Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Autism Spectrum Disorder (ASD) is a condition where the main features are impairments in social interaction, difficulty with communication, and restrictive and repetitive behaviors. Hyperbaric oxygen therapy involves inhaling up to 100% oxygen at a pressure greater than one atmosphere (atm) in a pressurized chamber. The aim of this study is to test the effectiveness of hyperbaric oxygen therapy on the symptoms of ASD.

Who can participate?
Children aged 3-18 with Autism Spectrum Disorder (ASD)

What does the study involve?
Participating children are re-diagnosed by a qualified psychologist and aspects of their behavior and IQ are tested. Participants provide blood samples and undergo a scan before the start of the treatment. Participants are randomly allocated into two groups. One group follows a gluten and casein free diet supervised by a dietician for 4 months before the hyperbaric oxygen sessions. The other group receives no dietary preparation. All participants have 40 1-hour sessions of hyperbaric oxygen therapy at 2 ATA pressure at a rate of once a day for 8 weeks. There are no treatments or tests for 4 weeks after that, then participants have another 40 1-hour sessions at 1 ATA pressure at a rate of once a day for 8 weeks. There are no treatments or tests for 4 weeks after that.

What are the possible benefits and risks of participating?
The possible benefits are improvements in ASD symptoms and signs, which we are testing in our study. Participants may experience confinement anxiety and ear discomfort.

Where is the study run from?
King Saud University (Saudi Arabia)

When is the study starting and how long is it expected to run for?
January 2012 to January 2014

Who is funding the study?
King Abdulaziz City for Science and Technology (Saudi Arabia)

Who is the main contact?
Prof. Laila Y. AL-ayadhi

Trial website

Contact information



Primary contact

Prof Laila AL-Ayadhi


Contact details

Director of KSU-Autism Research and Treatment center (99)
Supervisor of Shaik AL-Amodi Autism Research Chair
Department of physiology (29)
Faculty of Medicine
King Saud University
PO Box 2925
Saudi Arabia
+966 (0)1 467 0848

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Study the effectiveness of Hyperbaric Oxygen Therapy (HBOT) in Autism Spectrum Disorder (ASD): a randomized double-blind cross-over study



Study hypothesis

1. To determine the efficacy of HBOT on symptoms of ASD
2. To determine the effects of HBOT on oxidative stress markers, inflammatory biomarkers and immunological biomarkers in autistic children

Ethics approval

Not provided at time of registration

Study design

Randomized double-blind cross-over study

Primary study design


Secondary study design

Randomised cross over trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Autism spectrum disorder


1. This project will be conducted on 32 ASD children between 6 and 12 years of age
2. Written informed consent will be obtained from each child’s parent(s) prior to starting HBOT.
3. Each child will be re-diagnosed by a qualified psychologist using Autism Diagnostic Observation Schedule (ADOS), Childhood Autism Rating Scale (CARS 2) and the several aspects of their behavior and IQ for each candidate will be tested using Social Responsiveness Scale (SRS ), Children’s Communication Checklist (CCC) and Aberrant Behavior Checklist– Community (ABC-C), Stanford Binet Intelligence Scale
4. All ASD candidates with one of their parent will be screened according to HBOT criteria by
4.1. ENT specialist
4.2. Pediatrician
4.3. HBOT specialist
5. Blood samples of each candidate will be taken for testing of oxidative stress, inflammatory and immunological biomarkers
6. Single Photon Emission Computed Tomography (SECT) for ASD candidates before the session of HBOT and at the end of the project
7. ASD candidates will be divided into the following groups:
7.1. Group 1 No dietary preparation prior to HBOT session
7.2. Group 2 Dietary preparation ( gluten & casein free diet supervised by a Dietician for four months prior to HBOT session
8. All candidates will have 40 sessions for 1 hour of HBOT at 1 or 2 atmospheres absolute (ATA) and 100% oxygen (after adjustment for the pressure effect) every day over a 4-5 months period

Intervention type



Phase III

Drug names

Primary outcome measure

1. Behavioral psychological parameters measure
1.1. Autism Diagnostic Observation Schedule (ADOS)
1.2. Childhood Autism Rating Scale (CARS 2)
2. The several aspects of their behavior and IQ for each candidate will be tested using
2.1. Social Responsiveness Scale (SRS )
2.2. Children’s Communication Checklist (CCC)
2.3. Aberrant Behavior Checklist– Community (ABC-C)
2.4. Stanford Binet Intelligence Scale
2.5. Oxidative stress biomarkers (superoxide dismutase, gluthathione peroxidase, vit E, vit C)
2.6. Inflammatory biomarkers (IL-2, IL-7, IL-10)
2.7. Immunological biomarkers (IgG, IgA, anti-Myelin basic protein IgG, anti-ribosomal IgG , anti-ganglioside IgG)

Secondary outcome measures

Improvement in communication, social and speech, reflected on academic level

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Children with ASD (Autism spectrum disorders) aged between 6 and 12

Participant type


Age group




Target number of participants


Participant exclusion criteria

The following are the contraindications for the use of HBOT:
1. Pneumothorax
2. Previous chest surgery
3. Any lung disease
4. Viral infections
5. Recent (within the previous 2 months) middle ear surgery
6. Optic neuritis
7. Seizure disorders
8. Congenital spherocytosis
9. Psychiatric problems, especially claustrophobia
10. Recent dental procedures
11. Deafness or ringing noises in ears
12. Severe or frequent headaches
13. Migraine
14. Fainting or blackouts
15. Convulsions, fits or epilepsy
16. Concussion or head injury
17. Heart diseases
18. Pregnancy

Recruitment start date


Recruitment end date



Countries of recruitment

Saudi Arabia

Trial participating centre

King Saud University
Saudi Arabia

Sponsor information


King Abdulaziz City for Science and Technology (Saudi Arabia)

Sponsor details

King Abdulaziz City for Science and Technology Kingdom of Saudi Arabia
P.O Box 6086
Saudi Arabia

Sponsor type




Funder type


Funder name

King Abdul Aziz City for Science and Technology, King Saud University (Saudi Arabia)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

02/08/2016: Plain English summary added.