pearson correlation test was applied to see the correlation between four frequency pure tone average thresholds (average of 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz) and VEMP responses. The study was approved by the institutional ethical board and consent was obtained from all the subjects.


  Results Top


The data was obtained from only 55 ears (30 subjects) who met the inclusion criteria. The mean and standard deviation of P1, N1 and peak to peak amplitude obtained at the 99 dBnHL are shown in [Table 1].

The mean latency of P1 and N1 was prolonged and peak to peak amplitude was reduced in experimental group when compared to control group. An independent sample t-test was done to find if the VEMP parameters are significantly different between the control group and the experimental group. An independent t-test demonstrated that there was a significant difference in VEMP responses between control group and clinical group subjects for latencies P1 and N1. The peak-to-peak amplitude was also significantly different between control group and NIHL group [Table 2].

Obtained normative was compared with experimental group and the table below details the VEMP responses [Table 3].

The results from the current study indicate that out of the 55 ears, VEMP was absent in 16 (29.0%) ears. The latency was prolonged and the peak to peak amplitude was reduced in 19 (34.6%) ears. VEMP responses were obtained with normal latency (P1 and N1) and normal amplitude in 20 (36.4%) ears. The Pearson correlation test indicated significant correlation between pure tone average and different VEMP parameters tested (r = 0.67, P<0.01, r = 0.56, P<0.01 and r = -0.40, P<0.01, respectively for P1 latency, N1 latency and peak to peak amplitude) [Figure 1],[Figure 2],[Figure 3].


  Discussion Top


NIHL subjects demonstrated significant prolongation of latency and reduction in peak to peak amplitude when compared to control subjects. It was also observed that as the pure tone average increased, the latency was prolonged and amplitude was reduced in NIHL subjects. The correlation was positive for P1 and N1 latencies and negative for peak to peak amplitude in comparison with pure tone average. Wang et al. [14] reported an increasingly damaged saccule results in abnormal VEMPs (eg, absent or delayed VEMPs) in subjects with bilateral 4 kHz notched audiogram with hearing threshold of > 40dB at 4 kHz. An animal study in which guinea pigs were exposed to 136 to 150 dB sound pressure level for 20 min also demonstrated that the saccule and cochlea (pars inferior) are most readily damaged structures, where the utricle and semicircular canals (pars superior) remain free of structural changes. [15] The mechanism of noise-induced hearing loss can be classified as direct mechanical injury or metabolic damage to the organ of Corti. The latter includes ischemia, generation of reactive oxygen species (ROS), toxic free radicals, metabolic exhaustion, and ionic imbalance in the inner ear fluid. The extent of noise effect on cochlear blood flow appears to be heavily influenced by the duration and intensity of the noise exposure. [16] Although the cochlea receives its blood supply mainly from the common cochlear artery and the saccule is supplied by anterior and posterior vestibular arteries, all these arteries originate from the labyrinthine artery. Therefore, as Wang et al. [14] mentions, as the duration and intensity of the noise exposure increased, reduced blood flow may have led to permanent hearing threshold shifts and abnormal VEMP responses.

The current study indicated that the VEMP responses were abnormal or absent in 64% of the subjects in the experimental group. Wang et al. [14] reported abnormal VEMP in 50% NIHL subjects. Higher abnormal VEMP in this study may be due to the differences in the exposure duration and intensity of noise. Moreover, the subject inclusion from different occupation environment may be also contributing toward this difference. Another supporting study indicated bilateral sensory neural hearing impairment associated with symptoms of vestibular function dysfunction after chronic exposure to carbon di sulfide and noise. [4],[6]

The present findings suggest that malfunction of vestibular system is associated with NIHL. The results imply a strong possibility of vestibular system disturbances in subjects with chronic noise exposure, which can be identified by VEMP responses indicating saccular pathway abnormality. Therefore, metabolic damage to the sacculocollic reflex pathway may be, at least in part, responsible for the abnormal VEMPs in NIHL individuals.


  Conclusion Top


The present study demonstrated VEMP abnormalities in NIHL subjects reflecting the deviation in sacculo-collic function. Moreover, with an increase in the pure tone average hearing threshold, a VEMP abnormality also increases. It can also be concluded that VEMP, a noninvasive and user-friendly procedure, can be employed in noise-exposed individuals to assess sacculo-collic function.

 
  References Top

1.Noise induced hearing and noise induced vestibular disturbance. Retrieved Aug 19, 2009, Available from: http://www.dizziness-and-balance.com/disorders/hearing/noise.htm .  Back to cited text no. 1      
2.Golz A, Westerman ST, Westerman LM, Goldenberg D, Netzer A, Wiedmyer T, et al. The effects of noise on the vestibular system. Am J Otolaryngol 2001;22:190-6.  Back to cited text no. 2  [PUBMED]  [FULLTEXT]  
3.Shupak A, Bar-El E, Podoshin L, Spitzer O, Gordon CR, Ben-David J. Vestibular findings associated with chronic noise induced hearing impairment. Acta Otolaryngol 1994;114:579-85.  Back to cited text no. 3  [PUBMED]    
4.Salmivalli A, Rahko T, Virolainen E. The effect of loud noise on the vestibular system. Scand Audiol 1977;6:139-41.   Back to cited text no. 4  [PUBMED]    
5.Hodgkinson L, Prasher D. Effects of industrial solvents on hearing and balance: A review. Noise Health 2006;8:114-33.   Back to cited text no. 5  [PUBMED]  Medknow Journal  
6.Kowalska S, Sulkowski W, Sinczuk-Walczak H. Assessment of the hearing system in workers chronically exposed to carbon di sulphide and noise. Med Pr 2000;51:123-38.  Back to cited text no. 6      
7.Ylikoski J, Juntunen J, Matikainen E, Ylikoski M, Ojala M. Subclinical vestibular pathology in patients with noise induced hearing loss from intense impulse noise. Acta Otolaryngol 1988;105:558-63.  Back to cited text no. 7  [PUBMED]    
8.Sohmer H, Elidan J, Plotnik M, Freeman S, Sockalingam R, Berkowitz Z, et al. Effect of noise on the vestibular system- vestibular evoked potential studies in rats. Noise Health 1999;2:41-52.  Back to cited text no. 8  [PUBMED]  Medknow Journal  
9.Halmagyi GM, Curthoys IS, Colebatch JG, Aw ST. Vestibular responses to sound. Ann N Y Acad Sci 2005;1039:54-67.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]  
10.Minor LB. Clinical manifestations of superior semicircular canal dehiscence. Laryngoscope 2005;115:1717-27.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]  
11.Halmagyi GM, Curthoys I. Clinical testing of otolith functions. New York Academy of Sciences 2000; 871: 195-204. Retrieved Janu 30, 2006. Available from: http://www.annalsnyas.org/cgi/content/abstract/871/1/195  Back to cited text no. 11      
12.Colebatch JG. Vestibular evoked myogenic potentials. Curr Opin Neurol 2001;14:21-6.  Back to cited text no. 12  [PUBMED]  [FULLTEXT]  
13.Colebatch JG, Halmagyi GM, Skuse NF. Myogenic potentials generated by a click -evoked vestibulocollic reflex. J Neurol Neurosurg Psychiatry 1994;57:190-7.  Back to cited text no. 13  [PUBMED]  [FULLTEXT]  
14.Wang YP, Young YH. Vestibular evoked myogenic potentials in chronic noise induced hearing loss. Otolaryngol Head Neck Surg 2007;137:607-11.  Back to cited text no. 14  [PUBMED]  [FULLTEXT]  
15.McCabe BF, Lawrence M. the effects of intense sound on the non-auditory labyrinth. Acta Otolaryngol 1958;49:147-57.  Back to cited text no. 15  [PUBMED]    
16.Lamm K, Arnold W. The effect of blood flow promoting drugs on cochlear blood flow, perilymphatic pO2 and auditory function in the normal and noise-damaged hypoxic and ischemic guinea pig inner ear. Hear Res 2000;141:199-219.  Back to cited text no. 16  [PUBMED]    

Top
Correspondence Address:
Kaushlendra Kumar
Kasturba Medical College, Mangalore, Karnataka
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1463-1741.64973

Rights and Permissions


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]

This article has been cited by
1 Falls Risk and Hospitalization among Retired Workers with Occupational Noise-Induced Hearing Loss
Serge André Girard,Tony Leroux,René Verreault,Marilène Courteau,Michel Picard,Fernand Turcotte,Julie Baril
Canadian Journal on Aging / La Revue canadienne du vieillissement. 2014; 33(01): 84
[Pubmed] | [DOI]
2 Vestibular receptors contribute to cortical auditory evoked potentials
Neil P.M. Todd,Aurore C. Paillard,Karolina Kluk,Elizabeth Whittle,James G. Colebatch
Hearing Research. 2013;
[Pubmed] | [DOI]
3 Ocular Vestibular Evoked Myogenic Potential Using Different Test Stimuli
Dessai Teja Deepak,Jayashree S. Bhat,Kaushlendra Kumar
ISRN Otolaryngology. 2013; 2013: 1
[Pubmed] | [DOI]
4 Development of a surgical instrument for measuring forces applied to the ossicles of the middle ear
Sheedy, M. and Bergin, M. and Wylie, G. and Ross, P. and Dove, R. and Bird, P.
Australasian Physical and Engineering Sciences in Medicine. 2012; 35(4): 503-510
[Pubmed]
5 Association between Hearing Loss and Saccular Dysfunction in Older Individuals
Zuniga, M.G. and Dinkes, R.E. and Davalos-Bichara, M. and Carey, J.P. and Schubert, M.C. and King, W.M. and Walston, J. and Agrawal, Y.
Otology and Neurotology. 2012; 33(9): 1586-1592
[Pubmed]
6 Development of a surgical instrument for measuring forces applied to the ossicles of the middle ear
Michael Sheedy,Mike Bergin,Grant Wylie,Peter Ross,Richard Dove,Phil Bird
Australasian Physical & Engineering Sciences in Medicine. 2012; 35(4): 503
[Pubmed] | [DOI]
7 Association Between Hearing Loss and Saccular Dysfunction in Older Individuals
Maria Geraldine Zuniga,Roni E. Dinkes,Marcela Davalos-Bichara,John P. Carey,Michael C. Schubert,W. Michael King,Jeremy Walston,Yuri Agrawal
Otology & Neurotology. 2012; 33(9): 1586
[Pubmed] | [DOI]



 

Top