Although many toddlers with expressive vocabulary delay (“late talkers”) present with age-appropriate language skills by the time they are of school age, little is known about their broader behavioral and emotional profile. The aim of this study was to determine whether late talkers are at increased risk for behavioral and emotional problems during childhood and adolescence.
Participants were from the Western Australian Pregnancy Cohort Study. Early expressive vocabulary was measured by parent report at age 2 years using the Language Development Survey. Late talkers were defined as toddlers who scored at or below the 15th percentile on the Language Development Survey for their gender but were screened not to have any other developmental delays. The Child Behavior Checklist was used to measure problem child behavior with continuous z scores and clinical thresholds at ages 2, 5, 8, 10, 14, and 17 years. Potential confounders included maternal and family sociodemographic characteristics as well as prenatal smoking and alcohol exposure.
At age 2 years, late talkers (n = 142) had higher Child Behavior Checklist scores (representing poorer behavior) than control toddlers (n = 1245) in total, internalizing, and externalizing scales and higher risk for clinically significant internalizing and externalizing problems. Regression models, incorporating the confounding variables, revealed no association between late-talking status at age 2 years and behavioral and emotional problems at the 5-, 8-, 10-, 14-, and 17-year follow-ups.
Expressive vocabulary delay at the age of 2 years is not in itself a risk factor for later behavioral and emotional disturbances.
Response to, "Late Talking and the Risk for Psychosocial Problems During Childhood and Adolescence"
To the Editors,
The recently published article, "Late Talking, and the Risk for Psychosocial Problems During Childhood and Adolescence," aims to address the very important issue of whether toddlers with expressive language delay are at increased risk for behavioral and emotional problems during childhood and adolescence. The study has a number of strengths, including the utilization of data from a large population based sample, prospective longitudinal design, and adjustment for important potential confounders, such as prenatal maternal smoking. However, there are several methodological issues that undermine the validity of the authors' conclusions.
The most notable weakness of the study is the exclusion of children who were part of the initial cohort of toddlers, who were later diagnosed with a developmental or intellectual disability at any time up until the 17-year follow-up. This systematic exclusion of children later discovered to have developmental issues biases the study and limits its generalizability and implications. From a practical standpoint, information on a late talking child's future developmental status is not available to the clinician at the time when treatment decisions must be made. Although the authors report that late talkers are not at greater risk for behavioral problems later in childhood, clinicians need to be aware that this finding applies only to a limited group of late talkers in whom late talking was determined in retrospect to be an isolated developmental concern.
In addition, the study did not explore whether outcomes were different for late talkers who received intervention for language delay vs. those who did not, nor did it reassess language abilities at later time points. Yet, the authors conclude that a "wait and see approach to behavioral and speech and language intervention" for late talkers with "otherwise normal development" may be appropriate. Given the limitations of this study, as well the large evidence base that early intervention promotes better outcomes among children with language delay, this conclusion must be interpreted with great caution, and pediatricians are urged not to be falsely reassured about the consequences of language delay.
Conflict of Interest: