Search Results

The Neurometric Analysis System (NAS) is to be used by qualified medical professionals for the post-hoc statistical evaluation of the human electroencephalogram (EEG).

The Neurometric Analysis System (NAS) is a software program for the post-hoc statistical analysis of the human electroencephalogram (EEG). Digital EEG data from a host system is transferred to the NAS for display and user-review. The system requires that the user select approximately 2.00 minutes of artifact-free, eyes-closed, resting EEG from the recording for analysis. Analysis consists of the Fast-Fourier Transformation (FFT) of the data to extract the spectral power for each of the four primary frequency bands (delta, theta, alpha, and beta), and frequency information from the EEG. The results of this analysis are then subjected to univariate, bivariate, and multivariate statistical analyses and displayed in statistical tables and topographical brain maps of absolute and relative power, power asymmetry, and coherence for 19 monopolar and 8 selected bipolar derivations of the EEG. In all over 1200 measures are derived for comparison against a carefully constructed and statistically controlled age-regressed, normative database in which the variables have been transformed and confirmed for their Gaussian distribution. Each variable extracted by the analysis is compared to the database using parametric statistical procedures that express the differences between the patient and their appropriate age-matched reference group in the form of Z-scores. Multivariate features are compared to the normative database using Mahalanobis Distance Statistics. The Mahalanobis Distance statistic controls for the interrelationship of the measures of brain cortical function in the feature set, and provides an accurate estimate of their difference from normal. The multivariate measures permit an evaluation of regional indices of brain function that reflect the perfusion fields of the brain. Extracted feature sets are further analyzed to determine if the pattern of 'hits' (statistically, significant feature score values identified for the patient) are consistent with patterns of 'hits' identified in prior neurometric evaluations of clinical patients with known disorders. A step-wise discriminant analysis program classifies the patient in terms of their similarity to known neurometric-defined patterns of abnormality, providing a probability estimate of the patient's profile with the average profile of groups of individuals constituting the normative and clinical database. The discriminant classification program is restricted by confiniters potential outcomes to specific patient symptoms derived from the patient history. profile. Established discriminant functions were evaluated through the use of Receiver Operating Characteristic (ROC) curves for their sensitivity and specificity. The outcome of the statistical analysis is presented in report form that includes (a) patient demographic and history information, (b) selected EEG epochs, (c) statistical tables of monopolar, the lastery and multivariated feature values, and topographical brain maps. This information is to be read and interpreted within the context of the current clinical assessment of the patient by the attending physician. The decision to accept or reject the results of the neurometric analysis, and incorporate these results into their clinical appraisal of the patient, is dependent upon the judgment of the attending physician. The Neurometric Analysis System is complete in a set of five 3.5 diskettes, which contains. a demonstration program with sample neurometric studies, the NAS program, and the a demonstration program. The NAS was designed for implementation under DOS and Windows, and programmed using C++. The user interface was carefully designed and implemented to programmed comb procedures are used to record steps used in program usage, and the conduct of the analysis to insure appropriate function and operation of the software. The NAS can be installed in any appropriately configured IBM-compatible computer system, including systems designed specifically for the recording of digital EEG. The system functions with systems access of standard computer platforms and input-output devices, and printers.