• María G.Bertoluzzo[1],
• Stella M. Bertoluzzo[1],
• Rubén Rigatuso[1],
• Fabio E. Quattrin[1],
• Claudio A. R Marcón[1],
• Marta Bravo-Luna[2]

• 1 Workshop of Physics: A pedagogic alternative, Fac. Cs. Bioq. Y Farmaceuticas- UNR;
• 2 CIUNR

Address: Fac. Cs. Bioq. y Farm.- Area Física - Suipacha 531. (2000) Rosario. Argentina.
Phone: (054) - 0341 - 4804592/3 - Fax: (054) - 0341 - 4804592/3
E-mail: mbravoluna@iname.com.ar

Abstract:

The device is a modified mouse. Consisting of a separation of the system of coordinates that the mouse possesses in integrated form. Thus coordinates are moved independently by their corresponding knobs. The total movement of the cursor is plotted on the computer screen.

Support required for apparatus: An IBM compatible PC, with a mouse port, Windows 95/98

Approximate size of the apparatus: 20 cm x 15 cm x 5 cm

Does this apparatus require Electrical Power? Yes.

Is the apparatus intended for use with and overhead projector? No

Will you be present to set up your apparatus? Yes.

Equipment required to construct apparatus:

A mouse $6
Three flexible plastic tubes 0.3cm diameter; and length 10cm (x1), and 5 cm (x2).(Lengths are variable according to the mouse). A used ball point pen can provide it. $1
A couple of linear gears (1.5 cm diameter) with a 0.3 cm central hole. A fixation support (Available in toyshops) $2.5
A couple of gear (1.5 cm diameter) with a 0.3.cm central hole enabling a 90º rotation.
A fixation support. $2.5
Two knobs attached to a vertical support, where the plastic tubes are fixed, allowing their rotation. $2
An acrylic or wooden plate measuring 20 cm x 15 cm $5 An acrylic or wooden plate measuring 20 cm x 5 cm $2
Total .................................................................................................................$21

Description

• 1. Pierce two holes 15 cm apart and 2cm from the base in the smaller acrylic plate, to fix the knobs.
• 2. Set up the latter on the bigger acrylic plate with the knobs toward the front.
• 3. Connect each plastic pipe to the knob and insert the gears at the end of them.
• 4. Remove the carcass of the mouse to expose the electronic components. There are 2 small plastic guides where the rubber ball is located and as it moves translate this movement to the cursor on the screen.
• 5. Cut the lower part of the mouse to insert the linear gear
• 6. Fix linear gear to guide 1.
• 7. Extend guide 2 by means of the 10 cm plastic tube.
• 8. Place the mouse on the acrylic larger plate adjusting guide 1 parallel to the knob shaft, and guide 2 perpendicular to knob shaft 2 in such a way that guide 1 results parallel to the knob shaft 1, and guide 2 perpendicular to knob 2 shaft.
• 9. Place one of the linear gears inside guide 1 connecting it to the gear mounted in the knob shaft.
• 10. Put the 90º rotation gear at the end of the 10 cm tube.
• 11.Remove the original guide 2 support and extend it by the 10 cm tube in such a way that the 90º rotation gear becomes connected with the perpendicular gear mounted in the knob 2 shaft. (See figure).

This computer controlled x-y plotter could be used to detect early alterations in coordination of bilateral voluntary muscular movements in patients with Alzheimer´s disease. These patients manifest deficits in inter hemispheric integration of information as reported by Yamina Lamache et al [1]. Similar tests like the ones presented in that paper could be carried out using this plotter to evaluate bimanual coordination. (Preilowsky´s test)[2]. Subjects are requested to draw on an x-y plotter a line matching a sample line presented. This is done controlling the x axis by rotation of one knob with the index and thumb of one hand, and the y axis similarly with the other hand.

References

• [1] Yamina Lakmache et all. Proc. Natl. Acad. Sci. USA. Vol95, pp 9042-9046. July 1998-Psychology.
• [2] Preilowski, B.F.B. (1972) Neuropsychologia 10, 267-277