Table 1.
The percentages of hearing gain and recovery in studies that compared HBOT against medical therapy (MT) in ISSHL
| Author | Year | Dx | Study design | Medical therapy | Time till initiation of HBOT | Salvage? | Absolute hearing loss (dB) | Relative hearing loss (%)a | Complete recovery (%) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|
| Bayoumy [126] | 2019 | AAT | RS | SS vs SS + HBOT | 4.4 | No |
HBOT: 23.5 MT: 12.5 |
HBOT: 57.6 MT: 31.4 | HBOT: 61.1 MT: 8.3 | Early treatment (within 7 days) was significantly better than after 7 days in the HBOT group |
| Hosokawa [127] | 2018 | ISSHL | RS | SS vs ITS + SS vs HBOT + SS | 4.5 | No | NA | NA |
HBOT: 26.1 SS: 6.3 |
Overall recovery in the HBOT group was 78.3% vs 32.5% in the SS group (P < 0.001) |
| Khater [125] | 2018 | ISSHL | RS | MT: SS + ITS + Acyclovir vs HBOT + MT | ≤ 7 | No | HBOT: 54.8 MT: 43.8 | HBOT: 76.1 MT: 60.9 | HBOT: 72.7 MT: 45.5 | Early treatment (within 7 days) with combination therapy showed better results |
| Cho [124] | 2018 | ISSHL | PS | SS + ITS vs SS + ITS + HBOT | 4.1 | No | HBOT: 47.3 MT: 37.7 | HBOT: 65.7 MT: 40.8 | HBOT: 36.7 MT: 16.7 | Significantly better results in favor of HBOT on 0.5 and 1 kHz and word discrimination score |
| Krajcovicova [123] | 2018 | ISSHL | PS | MT: SS, BH, Agapurin vs MT + HBOT | ≤ 7 | No | HBOT: 20.0 MT: 11.5 | HBOT: 61.7 MT: 28.6 | HBOT: 6.4 MT: 0.0 | Better results for HBOT with regard to hearing gains and complete recovery (> 10 dB hearing gain) |
| Almosnino [122] | 2018 | ISSHL | RS |
ITS or SS (presalvage) ITS vs ITS + HBOT |
29.1 | Yes | HBOT: 17.9 MT: 15.0 | HBOT: 22.9 MT: 22.0 | NA | No difference between combination therapy and ITS alone as salvage therapy |
| Chi [121] | 2018 | ISSHL | PS | MT: SS + PF + DX vs MT + HBOT | 4.2 | No | NA | NA | HBOT: 26.7 MT: 10.0 | Better hearing recovery in the HBOT group (P = 0.043) |
| Sun [139] | 2018 | ISSHL | RS | ITS vs HBOT vs control | 5.3 + 10 | Yes | NA | NA | NA | No difference between the three groups |
| Xie [120] | 2018 | ISSHL | RS | SS, blood flow promoters + vitamin B complex + HBOT | 7.8 | No | NA | NA | 19.7 | Prognostic factors: initial hearing loss, vertigo, early onset of HBOT (better), number of HBOT treatments, profound hearing loss, flat and ascending audiogram |
| Van Haesendonck [119] | 2018 | AAT | PS | SS + HBOT | 4.1 | No | NA | NA | NA | Significantly less TFI, VASM SNHL, tinnitus and subjective hearing loss after HBOT |
| Ricciardello [118] | 2017 | ISSHL | RS | MT: IVS + SS + pantoprazole + glycerol (10%), enoxaparin sodium vs MT + HBOT | 7.2 | No | NA | NA |
HBOT: 44.1 MT: 31.8 |
Age, time since onset of hearing loss, audiometric type and vertigo were significantly correlated with recovery |
| Tasdöven [150] | 2017 | ISSHL | RS | SS vs SS + ozone (MT) vs HBOT | NA | No | NA | NA |
HBOT: 11.5 MT: 17.6 SS: 22.2 |
More response to treatment (gain > 15 dB) in the MT group compared to corticosteroids only and HBOT (82.4 vs 50.8 vs 61.5%) |
| Hosokawa [138] | 2017 | ISSHL | RS |
SS (presalvage) HBOT vs no therapy |
< 30 | Yes | NA | NA | HBOT: 9.6 MT: 6.2 |
Age, initial hearing level and time from onset of symptoms till therapy were all not significantly predictive for hearing recovery The percentage of no change was lower in the HBOT group (53.9%) compared to the control group (67.5%) |
| Hosokawa [131] | 2017 | ISSHL | RS | ITS + HBOT | ≤ 7 or > 7 | No | NA | NA | 25.5 | The improvement rate was significantly higher if treatment was within 7 days (82.2%) of onset of symptoms compared to > 7 days (42.7%, P < 0.001). Younger patients (≤ 60 years) had significantly better improvement rate |
| Ajduk [134] | 2017 | ISSHL | RS |
SS (presalvage) HBOT vs no therapy |
23 + 11.4 | Yes | NA | NA | NA | Significant hearing improvements at 0.25; 0.5 and 8 kHz after HBOT. Significant hearing gains on all frequencies when hearing loss was > 60 dB |
| Lamm [152] | 2016 | ISSHL | CR | ITS + HBOT | NA | Yes | NA | NA | NA | Beneficial effect of salvage HBOT |
| Akil [117] | 2016 | ISSHL | RS | SS + HBOT | 4.1 | No |
Uni: 22.1 Bi: 8.2 |
Uni: 32.0 Bi: 12.6 |
NA |
Unilateral vs bilateral ISSHL No effect of HBOT in bilateral hearing loss |
| Gülüstan [116] | 2016 | ISSHL | RS | ITS vs HBOT | 11.3 | Yes |
HBOT: 12.8 ITS: 20.2 |
HBOT: 21.1 ITS: 28.3 |
HBOT: 22.2 ITS: 20.0 |
No significant difference between HBOT and ITS |
| V/d Wal [153] | 2016 | ISSHL | CR | HBOT monotherapy | 333 min | No | NA | NA | 41.0 | HBOT resulted in hearing improvement in 80% of patients |
| Karatop-Cesur [132] | 2016 | ISSHL | RS | HBOT monotherapy | 6.8 | No | NA | NA | 53.8 | Better outcome with early treatment response (≥ 10 dB gain in the first week) |
| Sherlock [135] | 2016 | ISSHL | RS | HBOT monotherapy | 13 | No | 23 | 33.3 | NA | Younger age (< 60), hearing loss > 60 dB and early HBOT initiation were positive prognostic factors |
| Živaljević [154] | 2016 | ISSHL | RS | HBOT monotherapy | NA | No | 24.9 | 65.45 | 55.0 | Study recommended HBOT as primary treatment for ISSHL |
| Psillas [115] | 2015 | ISSHL | RS |
IVS + piracetam (presalvage) HBOT vs no therapy |
24 | Yes | HBOT: 14.9 MT: 2.6 |
HBOT: 21.8 MT: 3.7 |
HBOT: 6.6 MT: 0.0 |
No difference between patients within or later than 20 days. Authors suggest salvage HBOT after therapy failure |
| Pezzoli [114] | 2015 | ISSHL | PS |
IV mannitol (18%) + IV betamethasone (presalvage) Dexamethasone vs dexamethasone +HBOT |
9.7 days | Yes |
HBOT: 15.6 MT: 5.0 |
HBOT:21.6 MT: 8.2 |
HBOT: 4.3 MT: 0.0 |
Significant hearing improvement after HBOT for patients who failed primary therapy |
| Capuano [100] | 2015 | ISSHL | RS | IVS vs HBOT vs IVS + HBOT | < 90 | No | NA | NA |
HBOT: 58.0 IVS: 20.0 |
Significant more hearing gain when initial hearing ≥ 91 dB. Significant higher gains when therapy started within 14 days. Patients responding to therapy highest in combination group (84%) compared to HBOT and IVS (70% and 68%) |
| Edizer [113] | 2015 | ISSHL | RS | SS vs SS + LMWH vs SS + HBOT vs SS + LMWH + HBOT (MT) | No | NA | NA |
HBOT: 31.2 MT: 31.2 |
Time till treatment > 10 days had a worse prognosis. Age, degree of hearing loss and hypertension affect the prognosis of ISSHL | |
| Naiboğllu [112] | 2015 | ISSHL | PS | SS + HBOT vs SS + HBOT + ITS | ≤ 3 | No | 23.9 | 30.8 | 30 | Only beneficial effect of ITS in profound hearing loss |
| Attanasio [111] | 2015 | ISSHL | PS | HBOT + ITS | < 15 | No | 29.4 | 31.9 | 59.3 | No difference between HBOT treatment once or twice a day |
| Yildirim [110] | 2015 | ISSHL | RS | IVS + IV piracetam + HBOT |
Three groups ≤ 7, (8-14), > 14 |
No | 18.9 | 34.6 | NA | Treatment within 14 days significantly better than after 14 days |
| Guha [155] | 2015 | ISSHL | PS | HBOT monotherapy | NA | No | 17.6 | 22.1 | 54.9 | |
| Bonfort [109] | 2014 | AAT | RS | IVS, PF and HBOT | < 24 h | No | 18.3 | 53.8 | NA | |
| Yang [108] | 2013 | ISSHL | RS | ITS (MT) vs HBOT vs ITS + HBOT vs control | 5.2 | Yes | HBOT: 22.5 MT: 18.9 |
HBOT: 23.1 MT: 20.0 |
HBOT: 68.4 MT: 48.6 |
Significant difference in recovery rate (P = 0.018) in favor of combination therapy Significant higher gains on 0.25; 0.5, 2 kHz for combination therapy |
| Cvorovic [137] | 2013 | ISSHL | RCT | ITS vs HBOT | < 4 weeks | Yes | NA | NA | NA |
Significant hearing gain in favor of HBOT on 2 kHz (P < 0.05) Higher hearing gains in ITS group when initial hearing loss ≥ 81 dB |
| Suzuki [107] | 2012 | ISSHL | RS | SS + ITS vs HBOT + SS | 6.1 | No |
HBOT: 26.2 MT: 27.0 |
HBOT: 51.6 MT: 50.2 |
HBOT: 29.3 MT: 21.6 |
Significant higher recovery rate in favor of MT (79.4 vs 68.4%, P = 0.048). Prognostic factors: ITS, age, days from onset to treatment Results of study in favor of MT |
| Filipo [156] | 2012 | ISSHL | PS | HBOT + IVS vs HBOT + ITS | < 15 | No | NA | NA | NA | ITS better in patients with severe hearing loss (70–90 dB) |
| Imsuwansri [106] | 2012 | ISSHL | CR | SS + HBOT | 36 | Yes | NA | NA | NA | Case recovered completely after salvage HBOT |
| Alimoglu [99] | 2011 | ISSHL | RS | SS (A) vs HBOT (B) + SS (C) vs ITS vs HBOT (D) | ≤ 3, ≤ 15 or > 15 | No | NA | NA |
HBOT(B): 42.6 SS: 19.0 |
Treatment started within 15 days was significantly better in each group Hearing gain was significantly higher in group B compared to A |
| Liu [105] | 2011 | ISSHL | RS | SS vs SS + DX vs SS + DX + HBOT | ≤ 14 | No | NA | NA |
HBOT: 15.2 MT: 30.3 |
Significantly higher gain in the HBOT group when initial hearing loss ≥ 91 dB (P = 0.03) |
| Holy [130] | 2011 | ISSHL | RS | Methylprednisone + VD + HBOT | < 10, > 10 | Yes | NA | NA | 58.1 | More hearing recovery when treated within 10 days |
| Körpinar [157] | 2011 | ISSHL | RS | HBOT monotherapy | 11.2 | Yes | 29.5 | NA | NA | Prognostic factors: early onset, high number HBOT sessions, steroid usage, profound hearing loss |
| Ohno [104] | 2010 | ISSHL | RS |
SS + IVS (presalvage) SS + ATP + vitamins vs HBOT |
7.4 weeks | Yes | HBOT: 5.2 MT: 2.0 |
HBOT: 8.2 MT: 3.5 |
HBOT: 2.0 MT: 0.0 |
Very modest effect of HBOT due to very late start of therapy |
| Lafère [103] | 2010 | AAT | RS | T1: SS + piracetam vs HBOT + T1 vs HBOT + IVS + piracetam IV | 6–36 h | No |
HBOT: 20.6 MT: 5.58 |
NA | NA | Early treatment was beneficial in the HBOT groups |
| Cekin [102] | 2009 | ISSHL | RCT | SS vs HBOT + SS + famotidine | ≤3 | No | NA | NA |
HBOT: 55.3 MT: 42.9 |
Patients in the control group were more severely affected (95.9 dB vs 81.5 dB) |
| Ylikoski [78] | 2008 | AAT | RS | HBOT vs normobaric oxygen therapy | 16.8 | No | NA | HBOT: 69.3 NBOT: 56.2 | NA | More benefit from hyperbaric conditions compared to normobaric conditions |
| Fujimura [88] | 2007 | ISSHL | RS | SS vs HBOT + SS | 6.3 | No | NA |
HBOT: 64.4 MT: 56.0 |
HBOT: 17.9 MT: 25.4 | Hearing improvement rate was significantly higher in the HBOT group when initial hearing loss was ≥ 80 dB |
| Dundar [87] | 2007 | ISSHL | PS | NA | NA | NA | NA | NA | HBOT: 38.2 MT: 12.0 | |
| Satar [91] | 2006 | ISSHL | RS | MT: (vitamins + SS + DP piracetam) vs HBOT + MT | ≤ 5 | No |
HBOT: 35.5 MT: 37.0 |
HBOT: 52.1 MT: 45.0 | HBOT: 27.5 MT: 23.5 | Percentage improved ears is higher in the MT group (76.4 vs 60%, P = 0.364) |
| Desloovere [86] | 2006 | ISSHL | RS | MT: IVS + PF + starch vs HBOT (1.5 ATA) vs HBOT (2.5 ATA) |
HBOT (2.5): 30.8 HBOT (1.5): 54.3 |
Yes |
HBOT (2.5): 19.7 MT: 2.6 |
HBOT(2.5): 25.9 MT: 8.0 |
HBOT(2.5): 41.0 MT: 6.3 |
Early treatment with HBOT was significantly better (P < 0.0001) Significantly higher gain after HBOT-2.5 (19.7 dB vs 2.6) |
| Horn [85] | 2005 | ISSHL | PS | HBOT | 5.8 weeks | Yes | NA | NA | NA | No important differences |
| Winiarski [77] | 2005 | AAT | RS | Pharmacological treatment + HBOT | 7 | No | NA | NA | NA | Significant difference on 4.6 and 8 kHz when treatment was started within 5 days |
| Topuz [83] | 2004 | ISSHL | RCT | MT: SS, DX, DP, PF, salt restriction vs MT + HBOT | ≤ 14 | No | HBOT: 33.3 MT: 17.4 |
HBOT: 47.3 MT: 24.7 |
NA | Significantly higher hearing gains in HBTO patient when initial hearing loss greater than 61 dB |
| Racic [82] | 2003 | ISSHL | RS | IV PF vs HBOT | ≤ 7 | No |
HBOT: 46.4 MT: 21.5 |
HBOT: 59.0 MT: 26.9 |
HBOT: 47.1 MT: 6.3 |
Significant hearing gains in the HBOT group (P = 0.001). After 9 months, 94.5% of HBOT patients had physiological hearing or mild hearing loss compared to 18.8% in the control group |
| Aslan [81] | 2002 | ISSHL | RS | MT BH + SS + SGB vs MT + HBOT | 5.8 | No | HBOT: 37.9 MT: 20.0 |
HBOT: 55.7 MT: 28.6 |
NA | In the HBOT group hearing gains were significantly higher in younger patients (< 50 years) |
| Inci [158] | 2002 | ISSHL | RS | HBOT | NA | Yes | 9.7 | 12.8 | 3.9 | |
| Fattori [133] | 2001 | ISSHL | RCT | Buflomedil (IV) vs HBOT | ≤ 2 | No | NA | HBOT: 61.3 MT: 24.0 |
HBOT: 56.7 MT: 25.0 |
Authors recommend HBOT for ISSHL |
| Nakashima [80] | 1998 | ISSHL | RS | Vitamin B, vasodilator, metabolic activators | NA | Yes | NA | NA | NA | HBOT within 1 week of onset of SSNHL symptoms was significantly better |
| Schwab [142] | 1998 | ISSHL | RS | Plasma expanders + PF vs HBOT | < 14 | No |
HBOT: 15.6 MT: 10.7 |
NA | NA | |
| Cavallazzi [101] | 1996 | ISSHL | RS | MT: SS + DX + vitamins + antiviral drugs + nicotinic acid + flunarizine vs MT + HBOT | NA | No | NA | NA |
HBOT: 52.9 MT: 43.3 |
HBOT significantly better when treated within 3 days (95% vs 71%) |
| Vavrina [75] | 1995 | AAT | RS | Dextran + prednisone + HBOT vs control | < 3 | No |
HBOT: 121.3 MT: 74.3 |
NA | NA | |
| Dauman [159] | 1993 | ISSHL | PS | HBOT once or HBOT twice a day (both were combined with naftidrofuryl) | NA | No | NA | NA | NA | No difference between treating patients once or twice a day with HBOT |
| Zennaro [160] | 1993 | ISSHL | RS | Normovolemic dilution and HBOT | 87 | No | NA | NA | NA | Study obtained good results in more than half of the patients treated with HBOT |
| Pilgramm [76] | 1985 | AAT | PS | Sorbitol, dextran, betahistine + HBOT | NA | NA | NA | NA | NA | Beneficial effect of HBOT treatment (92% and 83% vs 87% and 62%) |
| Muzzi [89] | 1984 | ISSHL | RS | HBOT | <15, (15-30), > 30 | Yes | 8.6 | 16.0 | NA | ≥ 50 years had better hearing improvement |
| Demaertelaere [74] | 1981 | AAT | RS | NA | NA | NA | NA | NA | NA | |
| Goto [73] | 1979 | ISSHL | RS | MT (VD, SS, vitamins) vs HBOT + SGB vs MT + HBOT + SGB | NA | No | NA | NA | NA | All patients improved (10 dB) in the group with all the treatments combined |
| De Heyn [71] | 1976 | AAT | CR | VD vs VD and HBOT | NA | NA | NA | NA | NA | |
| Lamm [70] | 1971 | ISSHL | CR | NA | NA | NA | NA | NA | NA | |
| Appaix [69] | 1970 | ISSHL | CR | NA | NA | NA | NA | NA | NA |
NA not available, DP diazepam, DX dextran, PF pentoxifylline, BH betahistine, SGB stellate ganglion blocker, VD vasodilators, LMWH low-molecular weight heparin, SS systemic corticosteroids, ITS intratympanic corticosteroids, IVS intravenous corticosteroids, RS retrospective, PS prospective, CR case report
aRelative hearing gain has been calculated for studies by dividing the absolute hearing gain by the initial hearing loss. The studies were sorted by date of publication