Friday, March 7, 2014

Basic Visual Considerations for AAC Devices and Apps

Children with visual processing disorders such as cortical visual impairment tend to need specific visual accommodations than other AAC users.  The following recommendations are based off the CVI Range created by Dr. Christine Roman-Lantzy.  The CVI Range measures a child's visual processing abilities in the following ten areas: color, distance viewing, movement, latency, visual fields, complexity, light gazing, visual reflexive responses, visual novelty and motor.  For the purposes of this blog entry, I focused on the areas of the CVI Range that directly related to creating AAC communication boards.  For today's entry I am focusing on Color Preference, Latency (Delay), Visual Field Preference and Complexity.

For more information on photographing objects for AAC devices, please check out Andrea Schario's tips on photographing objects for children with visual impairments in the presentation from our webinar: Helping Children with Visual Impairments Explore, Learn and Communicate Using the iPad

Color Preference
It is common that children with visual impairments with Cortical Visual Impairment have a preferred color that they can fixate on for longer periods of time (red and yellow are the most common).  When creating a communication board for a child with CVI (or low vision), it is important for the therapist or special education teacher to talk to the Teacher of Students with Visual Impairments to help the student's IFSP/IEP determine what the user's preferred color might be. 

It is common that many dynamic AAC devices and apps give the user the options to choose the color of the border that surrounds the icon on the AAC device. I would recommend that the therapists consider using the child's preferred color as the boarder when creating a board on a dynamic display.

When considering a child with CVI's visual abilities, it is important for the child's AAC team to choose an app or device that visually isolates the choice the child made for an extended period of time to account for the child's visual processing delay.  For example, on the AnswersHD app, the user has the option to hold the child's choice in isolation for 2-6 seconds after they make their choice.  Since I have so many young kids, I usually error on the side of caution and keep this setting closer to the 6 second time.  

Visual field preference
If the child uses the right visual field over the left visual field or vice versa, it is important for the user to consider the placement of the child's icons on the his communication board. Whether the therapist or parent is creating a board with 2, 4, 6, icons, it is important that the team move the preferred icons to the child's weaker visual side so he or she can improve the visual input of their weaker side and also continue to improve on recognizing the picture on the icon.

Since many children with CVI struggle to focus on excess visual information on a page, I advise many AAC teams and therapists that it is better to keep the icons big, simple and bold with less icons present on a communication board.  When it comes to students with CVI and complexity, it is wise to always have less icons with high contrast, large, simple icons.  

1 comment:

  1. nova chat 10 was recommended to us for our low vision CP 3 yr old . However the screen cannot be made t show less than 4 buttons at a time. And the only way I can find to show four buttons is to restrict it to the most limited and basic vocab list. I like proloquo2go best but insurance won't cover an iPad. I want to know what are the best choices for aac device for low vision users.