Leg Cuffs Beat Sham by 4.5 Points in Early Alzheimer's, but the Sham Group Also Improved 5.3

External counterpulsation, a therapy that squeezes inflatable cuffs on the calves, thighs and hips between heartbeats, has been FDA approved for more than 40 years for chronic angina and heart failure, according to the University of Kansas Medical Center. Whether it helps memory is a separate question. A 190-person trial funded by the device maker now says it does, and the result comes with caveats that the social-media summaries dropped.

The trial is registered as NCT03721705 and was published in the American Journal of Alzheimer's Disease & Other Dementias. It enrolled adults with mild cognitive impairment or mild Alzheimer's dementia at 10 US sites, average age 68. Half got treatment pressure, which the Kansas team puts at 5 to 6 psi. Half got a sham that, per the registry, averaged no more than 0.5 psi. Both groups received 35 sessions over 12 weeks, then two a week for up to six months.

What the registry numbers show

The primary outcome was change on the Vascular Dementia Assessment Scale Cognitive Subscale, which runs from 0 to 120. The registry defines it plainly: "higher values represent more cognitive impairment." The treatment arm improved by 9.76 points from baseline and the sham arm by 5.31. That is a gap of about 4.5 points, which the Kansas medical center said in a 2023 release was roughly double the 2-point difference the FDA had wanted to see.

The sham result is the part to read slowly. More than half of the treatment arm's gain, 5.31 of 9.76 points, appeared in people who received almost no pressure. Practice effects from repeated cognitive testing, the attention of 35 clinic visits and ordinary placebo response can all produce gains of that kind. The registry data do not separate them. I could not find a base rate for sham-group gains in comparable dementia device trials, so the 5.31 has nothing to be measured against.

The percentages going around

ScienceAlert reported that 84 percent of patients in the full-pressure group improved during treatment, and that 75 percent still showed gains from their starting point six months after the last session. The same report quotes lead author Jack Juni of Renew Research giving 78 percent for improvement over personal baseline, and it does not explain the gap between 84 and 78. The journal paper blocks automated access, so these percentages rest on secondary reporting that I could not check against the paper.

Juni told ScienceAlert that "on average, participants gained five points on standard cognitive scales," which he equated to roughly one to two years of regained function. That translation is the sponsor's framing, not a measured outcome.

Who ran it, and what is missing

Renew Research, LLC is the registered sponsor and, per ScienceAlert, owns the device and paid for the trial. Patrick Moriarty, a professor of medicine at the University of Kansas Medical Center and the principal investigator, has received past support from the company, according to the same report. In the 2023 Kansas release he said of the brain-blood-flow data, "We showed that blood flow to the brain did increase with this treatment." The trial does not show that the therapy slows the disease itself.

Participants were diagnosed clinically rather than by blood biomarkers, so some may have had vascular cognitive decline instead of Alzheimer's disease. ScienceAlert noted that this could skew results. The registry lists participants and outcome assessors as masked, but the report says a sham is hard to disguise, so blinding may have been imperfect.

On safety, the registry counts treatment-related adverse events in 41 treatment-arm participants and 33 sham-arm participants, and serious ones in 8 and 9. The authors describe adverse events as minimal. The device is certified in the European Union for this use. The FDA has not granted the same approval, and ScienceAlert reports the company wrote to the agency last year about the delay.

Bottom line

What is actually known: the trial met its primary outcome on the registry numbers, and the sham arm improved substantially too. What is still being studied: whether the gap holds in a second, independent trial, and whether it reflects Alzheimer's disease or vascular decline. The evidence is promising and thin in the same sentence. Nothing here is medical advice, and treatment questions about memory loss belong with a neurologist.