GENUS Alzheimer's protocol: 60 min daily. General wellness: 15-30 min. Clinical trials used daily 1-hour sessions over months to years.

40 Hz gamma: most clinically validated (MIT GENUS). 10 Hz alpha: strongest visual SSVEP resonance. Individual alpha peak frequency varies; 8-13 Hz range for relaxation.

GENUS: fixed 40 Hz for full session. Relaxation: ramps from beta through alpha to theta over 30 min. Sleep: alpha down to delta. Pain protocols based on Maddison et al. 2023 meta-analysis: alpha for acute pain, theta for chronic.

Square wave at ~400 lux = original GENUS protocol. White light produces largest SSVEPs (Cao et al. 2020). 40% duty cycle shows 16% improvement in BCI studies vs. 50%. Heterochromatic mode alternates two colors to reduce perceived discomfort while maintaining gamma SSVEP (Agger et al. 2024).

~50 dB modulation depth (100,000:1 amplitude ratio). Sharp on/off pulses generate powerful evoked potentials via the thalamus. Works through speakers. Some studies show stronger cortical response than any other auditory method. Less effective below ~4 Hz where individual clicks become perceptible.

Two close-frequency tones mixed before reaching the ears create real acoustic amplitude modulation at the beat frequency. Significantly stronger auditory steady-state responses than binaural beats (Lopez-Caballero & Escera, eNeuro 2020). Works through speakers.

Only ~3 dB modulation depth (2:1 ratio). Only 36% of well-designed studies confirm EEG entrainment (Ingendoh et al. 2023). Optimal carrier: 340-500 Hz (Melnichuk et al. 2025). Sessions >20 min are significantly more effective. Effect size g=0.45 overall, g=0.69 for anxiety at theta/delta. Pre-task exposure outperforms during-task. Consider isochronic tones or monaural beats for stronger entrainment.

Somatosensory cortex resonance peaks at ~20-26 Hz (beta band). 40 Hz whole-body vibration reduced phosphorylated tau and prevented neuron death in mouse models (Suk et al. 2023). Participants prefer vibrotactile stimulation for comfort over visual/auditory. Peak response: fingertips (Meissner corpuscles at 2-40 Hz, Pacinian at 40-500 Hz). Android only; uses device vibration motor.

Photosensitive seizure warning. Do not use if you have epilepsy or are prone to seizures. Most dangerous frequency range: 15-25 Hz. Risk extends 5-60 Hz. 40 Hz has proven safe even in epilepsy patients with intracranial electrodes (Chan et al. 2022), but individual screening remains essential.

Modality effectiveness hierarchy (current evidence):
1. Combined audio-visual entrainment (broadest brain engagement)
2. Photic flicker / square wave (strongest single sensory)
3. Isochronic tones (~50 dB modulation depth)
4. Vibrotactile (proven third pathway, somatosensory cortex)
5. Monaural beats (real acoustic AM, no headphones)
6. Binaural beats (~3 dB modulation, weakest auditory)

GENUS protocol (MIT Tsai Lab): Combined 40 Hz audio-visual stimulation reduces amyloid-beta across the entire neocortex (Martorell et al. 2019, Cell). 1-hour daily sessions over ~2 years produced 109-164% increases in 40 Hz power (Chan et al. 2025). OVERTURE trial: 76% reduction in cognitive decline, 69% reduction in brain atrophy over 6 months. FDA Breakthrough Device Designation granted to Cognito Therapeutics.

Mechanism: Therapeutic benefits may operate through interneuron VIP release and glymphatic clearance rather than classical oscillatory entrainment. Photic driving responses and endogenous gamma may coexist as separate neural generators (Duecker et al. 2021, J Neurosci) — but clinical benefits are demonstrated regardless.

Personalization: Stimulation at an individual's peak oscillatory frequency produces stronger entrainment than fixed frequencies. A 2026 study showed personalized gamma frequency (from individual auditory evoked responses) produced superior connectivity vs. fixed 40 Hz. Closed-loop EEG-guided protocols achieve near-perfect target state induction where open-loop methods are inconsistent.

This tool is for research and personal exploration only — not a medical device.