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.