SKIL Analytics
SKIL Analytics divides the lifespan into maturational stages to improve accuracy, and allows statistical comparison to both high and low challenge conditions, four in all (eyes closed rest, eyes open rest, reading, and math) in 18 different montages including signals associated with 55 Brodmann areas (more information here). It incorporates more spectral coefficients from Kaiser's Periodicity Table than any other time-series software, and includes activity as well as functional connectivity trend analysis along with comma-delimited export of 21 different spectral parameters for use in clinical and neuroscientific research (for Excel, SPSS, etc). Among its unique features include a dominant frequency analysis for each Brodmann area, spectral entropy, site-centered connectivity, bispectral analysis, customizable frequency bands, and an advanced, automatic artifact management system.
List of Features
- Spectral Activity: Spectral magnitude, entropy, and relative magnitude (export). (We do not include spectral power although many groups use it. Spectral power is a suboptimal measure of rhythm central tendency, and often a legacy from 1965 when computers were slow and floating point operations took a long time to do (i.e., square root of magnitude vector in FFT). Power is not nearly as useful as spectral magnitude for estimating central tendency of EEG rhythm activity. Spectral power amplifies contributions of outliers considerably and is a better measure of magnitude variability than central tendency.)
- Connectivity: comodulation, coherence, phase lag, and (absolute value) asymmetry which we call "unity", a sensitive measure of asymmetry, computed as 1- |A-B|/(A+B). Also Corticality (comodulation - coherence on z-score). We also have site-centered connectivity indices and trending capability of comodulation and coherence and we use a Fisher-z transformation for normalization.
- Reliability: Replication comparison with lowest z-score presented, a very nice graphical feature!
- Trends: Magnitude, entropy, comodulation, coherence; 1-site x 5 frequencies or 5-site x 1-frequency, with overlap, relative %, and smoothing.
- Bispectral Analysis: band ratio, bicoherence, and bimodulation analysis.
- Peak Frequency analysis: Up to 0.125 Hz frequency resolution.
- Task/Baseline comparisons: EC, EO, Reading, Math
- Frequency Range: 0-64 Hz descriptive, 1-45 Hz inferential (2-38 Hz for all amplifiers).
- Lifespan Divisions: Three maturational stages (cf. Tanner sexual maturation scale) in terms of brain maturation (child, teen, adult). Two more stages to be added in the near future (tween, young adults).
- Normative Databases: Replicated recording conditions for each member's values -- this increases statistical power and reliability significantly. For z-score comparisons, 30 representative samples from a population are all that are typically needed for accurate estimation of the population mean and variance. In fact we provide new database inclusion, allowing for specialized databases. Collect EEG from 30+ individuals who are drawn from a reasonably homogeneous population (e.g., engineering students, artists, peak performers), and we can install this into the software to provide statistical comparisons to this group, allowing for differences in brain organization due to cultural and linguistic differences to be realized and not viewed as atypical or pathological. We have ongoing development of a few very interesting databases -- aviators, artists, death row inmates (for murder), and Carmelite nuns (from a Montreal research group).
- Source imaging:, we use our own heteromorphic solution (Brodmann montage), which is similar to isomorphic solutions (e.g., VARETA, LORETA) though we believe more accurate, allowing us to take into effect the knowledge of both structural and functional individual difference in brain organization.
- Reports: We use an open format (HTML) which can be amended in MS Word or OpenOffice and other programs; and we provide templates including information from the Brodmann Atlas to create comprehensive functional evaluation reports. Usage/popularity- Google indexing information for July 2011: SKIL 75,000 sites; DA Kaiser 300,000+ webpages; 6,370 Google Scholar citations; MB Sterman 78,600 webpages; 3,800 Google Scholar citations The Society for the Advancement of Brain Analysis annually includes some of the most exciting speakers in clinical neuroscience and related fields and has been sponsored by SKIL for a decade.