Research › QEEG, Methods & Mechanisms
Evaluation and Validity of a LORETA Normative EEG Database
Share
Study at a glance
- Area
- QEEG, Methods & Mechanisms
- Study type
- Observational study
- Authors
- Thatcher RW, North D, Biver C
- Journal
- Clinical EEG and Neuroscience
- Year
- 2005
- Participants
- 106 healthy adults (ages 18-82, 56 male)
- Population
- Adults, Older adults
- Protocol
- eyes-closed resting EEG, LORETA normative Z-scores
Key findings
- Log10 and Box-Cox transforms approximated a Gaussian distribution with 95.64% to 99.75% accuracy
- 1.21% to 3.54% of normative Z-scores fell beyond 2 standard deviations, and 0% to 0.83% beyond 3
- Maximum deviations matched the locations of left temporal lobe epilepsy, a right sensorimotor hematoma and a right hemisphere stroke
- Authors conclude parametric Z-score LORETA norms are valid and adequately sensitive
This study tested whether a Z-score normative database for low-resolution electromagnetic tomography (LORETA) is statistically sound and clinically valid. Eyes-closed EEG from 106 healthy adults was converted into LORETA current estimates at 2,394 gray matter locations from 1 to 30 Hz, and transforms were applied to bring the values close to a normal distribution. The database flagged the expected share of deviant values and placed the largest deviations at the sites of known epilepsy, hematoma and stroke. The authors conclude the database is valid with adequate sensitivity.