Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.
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Transcript of Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.
![Page 1: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/1.jpg)
Recent Research on Improving Diagnosis of Dyslexia
Rick Wagner
![Page 2: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/2.jpg)
Organization of Talk: 2 Parts
• Part 1. Quick review of an approach to identification of word-level RD based on using a constellation of symptoms.
• Part 2. Current work on how best to combine symptoms for accurate diagnosis.
![Page 3: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/3.jpg)
Part 1. Identification using Constellation of Symptoms
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Fundamental Problem
• Existing operational definitions of reading disability yield unstable phenotypes.
• Occurs for both traditional IQ-achievement discrepancy and RTI-based models.
• Represents weak link in the chain for research and detrimental for practice.
![Page 5: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/5.jpg)
Explanation of Instability
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Testing the Explanation with a Counterintuitive Prediction
• Common sense would predict that there should be more agreement and stability for identification of profound reading impairments compared to more mild reading impairments.
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Proposed Explanation of Instability Predicts the Opposite
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Counterintuitive Prediction Supported:1-Year Stability Decreases with Increasing
Severity
Degree of Impairment
Kappa AFAS Consistency
25th %-ile .38 .37 .47
20th %-ile .36 .32 .42
15th %-ile .34 .28 .37
10th %-ile .31 .23 .31
5th %-ile .27 .18 .24
3rd %-ile .23 .15 .21
![Page 9: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/9.jpg)
Second Source of Support for Proposed Explanation of
Instability• Stability of
classification should be greater for non-RD than for RD.
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We Understand the Problem: What is the Solution?
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We Understand the Problem: What is the Solution?
• More Information!
• Reduce error bars by looking at multiple indicators.
• Find ways to minimize or eliminate effect of cut-off.
![Page 12: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/12.jpg)
What are the Basic Facts about Word-Level RD?
• 1. poor nonword decoding• 2. impoverished sight-word vocabulary• 3. phonological impairment• 4. unresponsive to instruction/intervention• 5. listening comprehension better than RC• 6. familial risk for it• 7. co-morbidities common (e.g., ADHD) • 8. more common in males
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Constellation Approach to RD
• Addresses instability by considering more information (e.g., “constellation” of symptoms).
• By evaluating multiple symptoms, threshold for any one can be relaxed or eliminated by taking dimensional approach.
• Distinguishes causes, consequences, and correlates.
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Constellation Model
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Stability
• Consistency is defined as proportion of individuals identified in first grade who meet criteria in second grade.
• Low (.2 to .6) for various univariate models examined.
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Consistency Values for Constellation Model
Number of Symptoms Consistency Values
1 or more .70
2 or more .65
3 or more .59
4 or more .39
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Consistency Values for Constellation Model
Number of Symptoms Consistency Values
4 or more to at least 3 or more .66
4 or more to at last 2 or more .76
4 or more to at least 1 or more .91
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Conclusions for this Part of Talk
• 1. Instability in the phenotype of reading disability is problematical, but explainable.
• 2. Initial support provided for using more information by looking at theoretically-coherent constellation of related symptoms:
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Part 2. How Best to Combine Information
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A Bayesian Approach
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Paying a Visit to Reverend Bayes
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Real Example using Data
• Breast cancer is rare for women in their 40s.– 1.4%
• But what is the probability if a woman in her 40s has a positive mammogram?– If cancer is present, probability of positive
mammogram is 75%.– If cancer is not present, probability of positive
mammogram is 10%.
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Real Example using Data
• Applying Bayes theorem, the chance that a woman in her 40s with a positive mammogram has cancer is 10%.
• These kinds of analyses are used for public health recommendations about when to start getting mammograms.
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Examples of Using Bayes Theorem to Estimate Probability of Dyslexia
![Page 25: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/25.jpg)
Examples of Using Bayes Theorem to Estimate Probability of Dyslexia
• Let’s operationally define dyslexia as scoring at 5th %-ile on a factor score representing the 4 key symptoms:– Poor nonword decoding.– Poor sight word vocabulary.– Poor response to instruction.– Listening comprehension better than reading
comprehension.
![Page 26: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/26.jpg)
Male versus Female
• All we know is that you are male:– Chance of dyslexia increases from 5% to 7%.
![Page 27: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/27.jpg)
Male versus Female
• All we know is that you are male:– Chance of dyslexia increases 5% to 7%.
• All we know if that you are female:– Chance of dyslexia decreases from 5% to 3%.
![Page 28: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/28.jpg)
Low Scores in Predictor Test Battery
• Score at or below 20th % ile on battery of first-grade reading predictors (unit weighted composite of poor nonword decoding, impoverished sight words, response to instruction, and reaching comprehension compared to listening comprehension):– Chances of dyslexia go from 5% to 15%.
![Page 29: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/29.jpg)
Comorbid ADHD
• Chances of dyslexia go from 5% to 19%.
![Page 30: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/30.jpg)
Affected Parent?
• Chances of dyslexia go from 5% to 26%.
![Page 31: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/31.jpg)
Combinations
• ADHD and Male?– Chance of dyslexia is 24%.
![Page 32: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/32.jpg)
Combinations
• ADHD and Male?– Chance of dyslexia is 24%.
• ADHD, Male, and Affected Parent?– Chance of dyslexia is 76%.
![Page 33: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/33.jpg)
Combinations
• ADHD and Male?– Chance of dyslexia is 24%.
• ADHD, Male, and Affected Parent?– Chance of dyslexia is 76%.
• ADHD, Male, Affected Parent, Low Scores on Predictor Battery?– Chance of dyslexia is 92%!
![Page 34: Recent Research on Improving Diagnosis of Dyslexia Rick Wagner.](https://reader035.fdocuments.in/reader035/viewer/2022062320/56649d8e5503460f94a77f3f/html5/thumbnails/34.jpg)
Conclusions
• 1. Using a theoretically-motivated constellation of symptoms is promising for better identification of individuals with dyslexia.
• 2. A Bayesian approach can be used to combine multiple sources of information.
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Conclusions
• 3. Approach is flexible. As individual-level neurobiological indicators come online, they can be incorporated.
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Questions?