Prevalence and Correlates of Significant Spoken Language Delay in Preschool-Aged Children Seen at an Autism Clinic

Background: Understanding profiles of preschool-aged children with significant spoken language delay at time of autism evaluation is important to identify service delivery needs. Currently, little is known about the prevalence of spoken language delay in this population, and which factors may distinguish children with and without phrase speech.

Objectives: Data from children (ages 36 – 59 months) seen for evaluation at an interdisciplinary, urban autism clinic were examined to: (a) ascertain the prevalence of spoken language delay, defined as parent-reported lack of phrase speech by age 36 months, and (b) examine demographic, educational, and diagnostic differences among children with and without phrase speech.

Methods: Data were collected from a pre-appointment background and history questionnaire completed by caregivers. Parent-reported phrase-speech was validated by clinician-administration of ADOS Module1. Chi-square and t-tests were calculated to compare bivariate differences between groups.

Results: Demographic & Speech Profiles. Children (N=691) were mean age 47.41 months (SD=7.15); 80.46% were male; 62.37% were using phrase speech; 37.63% were not. Children without phrase speech were younger (M=45.12, SD=7.30 months) than children with phrase speech (M=48.80, SD=6.70 months), t₍₆₈₉₎=-6.76, p<0.001. No sex differences were found between groups (p=.66). Clinicians administered an ADOS Module1 for 90.85% of children whose parents reported no phrase speech (ADOS data available for n=468 children). A lower proportion of phrase speech was observed among children who were Other/Multi-Racial (57.81%) or Black/African American (46.26%), when compared to Caucasians (71.94%), X²_{(2, N=674)}=31.01, p<0.001. Families with private insurance had a greater proportion of children with phrase speech (66.88%) compared to families with Medicaid (50.98%), X²_{(2, N=691)}=17.05, p<0.001.

Early Intervention Status. The proportion of parents with concerns about their children’s language development was higher in children without (91.89%) versus with (61.88%) phrase speech, X²_{(1, N=292)}=31.66, p<0.001.The proportion of children who received early intervention services was greater in children without (45.10%) than those with (32.08%) phrase speech, X²_{(1, N=679)}=11.59, p=.001. Among children without phrase speech for whom data were available (N=257), 24.12% were not receiving speech therapy and, among a smaller subset with available data (N=111), only 9.01% had access to a speech generating device.

Diagnostic Status. The proportion of children identified as having autism based on clinical impression was higher in children without phrase speech (85.24%) compared to those with phrase speech (67.18%), X²_{(2, N=427)}=16.55, p<0.001. Mean ADOS Comparison Score among children without phrase speech (n=160) was higher (M=6.44, SD=2.70) than the mean Comparison Score (M=5.47, SD=2.77) among children with phrase speech (n=302), t₍₄₆₀₎=3.59, p<.001.

Conclusions: More than one-third of children seen for autism evaluation were not using phrase speech by age three years, and, despite parent concerns, more than half had not received early intervention. Children most at risk for spoken language delay were Non-White and those who received medical assistance. Results suggest the need for pediatrician and clinician training on the importance of early speech-language intervention for young children with autism and significant spoken language delay. Such training should include education on the value and efficacy of augmentative and alternative communication for this population with autism.