Hyperkinetic syndromes are characterized by excessive or involuntary movements throughout the day. These abnormal movements interfere with maintaining the ideal sitting position and cause positioning disorders that may have functional repercussions. To facilitate staying in the ideal position, therapists adapt sitting positions. Together with the patient, they choose the position that appears to be the most functional and comfortable. To maintain this position, the solutions proposed are mainly based on restraint (shells, abduction blocks, straps, etc.). These can be poorly tolerated by the patient, causing discomfort or even pain which can hinder participation. Repeated stresses on the supports, and on the chair itself, leads to frequent breakage. Also, depending on the underlying neurological mechanisms behind the abnormal movements, the question arises as to whether restraint increases the frequency or amplitude of abnormal movements by generating oppositional constraints, areas of discomfort and/or pain, or by reducing functional capacities and frustration caused by these abnormal movements (Cimolin et al. 2009). All these issues can have a significant impact on the quality of life of this population of patients suffering from abnormal movements and who are almost exclusively in wheelchairs. To address these issues, dynamic wheelchair systems have been have been developed to absorb the mechanical stresses generated by abnormal movements.
The chair's dynamic components absorb the force. When the patient's force ceases, the stored energy is returned by the dynamic component which, in turn, helps the patient return to his or her starting position. The ideal seating system enables controlled movement whilst providing mechanical stability.
This is a prospective, single-center pilot study comparing the two medical device modes using an ABAB-type Single Case Experimental Design methodology: The NETTI DYNAMIC chair in dynamic mode (interventional group; phase B) versus the same chair in static mode (control group; phase A). The subject will be his/her own control.
Phase B (intervention) will be performed by positioning the subject on the Netti Dynamic chair in its dynamic configuration. Phase A (control), on the other hand, will be performed positioned on the same chair, but in static mode (backrest and seat locked by means of a jack and pin, legrest and headrest replaced by standard elements and headrest replaced by standard components, making it impossible to adapt the chair's of the chair). In this way, the specific effect of the dynamic mode will be able to be controlled.
The ABAB study design was chosen for this study because it provides the highest level of evidence evidence (Level 1; OCEBM Levels of Evidence Working Group. (2011). "The Oxford 2011 Levels of Evidence." Oxford Centre for Evidence-Based Medicine). It is characterized by the presence of two phases (phase A: control phase and phase B: intervention phase) which are alternated twice.
Each phase must comprise three to five measures to enable reliable statistical analysis. This approach is particularly appropriate for evaluating medical devices, especially when the when the population concerned is heterogeneous. Indeed, an intensive, prospective study of a few individuals, using a methodology defined a priori, including systematic observations, repeated measurements and appropriate data analysis is the most appropriate in this case.
