OUR recent study demonstrated with the brain's automatic change-detection response, the mismatch negativity (MMN) of the event-related potentials (ERPs), that the duration of auditory sensory memory is significantly shorter in school-age children with CATCH syndrome than in healthy age-matched controls. One of the haracteristic symptoms of this syndrome, caused by a microdelection in chromosome 22, is cleft palate. The most common problems in these children, however, are learning difficulties and, according to our results, it is likely that these problems are not due to the dysmorphology of peripheral speech mechanisms only but are also caused by CNS dysfunctions. In the present study we show with MMN that auditory sensory memory is also shortened in school-age children with cleft palate but without the ATCH syndrome. It has been shown in previous studies with neuropsychological tests that although children with cleft palate have language and learning-related problems these difficulties are usually less severe than those of CATCH children. Likewise the present study demonstrates that the auditory sensory memory trace seems to decay more rapidly in CATCH children than in children with cleft palate.