>
> Date: Tue, 13 Oct 1998 14:21:33 +0100
> From: Glyn Heath
> Subject: Measurement of residual forearm volume changes during muscle co
>
> I am interested in assesing volume changes in residual forearms of
> amputees caused by contractions from the remaining muscles. Does
> anyone out there know of any device that can be used to measure
> volume changes or cross sectional area changes of muscles in real
> time during the contraction of residual muscles. Such a device must
> be able to provide data at a suitable sampling frequency to measure
> the volume/cross sectional area changes in real time during a
> contraction.
>
> Glyn. H. Heath..
>
Depending on how much you need to be able to tell where the volume change is,
you might be able to use a thin rubber bladder with a light weight silicone
oil inside the socket. As the volume changes, it will push oil out of the
bladder. By having a number of bladders arranged along the inside would allow
you to determine the area where the volume change is taking place.
If you intend to load the prosthesis, you will get a shift in the direction
of force couple that resists the load.
Using just isometric contractions you will get two muscle/muscle groups active
at one time.. this would tend to change your results.
Another method might be a foam “capacitor” made of a layer of foil, layer of
foam, and another layer of foil. As the volume increases, it will compress
the foam, increasing the capacitance in that area. If the caps are made of
“dots” you can make the area sensed quite small.
Steve
