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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Hyperbaric oxygen for hearing loss and tinnitus
Scientific title
For adults with sudden sensorineural hearing loss, with or without tinnitus, and with an onset within the past 14 days, does the application of hyperbaric oxygen therapy, in addition to the standard therapy of oral steriods, result in an improvement in hearing, tinnitus or quality of life?
Secondary ID [1] 288160 0
Nil known
Universal Trial Number (UTN)
Nil known
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Acute, sudden sensorineural hearing loss, with or without tinnitus where no definite cause can be identified. 237348 0
Condition category
Condition code
Ear 239669 239669 0 0

Study type
Description of intervention(s) / exposure
Hyperbaric oxygen therapy (HBOT). Daily sessions Monday to Friday for 2 hours at 2.0 ATA (202.6 kPa) while breathing 100% oxygen. Total number of treatments 15 over three consecutive weeks.
Participants will also take the standard medication (see below) starting on the same day as the first hyperbric oxygen session.
Intervention code [1] 237010 0
Treatment: Other
Intervention code [2] 237015 0
Treatment: Drugs
Comparator / control treatment
Prednisone orally, 50 mg daily for ten days and then tailing off by 5 mg per day until no further dose. Total 21 day course.
Participants will recieve a sham hyperbaric exposure involving 15 sessions on the same schedule as the HBOT group, but breathing air. These participants will be compressed to approximately 1.3 atmospheres at the start of each sham session to simulate the 'real' treatment. They will then be slowly returned to 1 ATA for the majority of the session time. The compression to 1.3 atmospheres will then be repeated at the end to simulate decompression.
Control group

Primary outcome [1] 240444 0
Pure tone average threshold (decibels) using standard pure tone audiometry at 500, 1000, 1500, 2000, 3000, 4000, 6000 and 8000 Hertz.
Timepoint [1] 240444 0
End of HBOT or sham therapy and three months post-therapy.
Secondary outcome [1] 244949 0
Visual analogue scale of tinnitus loudness
Timepoint [1] 244949 0
End of HBOT or sham therapy and three months post-therapy.
Secondary outcome [2] 244950 0
The Modified Amsterdam Inventory for Auditory Disability and Handicap. This is a measure of impact on daily life of hearing loss.
Timepoint [2] 244950 0
End of HBOT or sham therapy and three months post-therapy.

Key inclusion criteria
All adult patients (>18 yrs) presenting with idiopathic sudden sensorineural hearing loss (ISSHL), with or without tinnitus and where the first hyperbaric session can be administered within 14 days of the onset of symptoms. Diagnosis will exclude other causes of sudden hearing loss historically (e.g. Menieur’s disease, barotrauma, noise-induced hearing loss, ototoxic drugs) and by a magnetic resonance image (MRI) of the affected side to exclude an acoustic neuroma or other tumour.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Patient refusal (HBOT will not be offered to those who refuse to participate),
Contraindications to HBOT including inability to equalise the middle ear or respiratory sinuses, claustrophobia, pneumothorax, previous bleomycin administration or severe respiratory disease with carbon dioxide retention, presence of hearing decrement (documented) for greater than two weeks.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be the responsibility of a single central research officer not otherwise involved in the trial or in treatment of patients in any of the participating centres.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation officer will use a random number generating program provided at the ‘research randomiser’ site ( We will ensure approximately equal numbers of participants in each treatment group at each participating centre by using a separate randomisation schedule at each centre and permuted blocks. There will be three separate randomisations schedules for mild hearing loss (>10 to 30dB hearing loss at any frequency on pure tone audiometry), moderate hearing loss (>30 to 90dB) and severe hearing loss (>90dB) in order to examine the effect of HBOT at different levels of severity.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Stopped early
Data analysis
Reason for early stopping/withdrawal
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 237394 0
Name [1] 237394 0
Undersea and Hyperbaric Medical Society (part)
Address [1] 237394 0
21 West Colony Place
Durham, NC 27705
Country [1] 237394 0
United States of America
Primary sponsor type
Michael Bennett
c/- Dept. of Diving and Hyperbaric Medicine
Level 1, Prince of Wales Hospital
Barker St
NSW 2031
Secondary sponsor category [1] 236893 0
Name [1] 236893 0
Jan Lehm
Address [1] 236893 0
c/- Dept. of Diving and Hyperbaric Medicine
Level 1, Prince of Wales Hospital
Barker St
NSW 2031
Country [1] 236893 0
Other collaborator category [1] 793 0
Name [1] 793 0
Tom Kertesz
Address [1] 793 0
c/- Dept. Ear Nose and Throat Surgery
Prince of Wales Hospital,
Barker St
NSW 2031
Country [1] 793 0

Ethics approval
Ethics application status
Ethics committee name [1] 239525 0
South Eastern Sydney Area Health Service, NSW
Ethics committee address [1] 239525 0
Level 1, Edmund Blackett Building
Prince of Wales Hospital
Randwick, NSW 2031
Ethics committee country [1] 239525 0
Date submitted for ethics approval [1] 239525 0
Approval date [1] 239525 0
Ethics approval number [1] 239525 0

Brief summary
In this study, we aim to show whether hyperbaric oxygen therapy (HBOT) is beneficial for patients with sudden onset of hearing loss (with or without a ringing in the ears) where no cause can be found for the hearing loss.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 29961 0
Prof Michael Bennett
Address 29961 0
Dept Diving and Hyperbaric Medicine
Level 1, Prince of Wales Hospital
Randwick, NSW 2031
Country 29961 0
Phone 29961 0
+61 2 9382 3880
Fax 29961 0
Email 29961 0
Contact person for public queries
Name 13208 0
Prof Michael Bennett
Address 13208 0
c/- Dept. Diving and Hyperbaric Medicine
Level 1, Prince of Wales Hospital
Barker St.
NSW 2031
Country 13208 0
Phone 13208 0
+61 2 9382 3880
Fax 13208 0
Email 13208 0
Contact person for scientific queries
Name 4136 0
Prof Michael Bennett
Address 4136 0
c/- Dept. Diving and Hyperbaric Medicine
Level 1, Prince of Wales Hospital
Barker St.
NSW 2031
Country 4136 0
Phone 4136 0
+61 2 9382 3880
Fax 4136 0
Email 4136 0

No information has been provided regarding IPD availability
Summary results
No Results