Background Screening for developmental coordination disorder (DCD) in communicative disorders, using the M-ABC test has led to an overestimation of prevalence.

Aim To add new screening instruments, to determine true DCD and its relation with developmental speech–language disorder (DSLD) and deafness.

Sample 182 children from four special education schools, 142 with DSLD and 40 with deafness. DCD was classified with motor screening questionnaires, for parents (DCD questionnaire) and teachers (motor observation questionnaire), paediatric examination, M-ABC test (cut-off P15), and normal non-verbal IQ. Deafness was classified by audiology (loss >80 dB). Using cognitive, language and speech test scores, classification into productive (52), and receptive productive language disorder (46) was made.

Results Abnormal M-ABC scores were found in 56%. No DCD diagnosis, due to genetic syndromes (13%; deaf children 20%; DSDL 11%), other paediatric disorders (7.5%), schizis (6%) and incomplete returns (9%) were excluded. In 132 remaining children with DSLD (104) and deafness (28), no differences between groups were found in any measure. According to M-ABC scores, 47% would have DCD, but one in four had normal questionnaire scores. Based on M-ABC and either DCDQ or MOQ-T scores, 32% had true DCD, often with extreme scores (<P5; 65% total score; 74% manual dexterity score; 74% ball skill score; 43% balance skill score). 20% had been referred to physiotherapists.

Conclusion Broad screening for DCD in communicative disorders corrected the prevalence from 56% in the M-ABC test to 32% with the addition of normal (11%), or abnormal (23%) findings in motor screening questionnaires and routine physical examination (21%). One in three children have true DCD, with severely impaired overall and fine motor performance, interfering at home and in school.