Table 2.
Summary of factors significantly associated with receptive and/or expressive language in autistic children or EL-siblings.
| Receptive language | Expressive language | General language abilities | ||
|---|---|---|---|---|
| Biological factors | ||||
| Brain-based factors | ||||
| Cortical reactivity | 1 SIB (115) | |||
| Fractional anisotropy in the inferior longitudinal fasciculus | 1 ASD (104) | 1 ASD (104) | ||
| Frontal delta power | 1 SIB (72) | |||
| Frontal high-alpha power | 1 SIB (25) | |||
| Frontal theta power | 1 SIB (72) | |||
| Gamma power | 1 NOT (58) | 3 SIB (72) | ||
| Left frontal-central alpha coherence | 1 SIB (36) | |||
| Neural correlates of face processing | 1 SIB (65) | 1 SIB (65) | ||
| P3 peak latency | 1 SIB (39) | |||
| Speech processing | 1 SIB (27), 1 NOT (14) | |||
| Surface area left rostral middle frontal gyrus | 1 ASD (29) | |||
| Speech evoked auditory brainstem response | 1 ASD (29) | |||
| Temporal gamma power | 1 SIB (22) | |||
| Other biological factors | ||||
| Biological sex | 2 ASD (253) | |||
| Psychosocial and environmental factors | ||||
| Autism traits | ||||
| Hyporeactivity to sensory stimuli | 1 SIB (83) | |||
| Restricted and repetitive behaviors | 1 SIB (31), 1 NOT (104) | |||
| Severity of social communication impairments | 1 ASD (113), 1 SIB (31), 1 NOT (104) | 1 ASD (113), 1 NOT (104) | ||
| Environmental factors | ||||
| Maternal education* | 1 ASD (62) | 1 ASD (62) | ||
| Mother rigidity (Broader Autism Phenotype (BAP) characteristics | 1 ASD (16) | |||
| Serum folate levels | 1 ASD (1300) | |||
| Parental language input | ||||
| Maternal gesture use | 1 SIB (48) | |||
| Maternal mean length of utterance | 1 SIB (22) | 1 ASD (19), 1 SIB (40) | ||
| Parent verbal responsiveness | 1 SIB (83) | |||
| Paternal verbal responsiveness | 1 ASD (16) | |||
| Parental gesture quantity | 1 SIB (42) | |||
| Parent gesture type | 1 SIB (42) | |||
| Use of telegraphic speech | 1 ASD (55) | |||
| Social factors | ||||
| Frequency of other-directed vocalizations | 1 ASD (104) | |||
| Increased attention to eyes and face | 1 ASD (45), 1 SIB (37) | |||
| Increased attention to mouth | 1 ASD (54), 1 NOT (91) | 1 ASD (45)_ | ||
| Intentional communication | 1 ASD (87) | |||
| Joint attention | 3 ASD (359), 1 SIB (31), 1 NOT (50) | 2 ASD (169), 1 SIB (50), 2 NOT (280) | ||
| Larger latency to respond to to one another | 1 SIB (25) | |||
| Object imitation | 2 ASD (126) | |||
| Object play | 1 ASD (61) | |||
| Percentage simultaneous speech between parent and child | 1 SIB (25) | |||
| Preference for speech over nonspeech | 1 SIB (20) | |||
| Preference for synchronous over asynchronous videos | 1 SIB (45) | |||
| Relative preference for faces over objects | 1 SIB (14) | |||
| Social motivation | 1 ASD (87) | |||
| Social responsiveness | 1 ASD (249) | 1 ASD (249) | ||
| Symbolic comprehension | 1 ASD (249) | |||
| Age-related and developmental factors | ||||
| Early language abilities | ||||
| Early child vocalizations | 1 ASD (87) | |||
| Incremental language processing | 1 ASD (17) | |||
| Initial child language abilities | 2 ASD (177) | |||
| Cognitive factors | ||||
| Nonverbal cognition | 1 ASD (104), 1 SIB (31) | 2 ASD (239), 1 SIB (31), 1 NOT (42) | ||
| Gestures | ||||
| Child gesture quantity | 1 SIB (40) | |||
| Child gesture type | 1 ASD (72) | |||
| Motor skills | ||||
| Composite score motor skills | 1 ASD (38), 1 SIB (31) | 1 ASD (38), 1 SIB (31) | ||
| Fine motor skills | 1 SIB (499), 1 NOT (73) | 2 SIB (572), 1 NOT (73) | ||
| Gross motor skills | 1 SIB (499) | 1 SIB (499) | ||
| Motor imitation ability | 1 SIB (50) | |||
| Postural control | 1 SIB (8) | 1 SIB (8) | ||
| Speech production | ||||
| Speech production abilities | 1 ASD (27) | |||
| Word learning | ||||
| Ability to map differentially stressed labels to objects | 1 SIB (19) | |||
| Use of mutual exclusivity in word learning | 1 ASD (32) | |||
Note: Numbers refer to the number of articles in which each factor was found to be significantly related to one or more language measures. The number is followed by the population that was examined in each article: ASD for autistic children and SIB for EL-siblings. The number between brackets is the number of autistic children or EL-siblings in total included in the data collection project (i.e., without control group). Thus, 2 ASD (100), 1 SIB (20) indicates that the corresponding factor was identified in two articles examining in total 100 autistic children and in one examining in total 20 EL-siblings. Articles drawing from the same study sample are only taken into account once. NOT indicates that one or more studies did not replicate the significant effect.
Disclaimer: SIB groups are not split between those who go on to receive a diagnosis and those who will not. If this information is available, it is provided in the written summary of the specified factor below.
*This effect was rendered insignificant after correcting for multiple comparisons.