posted 09-19-2005 10:02 AM            

I see Lafayette are selling Arm Activity sensors, they look a similar version of the Piezo activity sensor except they go on the arm of the chair.

Has anyone tried them out yet?, if so do they work?

posted 09-19-2005 11:19 AM         

Lafayette had an old version that had a seat and two arm pads that were inflated. I don't know if the arm pads you are talking about are new or not.

I have an Axciton system and see no need for adding arm pads. Mine works great and I have heard similar comments from the people using the Lafayette sensor.

posted 09-19-2005 12:36 PM         

For sometime now I have been utilizing Layfayettes piezo sensing pads, five altogether- one under each arm, one on the seat, and one under each leg. I highly recommend utilizing all of them- I acknowledge some examiners may feel this is ‘overkill’ but you will be amazed how ‘sneaky and covertly’ clients are engaging in bodily movements. Overall, I think they are much more sensitive than the pnuematic air bladder style.

I connected the two arm pads together- and are displayed on one tracing line; the legs and ‘butt pad’ are connected together and are displayed on a separate tracing line. (I would have liked to have separated them all to reflect which individual limb was being moved, but lafayette DAS unit has insufficient input channels).

Now that I fully recommend them- what I don’t like about lafayette’s software is the “automatic re-centering feature.” It is difficult to determine if the examinee ‘moved and held’ a different arm/leg position- or whether they just had a movement ‘twitch’. What both pnuematics and piezo sensors do not pick up very well is deliberate, but fine motorskilled, "movements”- those clients that do so sneaky and covertly (for example lifting an index finger slightly and holding-, or a deliberate but very slow rotation of the foot from one position to another, or switching between hands and legs). Generally there needs to be some 'pressure difference' detected by the sensors for a change to occur and register on the trace line.