Greaves et al. are to be congratulated on the further development of the Assisting Hand Assessment (AHA), which now encompasses the lower age range of 8 to 18 months for children with unilateral upper limb dysfunction. The development of typical manual ability rapidly progresses during this 10-month period, starting from the transfer of objects from one hand to the other and the refinement of the radial/palmar grasp. Additionally, the Rasch analysis undertaken enables the measurement by observation of specific activities in the affected hand during spontaneous, bimanual activities using toys.
The AHA and Mini-AHA are criterion-referenced scales evaluating change over time. They are not norm-referenced scales and were not developed to discriminate children from the norm.
Two of the reasons for measurement are firstly, to make decisions about individual children and secondly, to evaluate the effectiveness of an intervention strategy.
The refinement of a measure by Rasch scaling concepts generates unidimensional, interval-scaled data; or to put it another way, it allows one to measure individual items on the scale so that appropriate individual goals can be set for children and measured over time in the clinical situation.
To establish that change has or has not occurred as a result of intervention, additional controls need to be included. A scientifically controlled, single case study design with randomized treatment periods can be used to control for change due to maturation or spontaneous recovery and to check for the maintenance of any change observed. A set baseline time period with no intervention (A) is followed by a similar set time period with intervention (B) and this is followed by a similar, final set time period with no intervention (A). Assessments using the validated measurement scale are taken at (1) the initial outset, (2) the beginning of the intervention period, (3) the termination of the intervention period, and (4) the termination of the follow-up period. The results of such assessments can be plotted on a graph. A steady baseline period followed by an upward line during the intervention period followed by a steady line during the final follow-up period would indicate that improvement had occurred as a result of the intervention.
If more extensive use of the AHA and the Mini-AHA is to be encouraged, a manual is needed which gives clear, explicit instructions to users on how to administer and score the measure in the same way. A training and certification compact disc would also facilitate this process. Currently, one can order an AHA test kit on an AHA training course or during the certification procedure. This may not be possible for potential users experiencing difficulty in obtaining funding for attendance at such courses.
Validated for children with upper limb dysfunction aged from 8 months onwards, the AHA and Mini-AHA (in conjunction with a severity classification system) should now be used as a foundation for the development of curves to delineate patterns of manual development, similar to those developed for gross motor function. The Manual Ability Classification System is currently only validated for children from 4 years of age. The creation of manual development curves needs to be undertaken with a much larger sample size than the 43 participants in the 2010 study. This would facilitate a prognosis for manual development and help individual children, their families, teachers, and therapists to make more informed decisions.