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?