| Study at a glance | |
|---|---|
| Published | Journal of NeuroEngineering and Rehabilitation, July 2026 |
| Study type | Pilot randomized controlled trial |
| Participants | 20 older adults (average age 70) with subjective cognitive decline |
| Treatment | One 40-minute session of 10 Hz rTMS to the left prefrontal cortex, vs. sham |
| Main finding | Faster reaction time on the Stroop task with active TMS; no change in memory |
What the study is about
Deep sleep is busy time for the brain. During it, the brain produces slow, rolling electrical waves known as slow-wave activity (SWA). These waves help lock in new memories and keep the brain running smoothly, and they naturally fade as we age.
This study focused on older adults with subjective cognitive decline: people who notice changes in their memory or thinking even though standard tests may not yet show a problem. This group is at higher risk of later cognitive decline, which makes them an important group for early, preventive approaches.
Why they did it
The researchers wanted to test a chain of ideas. Could a session of TMS during the day boost deep-sleep brain waves that night? And could that boost, in turn, improve memory, planning and attention by the next morning? If so, sleep could become a new route for supporting brain health in later life.
What they did
Twenty adults with an average age of 70 were randomly assigned to one session of either active TMS (11 people) or sham TMS (9 people). The active session was 40 minutes of excitatory 10 Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC), a region involved in focus and decision-making.
Participants spent nights in a sleep lab before and after the TMS session. Researchers recorded their brain activity with high-density EEG and gave them tasks measuring memory, executive control (planning and self-control), and vigilance (sustained attention).
What it showed
- Faster processing on one task. After active TMS, but not sham, participants responded faster on the Stroop task. In this classic test, people name the ink color of a word that spells a different color, such as “RED” printed in blue. It measures how quickly the brain can focus and filter out distractions.
- A link to deep sleep. Bigger increases in slow-wave activity across frontal and parietal regions went along with bigger Stroop improvements.
- No change elsewhere. The other memory, executive function, and attention measures did not improve significantly.
Why it matters
This study tested a new idea: whether TMS can work through sleep to support thinking. The connection between deeper sleep and faster processing suggests a real mechanism worth pursuing.
It also points toward a drug-free approach for people in the earliest stages of cognitive concern, a group with few proven options today.
What to keep in mind
- This was a pilot. With 20 participants, it was designed to test feasibility and generate ideas, not to prove a benefit.
- One session, one positive task. Only a single measure improved, and several did not. Results like this need to be repeated.
- Memory didn’t budge. The researchers note that multi-session treatment and larger trials are needed to see whether memory and executive function can improve.
- This is investigational. TMS is not FDA-cleared for cognitive decline.
The bottom line
A single session of TMS was followed by faster thinking speed in older adults worried about their memory, and the gain tracked with deeper sleep. It’s an early, small finding, but it opens an interesting path: using sleep as a lever for brain health.
At Junction Brain Health, we follow TMS research closely so our patients and referring providers know where the field is heading. Have questions about TMS? Contact our team.
Source: Stepan ME, Mayeli A, Kaskie R, Whitehead AB, Gerlach AR, Peng CW, Habte RF, Janssen SA, Wallace ML, Buysse DJ, Karim HT, Ferrarelli F, Wilckens KA. Effects of repetitive transcranial magnetic stimulation on cognition through sleep slow-wave activity in older adults. Journal of NeuroEngineering and Rehabilitation. 2026;23(1).
Link to study: https://link.springer.com/article/10.1186/s12984-026-02064-w