Objective For children with profound intellectual and motor disabilities (PIMD) the traditional psychological tests are inadequate to evaluate their cognitive capabilities due to their severe mental and physical limitations. A promising diagnostic tool for these children are event-related brain potentials (ERPs), as this technique does not require an active contribution or behavioral response.

Methods Electric brain activity (EEG) is recorded by electrodes placed on the skull during the presentation of visual, auditory, and tactile tasks. These passive tasks require no instruction to, nor a behavioral response of, the participant. By means of ERPs one can not only evaluate whether a sound, picture or vibration is detected but also whether a novel stimulus can be distinguished from a standard stimulus, thus providing information about selective attention and memory.

Results We recorded EEG data in more than 100 children with normal development between 6–12 years of age using the same visual, auditory and tactile tasks. These reference data allow us to assess individual children with PIMD and to determine whether functional processing is abnormal or shows a developmental delay. Next these individual profiles can be compared with standardized observational instruments. In several cases functional sensory and cognitive auditory/visual processing was established in children with PIMD that were thought to be deaf or blind. ERP profiles are also very useful for repeated measurements and the evaluation of treatments.

Conclusions The ERP technique yields important complementary information on the quality of cognitive functioning in children with PIMD that cannot be obtained otherwise.