What’s The Difference?
In the Vision Therapy Room, we often call a patient’s attention to change, and awareness of change in hopes that they pay attention to available information that may have been previously ignored. For instance, changes in body posture, changes in feeling, changes in space, and so on. Some patients quickly gain an awareness of the smallest changes, and with some patients you have to change the color of the walls, turn on the strobe light, and blare several metronomes and stand on your head before they notice a change. It always fascinates me when I work with monocular prisms that are separated by over 15 diopters and the patient asks “Aren’t those the same power?”. Well, not exactly.
For me though, the key to understanding change has three moving parts: First, is the patient solid in their Same/Not Same skills? Second, how much change is necessary? Lastly, do they pick up on a difference even though they are not saying it?
At the beginning, I approach the Same/Not Same concept with parquetry. We place two blocks on the table, one square and one triangle that are not the same color, and ask the patient to list differences, followed by a list similarities. I’m hoping to get past the programmed responses (color and shape) and get the patient thinking. Can they tell me that both shapes are made out of wood? Both shapes are on the table? Both came from a tree? Both shapes live in the office? Funny note here – had a patient tell me one time that they both would hurt if he threw them at me. Game over for him. On the differences side, thinking can expand into the shapes have different weight, different angles, perhaps they came from different trees. Once they get good at it, you can expand to abstract objects and have fun with it! Lots of times we’ll let the patient pick an item, and therapist pick an item – the have a competition of sorts. You give one answer, then I’ll give one answer and let’s see who runs out of answers first. And of course, I always lose. Again, the key here is to expand their thinking about what is the same and not the same about these items, because truly, understanding same/not same is a major brick in the foundation of appreciating change.
JND’s, or Just Noticeable Difference, is a more advanced skill set in the hierarchy of change that every Vision Therapy activity inherently addresses, either directly or indirectly. Most of us learn about JND’s with monocular lens/prism work, but as I said, it really applies to so much more. To figure this out, we need to ask ourselves a simple question:
What is the least amount of change possible (with any activity) before the patient notices a difference?
With Vectograms, for instance, we ask questions related to awareness of SILO. How far apart do you have to slide the cards before you patient realizes something is different? Once they notice the difference, will each incremental slide of the cards bring the same awareness of spatial shift? When you progress to jump ductions, how few diopters difference are necessary for the patient to appreciate change. With Parquetry, whether with matching, memory, or visual/verbal language skills, we work on awareness of different details and how to communicate them. Many times with a memory activity we work on the patient noticing large differences (we only have 3 blocks remaining of the 5 we started with) and work down to the smallest differences (one block is slightly turned).
Improving JND’s really applies to monocular flippers, prism jumps, visual perception, visualize/verbalize, and overall visual awareness. Simply put, when you know a change is happening, you can more easily react to it.
The last piece here for me is communication. Last July I blogged about how important effective communication, both verbal and non-verbal, can be. The piece was called “Lost in the Language” and it certainly applies here. I’m still a big believer in the patient’s answers are directly related to our questions. Sounds simple I know, but so simple that sometimes it’s overlooked. Sometimes, the best thing we can do for our patients, is simply ask the question differently.