Home Email this page Print this page Bookmark this page Decrease font size Default font size Increase font size
Noise & Health  
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Email Alert *
Add to My List *
* Registration required (free)  

   Article Figures
   Article Tables

 Article Access Statistics
    PDF Downloaded36    
    Comments [Add]    

Recommend this journal


  Table of Contents    
Year : 2022  |  Volume : 24  |  Issue : 113  |  Page : 75-81
Effect of constraint-induced music therapy in idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis

1 Department of Otorhinolaryngology, International Medical University, Seremban Clinical Campus, Seremban, Negeri Sembilan, Malaysia
2 Department of Surgery, International Medical University, Seremban Clinical Campus, Seremban, Negeri Sembilan, Malaysia
3 Department of Family Medicine, International Medical University, Seremban Clinical Campus, Seremban, Negeri Sembilan, Malaysia
4 Department of Otorhinolaryngology-Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia Health Campus, Kota Bharu, Kelantan, Malaysia

Click here for correspondence address and email
Date of Submission15-May-2021
Date of Decision16-Oct-2021
Date of Acceptance13-Nov-2021
Date of Web Publication25-Jul-2022

Background: Idiopathic sudden sensorineural hearing loss (ISSNHL) is commonly encountered in audiologic and otolaryngologic practice. Constraint-induced music/sound therapy (CIMT) is characterized by the plugging of the normal ear (constraint) and the simultaneous, stimulation of the affected ear with music, which is based on a well-established neurorehabilitation approach. Corticosteroid therapy (CST) is the current mainstay of treatment. The prognosis for hearing recovery depends on many factors including the severity of hearing loss, age, and presence of vertigo. Objective: To analyze the effectiveness of CIMT with CST in ISSNHL. Methods: We performed a systematic search, using specific keywords relevant to our study, in PubMed, Cochrane Central Register of Controlled Trials, and additional sources of published trials till December 2020. We then screened all search results obtained according to our inclusion/exclusion criteria and performed a quality assessment on all studies using the Newcastle–Ottawa scale and using MedCalc, a meta-analysis was performed on suitable studies. Results: The recovery rates of three included nonrandomized studies were assessed at 1 to 3 months. A total of 229 (CST: 131, CST + CIMT: 98) patients were pooled for meta-analysis. The meta-analysis using the random-effect model found the relative risk of recovery rate within 3 months to be 1.213 (95% confidence interval 0.709–2.074), a result that is not statistically significant. Conclusion: Although our analysis results do not demonstrate the noticeable effect of CIMT in ISSNHL, it can support be a gainful adjunct to CST for better hearing results than CST alone. Therefore, it needs further prospective randomized controlled multicenter trials with a large sample.

Keywords: Hearing loss, idiopathic, music, sudden sensorineural

How to cite this article:
Vasiwala RA, Elhariri SY, Teng CL, Mohamad I. Effect of constraint-induced music therapy in idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis. Noise Health 2022;24:75-81

How to cite this URL:
Vasiwala RA, Elhariri SY, Teng CL, Mohamad I. Effect of constraint-induced music therapy in idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis. Noise Health [serial online] 2022 [cited 2023 Jun 1];24:75-81. Available from: https://www.noiseandhealth.org/text.asp?2022/24/113/75/351964

Key Message: Music/sound therapy has some role to improve hearing in patients with ISSNHL.

  Introduction Top

Idiopathic sudden sensorineural hearing loss (ISSNHL) is characterized by a sudden hearing loss without precipitating factor and is diagnosed clinically in audiology and otolaryngologic practice. The global incidence of ISSNHL is 27 per 100,000 in western countries.[1] ISSNHL is defined by the United States National Institute for Deafness and Communication Disorders as a sensorineural hearing loss of 30 dB or more in at least three contiguous audiometric frequencies occurring within 3 days.[2] Although the potential differential diagnoses for ISSNHL are vast, in most patients an etiologic factor is not identified.[3] The lack of clarity regarding etiology has led to the development of varied treatment options. Although there is no agreement on the specific treatment for sudden deafness, a widely used standard treatment is a tapering course of oral corticosteroid, with a success rate of 50% to 80% against placebo or no treatment.[4],[5] Constraint-induced music/sound therapy (CIMT) applied by plugging an ear mold in the outer canal of the patient’s unaffected ear and presenting enjoyable music to the affected ear (frequency range 125–8000 Hz). Ask the patients whether they perceive the music with the affected ear to confirm that cross hearing does not occur. CIMT, because of its neuroplasticity effect on the nervous system reorganization, has been proposed as a potential treatment option. This therapy is not yet being recommended in the clinical practice guideline, but a few clinical studies appear to support it. Our objective for this systematic review is to synthesize the effectiveness of CIMT with corticosteroid therapy (CST) in ISSNHL.

  Methods Top

Protocol and registration

This systematic review is registered with Prospero. Registration number: PROSPERO 186606.

Eligibility criteria

Inclusion criteria:
  1. Observational studies or clinical trials that enrolled adult patients suffering from unilateral ISSNHL (hearing loss at least 30 dB in three or more consecutive frequencies in the audiogram).
  2. Music/sound therapy was administered to an intervention group.
  3. Drugs were administered to the control group.

The following studies were excluded: studies that included children, case reports, or observational studies without follow-up or studies assessing other interventions in addition to music therapy (e.g., cochlear implant).

Information sources and search strategies

The search of PubMed/Medline and Scopus was conducted till December 15, 2020 using a combination of these search strings: sensorineural hearing loss AND music therapy. Additional search using the above search terms was also conducted on Google Scholar. We did not restrict the year or language of the article. We also have verified the reference list of eligible articles as well as selected reviewed articles. All articles retrieved were processed in the EndNote X7 citation manager.

Study selection

Two investigators independently checked the titles and abstracts for eligible studies applying the eligibility criteria as in the study protocol. Any disagreement between investigators was resolved by consensus.

Data collection process and data items

Two investigators independently extracted data from the included studies and disagreement between investigators were resolved by consensus. The following data were extracted from the included studies: name, year and country of the studies, sample size (intervention and control group), details of the music therapy (target group), details of interventions (control group), assessment of hearing (frequency), follow-up duration, hearing threshold (baseline, follow-up), and hearing recovery rate.

Risk of bias in individual studies

The reviewer was not blinded to the authors, institutions, journals of publication, or results of the studies. On the Newcastle–Ottawa scale, one star was awarded for each item within the selection and outcome categories and two stars could be given for comparability.[6]

Summary measure

The recovery rate at 1 to 3 months is taken as the main outcome measure. It is defined as a 50% improvement in the hearing threshold at the follow-up in comparison with baseline data. Where baseline data are not available, comparison with the contralateral normal ear is acceptable. Recovery was defined as complete or normal as a hearing threshold of ≤25 dB (normal hearing) CIMT group or hearing improvement ≥90% compared to the baseline hearing. The recovery rate in interventions and control group was presented as dichotomous data. MedCalc software (MedCalc Software Ltd, Belgium) was used to synthesize the recovery rate. Data from individual studies were combined using either fixed-effect model or random-effect model, the latter is preferred in this study heterogeneity as determined using I2 exceeds 50%.[7] This systematic review has been prepared following the PRISMA guideline.[8]

  Results Top

Study selection

In the initial search, we found 73 studies in PubMed, Scopus, and Google Scholar [Figure 1]. No relevant studies were identified in the Cochrane Central Registry of Clinical Trials. After excluding duplicates and reviewing the title and abstract, only four articles met our inclusion criteria. Upon reviewing the full text of these four articles, one study by Sekiya et al.[9] was excluded because it contained similar data to that of Okamoto et al.[10] Thus, only three observational studies were included in this systematic review.
Figure 1 Flow chart of search results.

Click here to view

Study characteristics

Three studies with similar characteristics are presented in [Table 1]. All studies are observational studies, either prospective/retrospective or a combination. López-González et al.[11] used retrospective data, whereas Kuo[12] selected retrospective data of the year 2016 for the control group treated with the steroid and prospective data of the year 2018 for the intervention group treated with CST + CIMT. Okamoto et al.[10] used prospective data for both groups. Considering the sample size, the number of patients in each study was too small to attain statistical significance.
Table 1 Characteristics of included studies

Click here to view

There was some variability in the time interval between the onset of the hearing loss and treatment, from 1 to 10 days in all three studies. The intervention used was music in all included studies; however, in the study by López-González et al.[11] both used music and sound therapy.

There were some variabilities of the treatment option in the control group in all studies such as a different type of corticosteroid and dosage as well as nonsteroid therapy including vasodilator and antioxidant in the study by López-González et al.[11] Though the resulting outcome has shown a good recovery rate, it could also potentially result in a bias.

For example, López-González et al.[11] used corticosteroids, vasodilators, and speech or music as a treatment for 12 hours per day for 30 days. While Okamoto et al. and Kuo[10],[12] used CST with music for 6 hours/day for 30 days. Regarding the presentation of the music, López-González et al.[11] used speech or music initially to the healthy ear later changed to the pathologic ear as soon as the patient began to hear the music slightly (range of 60 ± 10 dB) in the affected ear. But the other two studies by Okamoto et al. and Kuo[10],[12] used constraint music presented to the deaf ear by plugging the normal ear. All three studies had used pure-tone audiometry for hearing assessment. The follow-up for hearing recovery was different in each study [López-González et al.: up to 1 year (30 days, 3, 6, and 12 months; Kuo: up to 1 month (2, 4 weeks); Okamoto et al.: up to 3 months (2 weeks, 3 months)].[10],[11],[12]

Risk of bias within studies

In our reviewed studies, all were found to have at least seven stars (good quality) according to the Newcastle–Ottawa scale.[6]

Results of individual studies

The hearing recovery and audiometric hearing threshold (dB) as outcome measure at 500, 1000, and 2000 Hz were as follows [Table 2].
Table 2 Mean hearing thresholds at baseline and after 1-month follow-up

Click here to view

López-González et al.: hearing loss before treatment was 75.0 ± 0.5 dB in both (CIMT + CST) groups. Hearing improved by 32.4 ± 1.8 dB (75.8 ± 0.5, 42.4 ± 0.2 dB) in the CIMT group and 12.7 ± 0.7 dB (74.7 ± 0.5, 54.8 ± 0.6 dB) in the control group (CST) after 2 weeks and 4 weeks of treatment, respectively, music with corticosteroid was more effective.

Kuo: CIMT group, hearing loss before treatment was 68.433 ± 26.19 dB, P = 0.531. Hearing improved after 2 and 4 weeks of treatment, 10.62 dB (57.71 ± 31.08 dB), and 23.47 dB (44.86 ± 25.69 dB), respectively. In the CST group, the hearing loss before treatment was 62.48 ± 25.11 dB, both P < 0.001. The hearing improved after 2 and 4 weeks of treatment, 19.62 dB (42.86 ± 24.87 dB), P < 0.001) and 32.4 dB (30.34 ± 22.93 dB), respectively. The recovery rate with corticosteroid was a little high compared to CIMT, but statistically not significant. The two groups were comparable in terms of mean pretreatment hearing threshold (68.33 ± 26.19 dB in the CIMT group and 62.48 ± 25.11 dB in the non-CIMT group, P = 0.531). In the CIMT group, the mean posttreatment hearing threshold at 2 weeks posttreatment (57.71 ± 31.08 dB) and 4 weeks posttreatment (44.86 ± 25.69 dB) was significantly better than before treatment (68.33 ± 26.19 dB; P = 0.004 and 0.008, respectively). In the non-CIMT group, the mean postoperative hearing thresholds were significantly better at 2 weeks posttreatment (42.86 ± 24.87 dB) and 4 weeks posttreatment (30.34 ± 22.93 dB) than they were preoperatively (62.48 ± 25.11 dB, both P < 0.001). The mean hearing threshold at 4 weeks posttreatment (30.34 ± 22.93 dB) also presented a significant improvement over the hearing threshold at 2 weeks posttreatment (42.86 ± 24.87 dB, P < 0.001).

Okamoto et al.: CIMT group, hearing loss before treatment was 25.7 dB (21.7–29.9 dB). Hearing improved after 2 and 4 weeks of treatment 7.1 dB (2.9–11.7 dB) and 2.7 dB (0.5–5.2 dB). In the CST group, the hearing loss before treatment was 24.8 dB (20.7–29.0 dB). Hearing improved after 2 and 4 weeks of treatment 15.6 dB (10.5–21.2 dB) and 13.6 dB (9.3–18.4 dB). Though the number of participants using CIMT was less, the hearing improvement was comparable.

Synthesis of results

The recovery rates of three included studies were assessed at slightly different periods: 30 days,[11] 4 weeks,[12] and 3 months.[10] The meta-analysis using the random-effect model found the relative risk of recovery rate within 3 months to be 1.213 [95% confidence interval (CI) 0.709–2.074], a result that is not statistically significant [Figure 2].
Figure 2 Forest plot of the relative risk of recovery rate between intervention and control groups in included studies.

Click here to view

  Discussion Top

In our analysis, the intervention group treated with CST and CIMT has demonstrated better outcomes, but we cannot conclude that the better outcome was solely caused by the CIMT. Either of the combination of CST and CIMT might have enhanced each other effect. Compared to the CST, which has a well-known side effect and dose and duration dependent, CIMT might establish a reasonable and safe alternative treatment for ISSHL. In our meta-analysis using the random-effect model noted the relative risk of recovery rate within 3 months was 1.213 (95% CI 0.709–2.074), statistically not significant. But a possible benefit may be missed due to too few participants. Perhaps, it is essential to have large numbers of participants and prospective randomized control trials in the future.

Researchers suggested numerous therapeutic approaches to treat ISSNHL including constraint music, but the idiopathic nature of this condition is an added dilemma.[13],[14],[15] Because some patients recovered well with treatment (drugs), others have permanent hearing loss and some of the studies reported 32% to 70% spontaneous recovery without treatment.[16],[17] Despite the fact of the unknown mechanism of action, corticosteroid is the most favored drug in North America.[18],[19] In addition, the combination of the steroid with other drugs did not prove effective in ISSNHL (antiviral with steroid therapy versus placebo with steroid therapy).[20] In our current review, studies also showed quite good results with corticosteroid alone after 4 weeks.[10]

In the unilateral ISSNHL, the music (CIMT) presented to the affected ear directly stimulates the ciliated cells in the cochlea transferring the mechanical energy into electrical impulses to the auditory cortex through the auditory nerve which promotes functional recovery by preventing maladaptive plasticity changes.[16] López-González et al. reported in their study, three patients did not take the prescribed medication but were treated with sound therapy alone and recovered as 43%, 11%, and 50%, respectively, which support the effectiveness of the music therapy.[11] It is an optimistic therapeutic start that may indicate a new direction for the management of ISSNHL.[21] The effect of music has been proved on animals by few researchers as acoustic conditioning in guinea pigs as well as acoustic deprivation in chinchillas.[22],[23] They noted, considering music as an acoustic stimulant, the hair cell damage in the cochlea was less compared to deprived one. This means, acoustic energy stimulates the ciliated hair cells in the cochlea and can be transformed into electrical impulses that are transmitted to the auditory cortex through auditory nerves.[11] It has been supported that acoustic stimulation can compensate afferent neural inputs and prevents maladaptive neuroplasticity in the brain. Both effects could promote hearing recovery.[23],[24] Besides, music had an added effect in presbycusis to restrict the progress of hearing loss in mice.[24],[25]

Furthermore, the high variability of the natural history of ISSNHL may be because of multiple factors contributing to the pathogenesis of the disease. Therefore, in some of the patient’s spontaneous recovery observed in the early stage and worst with persistent longer symptoms.[26],[27] CST for SSNHL is considered the gold standard but still controversial. In our selected studies, CST was used in the control group demonstrated good outcomes. In 2012, López-González et al. compared [control group (65), intervention group (67)] the outcomes in ISSNHL reported much higher hearing recovery among patients who underwent stimulation via sound therapy (intervention group 75.8 ± 0.5, after 2 and 4 weeks 42.4 ± 0.2) [Table 2] compared to those without acoustic stimulation.[11]

In 2014, Okamoto et al.[10] adopted a neurorehabilitation approach to improve hearing in patients with ISSNHL that is supported by a similar method of treating stroke patients (constraint-induced movement therapy).[28] He reported, an interaural hearing gap in the intervention group was significantly smaller than that in the control group [intervention group (22), control group (53)] at 1 and 6 months after treatment (intervention group: 25.7 ± 4.1, after 4 weeks to 6 months 2.7 ± 2.3), no statistical significance.[10]


We encountered few limitations in our meta-analysis. Only three observational/cohort studies are available to the date and included in our study. Potential bias is likely due to the type of study. High heterogeneity among the studies is like small sample size, hearing threshold variance, and the different time points of recovery. All the participants were given music therapy with the corticosteroid, unable to detect the exact effect of music therapy.

  Conclusion Top

Although our analysis results do not demonstrate the visible effect of CIMT in ISSNHL, it can support be a gainful adjunct to CST for better hearing results than CST alone. Therefore, it needs further prospective randomized controlled multicenter trials with a uniform large sample.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Alexander TH, Harris JP. Incidence of sudden sensorineural hearing loss. Otol Neurotol 2013; 34: 1586–9.  Back to cited text no. 1
National Institute of Health. Sudden Deafness. Bethesda, MD: National Institutes of Health 2018. NIH publication 00–4757.  Back to cited text no. 2
Hughes GB, Freedman MA, Haberkamp TJ, Guay ME. Sudden sensorineural hearing loss. Otolaryngol Clin North Am 1996;29:393-405.  Back to cited text no. 3
Chandrasekhar SS, Tsai Do BS, Schwartz SR et al. Clinical practice guideline: Sudden hearing loss (update) executive summary. Otolaryngol Head Neck Surg 2019;161:195-210.  Back to cited text no. 4
Mirian C, Ovesen T. Intratympanic vs systemic corticosteroids in first-line treatment of idiopathic sudden sensorineural hearing loss: a systematic review and meta-analysis. JAMA Otolaryngol Head Neck Surg 2020;146:421-8.  Back to cited text no. 5
Wells GA, Shea B, O’Connell D et al. The Newcastle-Ottawa Scale (NOS) for Assessing the Quality of Nonrandomised Studies in Meta-analyses. Ontario: University of Ottawa; 2001. http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp.  Back to cited text no. 6
Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials. JAMA 1995;273:408-12.  Back to cited text no. 7
Page MJ, McKenzie JE, Bossuyt PM et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. PLoS Med 2021;18:e1003583.  Back to cited text no. 8
Sekiya K, Fukushima M, Teismann H et al. Neuro-rehabilitation approach for sudden sensorineural hearing loss. J Vis Exp 2016;107:e53264.  Back to cited text no. 9
Okamoto H, Fukushima M, Teismann H et al. Constraint-induced sound therapy for sudden sensorineural hearing loss − behavioral and neurophysiological outcomes. SciRep 2014;4:3927.  Back to cited text no. 10
López-González MA, Cambil E, Abrante A, López-Fernández R, Terapia EF. Sound therapy in sudden deafness. Acta Otorrinolaringol Esp 2012;63:165-72.  Back to cited text no. 11
Kuo CL. Neuroplastic effect of constraint-induced music therapy on hearing recovery in patients with sudden sensorineural hearing loss. Neurol Neurosci Res 2019;2:1-9.  Back to cited text no. 12
Stokroos RJ, Albers FW. The etiology of idiopathic sudden sensorineural hearing loss. A review of the literature. Acta Otorhinolaryngol Belg 1996;50:69-76.  Back to cited text no. 13
Cole RR, Jahrsdoerfer RA. Sudden hearing loss: an update. Am J Otol 1988;9:211-5.  Back to cited text no. 14
Shikowitz MJ. Sudden sensorineural hearing loss. Med Clin North Am 1991;75:1239-50.  Back to cited text no. 15
Jones N, Ludman H. Acquired sensorineural hearing loss. In: Ludman H, Wright T, eds. Diseases of the Ear. 6th ed. London, England: Arnold Publishers 1998. p. 495-7.  Back to cited text no. 16
Eisenman D, Arts HA. Effectiveness of treatment for sudden sensorineural hearing loss. Arch Otolaryngol Head Neck Surg 2000;126:1161-4.  Back to cited text no. 17
Thurmond M, Amedee RG. Sudden sensorineural hearing loss: etiologies and treatments. J La State Med Soc 1998;150:200-3.  Back to cited text no. 18
Mattox DE, Simmons FB. Natural history of sudden sensorineural hearing loss. Ann Otol Rhinol Laryngol 1977;86:463-80.  Back to cited text no. 19
Conlin AE, Parnes LS. Treatment of sudden sensorineural hearing loss: II. A meta-analysis. Arch Otolaryngol Head Neck Surg 2007;133:582-6.  Back to cited text no. 20
Haberkamp TJ, Tanyeri HM. Management of idiopathic sudden sensorineural hearing loss. Am J Otol 1999;20:587-95.  Back to cited text no. 21
Fukushima N, White P, Harrison RV. Influence of acoustic deprivation on recovery of hair cells after acoustic trauma. Hear Res 1990;50:107-18.  Back to cited text no. 22
Niu X, Tahera Y, Canlon B. Protection against acoustic trauma by forward and backward sound conditioning. Audiol Neurootol 2004;9:265-73.  Back to cited text no. 23
Willott JF, Bross L. Effects of prolonged exposure to an augmented acoustic environment on the auditory system of middle-aged C57BL/6J mice: cochlear and central histology and sex differences. J Comp Neurol 2004;472:358-70.  Back to cited text no. 24
Noreña AJ, Eggermont JJ. Enriched acoustic environment after noise trauma reduces hearing loss and prevents cortical map reorganization. J Neurosci 2005;25:699-705.  Back to cited text no. 25
Gulya AJ. Sudden sensorineural hearing loss: an otologic emergency. Compr Ther 1996;22:217-21.  Back to cited text no. 26
Rajan R, Irvine DR, Wise LZ, Heil P. Effect of unilateral partial cochlear lesions in adult cats on the representation of lesioned and unlesioned cochleas in primary auditory cortex. J Comp Neurol 1993;338:17-49.  Back to cited text no. 27
Taub E, Miller NE, Novack TA et al. Technique to improve chronic motor deficit after stroke. Arch Phys Med Rehabil 1993;74:347-54.  Back to cited text no. 28

Correspondence Address:
Rafiq Ahmed Vasiwala
Department of Otorhinolaryngology, International Medical University, Clinical Campus Seremban, Jalan Rasah, 70300 Seremban, Negeri Sembilan
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/nah.nah_33_21

Rights and Permissions


  [Figure 1], [Figure 2]

  [Table 1], [Table 2]