Table 6.

Subgroup analyses for voice intensity difference between ASD and TD groups. The elicitation tasks and the age of participants were confounding factors.

	Pooled SMD	Heterogeneity (%)	p-value
Confounding factor
Task type
Narration	Only one study was available
Conversation	− 0.07 [− 0.94, 0.8]	90.6	< 0.001
Focus	− 0.24 [− 0.85, 0.38]	57.2	0.097
Cry	− 0.19 [− 0.56, 0.18]	0.0	0.926
Age of ASD participants
Infancy (age ≤ 2)	− 0.34 [− 0.7, 0.02]	13.7	0.327
Childhood (age: 2–11)	0.29 [− 0.53, 1.1]	85.8	< 0.001
Adolescence (age: 12–18)	Only one study was available
Adulthood (age > 20)	0.27 [− 0.93, 1.47]	86.4	< 0.001