Michelle L. Lange, OTR/L, ABDA, ATP/SMS
This blog is the third in a series on determining the optimal resistance when using dynamic components. The first blog in this series addressed determining resistance in the Dynamic Rocker Back Interface (DRBi) and the second blog addressed finding the optimal resistance when using Dynamic Footrests. In this final blog, we shall turn to the Dynamic Head Support Hardware.
Seating Dynamics offers Single Axis as well as Multi Axis Dynamic Head Support Hardware. The Single Axis hardware responds to neck extension by moving directly rearward and midline. The Multi Axis hardware moves rearward as well as in multiple directions in response to direction of force. Each hardware package comes standard with eight Blue elastomers, providing a Medium level of resistance. Four of these elastomers are designed to absorb and diffuse impact forces and the other four are designed for rebound – to return the client to a starting position. The elastomers are arranged differently in the Multi Axis configuration to accommodate multiple directions of movement. The Single Axis hardware ships with four additional Green (Firm) elastomers, if required, while the Multi Axis hardware ships with two additional Green elastomers.
How do I determine the most appropriate resistance level?
If the resistance is too soft in the Dynamic Head Support Hardware, you may observe too much extraneous head movement. Too little resistance can decrease stability and lead to neck hyperextension. This would be most likely if a softer elastomer was used (i.e. Yellow) than the standard Blue. If the resistance is too firm, little or no movement (and as a result, force diffusion) will be noted.
One unique consideration with Dynamic Head Support Hardware is leverage. The hardware utilizes a series of links to achieve the desired height of the head pad itself. This total length of links will vary with the height of the client and where the hardware is mounted on the back of the seating system. The longer the length, the more leverage is present. Increased leverage creates more force against the elastomers. If the lever arm is long, a firmer elastomer may be required.
As with all of our dynamic components, it is important to check the elastomers at least once a year for wear. If more movement is present than when the Dynamic Head Support Hardware was installed, the elastomer most likely needs to be replaced.
The ability to vary resistance better meets an individual’s unique needs. Although all of our Dynamic Components come standard with elastomers and/or springs, it is critical to evaluate the level of resistance required at installation and fitting with the client.