The association between language deficits and behavior problems has been demonstrated in several prior studies. In general, research in this area has revealed that poor expressive and/or receptive language skills are more common in children with antisocial behavior problems. Verbal intelligence tends to be lower among these children as well.

There have been relatively few studies, however, in which the language abilities of children with ADHD have been specifically investigated. Because language competence is critically important for successful social and academic functioning, the lack of in-depth study of language abilities in children with ADHD represents an important gap in the literature.

A study published in the Journal of Abnormal Child Psychology (McInnes et al., 2003, Listening comprehension and working memory are impaired in children with ADHD irrespective of language development, 31, 427-433) provides important new information on this topic. The study was designed to examine whether higher-level language comprehension skills in children with ADHD are impaired even when their basic language skills are adequately developed. Because high-level language comprehension skills are particularly critical to academic success as children move into higher grades, a deficiency in these skills could help explain why many children with ADHD are able to get by reasonably well during their early schooling, but often have increasing difficulty as they move into higher grades.

Participants in this study were seventy-seven 9-12 year-old boys recruited from a large pediatric practice and from a large public school in the same area. Boys recruited from the pediatric practice had been previously diagnosed with ADHD while boys recruited from the school either had a prior diagnosis of language impairment (LI) or had academic problems and were awaiting language assessments. In addition, a number of boys who were performing well academically were recruited from the same school to be included as control participants. Unfortunately, no girls were included in this study.

Parent and teacher behavior rating scales as well as 3 standardized measures of language ability were administered to confirm boys diagnosis and to classify them into 4 groups: ADHD only (n=21), ADHD + LI (n=18), LI only (n=19), or controls (n=19). Boys were classified as having language impairment if their scores on the language ability measures were significantly below average and if there was evidence that both receptive and expressive language deficits were present. Estimates of IQ and reading achievement were also obtained on all boys.

Listening comprehension ability was assessed via 2 different procedures. In one task boys were presented with 4 audiotaped passages and then tested on their comprehension of the facts presented. They were also tested on their ability to make correct inferences based on what they heard. Each passage contained novel information on familiar topics that children might encounter during classroom instruction and was followed by 6 factual and 10 inference questions.

The second comprehension task was intended to assess children's ability to self-monitor by testing children's abilities to detect errors in material presented to them. Children were read 8 passages, some of which contained errors that would cause the passage to not make sense. For example, a passage presenting a set of instructions for a familiar task presented those instructions in the wrong order. Or, a description of a topic that would be familiar to participants contained obvious factual errors. Children were instructed to listen carefully to the passages and to judge whether they made sense or had mistakes in them. The passages were presented twice so that children could make an initial judgment after the first reading and a final judgment after hearing the passage a second time. (Note: At the time of the listening comprehension assessment, boys were not receiving medication.)

RESULTS

An initial noteworthy finding is that among the 39 boys with ADHD who participated, assessments of language ability that were conducted during the study indicated that 18 were found to have a significant language impairment. Only 4 of these boys, however, had ever been previously assessed for possible language deficits, despite having chronic academic difficulties.

Analysis of the listening comprehension results indicated that boys with ADHD - even those who did not also have language impairment - performed worse than control boys in several areas. When responding to straight-forward factual questions related to the paragraphs that were presented, boys with ADHD performed as well as control boys, and better than boys with language impairment alone or language impairment and ADHD. On questions where boys needed to infer the correct answer on factual material that was presented, however, they were less capable than control boys, and did not do significantly better than boys with language impairment.

On the task where boys were required to detect errors in information presented to them, boys with ADHD again performed more poorly than control boys. They did however, appear to do somewhat better than boys with language impairment.

Interestingly, boys' performance on the language comprehension tasks was significantly related to ratings of ADHD symptoms completed by parents and teachers. Language comprehension skills showed stronger associations with ratings of attention problems than ratings of hyperactivity-impulsivity. This is consistent with the increasingly well-documented finding that it is the inattentive symptoms of ADHD that are most likely to compromise children's academic success.

SUMMARY AND IMPLICATIONS

The main finding of this study is that a community sample of boys with ADHD showed evidence of listening comprehension deficits even though they had adequate language abilities for their age as measured by standardized language tests. Although they comprehended factual details presented to them as well as children without ADHD, they had significantly greater difficulty with more subtle aspects of comprehension such as making inferences and monitoring the accuracy of information presented.

The authors suggest several important clinical implications of these findings. First, some academic problems in children with ADHD that are frequently attributed to their being non-compliant or having difficulty completing tasks may be an outcome of weak comprehension skills for complex information that is presented in classroom instructions, lessons, and textbooks. This may be especially relevant in higher grades where the requirements for accurate and efficient comprehension of new information increase are far greater than in early elementary school.

For example, the authors note that teachers may report that young children being assessed for ADHD have normal comprehension skills in early grades where comprehension tasks tend to focus on factual details rather than making correct inferences from narrative material. However, subtle differences with inferential comprehension that are not evident early on may begin to effect ADHD children's later learning and achievement. The authors suggest that teachers may need to fine tune their observations of students with ADHD to ensure they have understood information presented orally and in print, no matter how well developed their oral language skills appear on the surface.

Second, because a potential consequence of comprehension failure may include inappropriate and off-task behavior, which are core features of how children with ADHD often appear in classroom settings, it is possible that some behaviors used to diagnose ADHD may not be solely attributable to the core symptoms of inattention and hyperactivity-impulsivity. Instead, such behaviors may at least partially emerge in response to comprehension difficulties.

Thus, it may be important for assessments of children for ADHD to routinely include assessments of language functioning. This is important for 2 reasons. First, in the current study, many boys who diagnosed with ADHD were found to have co-occurring language impairments, and these language problems had not been previously detected. Thus, these boys could continue to struggle even if their ADHD was treated effectively because of language difficulties that were not being addressed.

In addition, as discussed above, many boys with ADHD whose basic language skills were intact had difficulty with higher-level language comprehension skills that could adversely impact their academic success, especially in higher grades.

When considering these findings, it is important to note that because boys' medication had been temporarily discontinued prior to the assessment of their listening comprehension skills. Thus, it is possible that the difficulty they experienced was at least partially determined by their primary difficulties with attention as opposed to a language comprehension problem per se. Thus, it would be interesting to test children's listening comprehension skills when they are both on and off meds to see whether the listening comprehension deficits reported here are mitigated by medication.

In summary, results from this interesting study suggest the possibility that listening comprehension deficits that co-occur with ADHD may underlie some of the behavioral symptoms and academic difficulties associated with ADHD. Comprehension deficits could also contribute to difficulties that many individuals with ADHD have in social relationships, which depend to a large extend on accurate comprehension of complex verbal information. Examining this latter issue would be an important topic for future research. Such research would also benefit from the inclusion of girls to ascertain whether the findings reported here apply to girls with ADHD as well.