#spatialneglect

My initial design for the clock was based on the way spatial neglect patients draw it when they are asked to represent the time. They squeeze all the numbers on one size due to their lack of attention to the stroke-affected side, unknowingly leaving a big white space. In wanting to design a clock that would enable the patients to read the time easily, I set out to create a working physical copy of their representation of the clock. To do this one thing was necessary: to slow down the clock mechanism to exactly half the speed. Through my research, I found out this could be done in one of two ways: either by altering the mechanical gear chain inside the motor, or by rewiring the electronic component of the quartz mechanism, neither of which turned out to be particularly easy for a beginner like myself. Nevertheless, I learned the basics of gear engineering and figured out the math, also with the help of an Masters Mechanical Engineer from Imperial University. 

The solution to the problem turned out to be theoretically quite simple, but practically almost impossible. I just needed to find a single gear, double to diameter of the driving gear of the motor, which had the same size but double the amount of teeth. By inserting that into the gear chain, it would force the whole thing to slow down by half. After having bought and tested 58 different gears off the internet, the possibility of finding a gear that was as small and as specific as I needed faded away quickly. I considered 3d printing, but that wouldn’t have worked because of the insanely minute scale of what I needed to produce. On top of that, I would’ve had to produce another contained for the gear mechanism that accommodated for the insertion of the new piece. 

So I moved onto my second option, which was electronic. Having been learning about Arduino’s in the last few weeks I was excited to test something out but, still in conversation with my engineering expert, I soon realised that, even if the software and code was correct, it would have been difficult to produce the clock as a standalone object, disconnected from the computed software. This would’ve have prevented it from being hung, which ultimately defeats the purpose of having a clock and of the project altogether. So that didn’t work either. 

 These problems had arisen from the initial design choices I’d made almost instinctively, so I decided to go back and revise. Eventually I came up with some new ideas, one of which seemed more promising. 

I decided to think of the clock in terms of its most basic components, re-thinking how it could work. Instead of having the hands move, could I have the numbers move instead? In this way, the hand could remain fixed on one side, the numbers moving around it, making it always visible for stroke victims with spatial neglect.  

This direction would enable me to still use the quartz mechanism I had without having to spend all my remaining time learning a new skill (while this would have been great and surely useful in the future, it really worried me in terms of achieving an appropriately finished outcome). I swapped each of the hands on the rotating central rod of the mechanism with three separate discs. These would rotate at the same speed of the hands, but they would indicated the numbers instead. 

I first cut a prototype out of mount board, just to figure out how everything would work together and how I should lay out the numbers. I quickly used some Letraset transfers I had lying around. 

Everything seemed to be working okay, except, since it wasn’t cut too precisely,  the discs were touching in parts creating friction and altering the speed. I thought that maybe my material choice was unsuitable, so the next day I tried cutting up some plastic to see if that was more rigid. 

Although the rigidity worked better, the material was just too heavy for the relatively weak mechanism. The motor wasn’t able to turn it, especially when upright. So I went back to mountboard, but this time decided to try laser cutting the shapes to have them fit the rod perfectly and not move around. I digitised my design and put it into a suitable Illustrator file for the machine to be able to process. I was worried that given the thickness of the material and the detail of the shapes I’d drawn, it wouldn’t work. Thankfully, I was wrong. 

Reynold Brown is his name, and Hollywood poster paintings from the 1950s-60s was his game. Although he passed away in 1991, there are many who would’ve thought him long gone by then, having disappeared from the commercial art world in 1979. In that year the artist suffered a terrible stroke to the right side of his brain, leaving him with many severe symptoms including hemispatial neglect. The following is an extract from the book Neurological Disorders in Famous Artists, by Julien Bogousslavsky & M. G. Hennerici:

Spatial neglect is a very complex and perplexing diagnosis that is challenging to treat for physical and occupational therapists alike. Unilateral spatial neglect is a syndrome in which patients act as if whole regions of space contralateral to their damaged brain lesions do not exist, although their visual field is normal (Kim, 2011).

            According to a study done by Kim et al. they completed a randomized control trial to try to determine if virtual training or visual scanning (control group) was more beneficial in treating spatial neglect. The study consisted of 24 stroke patients (n=24) displaying unilateral spatial neglect based on their score from the star cancellation and line bisection test. 12 patients were assigned to the conventional therapy program (visual scanning, reading and writing tasks), while the other 12 began a virtual reality training regime. The virtual reality training consisted of playing games in a virtual setting by watching a monitor and using computer recognizing gloves to complete various tasks. Each patient was given 30 minutes of therapy a day, 5 days each week, for a total of 3 weeks. Upon completion of the study, functional outcome scores were compared pre and post using the star cancellation test, line bisection test, Catherine Bergego scale (CBS), and the Korean version of modified Barthel index (K-MBI). The post-test scores showed a significant increase in the star cancellation test and CBS for patients undergoing the virtual reality training compared to visual scanning. However, changes in line bisection test score and the K-MBI in the virtual reality group were not statistically significant. This study shows that virtual reality training may be beneficial in treating unilateral spatial neglect. Keep in mind that these outcome measurements are not functional and both the VR and control groups did not show significant improvement in activities of daily living, motor performance of four limbs, cognition, and coordination for completing daily activities. One limitation to this study is that the severity of unilateral spatial neglect was not taken into consideration when randomizing the subjects into the control and experimental group.

            In another study, conducted by Bailey et al., they looked at treating unilateral spatial neglect with a visual scanning and cueing strategy versus left limb activation strategy. For this particular study they looked at 7 elderly stroke patients (n=7) using a nonconcurrent, multiple-baseline-across-subjects design. Five patients entered into the visual scanning and cueing group, while 2 patients followed a left limb activation strategy. The 2 patients in the limb activation group had some UE movement, thus the reason for the low number of subjects in that group meeting all inclusion criteria. Subjects completed 3 standardized tests pre and post intervention assessing the 2 treatments for unilateral spatial neglect Line Bisection Test (LBT), Star Cancellation Test (SCT), and the Baking Tray Task (BTT)). Each subject was given 10 sessions lasting 1 hour. In visual scanning and cueing strategy, the therapist encouraged active scanning to the left using visual and verbal cues along with mental imagery while completing functional tasks, such as reading and board games. In the left limb activation intervention, functional and goal-oriented left upper-limb activities in neglected hemispace were encouraged. Following both intervention strategies, the 2 subjects in the limb activation group and 3/5 subjects in visual scanning group showed improvements in 1 or more outcome measures.

            Using these studies to apply research to clinical practice can help make a case for each of the intervention strategies. Visual scanning, virtual training, and limb activation have all been shown to decrease the amount of left unilateral visual neglect in different patient populations. However, each intervention should be implemented on a case-by-case basis to see what works best for the individual. Also, research in this area has yet to determine the best course of action for treating unilateral visual neglect and further studies need to be completed to establish a gold standard for the treatment of left neglect. 

References

Bailey M. Treatment of visual neglect in elderly patients with stroke: a single-subject series using either a scanning and cueing strategy or a left-limb activation strategy. Physical therapy. 2002-08;82:782-797.

 http://ptjournal.apta.org/content/82/8/782

Kim Y. The effect of virtual reality training on unilateral spatial neglect in stroke patients. Annals of rehabilitation medicine. 2011-06;35:309-315.

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