Our three EEG channels: enough for precision measurement?

Yes. The midline is where functional brain measurement works best.

Sens.ai measures event-related potentials: the brain's electrical responses to a task, timed to the millisecond. Those responses are strongest along the midline, so Fz, Cz and Pz are the conventional sites for recording them rather than a cut-down version of a larger setup. Recording evoked potentials from a small number of well-chosen sites is standard clinical practice, not a shortcut. The midline also sits away from the scalp's main sources of muscle interference, which keeps the signal clean.

The three sensors also run front to back, which lets the system measure timing synchrony between the front and back of the brain: how well those regions fire in time with each other. Those timing features and the evoked responses are among the hundreds of biomarkers of brain function and performance our models are built on.