Thursday, April 16, 2009

teaching and reinforcing appropriate cane arc width

teaching appropriate cane arc width
In Rob’s (and Ashmead) 2002 article we find these statements:

“For this study, the widest part of the participants’ bodies were their shoulders. Across groups, conditions, and sessions, arc widths were 38.9 cm (or about 1 ft) wider than the participants’ shoulder widths”

“The participants increased their arc width-to-shoulder width differential when they were first reminded of the proper two-point touch technique, increased it further when they relaxed their technique, and then reduced it when they were reminded of the proper technique the second time. Given the differences in hand position and wrist bending already noted, it appears that the participants were not able to use biomechanical feedback to structure their technique. They erred on the side of caution and used arc widths twice as wide as prescribed so that any other deviation in technique would not shortchange body coverage.

The involvement of wrist movement and hand position is not sufficient to explain the pattern of arc widths across conditions. The movement of horizontal hand position to the right in the Normal and Comfort conditions, with an accompanying lessening of wrist extension, would lead one to expect smaller arc widths in the Normal and Comfort conditions and larger arc widths in the Classic1 and Classic2 conditions. However, arc width-to-shoulder differentials increased from the Normal to the Classic1 to the Comfort conditions and decreased in the Classic2 condition. This pattern of results is different from any of the other measures. It may indicate that arc width is not solely a biomechanical process but is strongly influenced by cognitive demand, more so than other aspects of the long-cane technique."

Does this mean that WiiCane feedback will be an effective tool because it will reinforce via a audio-tatctile-cognitive channel?

We do not have any hard data on teaching the production of an effective cane arc width. Motor-skills learning is well documented, but we have no studies on what constitutes a strategy or approach to reinforcing a target behavior. There is also scant annecdotal data.

Sadowski, J. (2004). Springboard. Re:View, 35(4), 160-164.

She’s Called on the Carpet to Teach Arc Width

I have used several methods to teach arc width. Most give an indication of the arc width by providing a stopping place for the cane on each side of the swing. Two canes extended on the floor, parallel to the line of travel and to each other, or a guide made of PVC pipe, effectively provide information concerning arc width, but they do not teach control of the arc width. I find many students enjoy hitting the boundary objects for the sound feedback and swing harder than is necessary. The result is that when the guide is taken away, the student is not in control of the swing and the arc width is too wide. As a result students may not develop the touch and control needed to demonstrate consistent, correct arc width.

One day while standing in the hall, pondering the problem, I spotted the rugs that were placed outside the classrooms for students to place their winter boots on to dry. The width was about the correct width of a particular student’s arc. We experimented with his standing centered on the carpet and swinging the cane back and forth. The rug edge provided feedback to help him know when to begin the counter arc. It helped him to learn the correct width and to develop the control of the cane that solid obstacle barriersdid not.Longer lengths of carpet can be used to permit the student to walk a distance and practice arcing the cane while moving. This provides an added bonus of feedback concerning straight line of travel.Pieces of rug can be found at carpet store remnant bins. Most dealers are willing to donate a section of carpet when they understand the use. Longer lengths can be used to permit the student to walk a distance and practice arcing the cane while moving. Storage and transport are relatively easy because the carpet pieces can be rolled up and secured with a bungee cord.

Jane Sadowski, COMS
Special Education Districts of McHenry/Lake Counties
1200 Claussen Drive, Woodstock, IL 60098

1 comment:

sl said...

Gene, thanks for posting this illuminating discussion of various perspectives on teaching blind travelers proper cane arc as one feature of safe and efficient travel. We will be revisiting the question of cane arc next, as soon as the rebuilt light strip is completed and functioning. My feeling is that we should start our cane mechanics lesson with a stationary exercise that calls for the WiiCane trainee to move the cane back and forth while standing under the light strip, so that he or she can attend to the feedback just for arc width, without having to worry about simultaneously listening for and responding to veering feedback. We know that we can give accurate feedback on arc width when the user is standing still, but we are less confident about doing it while moving, because of the problem of isolating rotation about the x-axis while the wii remote is (also) moving horizontally. Without being able to measure this tilt (which is caused by unintentional wrist roll), we can't be very confident about arc width, it seems. So, I would like to master arc width in a preliminary stationary lesson. Once they have mastered that, and if we can do it, we can add another lesson where arc width feedback is overlaid on veering feedback as a secondary parameter. In this situation, veering feedback would take precedence, and arc width corrective messages would only be played if veering was within the designated tolerable threshold.