5 ms·

EEG Accurately Predicts Autism as Early as 3 Months of Age

154 points by contourtrails 8y ago

tw1010 8y ago
I don't understand why there's such a massive focus on autism research, both on HN and in the news in general. It doesn't seem like a pareto optimal use of attention resources.
- loriverkutya 8y ago
  Because with early development, people on the spectrum could function better in the neurotypical environment, which means more people with ASD can work and need less support later.
- callesgg 8y ago
  On HN, cause ASD correlates highly with intrest in technology. On the news on average, don't have a good theory but mabbye just cause it is interesting forefront research.
fundamental 8y ago
Research paper in question: https://www.nature.com/articles/s41598-018-24318-x https://www.nature.com/articles/s41598-018-24318-x
neurotech1 8y ago
EEG in 3mo infants is "poorly organized" even compared to 24mo child, so it I would take this one with a grain of salt.
- fundamental 8y ago
  I was taking this with a hefty grain of salt, though at least on first pass they seem to have a reasonable cross-validation/testing procedure (which is usually one of my major complaints with comp-neurosci papers). As per 3 month infants, you can see that their classifier does have difficulties at that age bracket, though performance seems to start to saturate around 6 months (table 5). It would be interesting to give the paper another pass to see how more operational data collection could impact the quality of the data and thus classification results. EEG can be really hit-or-miss with different equipment. More-so with simple features such as the band power ones used within this paper.
  - nonbel 8y ago
    >"at least on first pass they seem to have a reasonable cross-validation/testing procedure (which is usually one of my major complaints with comp-neurosci papers)." It looks like the usual overfitting the cv to me... They had 1000 features, 200 datapoints, tried out "several different algorithms".
    - fundamental 8y ago
      That doesn't really diminish the results in my book. If you're trying to publish something it's basically assumed that you're going to try out several methods and show the one with better performance even if the performance difference is not statistically different. As per the number of features and data points: In this field you generally don't have a ton of subjects to sample from and the high dimensional features are a natural result of the array based recordings. It should be possible to perform dimensional reduction on the data, however the ML methods are already implicitly doing that step so it's not necessarily that important. My normal gripe is when the tested subjects have some data in the training fold and some data in the testing fold (even if the data points are separate). In those cases then the ML method can fit the statistics of a particular subject rather than the true target class (e.g. target movement of a cursor in a BCI). In this paper they explicitly are testing on a subject which was never trained. So, even though the data + particular supervised layer is going to budge the results around some, it should not be a night and day difference from what's expected in reality.
      - StavrosK 8y ago
        You have to account for the fact that you used so many algorithms, though. Using ten different algorithm makes it ten times more likely you'll fit your dataset well just by chance.
        fundamental 8y ago
        I acknowledge that the reported accuracy of a system will be higher if you take the max accuracy of 10 methods which have the same 'true' accuracy +- some noise. The results presented in table 5 of the paper are very unlikely in my opinion (as someone currently in the ML field and who has worked in the field of computational neuroscience) to be solely due to randomly trying different ML techniques without the underlying data providing a noteworthy difference between the target classes. If these results are replicated independently with a different dataset then the magnitude of the overselling of the method will be seen. I just don't think that it makes sense to doubt the results (i.e. with a grid of EEG sensors and bandpower features it is possible to identify a portion of autism cases) based upon this factor alone.
- jobu 8y ago
  In the Nature article they talk about using the combined analysis from multiple EEGs at different ages to increase accuracy. Also this: The accuracy of the HRA− outcome predictions was better at younger ages (3 to 9 months), then dipped in accuracy starting at 12 months. https://www.nature.com/articles/s41598-018-24318-x https://www.nature.com/articles/s41598-018-24318-x
callesgg 8y ago
Wow that is insanly cool. Especially considering that we don't even know what ASD is, or what could be causing it. Could this be used for a ASD scale?
- _Schizotypy 8y ago
  There has been recent research showing that part of the issue with asd is related to the glutamate system, specifically NMDA. Some sort of genetic transcription problem. Sorry I can't quote the exact paper off hand.
tnash 8y ago
"An experimenter blew bubbles to distract them." Wasn't expecting my daily does of cute in this Autism study's abstract, but got it anyway.
tbrownaw 8y ago
Not possible, that's before they've had most of their vaccinations. /s
- jamroom 8y ago
  I know you're being sarcastic, but it looks like there are 6 vaccines in the first 2 months: https://www.cdc.gov/vaccines/schedules/easy-to-read/child-easyread.html https://www.cdc.gov/vaccines/schedules/easy-to-read/child-ea... Not that I think it matters - I was just curious based on your post.
- toast0 8y ago
  It's not been conclusively proven that vaccinations can't go back in time to cause problems before they've been administered. /s
- dang 8y ago
  Please don't do this here.
deleted 8y ago
[deleted]
hannob 8y ago
Given that diagnosing Autism is hard and that all previous attempts at diagnosing it in a non-psychological way have failed this would be an extremely surprising result. Call me skeptical until it's reproduced independently.
talltimtom 8y ago
In this weird world that we live in this might actually help prevent a load of other deciders through increasing vaccination.
- burfog 8y ago
  That in turn causes other trouble. People adjust for perceived risk. For example, seatbelts and airbags make people less careful when driving. Vaccination makes people less careful about disease. There is no vaccine for enterovirus-68, which sometimes paralyses people. There is no vaccine for adenovirus-36, which is a cause of obesity. I could go on for a long time I think; lots of "harmless" viruses are turning out to cause serious problems. They can damage your heart, set off dementia, or give you cancer. The only effective answer is avoidance. This requires learning and behavior modification, so it isn't too popular, but nothing else is as effective.
  - wanderfowl 8y ago
    I'm having a [Poe's law](https://en.wikipedia.org/wiki/Poe%27s_law https://en.wikipedia.org/wiki/Poe%27s_law) moment here. You've just applied Abstinence Only Sex Education 'logic' to infectious disease. This is either brilliant satire of the odd arguments against harm reduction in general, or... you're serious, and I agree, it's a crying shame nobody taught all those poor smallpox victims how to modify their behavior.
- wanderfowl 8y ago
  Agreed. That was my first thought, too. Part of the reason that these silly vaccine/autism conspiracy theories are hard to shut down is the fact that Autism is harder to detect pre-vaccination, so there's confirmation bias here among parents of Autistic children. If this study provides nice evidence to the Anti-Vax crowd that Autism can be measured and detected well before vaccination age, this might help take some of the wind out of the sails of the movement. Of course, for many, science won't help, much like usable retroreflectors will only break down the fantasy for a subset of moon landing conspiracy theorists, but if it gets brought up even once in a Whole Foods somewhere, they've done a good thing.
projectramo 8y ago
This would be amazing if it works. The reason I say "if" and hedge my words is because the conventional wisdom is that autism is not a single disorder with a single underlying condition. It is a cluster of symptoms of varying intensity and it is (likely) caused by a host of underlying conditions. Two children diagnosed with the disorder can have no overlapping symptoms. If that is right, then the first step is to break it down into different kinds of conditions. (No eye contact is caused by X. Speech issues are caused by Y). However, if this test can effectively pick apart one of the underlying conditions and its symptoms that would be a huge step forward. We could definitively say whether a child has this particular version of "autism". After we tease apart a few more versions, the original condition will disappear and be subsumed by these other versions.
- tejohnso 8y ago
  > Two children diagnosed with the disorder can have no overlapping symptoms. Is there a precedent for this with other disorders? Seems to me that if there are no overlapping symptoms, it should be a separate disorder. Even if it's just arbitrary naming like "Type X" as in diabetes.
  - avip 8y ago
    IBS, asthma, schizophrenia, ADHD, and the list goes on and on.
  - dwringer 8y ago
    This might not be the most authoratative source, and I'm no medical expert, but this overview from Encyclopedia Britannica[1] nicely describes the diversity in how diseases are classified (I know we aren't using the term "disease" here but the concepts are presumably related in practice - I found this summary informative but welcome any informed corrections): > The most widely used classifications of disease are (1) topographic, by bodily region or system, (2) anatomic, by organ or tissue, (3) physiological, by function or effect, (4) pathological, by the nature of the disease process, (5) etiologic (causal), (6) juristic, by speed of advent of death, (7) epidemiological, and (8) statistical. Any single disease may fall within several of these classifications. [1] https://www.britannica.com/science/human-disease/Classifications-of-diseases https://www.britannica.com/science/human-disease/Classificat...
deleted 8y ago
[deleted]
devindotcom 8y ago
There's some really early eye movement based detection too. Good to see this. As others point out it isn't a binary but a hugely variant spectrum, but there are some commonalities that at the very least suggest that a child receive further screening or prepare the parent to watch for other symptoms. Regardless of the type and spectrum position, a kid with an early diagnosis/warning seems much more likely to have a good outcome than one that gets one while in pre-school or kindergarten.
monochromatic 8y ago
Does early diagnosis give better treatment options?
- scardine 8y ago
  Yes! The most effective treatment is behavioral therapy and the results are better if started early. At young age the brain is very plastic and for light cases you can teach all the things that are innate to neurotypical kids.
kpil 8y ago
5 % is quite a lot of misdiagnosed babies if this is implemented as a mass screening activity, 2-3 times higher than than what the internet seems to think is the actual ASD incidence, and I imagine that that number includes a lot of "highly functional" ASD cases What should a parent do when this happens? It will be only perhaps 20-30% risk that the baby actually do have ASD and not just a false positive. I imagine that ASD "prevention" is mostly behavioural training [I have no idea at all actually] - but how much time and effort would that take? What are the consequences for healthy babies? I imagine that most people would spend a lot of effort on anything that could help in cases like this. It's a bit problematic since it's not possible to know until after a couple of years if it's was a false positive or not. It might turn out that a lot (or most) of all successful recoveries was in fact "false positives".
- jiggunjer 8y ago
  What do you mean a false positive won't be detectable until a few years? I think by age 1 a parent will notice? Lack of eye contact, altered walking mechanism (foot dragging, tiptoes), non-responsiveness to voices, etc. So maybe a positive test means the kid gets more attention for a few months, that never hurt, right?
- alexandercrohde 8y ago
  What? 95% accuracy is outstanding. I see that you're saying if you said "No" for all babies, that'd be 95%, so that's a legitimate point. However, it sounds like it's better than that "We were also able to predict ASD severity, as indicated by the ADOS Calibrated Severity Score, with quite high reliability, also by 9 months of age." I imagine the intervention is ABA therapy (https://en.wikipedia.org/wiki/Applied_behavior_analysis#Efficacy_in_autism https://en.wikipedia.org/wiki/Applied_behavior_analysis#Effi...) or similar, which is costly, but otherwise not a risk.
  - DINKDINK 8y ago
    >95% accuracy is outstanding 95% specificity and 95% sensitivity isn't good enough to test the general population. See why here: https://news.ycombinator.com/item?id=16981888 https://news.ycombinator.com/item?id=16981888
DINKDINK 8y ago
Relevant stats: >The algorithms predicted a clinical diagnosis of ASD with high specificity, sensitivity and positive predictive value, exceeding 95 percent at some ages. More about the metrics you care about[1] Edit: Many people in this thread are talking about bayesian stats that it appears they don't full appreciate or understand. They're saying that 95% statistical accuracy is commendable. 95% sensitivity and 95% specificity aren't good enough to use in broad tests. Why? Autism has a 1/68 likely hood[2]. Meaning if you had a sample of 100 general-population people, tested them with this test, the likely hood of someone who tests positive for the test is actually positive (positive predictive value) is a measly ~20% (that is Probability that you have the condition given you test positive). Play around with these more at the following app: https://kennis-research.shinyapps.io/Bayes-App/ https://kennis-research.shinyapps.io/Bayes-App/ [1]https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity [2]https://www.autism-society.org/what-is/facts-and-statistics/ https://www.autism-society.org/what-is/facts-and-statistics/
- fundamental 8y ago
  Thanks for writing this summary. Plenty of people get the wrong idea when it comes to test accuracy for topics like health diagnosis. In the case of this particular topic it does seem like the outlined test could be another tool that doctors could utilize. If for instance a child has shown a change in developmental milestones then that observation comes with it's own (somewhat doctor specific) sensitivity and specificity. That information could be combined with the EEG test to improve the overall doctor+test accuracy. Nothing's going to be perfect, but the outlook is a bit more positive than presented in your example.
  - DINKDINK 8y ago
    >Nothing's going to be perfect, but the outlook is a bit more positive than presented in your example. Ideally what would happen is that the doctor would use their judgement to narrow down the candidates who the test is applied to who have strong priors of Autism. That would substantively increase PPV. You'd need a ~50% prevalence before you get to 95% PPV
- 8y ago

154 points by contourtrails 8y ago

I don't understand why there's such a massive focus on autism research, both on HN and in the news in general. It doesn't seem like a pareto optimal use of attention resources.

loriverkutya 8y ago
Because with early development, people on the spectrum could function better in the neurotypical environment, which means more people with ASD can work and need less support later.
callesgg 8y ago
On HN, cause ASD correlates highly with intrest in technology. On the news on average, don't have a good theory but mabbye just cause it is interesting forefront research.

fundamental 8y ago

Research paper in question: https://www.nature.com/articles/s41598-018-24318-x https://www.nature.com/articles/s41598-018-24318-x

neurotech1 8y ago

EEG in 3mo infants is "poorly organized" even compared to 24mo child, so it I would take this one with a grain of salt.

fundamental 8y ago
I was taking this with a hefty grain of salt, though at least on first pass they seem to have a reasonable cross-validation/testing procedure (which is usually one of my major complaints with comp-neurosci papers). As per 3 month infants, you can see that their classifier does have difficulties at that age bracket, though performance seems to start to saturate around 6 months (table 5). It would be interesting to give the paper another pass to see how more operational data collection could impact the quality of the data and thus classification results. EEG can be really hit-or-miss with different equipment. More-so with simple features such as the band power ones used within this paper.
- nonbel 8y ago
  >"at least on first pass they seem to have a reasonable cross-validation/testing procedure (which is usually one of my major complaints with comp-neurosci papers)." It looks like the usual overfitting the cv to me... They had 1000 features, 200 datapoints, tried out "several different algorithms".
  - fundamental 8y ago
    That doesn't really diminish the results in my book. If you're trying to publish something it's basically assumed that you're going to try out several methods and show the one with better performance even if the performance difference is not statistically different. As per the number of features and data points: In this field you generally don't have a ton of subjects to sample from and the high dimensional features are a natural result of the array based recordings. It should be possible to perform dimensional reduction on the data, however the ML methods are already implicitly doing that step so it's not necessarily that important. My normal gripe is when the tested subjects have some data in the training fold and some data in the testing fold (even if the data points are separate). In those cases then the ML method can fit the statistics of a particular subject rather than the true target class (e.g. target movement of a cursor in a BCI). In this paper they explicitly are testing on a subject which was never trained. So, even though the data + particular supervised layer is going to budge the results around some, it should not be a night and day difference from what's expected in reality.
    - StavrosK 8y ago
      You have to account for the fact that you used so many algorithms, though. Using ten different algorithm makes it ten times more likely you'll fit your dataset well just by chance.
      - fundamental 8y ago
        I acknowledge that the reported accuracy of a system will be higher if you take the max accuracy of 10 methods which have the same 'true' accuracy +- some noise. The results presented in table 5 of the paper are very unlikely in my opinion (as someone currently in the ML field and who has worked in the field of computational neuroscience) to be solely due to randomly trying different ML techniques without the underlying data providing a noteworthy difference between the target classes. If these results are replicated independently with a different dataset then the magnitude of the overselling of the method will be seen. I just don't think that it makes sense to doubt the results (i.e. with a grid of EEG sensors and bandpower features it is possible to identify a portion of autism cases) based upon this factor alone.
jobu 8y ago
In the Nature article they talk about using the combined analysis from multiple EEGs at different ages to increase accuracy. Also this: The accuracy of the HRA− outcome predictions was better at younger ages (3 to 9 months), then dipped in accuracy starting at 12 months. https://www.nature.com/articles/s41598-018-24318-x https://www.nature.com/articles/s41598-018-24318-x

callesgg 8y ago

Wow that is insanly cool. Especially considering that we don't even know what ASD is, or what could be causing it. Could this be used for a ASD scale?

_Schizotypy 8y ago
There has been recent research showing that part of the issue with asd is related to the glutamate system, specifically NMDA. Some sort of genetic transcription problem. Sorry I can't quote the exact paper off hand.

tnash 8y ago

"An experimenter blew bubbles to distract them." Wasn't expecting my daily does of cute in this Autism study's abstract, but got it anyway.

tbrownaw 8y ago

Not possible, that's before they've had most of their vaccinations. /s

jamroom 8y ago
I know you're being sarcastic, but it looks like there are 6 vaccines in the first 2 months: https://www.cdc.gov/vaccines/schedules/easy-to-read/child-easyread.html https://www.cdc.gov/vaccines/schedules/easy-to-read/child-ea... Not that I think it matters - I was just curious based on your post.
toast0 8y ago
It's not been conclusively proven that vaccinations can't go back in time to cause problems before they've been administered. /s
dang 8y ago
Please don't do this here.

deleted 8y ago

[deleted]

hannob 8y ago

Given that diagnosing Autism is hard and that all previous attempts at diagnosing it in a non-psychological way have failed this would be an extremely surprising result. Call me skeptical until it's reproduced independently.

talltimtom 8y ago

In this weird world that we live in this might actually help prevent a load of other deciders through increasing vaccination.

burfog 8y ago
That in turn causes other trouble. People adjust for perceived risk. For example, seatbelts and airbags make people less careful when driving. Vaccination makes people less careful about disease. There is no vaccine for enterovirus-68, which sometimes paralyses people. There is no vaccine for adenovirus-36, which is a cause of obesity. I could go on for a long time I think; lots of "harmless" viruses are turning out to cause serious problems. They can damage your heart, set off dementia, or give you cancer. The only effective answer is avoidance. This requires learning and behavior modification, so it isn't too popular, but nothing else is as effective.
- wanderfowl 8y ago
  I'm having a [Poe's law](https://en.wikipedia.org/wiki/Poe%27s_law https://en.wikipedia.org/wiki/Poe%27s_law) moment here. You've just applied Abstinence Only Sex Education 'logic' to infectious disease. This is either brilliant satire of the odd arguments against harm reduction in general, or... you're serious, and I agree, it's a crying shame nobody taught all those poor smallpox victims how to modify their behavior.
wanderfowl 8y ago
Agreed. That was my first thought, too. Part of the reason that these silly vaccine/autism conspiracy theories are hard to shut down is the fact that Autism is harder to detect pre-vaccination, so there's confirmation bias here among parents of Autistic children. If this study provides nice evidence to the Anti-Vax crowd that Autism can be measured and detected well before vaccination age, this might help take some of the wind out of the sails of the movement. Of course, for many, science won't help, much like usable retroreflectors will only break down the fantasy for a subset of moon landing conspiracy theorists, but if it gets brought up even once in a Whole Foods somewhere, they've done a good thing.

projectramo 8y ago

This would be amazing if it works. The reason I say "if" and hedge my words is because the conventional wisdom is that autism is not a single disorder with a single underlying condition. It is a cluster of symptoms of varying intensity and it is (likely) caused by a host of underlying conditions. Two children diagnosed with the disorder can have no overlapping symptoms. If that is right, then the first step is to break it down into different kinds of conditions. (No eye contact is caused by X. Speech issues are caused by Y). However, if this test can effectively pick apart one of the underlying conditions and its symptoms that would be a huge step forward. We could definitively say whether a child has this particular version of "autism". After we tease apart a few more versions, the original condition will disappear and be subsumed by these other versions.

tejohnso 8y ago
> Two children diagnosed with the disorder can have no overlapping symptoms. Is there a precedent for this with other disorders? Seems to me that if there are no overlapping symptoms, it should be a separate disorder. Even if it's just arbitrary naming like "Type X" as in diabetes.
- avip 8y ago
  IBS, asthma, schizophrenia, ADHD, and the list goes on and on.
- dwringer 8y ago
  This might not be the most authoratative source, and I'm no medical expert, but this overview from Encyclopedia Britannica[1] nicely describes the diversity in how diseases are classified (I know we aren't using the term "disease" here but the concepts are presumably related in practice - I found this summary informative but welcome any informed corrections): > The most widely used classifications of disease are (1) topographic, by bodily region or system, (2) anatomic, by organ or tissue, (3) physiological, by function or effect, (4) pathological, by the nature of the disease process, (5) etiologic (causal), (6) juristic, by speed of advent of death, (7) epidemiological, and (8) statistical. Any single disease may fall within several of these classifications. [1] https://www.britannica.com/science/human-disease/Classifications-of-diseases https://www.britannica.com/science/human-disease/Classificat...

deleted 8y ago

[deleted]

devindotcom 8y ago

There's some really early eye movement based detection too. Good to see this. As others point out it isn't a binary but a hugely variant spectrum, but there are some commonalities that at the very least suggest that a child receive further screening or prepare the parent to watch for other symptoms. Regardless of the type and spectrum position, a kid with an early diagnosis/warning seems much more likely to have a good outcome than one that gets one while in pre-school or kindergarten.

monochromatic 8y ago

Does early diagnosis give better treatment options?

scardine 8y ago
Yes! The most effective treatment is behavioral therapy and the results are better if started early. At young age the brain is very plastic and for light cases you can teach all the things that are innate to neurotypical kids.

kpil 8y ago

5 % is quite a lot of misdiagnosed babies if this is implemented as a mass screening activity, 2-3 times higher than than what the internet seems to think is the actual ASD incidence, and I imagine that that number includes a lot of "highly functional" ASD cases What should a parent do when this happens? It will be only perhaps 20-30% risk that the baby actually do have ASD and not just a false positive. I imagine that ASD "prevention" is mostly behavioural training [I have no idea at all actually] - but how much time and effort would that take? What are the consequences for healthy babies? I imagine that most people would spend a lot of effort on anything that could help in cases like this. It's a bit problematic since it's not possible to know until after a couple of years if it's was a false positive or not. It might turn out that a lot (or most) of all successful recoveries was in fact "false positives".

jiggunjer 8y ago
What do you mean a false positive won't be detectable until a few years? I think by age 1 a parent will notice? Lack of eye contact, altered walking mechanism (foot dragging, tiptoes), non-responsiveness to voices, etc. So maybe a positive test means the kid gets more attention for a few months, that never hurt, right?
alexandercrohde 8y ago
What? 95% accuracy is outstanding. I see that you're saying if you said "No" for all babies, that'd be 95%, so that's a legitimate point. However, it sounds like it's better than that "We were also able to predict ASD severity, as indicated by the ADOS Calibrated Severity Score, with quite high reliability, also by 9 months of age." I imagine the intervention is ABA therapy (https://en.wikipedia.org/wiki/Applied_behavior_analysis#Efficacy_in_autism https://en.wikipedia.org/wiki/Applied_behavior_analysis#Effi...) or similar, which is costly, but otherwise not a risk.
- DINKDINK 8y ago
  >95% accuracy is outstanding 95% specificity and 95% sensitivity isn't good enough to test the general population. See why here: https://news.ycombinator.com/item?id=16981888 https://news.ycombinator.com/item?id=16981888

DINKDINK 8y ago

Relevant stats: >The algorithms predicted a clinical diagnosis of ASD with high specificity, sensitivity and positive predictive value, exceeding 95 percent at some ages. More about the metrics you care about[1] Edit: Many people in this thread are talking about bayesian stats that it appears they don't full appreciate or understand. They're saying that 95% statistical accuracy is commendable. 95% sensitivity and 95% specificity aren't good enough to use in broad tests. Why? Autism has a 1/68 likely hood[2]. Meaning if you had a sample of 100 general-population people, tested them with this test, the likely hood of someone who tests positive for the test is actually positive (positive predictive value) is a measly ~20% (that is Probability that you have the condition given you test positive). Play around with these more at the following app: https://kennis-research.shinyapps.io/Bayes-App/ https://kennis-research.shinyapps.io/Bayes-App/ [1]https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity [2]https://www.autism-society.org/what-is/facts-and-statistics/ https://www.autism-society.org/what-is/facts-and-statistics/

fundamental 8y ago
Thanks for writing this summary. Plenty of people get the wrong idea when it comes to test accuracy for topics like health diagnosis. In the case of this particular topic it does seem like the outlined test could be another tool that doctors could utilize. If for instance a child has shown a change in developmental milestones then that observation comes with it's own (somewhat doctor specific) sensitivity and specificity. That information could be combined with the EEG test to improve the overall doctor+test accuracy. Nothing's going to be perfect, but the outlook is a bit more positive than presented in your example.
- DINKDINK 8y ago
  >Nothing's going to be perfect, but the outlook is a bit more positive than presented in your example. Ideally what would happen is that the doctor would use their judgement to narrow down the candidates who the test is applied to who have strong priors of Autism. That would substantively increase PPV. You'd need a ~50% prevalence before you get to 95% PPV
8y ago