. 2021 Apr 1;9(2):208–234. doi: 10.1007/s40489-021-00249-8

Table 1.

Descriptive summary of included studies

Reference	Participants • N (N eligible) • Gender • Age	Intervention agents • Relationship • Age (siblings)	Intervention characteristics • FIPs* • Intervention package • Setting • Dosage
Cardon (2012)	4 (4) 2 M; 2 F 24–42 months	4 mothers	PII, PP, R+, TAII, VM Video Modelling Imitation Training (VMIT) Home <8 h
Coolican et al. (2010)	8 (8) 7 M; 1 F 28–56 months	5 mothers, 3 fathers	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Clinic and home 6 h
Ferraioli & Harris (2011)	4 (4) 3 M; 1 F 41–64 months	4 brothers 6–8 years	DTT, MD, PMII, PP, PRT, R+, TD No program name Home 3–12 h
Gengoux et al. (2015)	23 (23) See Hardan et al. 2015	See Hardan et al. 2015	See Hardan et al. 2015
Gillett & Leblanc (2007)	3 (3) 3 M 4–5 years	3 mothers	MD, PII, PP, R+, TD Natural Language Paradigm (NLP) 2 clinic, 1 home 1.5–2 h
Guðmundsdóttir et al. (2019)	3 (3) 3 M 47–55 months	3 mothers	PII, R+, TD Sunny Starts; Decide Arrange Now Count Enjoy (Teaching DANCE) Telehealth (plus one session at home) 14–29 h
Guðmundsdóttir et al. (2017)	2 (1) 1 M 58 months	1 mother	PII, R+, TD Sunny Starts; Decide Arrange Now Count Enjoy (Teaching DANCE) Telehealth 53 h
Hansen et al. (2018)	3 (2) 1 M; 1 F 36; 57 months	2 mothers	PII, PP, R+, TD No program name Clinic Average 1.5 h
Hansen & Shillingsburg (2016)	2 (2) 2 M 32; 45 months	Parent (not specified)	PII, PP, R+, TD Modified Parent-Child Interaction Therapy (PCIT) Clinic 13–14 h
Hardan et al. (2015)	53 (25) 19 M; 6 F 4.1 (1.2) years	25 parents (not specified)	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment – Group (PRT-G) Clinic 16 h
Hong et al., 2018b	2 (2) 1 M; 1 F 51 months; 57 months	2 mothers	PII, PP, R+, TD No program name Self-directed, telehealth Total hours not calculated
Ingersoll & Gergans (2007)	3 (3) 2 M; 1 F 31–42 months	3 mothers	MD, PII, PP, R+, TD Reciprocal Imitation Training (RIT) Clinic 10–13 h
Ingersoll & Wainer (2013)	8 (7) 6 M; 1 F 44–63 months	7 mothers	PII, PP, R+, TD Project ImPACT Clinic 12–24 h
Ingersoll et al. (2016)	28 (28) 20 M; 8 F 46.08 (13.18) SD; 41.57 (12.24) TA months	26 mothers, 2 fathers	PP, PII, R+, TD Project imPACT Self-directed, telehealth 27 h
Jones and Feeley (2009)	3 (2) 1 M; 1 F 45; 48 months	2 mothers, 1 father	DTT, MD, PII, PP, PRT, R+, TD No program name Home Total hours unclear
Jull & Mirenda (2011)	2 (2) 2 M 59; 65 months	2 mothers 1 sister, 1 cousin (not directly trained) 6; 4 years	PII, PP, PMI, R+, SPG No program name Home Total hours unclear
Kaiser et al. (2000)	6 (3) 3 M 40–54 months	3 mothers	MD, PII, PP, R+, TD Enhanced Milieu Teaching (EMT) Clinic 18 h
Kasari et al. (2015)	86 (43) 35 M; 8 F 30.7 (3.5) months	43 mothers	MD, PII, PP, TD Joint Attention, Symbolic Play, Engagement & Regulation (JASPER) Clinic 10 h
Kasari et al. (2010)	38 (19) 15 M; 4 F 30.35 (0.93) months	Parents (not specified)	MD, PII, PP, TD No program name Clinic 18 h
Kasari et al. (2014)	112 (60) 50 M; 10 F 41.9 (10.0) months	Parents (not specified)	MD, PII, PP, TD Joint Attention, Symbolic Play, Engagement & Regulation (JASPER) Home 24 h
Kashinath et al. (2006)	5 (5) 4 M; 1 F 33–65 months	5 mothers	MD, PII, PP, R+, TD No program name Home 40–60 h
Koegel et al. (2002)	5 (5) 2 M; 3 F 46–67 months	5 mothers, 3 fathers	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Clinic 25 h
Lane et al. (2016)	2 (2) 2 M 31–35 months	2 mothers	PII, PP, R+, TD No program name Clinic 3 h
Law et al. (2018)	3 (3) 2 M; 1 F 30–52 months	3 mothers	PII, PP, R+, TD Map4speech (app); Project imPACT Self-directed, telehealth 4.5–10 h
Loughrey et al. (2014)	2 (1) 1 M 3 years	1 mother 1 father (not directly trained)	PII, PP, R+ No program name Clinic and home Total hours unclear
Madzharova & Sturmey (2015)	3 (1) 1 M 5 years	1 mother 1 sister (not directly trained) 5 years	PII, PMI, PP, R+, SPG No program name Home Total hours unclear
Mancil et al. (2009)	3 (2) 2 M 49; 58 months	2 mothers	FBA, FCT, PII, PP, R+, TD Modified milieu therapy Home <5 h
Manohar et al. (2019)	50 (26) 22M 4F 42.6 (17.5) months	Parents (not specified)	MD, PII, PP, R+, SN No program name Clinic and home 5.25–6 h
McDuffie et al. (2013)	8 (8) 4 M; 4 F 27–69 months	8 mothers	MD, NCR, PP, PII No program name Telehealth 24 h
McGarry et al. (2019)	11 (11) 8M, 3F 20–46 months	Parents (8 mothers, 3 fathers)	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Telehealth Total hours unclear
Meadan et al. (2016)	3 (3) 2 M; 1 F 2–4 years	3 mothers	MD, PII, TD Internet-Based Parent- Implemented Communication Strategies (i-PiCS) Telehealth Total hours unclear
Nefdt et al. (2010)	27 (13) 92.6% M 38.92 (14.57) months	Parents (not specified)	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Self-directed Average 2 h
Nunes & Hanline (2007)	1 (1) 1 M 55 months	1 mother	MD, PII, PP, R+ No program name Home Average 1 h
Oppenheim-Leaf et al. (2012)	3 (2) 2 M Both 4 years	1 brother, 1 sister Both 5 years	PMII, PP, R+, TD Program name not specified Home Total hours unclear
Park et al. (2011)	3 (3) 3 M 29–31 months	3 mothers	PECS, PII, PP, R+ Picture Exchange Communication System (PECS) Home 2.5–4 h
Penney and Schwartz (2018)	3 (3) 2M, 1F 48–65 months	2 mothers, 1 father	MD, PII, PP, R+, TD Reciprocal Imitation Training (RIT) Home and childhood center < 7 h
Randolph et al. (2011)	3 (1) 1 M 5 years	1 father	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Clinic 7–9 h
Reagon & Higbee (2009)	3 (2) 2 M 35; 47 months	2 mothers	PII, PP, SC, R+, TAII No program name Home Approximately 1 h
Rocha et al. (2007)	3 (3) 2 M; 1 F 26–42 months	2 mothers, 1 father	DTT, MD, PII, PP, PRT, R+, TD No program name Clinic 17 h
Rogers et al. (2019)	45 (45) 31 M, 13 F 2.1 (0.4) years	Parents (not specified)	FBA, MD, PII, PP, PRT, R+, TD Early Start Denver Model (ESDM) Clinic and home 36 h
Rollins et al. (2016)	4 (4) 4 M 28–33 months	4 mothers	PII, R+, TD Pathways Early Autism Intervention Home 12–19.5 h
Simacek et al. (2017)	3 (2) 2 F 3.5; 4 years	2 mothers, 1 father	FBA, FCT, PII, PP, R+, TD No program name Telehealth Total hours unclear
Stahmer & Gist (2001)	22 (22) Gender not specified 19–50 months	Parents (not specified)	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Clinic 12 h
Symon (2005)	3 (3) 3 M 34–64 months	3 mothers	FBA, MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Clinic 25 h
Tsao & Odom (2006)	4 (2) 2 M 41; 46 months	1 sister; 1 brother 11; 4 years	PMII, PP, R+ Stay-Play-Talk Play Time/ Social Time Getting Along with Others Home 3 h
Vernon et al. (2012)	3 (3) 3 M 28–51 months	2 mothers; 1 father	MD, PII, PP, PRT, R+, TD Pivotal Response Treatment (PRT) Home 16 h
Vismara et al. (2009)	8 (8) Gender not specified 26–35 months	8 parents (not specified)	FBA, MD, PII, PP, PRT, R+, TD Early Start Denver Model (ESDM) Clinic 12 h
Vismara et al. (2018)	24 (14) 11 M; 3 F 31.9 (10.4) months	11 mothers, 3 fathers	FBA, MD, PII, PP, PRT, R+, TD Parent Early Start Denver Model (P-ESDM) Telehealth 18 h
Vismara et al. (2013)	8 (8) Gender not reported 20–45 months	7 mothers, 1 father	FBA, MD, PII, PP, PRT, R+, TD Parent Early Start Denver Model (P-ESDM) Telehealth 22.5 h
Wainer & Ingersoll (2013)	3 (2) 2 M 26; 69 months	2 mothers	MD, PII, PP, R+, TD Reciprocal Imitation Training (RIT) Self-directed, Telehealth <2 h
Wainer & Ingersoll (2015)	5 (5) Gender not reported 29–59 months	5 mothers	MD, PII, PP, R+, TD Reciprocal Imitation Training (RIT) Telehealth 1.5 h
Walton & Ingersoll (2012)	4 (4) 4 M 45–57 months	2 brothers, 4 sisters 8–13 years	MD, PMII, PP, R+, TD Reciprocal Imitation Training (RIT) Home 5–10 h
Wang (2017)	4 (4) 3 M; 1 F 30–50 months	2 mothers, 2 fathers	PII, TD, TAII, VM No program name Home Total hours unclear
Zaghlawan & Ostrosky (2016)	2 (2) 2 M 37; 60 months	1 mother, 1 father	MD, PII, PP, R+, TD Modified Reciprocal Imitation Training (RIT) Home 5.5–8 h

Reference

Participants
• N (N eligible)
• Gender
• Age

Intervention agents
• Relationship
• Age (siblings)

Intervention characteristics
• FIPs*
• Intervention package
• Setting
• Dosage

Cardon (2012)

4 (4)

2 M; 2 F

24–42 months

4 mothers

PII, PP, R+, TAII, VM

Video Modelling Imitation Training (VMIT)

Home

<8 h

Coolican et al. (2010)

8 (8)

7 M; 1 F

28–56 months

5 mothers, 3 fathers

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Clinic and home

6 h

Ferraioli & Harris (2011)

4 (4)

3 M; 1 F

41–64 months

4 brothers

6–8 years

DTT, MD, PMII, PP, PRT, R+, TD

No program name

Home

3–12 h

Gengoux et al. (2015)

23 (23)

See Hardan et al. 2015

Gillett & Leblanc (2007)

3 (3)

3 M

4–5 years

3 mothers

MD, PII, PP, R+, TD

Natural Language Paradigm (NLP)

2 clinic, 1 home

1.5–2 h

Guðmundsdóttir et al. (2019)

3 (3)

3 M

47–55 months

3 mothers

PII, R+, TD

Sunny Starts; Decide Arrange Now Count Enjoy (Teaching DANCE)

Telehealth (plus one session at home)

14–29 h

Guðmundsdóttir et al. (2017)

2 (1)

1 M

58 months

1 mother

PII, R+, TD

Sunny Starts; Decide Arrange Now Count Enjoy (Teaching DANCE)

Telehealth

53 h

Hansen et al. (2018)

3 (2)

1 M; 1 F

36; 57 months

2 mothers

PII, PP, R+, TD

No program name

Clinic

Average 1.5 h

Hansen & Shillingsburg (2016)

2 (2)

2 M

32; 45 months

Parent (not specified)

PII, PP, R+, TD

Modified Parent-Child Interaction Therapy (PCIT)

Clinic

13–14 h

Hardan et al. (2015)

53 (25)

19 M; 6 F

4.1 (1.2) years

25 parents (not specified)

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment – Group (PRT-G)

Clinic

16 h

Hong et al., 2018b

2 (2)

1 M; 1 F

51 months; 57 months

2 mothers

PII, PP, R+, TD

No program name

Self-directed, telehealth

Total hours not calculated

Ingersoll & Gergans (2007)

3 (3)

2 M; 1 F

31–42 months

3 mothers

MD, PII, PP, R+, TD

Reciprocal Imitation Training (RIT)

Clinic

10–13 h

Ingersoll & Wainer (2013)

8 (7)

6 M; 1 F

44–63 months

7 mothers

PII, PP, R+, TD

Project ImPACT

Clinic

12–24 h

Ingersoll et al. (2016)

28 (28)

20 M; 8 F

46.08 (13.18) SD; 41.57 (12.24) TA months

26 mothers, 2 fathers

PP, PII, R+, TD

Project imPACT

Self-directed, telehealth

27 h

Jones and Feeley (2009)

3 (2)

1 M; 1 F

45; 48 months

2 mothers, 1 father

DTT, MD, PII, PP, PRT, R+, TD

No program name

Home

Total hours unclear

Jull & Mirenda (2011)

2 (2)

2 M

59; 65 months

2 mothers

1 sister, 1 cousin (not directly trained)

6; 4 years

PII, PP, PMI, R+, SPG

No program name

Home

Total hours unclear

Kaiser et al. (2000)

6 (3)

3 M

40–54 months

3 mothers

MD, PII, PP, R+, TD

Enhanced Milieu Teaching (EMT)

Clinic

18 h

Kasari et al. (2015)

86 (43)

35 M; 8 F

30.7 (3.5) months

43 mothers

MD, PII, PP, TD

Joint Attention, Symbolic Play, Engagement & Regulation (JASPER)

Clinic

10 h

Kasari et al. (2010)

38 (19)

15 M; 4 F

30.35 (0.93) months

Parents (not specified)

MD, PII, PP, TD

No program name

Clinic

18 h

Kasari et al. (2014)

112 (60)

50 M; 10 F

41.9 (10.0) months

Parents (not specified)

MD, PII, PP, TD

Joint Attention, Symbolic Play, Engagement & Regulation (JASPER)

Home

24 h

Kashinath et al. (2006)

5 (5)

4 M; 1 F

33–65 months

5 mothers

MD, PII, PP, R+, TD

No program name

Home

40–60 h

Koegel et al. (2002)

5 (5)

2 M; 3 F

46–67 months

5 mothers, 3 fathers

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Clinic

25 h

Lane et al. (2016)

2 (2)

2 M

31–35 months

2 mothers

PII, PP, R+, TD

No program name

Clinic

3 h

Law et al. (2018)

3 (3)

2 M; 1 F

30–52 months

3 mothers

PII, PP, R+, TD

Map4speech (app); Project imPACT

Self-directed, telehealth

4.5–10 h

Loughrey et al. (2014)

2 (1)

1 M

3 years

1 mother

1 father (not directly trained)

PII, PP, R+

No program name

Clinic and home

Total hours unclear

Madzharova & Sturmey (2015)

3 (1)

1 M

5 years

1 mother

1 sister (not directly trained)

5 years

PII, PMI, PP, R+, SPG

No program name

Home

Total hours unclear

Mancil et al. (2009)

3 (2)

2 M

49; 58 months

2 mothers

FBA, FCT, PII, PP, R+, TD

Modified milieu therapy

Home

<5 h

Manohar et al. (2019)

50 (26)

22M 4F

42.6 (17.5) months

Parents (not specified)

MD, PII, PP, R+, SN

No program name

Clinic and home

5.25–6 h

McDuffie et al. (2013)

8 (8)

4 M; 4 F

27–69 months

8 mothers

MD, NCR, PP, PII

No program name

Telehealth

24 h

McGarry et al. (2019)

11 (11)

8M, 3F

20–46 months

Parents (8 mothers, 3 fathers)

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Telehealth

Total hours unclear

Meadan et al. (2016)

3 (3)

2 M; 1 F

2–4 years

3 mothers

MD, PII, TD

Internet-Based Parent-

Implemented Communication Strategies (i-PiCS)

Telehealth

Total hours unclear

Nefdt et al. (2010)

27 (13)

92.6% M

38.92 (14.57) months

Parents (not specified)

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Self-directed

Average 2 h

Nunes & Hanline (2007)

1 (1)

1 M

55 months

1 mother

MD, PII, PP, R+

No program name

Home

Average 1 h

Oppenheim-Leaf et al. (2012)

3 (2)

2 M

Both 4 years

1 brother, 1 sister

Both 5 years

PMII, PP, R+, TD

Program name not specified

Home

Total hours unclear

Park et al. (2011)

3 (3)

3 M

29–31 months

3 mothers

PECS, PII, PP, R+

Picture Exchange Communication System (PECS)

Home

2.5–4 h

Penney and Schwartz (2018)

3 (3)

2M, 1F

48–65 months

2 mothers, 1 father

MD, PII, PP, R+, TD

Reciprocal Imitation Training (RIT)

Home and childhood center

< 7 h

Randolph et al. (2011)

3 (1)

1 M

5 years

1 father

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Clinic

7–9 h

Reagon & Higbee (2009)

3 (2)

2 M

35; 47 months

2 mothers

PII, PP, SC, R+, TAII

No program name

Home

Approximately 1 h

Rocha et al. (2007)

3 (3)

2 M; 1 F

26–42 months

2 mothers, 1 father

DTT, MD, PII, PP, PRT, R+, TD

No program name

Clinic

17 h

Rogers et al. (2019)

45 (45)

31 M, 13 F

2.1 (0.4) years

Parents (not specified)

FBA, MD, PII, PP, PRT, R+, TD

Early Start Denver Model (ESDM)

Clinic and home

36 h

Rollins et al. (2016)

4 (4)

4 M

28–33 months

4 mothers

PII, R+, TD

Pathways Early Autism Intervention

Home

12–19.5 h

Simacek et al. (2017)

3 (2)

2 F

3.5; 4 years

2 mothers, 1 father

FBA, FCT, PII, PP, R+, TD

No program name

Telehealth

Total hours unclear

Stahmer & Gist (2001)

22 (22)

Gender not specified

19–50 months

Parents (not specified)

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Clinic

12 h

Symon (2005)

3 (3)

3 M

34–64 months

3 mothers

FBA, MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Clinic

25 h

Tsao & Odom (2006)

4 (2)

2 M

41; 46 months

1 sister; 1 brother

11; 4 years

PMII, PP, R+

Stay-Play-Talk

Play Time/ Social Time

Getting Along with Others

Home

3 h

Vernon et al. (2012)

3 (3)

3 M

28–51 months

2 mothers; 1 father

MD, PII, PP, PRT, R+, TD

Pivotal Response Treatment (PRT)

Home

16 h

Vismara et al. (2009)

8 (8)

Gender not specified

26–35 months

8 parents (not specified)

FBA, MD, PII, PP, PRT, R+, TD

Early Start Denver Model (ESDM)

Clinic

12 h

Vismara et al. (2018)

24 (14)

11 M; 3 F

31.9 (10.4) months

11 mothers, 3 fathers

FBA, MD, PII, PP, PRT, R+, TD

Parent Early Start Denver Model (P-ESDM)

Telehealth

18 h

Vismara et al. (2013)

8 (8)

Gender not reported

20–45 months

7 mothers, 1 father

FBA, MD, PII, PP, PRT, R+, TD

Parent Early Start Denver Model (P-ESDM)

Telehealth

22.5 h

Wainer & Ingersoll (2013)

3 (2)

2 M

26; 69 months

2 mothers

MD, PII, PP, R+, TD

Reciprocal Imitation Training (RIT)

Self-directed, Telehealth

<2 h

Wainer & Ingersoll (2015)

5 (5)

Gender not reported

29–59 months

5 mothers

MD, PII, PP, R+, TD

Reciprocal Imitation Training (RIT)

Telehealth

1.5 h

Walton & Ingersoll (2012)

4 (4)

4 M

45–57 months

2 brothers, 4 sisters

8–13 years

MD, PMII, PP, R+, TD

Reciprocal Imitation Training (RIT)

Home

5–10 h

Wang (2017)

4 (4)

3 M; 1 F

30–50 months

2 mothers, 2 fathers

PII, TD, TAII, VM

No program name

Home

Total hours unclear

Zaghlawan & Ostrosky (2016)

2 (2)

2 M

37; 60 months

1 mother, 1 father

MD, PII, PP, R+, TD

Modified Reciprocal Imitation Training (RIT)

Home

5.5–8 h

*All studies included naturalistic interventions (NI); therefore, NI was not listed

FIPs (Wong et al., 2015). DTT: Discrete Trial Training. FBA: Functional Behavior Assessment. FCT: Functional Communication Training. MD: Modelling. PII: Parent-implemented intervention. PMII: Peer-mediated instruction or intervention. PP: Prompting. PRT: Pivotal Response Treatment. R+: Reinforcement. SC: Scripting. TAII: Technology-aided instruction and intervention. TD: Time delay. VM: Video modelling.