This contribution presents a case study based on an episode of the television series Shin Chan (subtitled for deaf and hard of hearing children) and the results of its viewing by several groups of Spanish children with hearing disabilities (and children with good hearing in order to establish a comparison between both groups). The focus of the study is on communicative efficiency of the subtitles. The intention behind the study is to verify the functionality of the existing criteria in use in Spain and published by AENOR (Standard UNE 153010 Subtitling for the deaf and hard of hearing. Teletext subtitling). At the end of the contribution, proposals are made to complete the existing criteria and to focus on the areas for which the standard did not provide solutions (linguistic issues mainly). In addition, improvements are suggested for implementation into the existing standard, with a view to a possible revision of the standard for digital TV (DTV) in those areas in which it is clearly deficient).