Last week, I spent one fascinating day at the Eighth World Congress on Brain Injury in Washington, D.C. where I heard a compelling talk on the potential benefits of hyperbaric oxygen therapy for brain-injured patients.
Dr. Paul G. Harch described his pilot study: 30 young soldiers, all of whom had sustained blast concussion injuries while fighting in Iran and Iraq. After 40 treatments of hyperbaric oxygen therapy (HBOT), they had significantly improved cognition, memory, and mood, and fewer headaches and symptoms of PTSD. Dr. Harch also showed some brain imaging data that indicated increased blood flow to the brain after these treatments.
SPECT images show increased cerebral blood flow after HBOT. Photo courtesy of Dr. Paul Harch
The injuries occurred an average of 6 months before treatment, suggesting that hyperbaric oxygen (HBOT) may stimulate a natural repair process in the brain as has been seen in other injured tissue, Dr. Harch said. Angiogenesis could bring new blood to damaged neurons that have been idling in neutral, awakening them to full function. Neurogenesis also could be at work, he said, although he had no data to support either of these ideas.
For nearly an hour at the meeting, physicians thronged Dr. Harch asking him about the potential of HBOT for various brain injuries, multiple sclerosis, and other neurologic problems. More often than not, Dr. Harch’s reply to their question was: “That [person] is treatable and will benefit from HBOT.”
Clearly passionate, Dr. Harch zealously preached the Book of HBOT. But his missal is incomplete, because he did not disclose the details of his practice and commercial interests. Dr. Harch didn’t mention the new book he just published, which touts HBOT for just about everything from brain injury to Alzheimer’s to wrinkles. Also, he runs a business in New Orleans that provides hyperbaric therapy for approved uses, like decompression sickness and wound healing, as well as for off-label uses like autism, cerebral palsy, multiple sclerosis, and traumatic brain injury.
And, while the results of his 30-person observational trial were intriguing, they do not a miracle make. He now hopes to launch a 1,000-person trial. But, again, he plans another single-arm observational study with no comparator group. Bayesian statistics would negate the use of a comparator, he told me.
That comment, combined with the undisclosed financial information, gave me that weird stomach lump feeling – an irrefutable warning sign familiar to any journalist. For perspective, I turned to Dr. Steven Novella, a fellow blogger and Yale University neurologist who writes NeuroLogica. Let’s just say he wasn’t impressed by the results of Dr. Harch’s study.
“The claim that with Bayesian analysis you do not need a control group is completely wrong and displays a frightening misunderstanding of scientific methodology,” he told me. “The point of a control group is to control for variables. Bayesian analysis does not replace that. In fact, Bayesian analysis can only be meaningfully done if you have some p-value or other measure of probability based on the study, which you do not have if you don’t have a control group. It seems to me that he wants to do the kind of study that is guaranteed to show that his treatment works. This is what you do if you want to promote a treatment, not study it.”
The next proper step, according to Dr. Novella, would be a larger, double-blind study. And, in fact, three randomized, sham-controlled trials of HBOT are being planned by the Department of Defense.
Dr. Harch told me the research money should have supported his endeavors. Ironically, two of the principal investigators on the new trials each told me that Dr. Harch refused to assist with their trial’s design. Yet his work – with all its methodological flaws – is the genesis for the very studies that could ultimately substantiate the gospel truth of his preaching that hyperbaric oxygen can heal the wounded brain.
But until data replace simple faith, Dr. Harch remains the prophet crying in the wilderness.
– Michele Sullivan (on twitter @MGsullivan)