EEG Interpreter using ASP
Bailey EvertsDr. Yuanlin Zhang
Problem Description Approach to obtaining the Knowledge used to solve the problem
The declarative knowledge used to solve the problem
Physician’s Input Report Generation Demo Questions
Contents
Input: The frequencies from the left and right side of the posterior, central and anterior of brain, and the physician’s observations.
Output: A list of abnormalities, if there is any, and their corresponding clinical correlations
Goal: identify the “declarative” knowledge used to decide the output from the input.
Problem Description
Knowledge sources: the BASIC program written by K.J. Oommen, M.D.
Translate BASIC program into Tables of “procedural” knowledge in a systematic way◦ Frequency Analysis◦ Physician’s Input
Translate “procedural knowledge” in the Tables into declarative knowledge
Translate declarative knowledge into ASP program
Approach
Notations◦ Section refers to posterior, central or anterior◦ Side refers to left or right
Definitions
Declarative knowledge
Lower Bound Frequency (Hz)
Upper Bound Frequency (Hz) Wavetype
0 4 Delta
4 8 Theta
8 14 Alpha
14 40 Beta
40 - Mu*
Definitions: Wavetypes
* Different than BASIC code
Section Normal Wave
Posterior Alpha
Central Theta or Alpha
Anterior Beta
Definitions: Normal Wave
A section is said to be symmetric if the frequency on the left is the same as the frequency on the right. It is asymmetric if it is not symmetric.
A section is said to be bilateral asymmetric if the wavetype on each side of a section is the same but the frequency is different.
Definitions: symmetry
A side of a section is abnormal if the wave of this side is not normal.
A side of a section is said slowing if its frequency is less than the normal frequency of this side.
A side of a section is said to have beta activity if the frequency of this side is greater than the normal frequency for that section.
A side of a section is said to be slowing with respect to the other side if both sides have a normal frequency, but that side is slower than the other side
When there is a frequency that is not normal we say that there is an abnormality.
Definitions: abnormality
Slower than normal◦ Describing Slowing:
A side is Delta Slowing if it has Delta Wave. A side is Theta Slowing if it is slowing and has Theta
Wave. (Posterior or Anterior) Alpha Activity: Alpha Wave (Anterior
◦ Clinical Correlation: An underlying lesion Faster than normal (Beta Activity)
◦ Describing Beta Activity Beta Activity: Beta Wave (Posterior & Central) Prominent Beta Activity: Mu Wave (Anterior)
◦ Clinical Correlation: An underlying skull defect
Frequency Analysis: Faster/Slower
Abnormality Types are Delta Slowing, Theta Slowing, Alpha Activity, Beta Activity, Prominent Beta Activity
Locations are occipital (for posterior), central (for central), and frontal (for anterior)
Merge is either bilateral symmetric or bilateral asymmetric
If both sides of a section have Abnormality Type “T”, Location “L”, and Merge “M” then the abnormality is described as M + L + T (i.e “bilateral symmetric frontal slowing”)
For Output of Frequency Analysis Abnormalities
If both sides of a section have the same abnormality type we do not describe the sides individually
To describe an abnormality type “T” on side “S” in location “L” we use the form S + L + T (i.e. “left parieto-occipital theta slowing”)
cType is either “skull defect” or “lesion” To describe a clinical correlation we use the
form “an underlying” + L + cType (i.e “an underlying frontal skull defect”)
For Output of Frequency Analysis Abnormalities
Classify as slowing or beta
Describe symmetry
Specify type of slowing/beta
Frequency Analysis: ASP Part
Describing bilateral symmetry
Describing abnormalities on a single side
Describing merged abnormalities
Frequency Analysis: ASP Part
Physician’s Input Paroxysmal Stage I Sleep* Later Stage(s)* Epileptiform Activity* Photic Stimulation* Hyperventilation* Seizure(s) or Other
Events* Cardio-Pulmonary
Events & Patterns of Uncertain Significance
Excess Artifacts* Potential for Abnormalities
Physician’s Input: ASP
Report Generation
Header Introduction Description Interpretation Footer
Report Generation: ASP Output
Demo
Questions?