77.5 Hz versus sham over 2 weeks after stroke
Q: Did 77.5 Hz current help stroke cognition more than sham?
A: A 2026 triple-blind trial compared 77.5 Hz high-intensity alternating current with a sham device in people whose thinking had slowed after a stroke. More people in the active group improved on the Montreal Cognitive Assessment, both right after two weeks and four weeks later.
Who was in the trial
The trial was for people living with post-stroke cognitive impairment. Seventy people were randomized at the Department of Rehabilitation Medicine, Third Affiliated Hospital of Sun Yat-Sen University, in Guangzhou. The compared groups were 34 people on the active current and 34 on the sham device. The intention-to-treat look at all 70 agreed with the smaller compared groups.
The paper is a triple-blind randomized trial in Brain Stimulation, 26 October 2026, by Yinan Ai, Shuxian Zhang, Li Huang, Qilin Cheng, Yuanwen Liu, Mingyu Yin, Fang Zheng, Shaoping Wu, Ziying Ye, Haiqing Zheng, Liying Zhang, and Xiquan Hu.
What the two groups received
The active group received high-intensity transcranial alternating current at 15 mA and 77.5 Hz for 40 minutes, twice a day, five days a week, for two weeks. The sham group used the same kind of device with no current. Both groups were blinded, and so were the people scoring the tests.
The main score was the Montreal Cognitive Assessment. They also scored forward and backward digit span, a working-memory test, and they measured oxygenated blood in the left, right, and medial prefrontal cortex with near-infrared light.
The scores that moved
Right after the two weeks, 73.5 percent of the active group met the Montreal Cognitive Assessment response mark, against 38.2 percent with sham. That gap was unlikely to be chance, P = 0.003. Four weeks later the active share was 88.2 percent and the sham share was 55.9 percent, again P = 0.003.
Forward and backward digit span also improved more in the active group at both visits. At the first brain scan, oxygenated blood rose more in the left, right, and medial prefrontal regions in the active group, each with q = 0.033 after correction. The authors called the current generally well tolerated, and they said it improved global cognition and working memory.
What faded at the later scan
The thinking-score gap was still there at four weeks. The brain-scan gap was not. At the second scan, no prefrontal region still showed a significant difference in oxygenated blood. The authors treated that scan as exploratory. It suggests a change in cortical activity beside the score change, and it does not prove a mechanism.
The figures here are the ones in the Brain Stimulation summary of 26 October 2026. A home coil is not the hospital device, and 15 mA is their current, not a number stored in a tone.
A 77.5 Hz session at home
If you want the hour they used, open the trial-setting row for 77.5 Hz and sit for 40 minutes. Headphones or the Tesla-Rodin Vortex Coil are the ways a reader uses a chosen tone today. Tesla's alternating current is the lineage. The app is the door.
The memory set and the focus sets on this page match the scores they measured. They are not the hospital session. Sit with one, quietly, and let the tone be the session.
The paper
Read the published summary on PubMed 42933772, or open the journal record at doi.org/10.1016/j.brs.2026.103234.
KYMA is working to establish a science-based podcast, because reliable information about this topic is almost impossible to find on ordinary social media.
| Result | What the paper reported |
|---|---|
| Thinking-score response after 2 weeks | 73.5 percent with 77.5 Hz current, 38.2 percent with sham, P = 0.003 |
| Thinking-score response 4 weeks later | 88.2 percent with the active current, 55.9 percent with sham, P = 0.003 |
| Working memory | Forward and backward digit span improved more in the active group at both visits |
| Prefrontal blood oxygen | Higher in the active group at the first scan, q = 0.033; no regional difference remained at the later scan |
Related tones in the KYMA library
Open these library sets if you want a stored program for the same topic. They are here because they match the subject of the paper. A magnetic-field setting is not stored in the tone.
Labeled trial setting from a 2026 sham-controlled stroke cognition study in Guangzhou. Forty-minute sessions at 77.5 Hz, twice a day, five days a week, for two weeks. · 40 minutes
Extended 40 Hz session for memory consolidation and cognitive enhancement based on MIT research. · 30 min
Upper SMR for extended periods of sustained attention. Supports long study sessions or detailed work. HEADPHONES REQUIRED. · 45 minutes
Classic alpha frequency for relaxed, alert focus. Ideal for studying, reading, or light cognitive work without stress. HEADPHONES REQUIRED. · 45 minutes
Frequently asked questions
What frequency did they use for the stroke sessions?
They set the active device at 77.5 Hz for 40 minutes, twice a day, five days a week, for two weeks. Open the trial-setting row, 77.5 Hz Post-Stroke Cognition Trial, for that number and that session length. The hospital current was 15 mA, and that strength is not in the tone. The library set 40 Hz Gamma - Memory Enhancement matches the working-memory scores, and 14 Hz SMR - Sustained Attention and 10 Hz Alpha - Relaxed Focus match the focus side of the same topic. The hospital did not test those library sets.
Did the thinking scores stay higher four weeks later?
The Montreal Cognitive Assessment response was still higher in the active group four weeks later, 88.2 percent versus 55.9 percent. Forward and backward digit span also improved more in the active group at that visit. The later prefrontal blood-oxygen scan no longer showed a regional difference.
Where can I open 77.5 Hz?
Open the trial-setting row, 77.5 Hz Post-Stroke Cognition Trial, and sit for the 40 minutes they used, with headphones or a coil. The library set 40 Hz Gamma - Memory Enhancement is there because the trial measured working memory. 14 Hz SMR - Sustained Attention and 10 Hz Alpha - Relaxed Focus match the focus side of the same topic. The 15 mA figure stays with the hospital device.