Peter Washington

Mr. Peter Washington

Stanford University
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 November 2018 in PLOS Medicine
Verified
Journal Article
Open access
PDF file
QTQandeel Tariq
Qandeel Tariq
JDJena Daniels
Jena Daniels
JSJessey Nicole Schwartz
Jessey Nicole Schwartz
Peter WashingtonPeter Washington
Peter Washington
HKHaik Kalantarian
Haik Kalantarian
DWDennis Wall
Dennis Wall
The standard approaches to diagnosing autism spectrum disorder (ASD) evaluate between 20 and 100 behaviors and take several hours to complete. This has in part contributed to long wait times for a diagnosis and subsequent delays in access to therapy. We hypothesize that the use of machine learning analysis on home video can speed the diagnosis without compromising accuracy. We have analyzed item-level records from 2 standard diagnostic instruments to construct machine learning classifiers optimized for sparsity, interpretability, and accuracy. In the present study, we prospectively test whether the features from these optimized models can be extracted by blinded nonexpert raters from 3-minute home videos of children with and without ASD to arrive at a rapid and accurate machine learning autism classification. We created a mobile web portal for video raters to assess 30 behavioral features (e.g., eye contact, social smile) that are used by 8 independent machine learning models for identifying ASD, each with >94% accuracy in cross-validation testing and subsequent independent validation from previous work. We then collected 116 short home videos of children with autism (mean age = 4 years 10 months, SD = 2 years 3 months) and 46 videos of typically developing children (mean age = 2 years 11 months, SD = 1 year 2 months). Three raters blind to the diagnosis independently measured each of the 30 features from the 8 models, with a median time to completion of 4 minutes. Although several models (consisting of alternating decision trees, support vector machine [SVM], logistic regression (LR), radial kernel, and linear SVM) performed well, a sparse 5-feature LR classifier (LR5) yielded the highest accuracy (area under the curve [AUC]: 92% [95% CI 88%–97%]) across all ages tested. We used a prospectively collected independent validation set of 66 videos (33 ASD and 33 non-ASD) and 3 independent rater measurements to validate the outcome, achieving lower but comparable accuracy (AUC: 89% [95% CI 81%–95%]). Finally, we applied LR to the 162-video-feature matrix to construct an 8-feature model, which achieved 0.93 AUC (95% CI 0.90–0.97) on the held-out test set and 0.86 on the validation set of 66 videos. Validation on children with an existing diagnosis limited the ability to generalize the performance to undiagnosed populations. These results support the hypothesis that feature tagging of home videos for machine learning classification of autism can yield accurate outcomes in short time frames, using mobile devices. Further work will be needed to confirm that this approach can accelerate autism diagnosis at scale.

1 May 2019 in JAMA Pediatrics
Verified
Journal Article
Closed access
PDF file
CVCatalin Voss
Catalin Voss
JSJessey Schwartz
Jessey Schwartz
JDJena Daniels
Jena Daniels
AKAaron Kline
Aaron Kline
NHNick Haber
Nick Haber
DWDennis Wall
Dennis Wall
Autism spectrum disorder (ASD) prevalence has increased dramatically in the United States in the past few decades to 1 in 59 children.1 While the symptoms of ASD vary widely, difficulty with socialization is a core deficit.2 Children struggle to engage in joint attention, sustain eye contact, and recognize facial expressions.2-5 Experts recommend 20 hours per week of applied behavioral analysis (ABA)2,6 often incorporating naturalistic developmental behavioral interventions7 with a behavioral therapist for at least 2 years.2 Although these behavioral interventions are effective, they are costly (between $40 000 and $60 000 per child per year8), and many children face challenges generalizing therapy to real-world contexts.7 Furthermore, the increase in prevalence of ASD has outpaced availability of behavioral therapists, creating wait-lists of up to 18 months in the United States.9 Learning aids based on novel ubiquitous technologies using machine learning can begin to address these problems by creating opportunities for therapy that are accessible outside of the clinician’s office. Such tools may generalize to the natural environment where the social skills are used and act as a care bridge while children wait for standard therapy.

24 April 2019 in Journal of Medical Internet Research
Verified
Journal Article
Open access
QTQandeel Tariq
Qandeel Tariq
SFScott Lanyon Fleming
Scott Lanyon Fleming
JSJessey Nicole Schwartz
Jessey Nicole Schwartz
KDKaitlyn Dunlap
Kaitlyn Dunlap
CCConor Corbin
Conor Corbin
DWDennis Wall
Dennis Wall
Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet

1 July 2019 in Artificial Intelligence in Medicine
Verified
Journal Article
Open access
HKHaik Kalantarian
Haik Kalantarian
KJKhaled Jedoui
Khaled Jedoui
Peter WashingtonPeter Washington
Peter Washington
QTQandeel Tariq
Qandeel Tariq
KDKaitlyn Dunlap
Kaitlyn Dunlap
DWDennis Wall
Dennis Wall
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by repetitive behaviors, narrow interests, and deficits in social interaction and communication ability. An increasing emphasis is being placed on the development of innovative digital and mobile systems for their potential in therapeutic applications outside of clinical environments. Due to recent advances in the field of computer vision, various emotion classifiers have been developed, which have potential to play a significant role in mobile screening and therapy for developmental delays that impair emotion recognition and expression. However, these classifiers are trained on datasets of predominantly neurotypical adults and can sometimes fail to generalize to children with autism. The need to improve existing classifiers and develop new systems that overcome these limitations necessitates novel methods to crowdsource labeled emotion data from children. In this paper, we present a mobile charades-style game, Guess What?, from which we derive egocentric video with a high density of varied emotion from a 90-second game session. We then present a framework for semi-automatic labeled frame extraction from these videos using meta information from the game session coupled with classification confidence scores. Results show that 94%, 81%, 92%, and 56% of frames were automatically labeled correctly for categories disgust, neutral, surprise, and scared respectively, though performance for angry and happy did not improve significantly from the baseline.

13 December 2019 in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
Verified
Journal Article
Closed access
Peter WashingtonPeter Washington
Peter Washington
NPNatalie Park
Natalie Park
PSParishkrita Srivastava
Parishkrita Srivastava
CVCatalin Voss
Catalin Voss
AKAaron Kline
Aaron Kline
DWDennis Wall
Dennis Wall

2 August 2018 in npj Digital Medicine
Verified
Journal Article
Open access
PDF file
JDJena Daniels
Jena Daniels
JSJessey N. Schwartz
Jessey N. Schwartz
CVCatalin Voss
Catalin Voss
NHNick Haber
Nick Haber
AFAzar Fazel
Azar Fazel
DWDennis Wall
Dennis Wall
Although standard behavioral interventions for autism spectrum disorder (ASD) are effective therapies for social deficits, they face criticism for being time-intensive and overdependent on specialists. Earlier starting age of therapy is a strong predictor of later success, but waitlists for therapies can be 18 months long. To address these complications, we developed Superpower Glass, a machine-learning-assisted software system that runs on Google Glass and an Android smartphone, designed for use during social interactions. This pilot exploratory study examines our prototype tool’s potential for social-affective learning for children with autism. We sent our tool home with 14 families and assessed changes from intake to conclusion through the Social Responsiveness Scale (SRS-2), a facial affect recognition task (EGG), and qualitative parent reports. A repeated-measures one-way ANOVA demonstrated a decrease in SRS-2 total scores by an average 7.14 points (F(1,13) = 33.20,p = <.001, higher scores indicate higher ASD severity). EGG scores also increased by an average 9.55 correct responses (F(1,10) = 11.89,p = <.01). Parents reported increased eye contact and greater social acuity. This feasibility study supports using mobile technologies for potential therapeutic purposes.