Normative Databases
Statistical comparison of individual cortical activity against FDA-cleared datasets of age and sex-matched healthy controls.
The Necessity of Baselines
Raw EEG microvolts mean little in isolation. A 10μV Alpha amplitude might be perfectly normal for a 60-year-old male but pathologically low for a 10-year-old child. Normative databases provide the Z-score transformations necessary for clinical diagnosis.
NeuroGuide (N=625)
We primarily utilize the NeuroGuide database, which boasts extremely strict inclusion criteria. It excludes individuals with any history of TBI, psychiatric diagnosis, learning disabilities, or significant medication use. This ensures the "normative" group represents a truly healthy baseline.
Z-Score Interpretation Matrix
| Z-Score Range | Clinical Significance | Percentile |
|---|---|---|
| -1.0 to +1.0 | Normal Variance | ~68% |
| ± 1.5 to 2.0 | Mild Deviation | ~95% |
| > ± 2.5 | Pathological | > 99% |
Common Mistakes in Application
A frequent error in the field is applying normative comparisons to data recorded with the eyes open, while referencing an eyes-closed database. State dependency is critical; Alpha dominant frequency drops significantly when eyes open.