WHAT ARE WE TO MEASURE

I , and others, have frequently stressed in editorials in this journal that we should be conducting control trials of therapy for disabled children, and have lamented the fact that so few have been carried out. Perhaps unfairly, I have not confessed to the obstacles which I have personally encountered when trying to set up control trials. Apart from the difficulty of persuading convinced therapists that the techniques they use should be subjected to that sort of assessment and getting them to agree to such a study, the capacity to carry out a study in the past has been severely limited by problems of determining exactly what is to be assessed and deciding on the tools that might be used to assess it. What has been needed is a lot of preparatory work on producing suitable assessment tools and evaluating them in different situations. We are grateful, therefore, to Hallam and her colleagues (p. 602) for carrying out a simple but informative study to look at precisely this issue. What do we want to know? Obviously, it seems handy to have some outline of the child's general development, and, as Hallam et al. point out, parents like and are eager for a simple assessment of their child's development on a normal developmental scale. The well-known Griffith and Bayley Scales are the ones that are commonly used for these types of assessment, but they give no understanding of the disability that the child has and hence it is difficult to use them to assess a therapy that attempts to improve the disability. When there is a specific disability, such as a motor disorder, we are likely to want to use a scale that gives us more information about movement, and perhaps to ignore some of the general areas. Thus a scale that measures movement alone may be a useful one; and Hallam et a/. have used the Motor Assessment of Infants produced by Chandler et at.'. However, there are dangers in using such a scale, bearing in mind the integrative action of the nervous system-for example, vision plays a major part in controlling fine movements (although we can manage without it). Alternatively, one can look at specific measurements and recording of the actual status of the muscles, for example the Evans and Alberman limb-by-limb assessment reported by Hallam and colleagues. However, this too has its limitations: not giving a full picture of the child's development and being deliberately restricted in the amount of information it records. Using these measuring tools we t ry to pinpoint the mechanisms that drive the (A rr)