Classifying communication ability in cerebral palsy

Abstract

This commentary is on the original article by Vander Zwart et al. on pages 180–188 of this issue. We live in an age of burgeoning functional classification systems for individuals with cerebral palsy (CP). Systems are now available that describe gross motor function, manual ability, communication, and eating/drinking ability.1 The purpose of these systems is to capture a child's usual, everyday functioning in a way that diagnostic labels cannot. This has clear benefits for clinical practice and research. The Communication Function Classification System (CFCS) is a relative newcomer to the field.2 A key aspect of communication is that it involves two or more people working together to construct meaning. It also encompasses motor, cognitive, linguistic, and social dimensions. In children with CP the development of receptive language is particularly influenced by intellectual disability, and expressive speech skills by motor impairment.3 The CFCS takes a bold stance in that levels of function refer not to speech ability, but to the effectiveness and efficiency of communication in both sender and receiver roles irrespective of the method of communication. The child's particular methods of communication (speech, eye-gaze, speech generating devices, etc.) are recorded separately. As with the more established functional classification systems the usefulness, ease of application, stability over time, and predictive value of the CFCS will require testing across the age range, and in a variety of cultural and linguistic groups. In addition to exploring the validity of a Dutch version of the CFCS, the article by Vander Zwart et al.4 attempts to tease out some of the factors that contribute to the composite level of function. The advantage conferred by intelligible speech is clearly seen when focusing on a child's ability to communicate effectively with unfamiliar partners. Speech generating devices appear to impact negatively on the pace of communication. Severe receptive language difficulties are generally associated with lower levels of overall communication functioning. As with the English language version of the CFCS,2 the Dutch group found a tendency for parents to classify their child's communication at a higher level than speech and language therapists (SLTs); often significantly higher. Parents judging their children to be more able when compared to clinicians may not be unusual: in a study of interrater reliability of the Eating and Drinking Ability Classification System, parents assigned the same or a higher level of ability compared with SLTs, but where differences occurred this was only by one level.5 Classification of communication may differ by more than one level, and this seems to point to something important about the lived experience of parents of children with CP. A recent total population study of young people with bilateral CP, where 63% of 16- to 18-year-olds had some speech impairment (including 30% with little or no speech), found that almost 90% of parents reported their young person to be able to communicate one-to-one with adults.6 The parents’ reported satisfaction with their young person's communication may be substantially informing their judgments on a classification system. It is possible that SLTs are more able to reflect on how a child communicates outside the family. Whilst the user instructions for the CFCS specifically prompt users to consider communication with unfamiliar partners, this may need additional emphasis. A child who can successfully communicate basic needs or emotions to unfamiliar partners may have limitations in more sophisticated functions such as reporting past events or asking questions. Highlighting a range of communication acts may help to differentiate between children who are context- and/or person-dependent and those who can function more autonomously. The influence of age on classifying communication also requires further research. It has been suggested that reliability of the CFCS increases over 5 years of age.2 As with the Gross Motor Function Classification System, stratification into age bands is likely to be necessary in order to reflect changes in communication demands, particularly during interaction with unfamiliar partners.