AKTR4

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AKT-R4

• Andy Aiken

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Overview

• Cognitive psychology of diagnosis
• Diagnosis Web
• Proposed work AKT-R4

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Diagnosis

• How do clinicians perform diagnosis?
• How is it taught?
• What is the cognitive psychology?

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Diagnosis

• Differential Diagnosis
• What is a differential diagnosis?
• Requires the diagnostician to memorise (or have
  handy) a vast amount of information
• Simplistic view of the process, but shortcuts
  will eventually be learned for the more common
  complaints

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Diagnosis

• Two important mechanisms
• Hypothetico-deductive reasoning (HDR)
• Compiled knowledge (illness scripts)

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Hypothetico-Deductive Reasoning

• Given initial facts, work forward to likely
  hypotheses
• These are the differential diagnoses

Facts
Hypotheses
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Hypothetico-Deductive Reasoning

• Identify other facts which should be present for
  these hypotheses to hold, and investigate them
• Can attempt to distinguish between a set of
  competing hypotheses, or get additional
  confirmation for a hypothesis

Facts
Hypotheses
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Hypothetico-Deductive Reasoning

• Repeat until satisfied
• One hypothesis is notably more likely than others
• One likely hypothesis is especially significant
• The courses of action are similar

Facts
Hypotheses
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Illness Scripts

• Feltovich, 1984
• Compiled knowledge used in medical diagnosis
• Comprises three knowledge sources
• Faults
• Consequences
• Enabling conditions
• Says nothing about how they are used

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Diagnosis Web

• HDR requires significant processing
• Illness scripts dont explain the process of
  diagnosis
• Diagnosis Web
• A more inclusive explanation
• More knowledge sources
• Links between them indicate cognitive processes

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Diagnosis Web
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AKT-R4

• A classification tutoring system
• Will be aimed at novice diagnosticians
• Medical students, but not limited to medical
  domains
• An aid to diagnosis
• Supports the students reasoning without taking
  over

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AKT-R4

• User loads a knowledge base of previous cases
• User presents a new case to the system
• The system displays two lists
• Likely (differential) diagnoses
• Potential next steps (descriptors to find values
  for) to hone in on the correct diagnosis
• Providing more data for the case updates these
  lists automatically

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AKT-R4

• Can be used to diagnose real cases
• Also works as a tutoring system
• Generates test cases from sample data
• Gives feedback and scales difficulty according to
  student model
• Scaffolds users knowledge without taking control

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Summary

• Classification is a complex task that is acquired
  rather than taught
• The two classification mechanisms are
  hypothetico-deductive reasoning (HDR) and
  compiled knowledge (such as illness scripts)
• Combining HDR and illness scripts leads to the
  Diagnosis Web
• AKT-R4 will be a tutoring system, and will
  incorporate the Diagnosis Web to mirror how
  diagnosis is performed

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Questions?