Over the past 12 months optometrists have moved steadily toward embracing neuro-developmental concepts. Optometrist Sue Larter reports on a treatment program she unearthed at the 6th International Congress of Behavioural Optometrists held in Los Angeles, U.S.A, last year.
The Clinic-Based Vision Therapy (NVR) system is a real space visual therapy system that uses an interactive interface combining blue tooth remotes, Wii balance board and an Infrared Head Sensor with a Windows operating system and DLP projector.
It offers greater challenges and successful outcomes for patients with neurological insult, acquired brain injury, post trauma vision syndrome, and stroke, as well as children with visually related learning problems.
The NVR was developed by Dr. Allen Cohen from SUNY College of Optometry, New York City, U.S.A, who has worked with brain injured and LD patients for more than 35 years, and was frustrated by the lack of high level ‘top down’ processing control in therapy equipment.
This Vision Therapy system offers the patient a range of free space activities integrating vision with balance, audition and body awareness
How it Works
The NVR offers the patient a range of free space activities integrating vision with balance, audition and body awareness. The patient works two to three metres from the projection screen. Once the lower levels of eye movement control and eye-hand coordination are mastered, the bar is raised by using the head sensor, which provides auditory feedback about head position while doing each activity.
Further challenges are then added by having the patient stand on the balance board, allowing tactile feedback through the handset about imbalance. Red/blue glasses provide suppression awareness and binocular feedback.
The interactive nature of the NVR is its great strength. Most therapists already use various means to provide their patient with increasing awareness of body position and auditory integration, but this system is far more sophisticated.
Optometrist Lesley Vedelago from Browns Plains, Queensland, has been using NVR with TBI/stroke and adult CP patients and says she “finds it invaluable, especially for integration of balance/vision/auditory due to the feedback they receive. Patients are keen to see their own progress”.
The Underlying Science
Neuroplasticity has been proposed as the mechanism for why Vision Therapy works. Rehabilitation therapists apply the principles of repetition, motivation, loading, multi-sensory integration and feedback to effect functional change in their patients. Behavioural optometrists apply the same neurodevelopmental concepts when doing Vision therapy.
Cortical plasticity research shows that new neural pathways can be forged through repetitive stimulation, a fact well-known by sportsmen and musicians. While you may have a particular talent for catching or hitting a ball, or may know the sequence of notes in a piece of music, this does not necessarily ensure your performance will impress without a lot of practice.
Changes in brain circuitry depend in part upon the growth of new connections, or synapses, between neurons, and the elimination of unused ones. It is suggested that the fastest learning occurs by strengthening existing connections.
Known as long term potentiation, the process consolidates a previously ineffective synapse via one or more secondary connections. This is why it is often reported that Vision Therapy has helped listening, learning and sports skills: the use of auditory input to stimulate timed eye movements with balance tasks helps both the visual, auditory and proprioceptive pathways due to shared synapses; all of which leads to more efficient information processing.
Eye Movement Control
One of the main skills trained in any Vision Therapy program, the NVR being no exception, is eye movement control. Neuroscientist, Dr. Burkhart Fischer, in his book ‘Looking for Learning’, proves the critical nature of both saccadic eye movement (the fast eye movements from one object of interest to another), anti-saccades (conscious control by looking away from a suddenly presented stimulus), and fixation stability, to reading.
He claims that eye movements are essential for visual perception and has shown that there are significant differences in the above skills between normal, dyslexic, and LD children. Furthermore he has shown that by training saccades and fixation there is flow on into academic improvement.
The five NVR treatment modules all deal with some aspect of eye movement and fixation anomalies. Most importantly they are designed to give the patient constant, top down feedback about their head position and body balance as they practice and refine their ability to perform the various tasks.
Wii Balance Board
Behavioural optometrists have been using balance boards in therapy since the 1930s. Traditionally, we have used boards with varying degrees of difficulty, achieved by having higher, narrower, or rounder bases attached to the boards. What the Wii does that is conceptually and cognitively different is that the board itself is stable. The Wii balance board provides feedback to the patient regarding whether they are stable when they are apparently standing still.
Further feedback regarding body balance is provided once the eyes and hands are employed doing the different tasks that the NVR offers. The head sensor adds another level of input to the brain to allow the patient to more precisely monitor and change what they are doing. The NVR program keeps records of progress for each patient.
The Treatment Modules
The Visual Motor Enhancer uses a virtual rotator with variable targets, speed and direction of rotation, plus the option of red/blue to control suppression and build binocular function. Developing and enhancing fixation and pursuits while integrating balance is quite a challenge, but the built-in feedback systems enhance the learning.
The Ocular Vestibular Integrator addresses symptoms of dizziness and disequilibrium often experienced by head trauma patients. The bullseyes can be positioned to help train awareness in various segments of the visual field. We have found it to be an excellent adjunct to our other therapies for children with LD as well.
The Dynamic Ocular Motor Processing game includes contour interaction and associated random clues for fixation, incorporating both magno- and parvocellular processing. The procedures are designed to enhance saccades, scanning, visual spatial processing speed and visual sequencing, as well as dynamic sensory binocular fusion.
The Visuomotor Integrator will appeal to all the golfers out there. The stimulus is a golf cart that the patient has to ‘drive’ around obstacles. At higher levels, the cart randomly changes speed and direction – quite a challenge to control while keeping head and body still.
Tracey, who suffered a TBI (traumatic brain injury) in 2003 said “With traditional vision therapy I’ve found it pin-points my weak spots so quickly and without warning that I often find myself triggered into a “turn” and it can take days to recover.
“The NVR system, however, provides me with instant feedback so I can adjust my posture and vision as I play each game. I still work on “manual” with peripheral vision, balance and depth perception so I am exhausted by the end of each session but so far, I have not had a “turn” from overloading my system. I also feel a great sense of achievement that I am doing better each session.”
Sue Larter is a behavioural optometrist based in Sydney, New South Wales. Clinic-based Vision Therapy lies at the pinnacle of offerings from Fellows of the Australasian College of Behavioural Optometrists (ACBO) who have moved steadily toward embracing neuro-developmental concepts over the past 12 months.
References
1. Huang JC Neuroplasticity as a proposed mechanism for the efficacy of vision therapy and rehabilitation. J Behav optom 2009; 20:96-100
2. Barry S. “Fixing my Gaze: a scientist’s journey into seeing in three dimensions” Basic Books 2009
3. Fischer B. “Looking for Learning: Auditory, Visual and Optomotor Processing of Children with Learning problems” Nova Science Publishers 2007
