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. 2022 Aug 4;12(8):267. doi: 10.3390/bs12080267

Table 1.

Summary of Studies Included in Review (n = 21).

Study Study Design and Participants Treatment Features Dependent Variables Moderators Main Findings
Vivanti et al., 2013 [25] Interventional single group
Total sample:
n = 21
Mage = 38 ± 11.5 months		 Group-based ESDM
Intensity: 15–25 h/week
Duration: 1 year		 Visual Reception;
Fine Motor; Receptive Language; Expressive Language; Symptoms severity		 Functional use of objects; Imitation;
Goal Understanding; Symptom severity;
Social Attention; Chronological age;
DQ		 Functional use of objects was positively associated with Visual Reception, Fine Motor and Expressive Language domains gains and alone explained 70% of the variance of the Visual Reception domains;
Imitation was positively associated with Visual Reception, Fine Motor and Receptive Language domains gains;
Goal Understanding was positively associated with Receptive Language gains and explained alone 30% of the variance of Receptive Language; Symptom severity was negatively associated with Receptive and Expressive Language gains and alone explained 40% of the variance of Expressive Language; Chronological age was negatively associated with Expressive Language;
Functional use of objects was not associated with Receptive Language, Symptoms severity
Social attention was not associated with Visual Reception, Fine Motor, Receptive and Expressive Language, Symptoms severity;
Goal Understanding was not associated with Visual Reception, Fine Motor, Expressive Language, Symptoms severity;
Imitation was not associated with Expressive Language, Symptoms severity;
Chronological Age was not associated with Visual Reception, Fine Motor, Receptive Language, Symptoms severity;
DQ was not associated with Visual Reception, Fine Motor, Receptive and Expressive Language, Symptoms severity;
Symptom severity was not associated with Visual Reception, Fine Motor, Symptoms severity
Vivanti et al., 2016 [26] Observational case control study
Total sample:
n = 60
Younger group (18–48 months): n = 32
Mage = 33.25 ± 7.2 years
Older group
(48–62 months): n = 28 Mage = 49.54 ± 5.36 years		 Group-based ESDM
Intensity: 15–25 h/week 		Verbal DQ; NonVerbal DQ; Adaptive behavior; Symptom severity Chronological age Chronological age was inversely associated with Verbal DQ gains;
Changes in NonVerbal DQ, Adaptive behavior, Symptom severity were not associated with Chronological age
Sinai-Gavrilov et al., 2020 [27] * Repeated measures factorial
design
Total sample:
n = 51
PB-ESDM:
n = 26
Mage = 43.65 ± 7.37 years
MDI group:
n = 25 Mage = 45.12 ± 4.8 years		 preschool-based ESDM
Intensity: 44 h/week
Duration: 8 weeks		 DQ; Communication;
Daily living skills; Socialization; Motor skills; Adaptive behavior 		Symptom severity;
Fine Motor Skills;
Visual Reception; Receptive Language; Expressive Language;
DQ;
Adaptive behavior;
Chronological Age;
Gender		 High responders had lower Symptom severity, higher DQ and higher Adaptive behavior compared to low responders;
No between-group changes emerged for Gender and Chronological age
Latrèche et al., 2021 [28] Longitudinal cohort study
Total sample:
n = 95
Mage = 2.81 ± 0.65 years
ESDM-AF+ group: n = 25
Mage = 2.83 ± 0.48 years
ESDM-AF- group: n = 26
Mage = 2.68 ± 0.68 years
CT-AF+ group: n = 16 Mage = 3.04 ± 0.55 years
CT-AF- group: n = 14 Mage = 2.62 ± 0.67 years		 ESDM
Intensity:
20 h/week		 DQ Attention to face Children with more Attention to face at baseline (ASD-AF + ) demonstrated statistically significantly higher DQ scores over time, especially in the verbal domain
Robain et al., 2020 [29] Observational case-control study
Total sample:
n = 60
Mage = 3.0 ± 0.8 years
ESDM-GR group: n = 9
Mage = 2.61 ± 0.39 years
ESDM-SR group: n = 13
Mage = 2.57 ± 0.37 years
CT-GR group:
n = 23
Mage = 3.36 ± 0.72 years
CT-SM group:
n = 15
Mage = 3.20 ± 1.10 years		 ESDM
Duration:
1 year		 RRB;
Social Affect; Symptom severity;
DQ		 Social orienting;
Maladaptive behavior		 Social orienting predicted changes in Social Affect, Symptom severity and DQ changes after ESDM treatment, in that ESDM-SR group reported lower Symptom severity and higher DQ over time;
Higher Maladaptive behavior were associated with lower DQ after treatment but not with DQ changes over time
Social orienting was not predictive of RRB mean change over time
Contaldo et al., 2020 [30] Pre-post single-group design
Total sample:
n = 32 Mage = 28.8 ± 6.5 months		 Community-based ESDM
Intensity: 4 h/week
Duration: 1 year 		Communication;
Socialization; Cognition and Play;
Motor skills;
Number of learning objective acquired by each child in a month; Adaptive functioning; First Communicative Gestures;
Actions with objects;
Imitation; Receptive Lexical Quotient;
DQ		 First Communicative
Gestures;
Actions with objects; Receptive Lexical Quotient; Word Production;
Imitation;
DQ;
Symptom severity; Chronological age 		Number of First Communicative Gestures were positively associated with gains in Communication, Socialization, Cognition and Play, and Motor skills and with the number of learning objective acquired by each child in a month;
Actions with objects were positively associated with gains in Socialization, Cognition and Play, and Motor skills and with the number of learning objective acquired by each child in a month;
Receptive Lexical Quotient was positively associated with gains in Socialization, Cognition and Play, and Motor skills and with the number of learning objective acquired by each child in a month;
DQ was positively associated with gains in Socialization, Cognition and Play, and with the number of learning objective acquired by each child in a month
Symptom severity was negatively associated with gains in Socialization and Motor skills and with the number of learning objective acquired by each child in a month;
Actions with objects and Receptive Lexical Quotient were not associated with the Communication domain;
Symptom severity was not associated with Communication and Cognition and Play domains;
DQ was not associated with Communication and Motor skills domains;
Chronological age, Word Production, and Imitation were not associated with any changes neither with the rate of learning objectives acquisition
Fossum et al., 2018 [31] * Prospective single-subject design
Total sample:
n = 57
Mage = 47.84 ± 8.86 years		 PRT;
Duration: 1 year 		Communication Toy contact;
Social avoidance;
Verbal self-stimulatory behavior;
Positive affect;
Cognitive abilities; Expressive language;
Chronological age; Symptoms severity 		Higher levels of Expressive Language, Cognitive ability, Toy contact, Positive affect, lower Social avoidance and Verbal self-stimulatory behavior at baseline appeared to predict treatment outcome in Expressive language;
Chronological age and Symptom severity were not predictive of Communication outcome
Schreibman et al., 2009 [32] * Single-subject multiple baseline design across participants
Total sample:
n = 6
Rage = 2–4 years
Nonresponders with high toy contact:
n = 3
Mage = 26 month
Nonresponders with low avoidance:
n = 3
Mage = 34.67 months		 PRT + DTT
Intensity: 18 h/week 		Communication Toy contact;
low avoidance 		Higher Toy contact is a key characteristic of PRT treatment responders, whereas low avoidance is not associated with a better response to PRT
Tiura et al., 2017 [33] Longitudinal study
Total sample:
n = 35
Mage = 2.10 years		 EIBI
Intensity: 9–30 h/week 		Communication; Social–emotional;
Adaptive behavior;
Physical development		 Cognitive functioning; Speaking English as the primary language;
Gender;
Symptom severity;
Chronological age		 Children with higher Cognitive functioning predicted rapid growth across the four dependent variables;
Participants who spoke English as a primary language had faster growth rates in the social–emotional and physical development domains;
Male participants tended to improve more quickly in the areas of Adaptive behavior and Physical development;
Children with higher Symptom severity tended to improve at a slower pace in the Physical development domain;
Speaking English as the primary language was not associated with Adaptive behavior and Communication;
Gender was not associated with Social–emotional and Communication;
Symptom severity was not associated with Adaptive, Social–emotional and Communication;
Chronological age did not predict growth rate
Magiati et al., 2011 [34] Longitudinal study
Total sample:
n = 36
Mage = 3.4 ± 0.6 years		 EIBI
Intensity: 15–40 h/week;
Duration:
22–90 months		 Cognitive functioning; Language skills; Adaptive behavior;
Symptom severity		 Cognitive functioning;
Language skills;
Adaptive behavior;
Symptom severity;
Chronological age		 Cognitive functioning, Language and Adaptive behavior skills were predictive of outcomes after 4–5 years of intervention;
Chronological age was not associated with treatment outcomes;
Symptom severity was not predictive of outcomes
Hedvall et al., 2015 [35] Observational Case Crossover
Initial group:
n = 198
Mage 39 ± 8.5 months
GM group:
n = 30
Mage = 41 ± 8.7 months
LM group:
n = 23
Mage = 33 ± 7.9 months		 EIBI
Intensity: 15–40 h/week
Duration: 2 years		 Adaptive behavior Cognitive functioning; Chronological age; Developmental milestones at 18 months;
Regression;
Symptom severity;
Gender		 Children in the LM group had been referred at significantly lower ages;
Symptom severity was significantly higher in the LM group as compared to the GM group;
Most of the children in the GM group significantly had passed the expected developmental milestones at the 18-month check-up;
The GM group had a significantly higher cognitive level
Laister et al., 2021 [36] * Longitudinal pre-post design
Total sample:
n = 56
Mage = 41.96 ± 7.5 years 		ESDM
Duration: 12 months		 Social skills; Language skills Verbal DQ;
Nonverbal DQ;
Fine Motor skills;
Gross Motor skills;
Visual Reception; Receptive Language; Expressive Language; Gestural approach behavior;
Social approach behaviors; Problem behavior; Chronological Age		 Verbal and Nonverbal DQ, Fine Motor skills, Visual Reception, and Gestural Approach Behavior were significantly higher for the High responder group who gains the most in social and language skills;
Receptive Language, Expressive Language, Problem Behavior, Chronological Age, and Social approach behaviors were not significantly different for the two groups;
Gestural approach behaviors were found to significantly predict Verbal and Nonverbal DQ;
Sherer and Schreibman, 2005 [37] * Multiple baseline design across participants
Total sample: n = 6
Responders:
n = 3
Mage = 3:3 years;
Nonresponders:
n = 3
Mage = 4:2 years 		PRT
Intensity: 10 h/week		 Language Skills; Adaptive Behavior;
IQ;
Symptom severity;
Play skills 		Toy Contact/Object Manipulation;
Approach behaviors; Avoidant behaviors;
Verbal Self-Stimulatory behaviors;
Nonverbal Self-Stimulatory Behaviors		 Children with higher Toy contact/Object Manipulation, Approach behavior and Verbal Self-Stimulatory behaviors but lower Avoidant behaviors responded better to treatment than children in the nonresponder group
Smith et al., 2010 [38] Observational case control study
Total sample:
n = 45
Mage = 50 ± 10 months		 EIBI
Intensity: 14 h/week
Duration: 12 months		 Expressive Language; Receptive Language
Adaptive behavior;
Symptoms severity;
Problem behavior 		IQ Significant main effects of IQ on Expressive and Receptive Language, Communication, Adaptive behavior and Symptom severity were found;
Non-significant effects of IQ on Problem Behavior emerged
Sallows and Graupner, 2005 [39] Interventional Parallel Group Study
Total sample:
n = 23
UCLA group:
n = 13
Mage = 33.2 ± 3.89 months
Parent group: n = 10
Mage = 34.2 ± 5.06 months		 UCLA EIBI
Intensity: 40 h/week
Duration: 2 years 		IQ;
Language skills;
Social skills;
Early Learning Measure		 IQ;
Daily Living skills;
Social skills;
Communication; Symptoms severity;
Early Learning Measure		 IQ was best predicted by Early Learning Measure, IQ, Social skills, lower Symptom severity;
Daily Living skills and Communication did not predict changes in IQ;
Language skills was predicted by the ability to imitate, Daily Living skills and Communication;
IQ, Social skills and Symptom severity did not predict changes in Language skills;
Social skills was predicted by the ability to imitate, Early Learning Measure, Symptom severity;
Daily Living skills, IQ and Communication did not predict Social skills
Smith et al., 2015 [40] Interventional Single Group Study
Total sample:
n = 71
Mage = 3.27 ± 0.65 years		 EIBI
Intensity: ≥15 h/week
Duration: 24 months
IQ;
Adaptive
behavior; Symptom severity;
Social skills;
Communication;
RRB		 Chronological age;
IQ;
Social Engagement;
Social approach;
Joint attention;
Imitation;
Sensorimotor rituals
Higher values of outcome variables at intake predicted better outcome in IQ, Adaptive behavior, Symptom severity;
Lower Chronological age predicted better outcome for IQ, Adaptive behavior, and Communication;
Higher IQ predicted IQ level, Adaptive behavior and lower Symptom severity;
Higher Social Engagement scores at intake predicted higher IQ and Adaptive behavior;
Sensorimotor rituals did not predict any outcome;
Social engagement did not predict Symptom severity outcome;
Chronological age did not predict Social Interaction deficit and Symptom severity;
IQ did not predict Social Interaction and RRB
Klintwall and Eikeseth, 2012 [41] Interventional Single Group Study
Total sample:
n = 21
Mage = 3.7
Rge = 2.3–4.11 years		 EIBI
Intensity: 20 h/week		 Learning rate of Adaptive behavior Automatic reinforcers;
Socially-mediated reinforcers;
Chronological age;
Adaptive behavior		 The number of Socially-mediated reinforcers was found to be a significant predictor of increase in the learning rate, vice-versa for the number of automatic reinforcers;
Chronological age was also found to be a significant predictor of learning rate: older children exhibited larger treatment gains;
Adaptive behavior did not predict learning rate
Pellecchia et al., 2016 [42] Interventional Single group Study
Total sample: n = 152 Mage = 6 ± 0.9 years		 STAR
Duration: 3 years		 IQ Language and Communication;
Adaptive behavior;
Challenging behavior;
Symptom severity;
Social skills;
Chronological age; Symptoms associated with co-occurring psychiatric difficulties 		Social anxiety symptoms significantly predicted IQ outcome, in that increased social phobia was associated with a decrease in cognitive functioning;
Chronological age significantly predicted IQ changes, in that lower age was associated with a decrease in cognitive functioning;Language and Communication, Adaptive skills, Challenging behaviors, Symptom severity, Social skills and other co-occuring psychiatric difficulties did not predict any change in IQ
Ben-Itzchak et al., 2014 [43] Interventional Parallel Study
Total sample:
n = 46 Mage = 25.5 ± 3.95 months		 ABA-based treatment
Intensity: 20 h/week		 Communication;
Daily Living skills; Socialization; Motor skills;
Fine Motor;
Visual Reception; Receptive Language; Expressive Language;
Symptoms severity		 IQ Higher IQ was associated with increases in Communication, Daily Living skills, Socialization;
A lower IQ was associated with an increase in Fine Motor and Receptive Language;
IQ did not predict Symptom severity
Remington et al., 2007 [44] * Interventional Parallel Group Study
Total sample:
n = 44
Range = 30–40 months
EIBI group
n = 23
Mage = 35.7 ± 4.0 months
Control group
n = 21
Mage = 38.4 ± 4.4 months		 EIBI
Intensity: 25.6 h/week
Duration: 2 years 		IQ;
Language skills		 IQ;
Adaptive behavior; Communication;
Socialization;
Daily Living skills;
Motor skills;
Problems behavior; Symptoms severity 		Children who responded better to intervention had higher IQ, higher Adaptive behavior, Communication and Social Skills scores, lower Motor skills scores, more Problems behaviors and higher Symptoms severity;
No between-group differences were found for Daily living skills
Eldevik et al., 2012 [45] Interventional Parallel Group Study
Total sample:
n = 43
EIBI group:
n = 31
Mage = 42.2 ± 9 months
TAU group:
n = 12
Mage = 46.2 ± 12.4 months		 EIBI
Intensity: 10–20 h/week
Duration: 2 years		 Communication;
Socialization;
Daily Living skills;
Adaptive behavior;
IQ		 Chronological age;
IQ;
Adaptive behavior;
Gender;
Diagnosis		 Chronological age positively correlated with gains in Adaptive behavior scores;
IQ positively correlated with changes in the Socialization domain;Gender was not associated with any of the dependent variables

Notes. * indicates responders’ profile studies. CT: community treatment; CT-AF-: CT subgroups with lower attention to face; CT-AF+: CT subgroups with higher attention to face; CT-GR: CT geometrical responder subgroups; CT-SR: CT social responder subgroups; DQ: Developmental Quotient; ESDM: Early Start Denver Model; EIBI: Early Intensive Behavioral Intervention; ESDM-AF-: ESDM subgroups with lower attention to face; ESDM-AF+: ESDM subgroups with higher attention to face; ESDM-GR: ESDM geometrical responder subgroups; ESDM-SR: ESDM social responder subgroups; GM: children who gained the most; LM: children who lost the most; MDI: Multidisciplinary Developmental Intervention; PB-ESDM: Preschool-based ESDM; RRB: Restricted interest and Repetitive Behaviors; STAR: Strategies for Teaching based on Autism Research [46]; TAU: Treatment As Usual.