Children with specific language impairment are more likely to reach motor milestones late

Background: Delayed language development without an obvious cause is considered an isolated developmental disorder and is called specific language impairment (SLI). SLI is probably the most prevalent developmental disorder in childhood with a generally cited prevalence of 7%. This study aimed to investigate whether SLI is always an isolated disorder or if children with SLI also have delayed motor development. Methods: We used data of an earlier study with a prospective nested case-control design in which developmental data were collected from child health care files. Cases were children (4-11 years) with diagnosed SLI. They were matched by sex and date of birth with control children attending mainstream education. Data of both groups on seven gross and six fine motor milestones which had been registered in the Dutch Developmental Instrument between the ages of 15-36 months were retrieved from child health care files. McNemar tests were performed to test for differences in reaching motor milestones at the age norm between the case and control group. Results: Data from 253 children in each group were available. A significant difference was found between both groups in the proportion failing to reach three of the seven investigated gross motor milestones at the age norm (p < 0.05). The proportion of children not reaching the motor milestone at the age norm was significantly higher for five of the six fine motor milestones in children with SLI compared with control children (p < 0.05). Conclusions: More children with SLI are late in reaching motor milestones than children without SLI. This means that it is debatable whether SLI can be regarded as a “specific” impairment, which is not associated with other developmental problems. A broader developmental assessment is therefore indicated when diagnosing SLI.