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What do you need right now? Pick one — it takes you straight there. Everything here is rated by real evidence, and we tell you when something's only a "maybe" or outright nonsense.
New here? Calm down (slow breathing) and Reset are the best-evidenced places to start. Tap The receipts at the bottom anytime to see the science behind every tool.
🐕 Watchdog
The sound-wellness world runs on confident nonsense. We track the popular claims and call them honestly — proven, mixed, or junk — and we update as the science moves. That last part is the point: findings change, so our verdicts change with them. Nothing here is frozen marketing.
Myth ledger popular claims, graded
Junk
"528 Hz repairs your DNA"
The flagship "miracle tone." No mechanism, no evidence. DNA doesn't have a resonant healing frequency. A pure 528 Hz tone is just a slightly sharp C — pleasant, inert.
Junk
"432 Hz is the natural, healthier tuning"
A tuning preference dressed up as physics. No health effect over standard 440 Hz has ever been shown. Tune to whatever sounds nice.
Half-true
"Binaural beats tune your brainwaves"
A modest calming/anxiety effect shows up in studies — but a 2023 review found beats don't reliably entrain brain oscillations. So the effect may be real while the "brainwave" story is wrong. details ↓
Overhyped
"40 Hz sound cures Alzheimer's at home"
Real lab research, wildly oversold. Human trials are tiny, and gentle phone-speaker delivery likely can't entrain the brain the way lab rigs did. Experimental, not treatment. details ↓
Half-true
"Humming heals — it boosts nitric oxide"
Humming really does raise nasal nitric oxide ~15×. But a 2024 study found that boost didn't improve mood or thinking. Mechanism real, benefit unproven. details ↓
Myth
"The brown note makes you lose control"
No secret frequency does that. Tested, busted — and your phone can't even produce sub-20 Hz. details ↓
Debunked
"The Mozart effect makes you smarter"
A tiny, temporary spatial-task blip in 1993, inflated into a myth and sold as baby-genius music. Meta-analyses found it doesn't hold. details ↓
What we changed the learning loop, in the open
Downgraded
Binaural beats: Moderate → Mixed
After re-reviewing, we added the 2023 finding that beats don't reliably entrain brainwaves, and lowered the rating to match.
Caveated
Gamma 40 Hz: added a delivery warning
A 2025 paper showed comfortable/quiet delivery entrains the brain far less than lab strobes. We now say plainly: a phone speaker probably can't reproduce the studies.
This page is hand-maintained for now. The plan: an agent that watches new research and drafts updates here for human review — so verdicts track the evidence, not the hype. Found something we got wrong? That's the whole point — tell us.
Hz
A pure tone generator. Sine is the gentlest on the ears; square and saw are rich in harmonics and much louder-feeling — start quiet.
Binaural beats only work over headphones — each ear needs its own channel. Effects on focus/relaxation are modest and vary per person; this is not medical treatment.
The genuinely useful one. White masks broadband distraction; pink is softer and popular for sleep; brown is deeper, like rainfall or surf. Good evidence for masking + focus, honest about what it is.
Your ideal noise level is personal — research suggests people who struggle to focus benefit from more background noise, while others do better with less. Nudge until thinking feels easiest, then save. It auto-applies whenever you open this tab.
The 40 Hz pulse is the active ingredient — it's locked. You're hearing the carrier switched on/off 40 times a second (gamma rhythm).
Experimental. 40 Hz sensory stimulation is in early clinical research for cognition (mild Alzheimer's / MCI) — small trials, safe so far, decline-slowing trend only. It is not a treatment and no substitute for medical care. Just the honest state of the science.
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Recommended timings evidence-aligned
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In-page alarms only fire while this tab is open in your browser. For real away-from-screen reminders, use “Export to calendar”, or ask me to set phone alarms for your routine.
Your music is yours.
This is the one corner with no health claim by default. Which songs move you is personal — and that bond is the point: motivation, a mood lift, a hit of reward, confidence. What's actually proven: the right tempo helps you push harder in a workout, and music you love lights up the brain's reward system. We won't pretend a specific track "heals" anything. This generative bed is a starting point — bring your own.
Slow, soft, no pulse — for winding down or sleep.
Original, generative calm music — slow evolving chords, royalty-free, made live in your browser. Why generative and not a famous track? Two honest reasons: copyrighted songs can't be embedded, and the science shows the benefit comes from music's general qualities (gentle tempo, music you enjoy), not any single "magic" piece. Best paired with the auto-stop timer.
Slow paced breathing — the orb expands to breathe in, contracts to breathe out. Around 6 breaths/min is most people's "resonance" rate, where heart rate and breathing sync up. Hit Start for a soft tone that swells with each breath, or leave it visual-only.
Find your rate: try 4.5–7 and settle on whatever feels smoothest and most natural. Don't force it.
A simple meditation timer: a bell to open, optional interval bells, and a closing bell with a gentle fade. Pick silence or soft noise underneath. Press Start to begin. Mindfulness practice has solid evidence for easing anxiety, low mood and stress — modest but real.
Chant drone: a soft root-fifth-octave tone to chant a long "ooo / OM" or a mantra against. The real benefit is rhythm — chanting in long phrases naturally paces your breath toward ~6 breaths/min, the same resonance slow-breathing uses. Chant on each out-breath, easy volume; pair with the Breathe tab's coherent pace if you want a visual guide.
Dry land only. Never do breath-holds in or near water, and never in water without a trained buddy. Hypoxic blackout strikes underwater with no warning and is a leading killer of strong swimmers.
Do NOT hyperventilate. Over-breathing before a hold removes your urge to breathe and lets oxygen crash — that's what causes blackout. Breathe slow and normal.
Sit or lie somewhere safe. Stop immediately if dizzy, tingling, or lightheaded.
Skip this if pregnant or if you have heart, lung, or blood-pressure conditions, unless a doctor clears you. This is a timer, not instruction — learn from a certified freediving course (AIDA / SSI / PADI).
Ready
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CO₂ table · 6 rounds
CO₂ tables (fixed hold, shrinking rests) build tolerance to the urge to breathe; O₂ tables (fixed rest, growing holds) build tolerance to low oxygen. Both are standard dry freediver training. Breathe slowly and naturally in the rest phases — never force big breaths.
These methods are unproven or only preliminarily studied. They're here so the group can test them and report back — your feedback is shared anonymously and becomes the data that shows what actually helps. This is citizen science, not medical advice.
SOVT exercises (humming, lip trills, straw phonation) are used by voice therapists, but this app can't assess or treat an injured voice.
Hoarseness lasting more than 2 weeks, pain on speaking, or losing your voice → see an ENT or speech-language pathologist. Don't push through pain.
1 · Warm-up semi-occluded vocal tract
Lips closed, teeth slightly apart. Hum a comfortable note and feel the buzz on your lips and face. Easy volume — never strain.
Press the main play button to hear the reference tone, then match it with your chosen gesture. The siren glides up and down for warm-up; hold-pitch is for matching.
2 · Pitch monitor sing & see your note
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start the mic and sing
Stays on your device — nothing is sent or recorded here.
3 · Record & compare accent shadowing
Shadowing — imitating a native model almost in real time — is the best-supported way to work on accent (it reliably helps comprehensibility, intelligibility and prosody; individual-sound gains are less certain). Play a model clip you trust in another app, shadow it, and record yourself here to compare. A coach or SLP accelerates this a lot.
Small, weird, and mostly backed by real studies. We clearly label the one that isn't — because debunking nonsense is the whole point of this app.
Validated-ish (survey)
Hiccup killer
Folk cures are a coin-flip. The trick that actually beat them in a study is a rigid straw you suck water through so hard your diaphragm surrenders, then swallow. No straw handy? We'll coach the same move — a hard pull and a swallow and a hold.
Ready
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Real illusion
The staircase that never ends
An audio optical-illusion: a tone that seems to climb forever and goes nowhere (a Shepard tone — the trick that makes Dunkirk feel unbearable). Pure acoustics, zero mysticism. Headphones or speakers, low volume.
Validated
Get the song out of your head
Stuck song? Chew gum. Working your jaw ties up the same inner-voice machinery that loops the tune, and the earworm fades. Cheaper than therapy, tastier than silence. (Sorry — this is the one thing the app can't do for you.)
MYTH — debunked
The "brown note"
Legend says a secret low frequency makes you lose bowel control. It doesn't — it's been tested and busted, and your phone can't even reproduce sub-20 Hz. We mention it only to promise: we will never sell you a frequency that does anything to your bowels.
Validated
Why a banger gives you goosebumps
That shiver at the key change? Your brain's reward system lighting up the same circuitry that responds to food, sex, and drugs. Music is a free, legal vice — and the chills are measurable, not mystical.
These can genuinely help manage symptoms, and a few produce big in-the-moment changes — but they don't cure, and "fixed" is rarely the right word.
They work best alongside a professional: a speech-language pathologist (stuttering, voice), a physiotherapist (movement), or your doctor. Stop if anything hurts.
Stutter aid · Delayed Auditory Feedback headphones required
Hearing your own voice a fraction of a second late often smooths stuttering — it's the principle behind devices like SpeechEasy. It reliably reduces disfluency for many people (most in reading aloud); everyday-speech and long-term gains are smaller, so treat it as an aid and practice tool, not a cure. Wear headphones or the mic will howl.
Stays on your device.
Pacing metronome speech rhythm · gait cueing
A steady beat helps two different things. Speaking one syllable per click ("rhythmic speech") reduces stuttering. And walking in time to a beat — rhythmic auditory stimulation — measurably improves gait speed and stride length in Parkinson's. Speech pacing: try ~60–90. Walking cue: ~100–120, or match your comfortable steps and nudge up slightly.
Click = one syllable, or one step.
Already in the app
Subgroup evidence
ADHD & focus → Noise tab
For some inattentive people, steady broadband noise improves concentration (white / pink / brown on the Noise tab). It helps a subset, not everyone — try it and judge for yourself.
Strong
Anxiety / panic → Breathe tab
Slow breathing with a long exhale is among the best-evidenced self-regulation tools there is. The Breathe tab's coherent and long-exhale pacers are built for exactly this.
Built for long screen days — coding with AI, doomscrolling, grinding until the brain fogs. These quick resets genuinely lift fatigue and steady you in the moment. What they can't do is cure burnout: if you've been fried for weeks, the real fix is bigger — workload, sleep, boundaries, and sometimes proper help.
Pick a reset
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Pick one and it runs in place — no setup, about a minute, then back to work.
Labels say exactly what they are. No "chakra clearing", no "manifestation frequencies" — just the actual signal and the actual, modest reason someone uses it.
The receipts
Every mode maps to peer-reviewed work, rated by how strong the evidence actually is — including where it's thin, mixed, or absent. No cherry-picking. Tap any DOI to read the source.
StrongModerateEmergingMixedNo evidence
Emerging
40 Hz gamma stimulation → cognition
The strongest case for a specific frequency doing something — but read the fine print. In Alzheimer's mouse models, 40 Hz sensory stimulation reduced amyloid burden by roughly 37–53%. Human trials, though, are tiny (often 5–15 people), heterogeneous, and partly genotype-dependent; the researchers themselves call it "not sufficient evidence of efficacy." Two honest catches matter for an app: the lab studies used calibrated light/sound rigs, and a 2025 paper warns that gentler, comfortable delivery produces much weaker brain entrainment — so a phone or laptop speaker may simply be too weak to reproduce these effects. Treat this as experimental, not a treatment, and not a substitute for medical care.
Systematic review & meta-analysis (literature to Nov 2025): gamma-frequency auditory/visual stimulation in AD & MCI. Translational Psychiatry (2025). 10.1038/s41398-025-03788-4
2-year human extension, n=5 mild AD (gains only in some subtypes): Chan et al. Alzheimer's & Dementia (2025). 10.1002/alz.70792
Weak-delivery caveat — comfortable systems entrain the brain far less than strobe rigs: J. Alzheimer's Disease (2025). PubMed 41134991
Mechanism & preclinical review (~37–53% amyloid reduction; "slowing trend" in limited human trials): Frontiers in Aging Neuroscience (2025). 10.3389/fnagi.2025.1710041
Modest / mixed
Binaural beats → anxiety, attention, memory
A meta-analysis of 22 studies found a medium overall effect (Hedges' g ≈ 0.45) on anxiety, memory, attention and pain. But here's what the apps selling "brainwave entrainment" won't tell you: a 2023 systematic review found binaural beats don't reliably entrain brain oscillations at all — so the headline "tune your brainwaves to X Hz" story is shaky, even where a calming effect shows up. And cognitive effects are mixed across studies. Real but modest, mechanism uncertain, person-dependent — and only over headphones, since each ear needs its own tone.
Meta-analysis (g ≈ 0.45 on cognition, anxiety & pain): Garcia-Argibay et al. Psychological Research (2019). 10.1007/s00426-018-1066-8
Mixed effects on memory & attention: Basu & Banerjee. Psychological Research (2023). 10.1007/s00426-022-01706-7
Mixed
Pink noise → deep sleep & memory
Here's the nuance the wellness sites skip: the famous result used pink-noise pulses phase-locked to slow brain waves during sleep — not background pink noise on a loop. In 13 older adults that synced stimulation increased slow-wave activity and verbal recall (d ≈ 0.63). But replication is inconsistent — a later study found no memory benefit — so treat it as a real lab effect, not a guaranteed one, and not the same thing as continuous pink noise.
Original study (phase-locked pink noise, n=13 older adults): Papalambros et al. Frontiers in Human Neuroscience (2017). 10.3389/fnhum.2017.00109
Failed replication / null result: Schneider et al. (2020), discussed in Frontiers in Sleep meta-review (2023). 10.3389/frsle.2023.1294957
Widely used to mask distracting sound, and many people find it helps subjectively. But controlled evidence that continuous broadband noise actually improves sleep quality is weak and mixed — it's better understood as masking unwanted sound than as an active treatment. Honest framing: a useful tool, not a clinical intervention.
See the slow-wave-sleep reviews above for why timed stimulation differs from continuous noise; broad masking lacks strong RCT support.
The "528 Hz repairs your DNA / raises your vibration" claims have no credible scientific support. 432 Hz is just an alternative concert-pitch tuning with no demonstrated health effect. These are excluded from SIGNAL's benefit modes on purpose — including them as "healing frequencies" would be the exact dishonesty this tool exists to avoid. You can still play any tone you like in the Tone tab; it's just labeled for what it is.
No peer-reviewed evidence supports specific-frequency "healing" claims. Burden of proof sits with the claim; none has met it.
Strong
Music → mood, stress & anxiety
This is the best-supported claim in the whole app. A multilevel meta-analysis of 104 randomized trials (9,617 people) found music interventions reliably reduce both psychological and physiological stress. Cochrane reviews back this for pre-surgery anxiety and for patients in care. What drives it: tempo (roughly 60–80 bpm), and especially letting the listener choose music they like — self-selected music works better than anything imposed.
What is NOT supported: the "Mozart makes you smarter" claim. The largest meta-analysis (~40 studies, 3,000+ people) found no specific Mozart effect — any bump was a short-lived mood/arousal effect from enjoyable music, present mainly in the original lab's own studies. A 2023 re-analysis confirmed it persists as a myth, not a finding. Likewise, fetuses can hear in the third trimester and newborns may recognise melodies heard in the womb, but "play music to make your baby smarter" has no credible support. Music is great for how you feel — not a cognitive upgrade.
Meta-analysis (104 RCTs, n=9,617): de Witte et al. — music interventions & stress. Health Psychology Review (2020). 10.1080/17437199.2019.1627897
Cochrane review: Bradt, Dileo & Shim — music for preoperative anxiety. Cochrane Database Syst. Rev. (2013). 10.1002/14651858.CD006908.pub2
Slow, paced breathing at roughly six breaths per minute (≈0.1 Hz) brings heart rate and breathing into "resonance," sharply increasing heart-rate variability — a marker of a calm, well-regulated nervous system. Each person has a slightly different resonance rate (about 4.5–7 breaths/min), which is why the pacer is adjustable. This is the mechanism behind HRV biofeedback, studied for anxiety, stress and performance.
Mechanism review: Lehrer & Gevirtz — how and why HRV biofeedback works. Frontiers in Psychology (2014). 10.3389/fpsyg.2014.00756
Slow-breathing systematic review (pranayama / paced breathing): Zaccaro et al. Frontiers in Human Neuroscience (2018). 10.3389/fnhum.2018.00353
Note: the validated active ingredient is slowing the breath (and lengthening the exhale). Named patterns like box and 4·7·8 are popular variants of that, not separately proven.
Moderate
Tempo & pace → arousal, effort, performance
Tempo sets your pace and arousal. Milliman's classic field study showed slow background music slowed shoppers and changed spending; the same lever works on you — slow to settle, fast to energize. For movement, music synchronized to your tempo lowers perceived effort and can lift output; Karageorghis & Terry estimate well-chosen music can improve exercise performance by a meaningful margin, on par with some ergogenic aids.
Pre-task music & exercise — systematic review with multilevel meta-analysis. Frontiers in Psychology (2023). 10.3389/fpsyg.2023.1293783
Music in exercise & sport, meta-analysis (better performance, lower perceived exertion; fast tempo > slow): Terry, Karageorghis et al. Psychological Bulletin 146(2):91–117 (2020).
Person-specific
Background noise → focus (varies by person)
Counter-intuitively, a moderate amount of auditory noise can improve concentration for some people — proposed to work via "stochastic resonance." In one study, white noise helped attention-deficit children's cognitive performance while slightly hurting high-attention peers. The catch: the ideal level is personal, which is exactly why the calibration tool exists. Evidence is mixed and still developing — treat it as a tool to test on yourself, not a guarantee.
Söderlund, Sikström & Smart — noise benefits cognition in ADHD. Journal of Child Psychology & Psychiatry (2007). 10.1111/j.1469-7610.2007.01749.x
Moderate
Meditation → anxiety, mood, stress
A careful meta-analysis of 47 trials (3,515 participants) — one that specifically used active control groups to rule out placebo — found mindfulness meditation produced small-to-moderate reductions in anxiety, depression and pain. Honest framing: real and worthwhile, but modest, and not shown to beat other active treatments like exercise or therapy. Mantra-style meditation had weaker evidence. A timer with bells doesn't "do" the meditation — it just gets out of your way so you can.
Structured dry apnea work (CO₂ and O₂ tables) is the standard way freedivers extend breath-hold time, driving real physiological adaptations — but the same review documents maladaptations too, so it's not risk-free. The serious danger is hypoxic blackout: over-breathing (hyperventilation) before a hold strips out CO₂, removes the urge to breathe, and lets oxygen fall to unconsciousness without warning — the leading cause of breath-hold drowning. That's why this tool is dry-land only, tells you never to hyperventilate, and is no substitute for certified instruction and a trained water buddy.
State-of-the-art review (adaptations & maladaptations): Elia et al. European Journal of Applied Physiology (2021). 10.1007/s00421-021-04664-x
These three are early-stage on purpose. Cyclic sighing is the best-supported: a randomized trial found it lifted mood and lowered arousal, beating mindfulness over a month. Humming reliably raises nasal nitric oxide ~15-fold, but a 2024 study found that boost did not improve mood or thinking — so the calming claim is unproven and worth testing. Power breathing (cyclic hyperventilation with retention) was one arm of the same 2023 trial; broader immune/adrenaline claims remain preliminary, and deliberate over-breathing can cause fainting — never near water, never standing. The Lab's whole point: log what you actually notice, and let the aggregate feedback show whether these earn promotion out of "experimental."
Breathwork RCT (cyclic sighing, box, cyclic hyperventilation): Balban et al. Cell Reports Medicine (2023). 10.1016/j.xcrm.2022.100895
Humming & nasal nitric oxide: Weitzberg & Lundberg. Am. J. Respiratory & Critical Care Medicine (2002). 10.1164/rccm.200202-138BC
Caveat: a 2024 trial found humming-induced nitric oxide did not improve cognition or emotional processing (PubMed 38573928) — mechanism present, benefit unproven.
Strong / moderate
Vocal exercises & accent training
Semi-occluded vocal tract (SOVT) gestures — humming, lip trills, straw phonation — lower the effort the vocal folds need and are a mainstay of both singer warm-ups and clinical voice therapy; randomized trials show improved vocal quality in people with voice disorders. They're great for warming up and building easy phonation, but they don't diagnose or fix an injured voice — persistent hoarseness or pain needs an ENT or speech-language pathologist. For accent, shadowing (imitating a native model almost in real time) is the best-evidenced self-practice method: a 2025 review of 44 studies found it improves comprehensibility, intelligibility, accentedness and prosody, though gains on individual speech sounds were inconclusive. The pitch monitor and recorder here support that practice — they don't replace a coach.
SOVT therapy RCT (lip trill / straw / water resistance): Meerschman et al. Int. J. Language & Communication Disorders (2019). 10.1111/1460-6984.12431
SOVT for vocal-fold nodules, RCT in children: J. Speech, Language & Hearing Research (2024). 10.1044/2024_JSLHR-24-00243. Foundational rationale: Titze, JSLHR (2006).
Shadowing for pronunciation, systematic review of 44 studies: Journal of Second Language Pronunciation (2025). 10.1080/29984475.2025.2546827
Moderate → preliminary
Chanting & mantra
The best-established effect of chanting is indirect but real: reciting a mantra or prayer in steady phrases slows breathing to about six breaths a minute, which raises heart-rate variability and baroreflex sensitivity — the same resonance benefit as deliberate slow breathing. So a lot of chanting's calm is slow breathing in disguise. On top of that, mantra-based meditation shows small-to-moderate reductions in anxiety, stress and depression across trials, though the effect shrinks against active control conditions and study quality varies. Claims specific to "OM" — like a small pilot showing limbic-system quieting on fMRI — are intriguing but preliminary (tiny samples). And any "sacred/healing frequency" chant claim (528 Hz and friends) has no support; the rhythm and the breathing are doing the work, not a magic pitch.
Mantra-based meditation, systematic review & meta-analysis (small-to-moderate effects): Int. J. Environmental Research & Public Health (2022). PMC8949812
OM chanting fMRI (pilot, n=12, limbic deactivation): Kalyani et al. Int. J. Yoga (2011). 10.4103/0973-6131.78171
Receipts
The fun, sourced
Hiccups: a rigid suck-and-swallow straw (FISST / "HiccAway") stopped hiccups in ~92% of users — though that figure is a user survey, not a blinded trial, so call it promising rather than proven. It works by forcing a hard inspiration (phrenic nerve) plus a swallow (vagus) — the same reflexes our no-straw guide leans on. Earworms really do fade when you chew gum, because jaw movement ties up the inner-voice loop. Music chills are a measurable reward-system response, not woo. The Shepard tone is a genuine, well-understood auditory illusion (Roger Shepard, 1964) — no health claim, just a clever stack of octaves. And the "brown note"? No evidence it exists; it's been tested and busted.
For stuttering, altered auditory feedback (hearing your voice delayed or pitch-shifted) and rhythmic, metronome-paced speech both reliably reduce disfluency — but mostly in reading and in-the-moment; carry-over to everyday speech and lasting change are weaker, and a speech-language pathologist's therapy is the evidence-based core. For Parkinson's, rhythmic auditory stimulation (walking to a beat) has solid meta-analytic support for improving gait speed and stride length, though it's an aid used with physiotherapy, not a cure. For ADHD, steady noise helps a subgroup focus, not everyone. None of these "fix" a condition — they manage and sometimes markedly improve it.
Noise & attention in inattentive children: Söderlund et al. J. Child Psychology & Psychiatry (2007). 10.1111/j.1469-7610.2007.01749.x
Real, but bounded
One-minute resets: what a minute can & can't do
Short micro-breaks reliably boost vigor and cut fatigue — small but real effects — so they're good for steadying you and clearing that wired, foggy feeling. The honest catch from the same meta-analysis: a break under ten minutes refreshes how you feel but doesn't fully restore performance on hard cognitive tasks, which need longer breaks. Brief nature exposure — even seconds of greenery or a glance out a window — restores tired attention. The popular "20-20-20" eye rule is barely supported by trials, so rest your eyes by all means, but don't expect a cure. And burnout itself is a recognized occupational syndrome that no app fixes in a minute — treat these as circuit-breakers and relief, not treatment.
Micro-breaks meta-analysis (vigor ↑, fatigue ↓; performance only on easy tasks): Albulescu et al. PLOS ONE (2022). 10.1371/journal.pone.0272460
Reminder: this is information, not medical advice. Nothing here treats, cures, or prevents any condition. If something matters for your health, talk to a clinician.