Hyperbaric Oxygen Induces Late Neuroplasticity in Post Stroke Patients — Randomized, Prospective Trial

Efrati et al. (2013, PLOS One) is the trial that fundamentally challenged the prevailing view that stroke recovery has a fixed window of 6 months post-event. The paper's title — 'Hyperbaric oxygen induces late neuroplasticity in post-stroke patients' — telegraphs the headline finding. What the trial measured. Three primary outcomes: National Institutes of Health Stroke Scale (NIHSS) score, Activities of Daily Living (ADL) performance, and quality-of-life metrics. These were complemented by SPECT (single-photon emission computed tomography) brain imaging to objectively measure cerebral blood flow before and after the protocol. The trial was deliberately designed to be unable to be explained by self-report bias. Who was studied. Seventy-four patients (after exclusions, an effective n=59) who had suffered a stroke between 6 and 36 months earlier. This time-since-event window is the critical inclusion criterion: it is the period after which conventional rehabilitation medicine has historically considered most recovery to have plateaued. The cohort included both ischemic and hemorrhagic stroke survivors with measurable neurological deficits at baseline. Protocol parameters. Forty HBOT sessions at 2.0 ATA, 100% oxygen, 90 minutes per session, 5 days per week — totaling approximately 8 weeks of treatment. Patients were randomized into two arms with a crossover design: one group received HBOT first, then waited; the other waited first, then received HBOT. This crossover allowed each patient to act as their own control, addressing concerns about between-subject variability. Results. The HBOT period produced statistically significant improvements in neurological function (NIHSS), ADL, and quality-of-life scales in BOTH groups. The control (waiting) period produced no improvement in either group. This pattern — improvement only when receiving HBOT, not while waiting — is methodologically powerful because it controls for spontaneous recovery and for placebo. The SPECT imaging confirmed reactivation of cerebral blood flow in regions adjacent to and surrounding the original infarct, providing the objective biological correlate. Limitations. The crossover design without a sham arm is a weaker blinding setup than a sham-controlled RCT — patients knew when they were receiving HBOT vs. not. The follow-up window did not extend years post-protocol; durability of gains was not tested in the original paper (later cohort work, including the 2020 Leitman/Hadanny extension to n=162 patients up to 22 years post-stroke, has addressed this gap). Sample size was modest, though typical for HBOT. What it means in practice. The Efrati 2013 protocol — 40 sessions at 2.0 ATA, 90-minute sessions, 5 days per week — is the directly-cited reference for chronic stroke recovery on the Saturate stroke condition page. The 6–36 month inclusion window is itself the practical takeaway: patients who have been told 'you've plateaued' may still have measurable recovery available. Soft-shell home chambers cap at 1.5 ATA; the originally published evidence is for 2.0 ATA in clinical chambers. How it relates to other indexed trials. Efrati 2013 (stroke) and Boussi-Gross 2013 (TBI) are companion papers from the same Israeli group, demonstrating that the same neuroplasticity mechanism applies in both conditions. The Leitman/Hadanny 2020 cohort extension confirmed durability and extended findings to a 22-year post-stroke population. Together they form the strongest published evidence for HBOT in chronic neurological recovery. Source: PubMed PMID 23335971.