Monday, October 12, 2009

wii cane feedback logic and testing procedures - draft

WiiCane procedures for initial testing

The following drafts are for everyone’s consideration and critique.

This weekend I visited Touch Graphics and saw the working model of the WiiCane and course. It is quite amazing. On the HD digital display at the end of the 32 foot course, you can see the cane movements precisely as the cane/subject moves. The equipment and remote software are working and it’s impressive. The user interface and the software to create the feedback loops are the next steps.

I will use the term “detectable” to mean that the WiiRemote can detect the infrared lights suspended above the course.

I will use the term “expected cane tip-placement” to mean that the cane tip lands within a tolerance of 2 inches on the left or right on the surface in front of the subject that is equal to the widest part of the subject’s body’s lateral plane.

These comments do not include procedures for deafblind subjects.

General considerations and concerns:
· The subject may not role their wrist as they move the cane; this will cause the cane to be undetectable. Subjects’ rolling behavior will need to be corrected with intervention.
· The subjects will need to stay with the detectable lateral area during testing. If they move out of this area, the tester will intervene to move then back into the detectable area.
· All subject will align for each trial on the course by squaring-off , placing the back of their footwear into cutouts of a wooden board properly located at the start of the course
· All subjects will wear customized goggles to occlude vision to the point of LP.
· All subjects will wear wireless headphones that are expected to deliver the feedback loop and prevent echolocation.


Logic for creating the feedback loops

VEERING
· When the subjects’ midline exceeds 16 inches from the intended straight-line of travel, the subject will hear a message
· The feedback loop will say the following is high quality electronic speech: “move to the left [or right]”
· The feedback message will repeat each time the subject exceeds16 inches from the intended path.

CANE COVERAGE
· The software will check the subject’s cane tip-placements after the first three lateral sweeps. Thereafter, the software will check the most recent three cane sweeps/tip-placement.
· Feedback will, of course, be issued only if the previous feedback statement has completed.
· The software will select a feedback statement based on the following logic:
- if the cane tip-placements for the three most recent sweeps result in the expected cane tip-placement, then the subject will hear: “Good”
- if the cane tip-placements for the three most recent sweeps result in cane tip-placement further from the subject’s midline than the expected cane tip-placement, then the subject will hear: “Too wide”
- if the cane tip-placements for the three most recent sweeps result in cane tip-placement nearer to the subject’s midline than the expected cane tip-placement, then the subject will hear: “Too narrow”
- if the cane tip-placements on the most recent three sweeps are asymmetrical (not too wide or too narrow on both sides), the greater lateral displacement from the expected cane tip-placement will determine the feedback and the subject will hear: “To wide [or narrow] on the right [or left]


Procedures for conducting trials

For the first trial for each subject, the subject will be have the experiment explained; the testers may use whatever appropriate language is necessary, and take as much time as they feel is reasonable for the subject to understand and be comfortable. Subjects will be asked if they are comfortable with the headphones and the goggles. Verbal and non-verbal response will indicate whether the subject should continue. They will then be walked/guided once down the course, shown the end of the course and the safety obstacle. They will then be walked/guided back to the start of the course. Subjects will always complete trials for veering before trials for coverage.

VEERING AND CANE COVERAGE

· The subject will align at the start of the course.
· The subject will be told to swing there cane and walk forward in a straight line
· The subject will walk unimpeded unless they become undetectable. If the subject becomes undetectable, the tester may physically prompt or manipulate him/her back onto the course from behind the subject.
· When the subject ends the course, they will be walked/guided to the beginning of the course.
· Each subject will complete 10 trials on any particular day, on up to 5 separate days. This number will be doubled at one test site. This procedure will be repeated for all trials for each behavior, veering and coverage.

13 comments:

zeveland said...

Thanks, Gene! Quick question - you say: The subject will walk unimpeded unless they become undetectable. If the subject becomes undetectable, the tester may physically prompt or manipulate him/her back onto the course from behind the subject.

How far back onto course do you expect the tester to lead the subject? Just until he or she is detectable again? Until he or she is back on the center line of the course? All the way back to the start position?

If either of the first two, the system might be able to guide the subject back through voice prompts, without tester intervention. Would this be a good thing?

Bonnie Dodson-Burk said...

It is exciting to hear that the equipment is working well! Thanks for posting the feedback schedule. Overall, I think it is very good.

I had the same question Zack had about how far back the subject would be taken if s/he moves outside the detectable lateral area?

SUBJECT’S AGE: I think your feedback procedures are good for older children and adults, who know their left and right. Is this feedback schedule designed for subjects of all ages? If so, I think we need to determine if the younger subjects know left/right and can their bodies and their cane tips left/right on command. Also, they would need to understand "too wide" and "too narrow". If they do not understand these verbal commands because they don't have the concepts of laterality and width (relative to their own bodies), then veering and cane tip width feedback would not be beneficial. Do we look at other skills for these subjects or just not use these subjects? I know we have a limited supply of subjects and time but I’m concerned about the younger students not showing any improvement because they don’t have the prerequisite skills.

VEERING - did you pick the 16 inches from midline parameter based on Guth's work? Have you considered different measurements for young children versus adults or don't you think this is necessary? 16 inches from midline for a child who is only 12 inches wide somehow seems different than 16 inches from midline for a heavy set adult who is 20 inches wide. Maybe I am not thinking about this properly.

CANE ARC WIDTH - I am glad to see the feedback for asymmetrical feedback - "too far left" or "too narrow right". I agree with the idea of not giving feedback until the cane arc width is outside the identified cane tip placement for 3 steps. I think the 2 inches tolerance may be too narrow of a parameter for expected cane tip placement for children or subjects who have seldom used a cane prior to this time. As Dona said, it is often better to allow the person’s arc to be a little wider. I would be reluctant to tell a child that the cane tip is too wide if it is 2 inches beyond the expected cane tip placement as then the child may overcorrect and err on the side of too narrow. Do you think the tolerance could be 2 inches for the “too narrow” parameter and 3-4 inches for the “too wide” parameter?

I have no suggestions for your feedback for conducting trials. I like the idea of explaining the equipment, procedures, etc and giving the subjects time to become comfortable. I also think it is good for each subject to walk along the course to the end and return to the beginning before starting any data collection.9

GB said...
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GB said...

Bonnie and Dona brought up great questions and gave terrific feedback in emails. Here are parts of Bonnie's email, and my responses:

Bonnie: SUBJECT’S AGE: I think your feedback procedures are good for older children and adults, who know their left and right. Is this feedback schedule designed for subjects of all ages? If so, I think we need to determine if the younger subjects know left/right and can their bodies and their cane tips left/right on command. Also, they would need to understand "too wide" and "too narrow". If they do not understand these verbal commands because they don't have the concepts of laterality and width (relative to their own bodies), then veering and cane tip width feedback would not be beneficial. Do we look at other skills for these subjects or just not use these subjects? I know we have a limited supply of subjects and time but I’m concerned about the younger students not showing any improvement because they don’t have the prerequisite skills.

Gene: I agree with everything you said.

My remediation so far: the talking and prep time before the trials; I suggest that we give feedback in the corresponding ear (“move to the left” in the left ear”). Do you think that would help? No doubt some potential subjects will be eliminated.


Bonnie: VEERING - did you pick the 16 inches from midline parameter based on Guth's work?

Gene: Guth’s course was defined as 2 meters wide and feedback was give then the infrared beams were broken. So I estimated our distance based on that, but this was a initial “guesstiamte.“

Bonnie: Have you considered different measurements for young children versus adults or don't you think this is necessary? 16 inches from midline for a child who is only 12 inches wide somehow seems different than 16 inches from midline for a heavy set adult who is 20 inches wide. Maybe I am not thinking about this properly.

Gene: The distance veered will be the same no matter the size or width of the subject, no? I want to initiate the feedback loop based on distance veered. Does thaqt make sense?


Bonnie: Do you think the tolerance could be 2 inches for the “too narrow” parameter and 3-4 inches for the “too wide” parameter?

Yes, I agree with you and Dona and will suggest these numbers.

GB said...

Zach,

I am reticent to complicate the feedback loop with confounding information not related to the target behavior. I am drawing on my real-life experience where physical prompting is less intrusive to the traveler who might be focusing on the cognitive portions of a biomechanical task. Spoken interruptions seem more intrusive and can terminate the student’s focus, where a gentle prompt keeping a person moving forward has seemed to work better.

That all said, my actual answer is, Don’t know yet. I am thinking when we actually do this, I (and Ting) will become aware enough that when the feedback loop is on for cane coverage we’ll be easily able to notice when the person’s cane is undetectable abd we’ll move then back toward the center of the course.

Naturally, when the feedback loop is about veering, then I expect the spoken commands will (mostly) handle the situations.

sl said...

Hi Gene, Zach and Bonnie.
An interesting discussion. I am very comfortable with the direction that Gene is going in terms of detecting behavior and issuing feedback. I am going to post a message now that will describe the current state of affairs on the technology side. It sounds like you have the pedagogy and user subjects issues side under control. I think you should continue to flesh out a variety of usage scenarios, where you can lay out how the system will respond given different user profiles.

Bonnie Dodson-Burk said...

Gene - in regards to the veering, I'm still thinking that relative to the person's step length and body width, 16 inches off midline from the intended straight line of travel is somehow different for younger kids. Maybe I am just showing my lack of intelligence. I need to think more about this.

VEERING - For those young children who demonstrate they don't know right from left, I typically will "nudge" them toward the correct direction when they veer. Does this mean me walking up close enough to them to touch them may be impacting their straight line? Maybe. I'm not worried about research design when I teach. I'm not sure if the young children would understand talking in the same side ear. The children I have taught would probably NOT get this. I can't think of a better solution.

ARC WIDTH - again, for young children I give them tactile feedback about arc width when they are first learning touch technique, because some of them do not have a spatial concept of their own body width. Some will not understand too wide and too narrow. So I show them arc width with my feet, a PVC cane arc definer, or by helping them swing their cane with hand over hand assistance.

I am thinking we need to develop the same type of feedback for younger kids that we develop for deaf-blind subjects - something that does not depend upon words.

Some O&M instructors may think it boils down to younger children needing lots of instruction and tactile feedback to learn something as complicated as touch technique. Others might think it is a matter of a child with a cane walking through obstacles realizing he needs to swing his cane to not bump his body into objects. I'm having difficulty figuring out how the Wii cane will fit into a young child's O&M instructional program, other than for fun or feedback after they learn the cane basics.

GB said...

Bonnie,

Considering the variation in stride-length, I agree with you. Sixteen inches from midline is different if forward movement is significantly different. (I still don't think the subject’s width is a concern in this calculation.) But this starting point of 16” is almost arbitrary. I am open to you suggestions; do you think we should give kids feedback sooner than when they veer 16" from the intended line of travel? What criteria might we use?

I don't have a solution about the veering feedback loop, except what you suggest--vibratory feedback when a subject doesn’t get lateral direction(but how if that different than sounds on the left/right?)

Physical nudging is common--I use it, but it does not treat or improve veering. It just keeps travelers going forward and probably concentrating on other tasks like their cane movement. (Do you agree?)

I also work on arc width/coverage with physical barriers, but the WiiCane is supposed to improve on this with the feedback loop. The ability to move forward for 32 feet and get feedback on cane tip placement (i.e., coverage) would be a great advantage --- if the feedback is interpretable.

Unfortunately, the fun part is not yet built in.

Bonnie DB said...

Gene,

I work mostly with young children who have cognitive and/or neurological challenges in addition to visual disabilities. I think the touch technique is so complex for preschool age children that physical cueing, hand over hand, arc width definers, etc are crucial for success. What has been developed in this project seems great for older children and adults. I am trying to keep an open mind. Maybe young children who have no other disabilities may pick it up faster than I imagine using the Wii Cane feedback system. Of course I use alternative mobility devices with many preschoolers and don't introduce a cane until kindergarten. Or else my preschoolers use diagonal technique holding the cane in the left hand and follow the right wall, keeping the cane tip in the seam where the floor and the wall meet.

VEERING - Young children, in general, don't develop a consistent gait pattern until age 6-7 years. It is no different for young blind children. I don't work with my preschool age children a lot on reduction of veering. I mostly teach them to follow a tactile surface and use auditory cues to help with straight line travel. They simply don't do very well with straight line travel for long distances without having something to follow. That is why I use that backward chaining we spoke about in one of the conference calls - starting just a few feet from the destination. I think you will have kids that veer within a few steps after squaring off. Is there a possibility for the veering study of starting young kids closer to the finish line?

As children get older and have a mental notion of "straight" then I can start working with them on veering. I don't know if nudging helps reduce veering. Sorry.

The more I think about the 16 inches, the more I am OK with it. I think we just have to try it. I don't have a better solution.

ARC WIDTH - Just getting young children to swing the cane across in front of their body is an achievement. I think of successive approximations toward a goal. The final goal is obviously an arc 1-2 inches wider than the body on both sides. Would it make sense to work with the younger children who have never used touch technique for some time period before they enter the official data trials? If they have no idea what you are trying to get them to do, would we keep them as subjects? Or keep them and learn if the Wii cane works? In my mind, the Wii cane feedback system is great for people to help them perfect cane skills. Again, I am not sure about young children who don't have conceptual understanding of left, right, wide, narrow, and straight line.

I'm rambling. Bottom line for young kids I suggest we shorten the path, give touch feedback along with the verbal, and see what happens. I hope we can try this first on adults and school age children. This might lead us to some answers about how to revise things for young children.
Bonnie

GB said...

Bonnie. Thanks. I agree with you and have made the case before to measure the cane sweep, not the taps. I also doubt kids will use 2-point-touch and I am suggesting to the team that we not use tapping as a primary indicator to track the cane. To make the device truly useful it should simply look at the cane at its lateral apex.

Guth says, and I tend to agree, tht veering is corrected when travelers learn what it feels like to walk staight. I'm not sure there is a strong cognitive component.

Bonnie, we may not be able to affect arc coverage (not really width) with kids --- or we might move them toward "correct" movements.

I think those of us on the pedagogy side need to remember that failure is okay on aspects of the project. This is a research project and we may find that only older kids, cognitively intact children, and older traveler benefit. Research is always risky.

Let's all consider these issues and revisit it next week.

GB said...

Hi everyone! I just saw a video by Dr. Bil Hawkins who used a WHISTLE to give feedback for veering while crossing the street. Now, I would never, ever suggest that we distract students while crossing streets by sending them coded messages about their veering (perfect scenario for the need for isolated veering training OFF THE STREET with the wiicane!), but this auditory feedback might be something that could work with Wiicane. We can ask Bil for details, but from the video it seemed that if the student veered a little to the left, he got a long, slow descending whistle. If he veered sharply to the right, he got a quick rising whistle. Bonnie, do you think kids who can't remember L-R could learn that if the "left veer" (descending) whistle was played in the left ear it meant they had veered to the left, and if the "right veer" (rising) whistle was played in the right ear, they had veeered to the right? P.S. I tried to log into the blog to publish my comments, it said it was emailing me my new password but I've gotten no message. So I'll continue to email comments, hope that's okay. -- Dona

Gene's response
Dona and Bonnie,

(My keyboard is still giving me problems so forgie all the typos)

How interesting that Bil came up with the same idea -- real time feedback to the taveler, as Guth.

The idea of sounds for the feedback loop has been considered since the beginnjing, and they will certainly be introduced at some point in a more sophisticated version. If they work better than spoken message then I say we go for it now.

Here's my big problem with this and maybe Bonnie or you could explain so my simple mind can get it . . . what's the diference between learning the word RIGHT and what it means, from learning a particular sound and what it means. They seem like very similar cognitive tasks. Both use the auditory pathways, both require the child to understand the difference between lef/right, and both require the child to pair a label (sound or word) with the proper concept and react to it.

So what's the difference and wy would one be bette/easier than the other? In my gut I would suspect the word would be easier. But what the heck do Iknow!?

(I'm still hoping that an actual signal in the left ear would help a child move to the left, Bonnie has her doubts.)

Gene

Dona said...

Yeah, I agree, but then I don't know about children. Perhaps it is easier to remember and process a new simple signal than words that their parents and teachers have been trying to drill into them and maybe are loaded with emotional baggage of failure to understand.

Either way, perhaps before the trials, you could test the child to find out if she readily knows right-left and if not, whether it is easier for her to remember a signal than to remember the words. If a little review of left-right on-the-spot does the trick at least for the time of the trial, then no need for whistles and signals but if not, try the signals.

I'll try posting this on the blog, see what happens.

Dona said...

Bonnie you raise some issues that I've been thinking about.

One goal of the Wiicane program is to improve the width of the arc of the cane, right?

Should we be using this with children who are not yet ready to learn to use the cane correctly? Does it make sense to focus on precision of cane arc width if they haven't yet even grasped the concept of moving the cane side to side in rhythm and in step? I am not experienced teaching young children but with older children and adults, although I will DEMONSTRATE correct arc width very early (one of the first things), I usually don't work on IMPROVING it until they have mastered the general movement of the cane (being in rhythm and in correct step with the feet, holding and moving the hand generally in the right position, etc.).

Would we be out of line if we say that the subjects must have at least a tentative grasp of how to move the cane correctly?

I would think that younger children would benefit from improving their straight line of travel so if we can figure out how to give feedback to children who don't yet know L-R, that would be great, but not necessarily the cane technique.