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Kim Henry, BS, BSEE
Rehabilitation Technology Specialist
Sentient Systems Technology, Inc.
2100 Wharton Street
Pittsburgh, PA 15203
This paper describes the selection methods available on the DynaVox 2, DynaVox 2c, and DynaMyte augmentative communication systems. Features that influence and enhance how a person interacts with and makes choices on a DynaVox 2/2c or DynaMyte device are described.
During the presentation, different selection method configurations will be demonstrated and shown in video tape clips. Additional handouts of sample page layouts and user setup files will be provided. Hints will be included about how to set up and apply selection method options and related features to personalize a DynaVox dedicated device.
When considering what the term "access" means in relation to assistive technology, and particularly, augmentative and alternative communication (AAC) systems, two key components must be considered. The first is "control interface." The second is "selection method."
Control interface refers to the technology a person interacts with in order to access an AAC system (Cook and Hussey, 1995). A control interface can be a touch panel, a mouse, a switch, or any hardware that can produce a signal which the AAC device can accept.
The term selection method encompasses the processes which respond to input from the control interface and result in the selection of an available item. There are several types of selection methods and their implementation can vary from one AAC system to another.
The dynamics that occur when a person makes selections via some combination of control interface and selection method is a large part of what "access" is all about.
The type of access that a person uses to interact with an AAC device significantly influences communication. Therefore, the process of choosing and implementing an access strategy or multiple strategies can be challenging. Consideration should be given to how an access strategy impacts on a person's speed, accuracy, control, reliability, and endurance (Angelo, 1997).
Several evaluation protocols, assessment tools, and screening techniques that take into account a person's seating and positioning, visual perception, and motor skills have been described (Angelo, 1997, Cook and Hussey, 1995, Glennen and DeCoste, 1997, Reichle, York, and Sigafoos, 1991).
This section briefly describes each of the six selection methods available on the DynaVox 2 family of products.
The Touch Enter selection method is available on the DynaVox 2/2c and DynaMyte devices. This option lets you choose a button or the Message Window by directly selecting the object. When Touch Enter is the active selection method, the object is chosen when the person activates the input device. Visual feedback is always provided to the user. When an object is selected, it is highlighted.
The DynaVox 2/2c and DynaMyte devices all have a built-in touch panel. In addition, a MicroSoft compatible mouse attached to the Serial port of a device can be used in the Touch Enter selection method. When the input device is a mouse, the selection process is a "point and click" operation.
Two Touch Enter parameters can be adjusted to accommodate a person's physical motor abilities: Hold-down Time and Release Time. The Hold-down Time setting determines how long the input device must be activated before the highlighted object is selected. The Release Time setting determines the minimum amount of time between selections.
The Touch Exit selection method is available on the DynaVox 2/2c and DynaMyte devices. This option also lets you choose a button or the Message Window by directly selecting the object. However, when Touch Exit is active, the object is chosen when the person releases the input device. Visual feedback is always provided to the user. When an object is selected, it is highlighted.
The DynaVox 2/2c and DynaMyte devices all have a built-in touch panel. In addition, a Microsoft compatible mouse attached to the Serial port of a device can be used in the Touch Exit selection method. When the input device is a mouse, the selection process requires the mouse button be held down while pointing and is released to make a selection.
Two Touch Exit parameters can be adjusted to accommodate a person's physical motor abilities: Hold-down Time and Release Time. The Hold-down Time setting determines how long the input device must be activated before the highlighted object is selected. The Release Time setting determines the minimum amount of time between selections.
The Audio Touch selection method is available on the DynaVox 2/2c and DynaMyte devices. It combines Touch Exit with audio feedback. This option is intended for a person who has the physical abilities to use a touch panel or mouse, but who has limited vision and needs to rely on auditory cues to make selections.
Hold-down Time and Release Time are two Audio Touch parameters that can be adjusted to accommodate a person's physical motor abilities.
Audio feedback must be set up and activated for Audio Touch to be used successfully. There are six audio feedback characteristics that can be personalized: the announcer's voice, volume, rate, and speaker port, the button field used as the source for the auditory cues, and whether combinations of the Message Window or blank buttons are announced.
Consider the following scenario. A page with 40 buttons is displayed on the screen. Most of these buttons are Symbol buttons. There are a few Command and Link buttons. The person using the DynaVox cannot see the individual button label text, however can discriminate some of the symbols. Audio Touch has been set up to present auditory cues from the Label button field in the DECtalk voice Paul, at a low volume, with a rate of 225 words per minute, and through a personal speaker attached to the Speaker port of the DynaVox. As this person's finger moves across the touch panel and enters a button region, the Label is announced. When the desired button is reached, lifting off the touch panel results in a button being selected.
The Scan selection method is available on the DynaVox 2/2c and DynaMyte devices. This option highlights buttons and the Message Window in a pattern you choose. A visual or auditory scanning process can be configured.
There are four scan types for single and two switch inputs. Both auto scan and step scan options are available. In combination with the scan type, one of 7 scan patterns can be chosen as the person's main scan pattern. The DynaVox 2 systems also support page specific custom scan patterns.
In addition, there are over 8 features that can be used to customize the scanning process. These features range from options to omit the Message Window from the scan pattern to whether the scan stops after the contents of the Message Window is spoken.
When access is based on a selection method in which the user depends upon visual cues such as a highlight to make selections, consistency in the use of color in page layout decisions is very important. The movement of a highlight can be made very difficult to distinguish when buttons have a number of different background colors.
For auditory scanning, setting up an environment in which the user can differentiate between the auditory prompt and the communication message is essential. Consideration must be given to whether the auditory cues are spoken in a voice and rate that is different than the main voice settings. The degree of similarity between the auditory cue text and other spoken feedback must also be evaluated.
The Switch Joystick selection method is available on the DynaVox 2/2c devices. This option is a "directed scanning" process where a highlight moves up, down, left, and right. An object can be selected either by pausing for a defined amount of time or by activating a switch.
There are several other parameters that can be used to personalize this selection method. The speed at which the highlight moves when a sustained input is present can be adjusted. The position of the highlight after a button is selected can be set to remain on that button or move to a button in the center of the screen. Another feature of Switch Joystick is called "Joystick Wrap". It determines whether the highlight stops moving when it reaches the boundary of the page/popup or cycles around to the other side and continues moving.
When Switch Joystick is the active selection method 2 to 5 switch inputs must be provided to move the highlight and make selections.
An example of implementing access with the Switch Joystick selection method and a 3 switch control interface could be accomplished using the Joystick Wrap function. One switch would control the vertical movement of the highlight and another the horizontal. The third switch would be the select input.
Because of the available Switch Joystick features, access through a directional-based selection method strategy is possible with less than 4 or 5 switch inputs.
The Mouse Pause selection method is available on the DynaVox 2/2c and DynaMyte devices. This option is a "point and dwell" process where a cursor, accompanied by a highlight, moves in all directions. An object is selected by pausing for a defined about of time.
A Microsoft compatible mouse or similar input device (trackball or head movement system) must be connected to the Serial port of the DynaVox 2 system when Mouse Pause is the active selection method.
Mouse Pause does not require a "select" input, so a person's operation of the mouse-type input device must only generate the directional output.
Different types of auditory feedback can be combined with any selection method to further enhance a person's access and operation of a DynaVox 2/2c or DynaMyte device. This is accomplished through the Button Feedback setting in the Selection Method menu. There are four choices: Label, Message, Click, and None. With Button Feedback set to either Label or Message, the DynaVox 2 system speaking the contents of that button field immediately after the button is selected. The Click option results in a clicking sound similar to a computer keyboard click.
Button Feedback can be a useful auditory verification that a button was selected, especially when a Hold-down time or Release time is being used to improve accuracy.
Access is dependent upon the combination of a control interface and a selection method. Features that influence how a person interacts with and makes choices on a DynaVox 2/2c or DynaMyte device were discussed. Handouts showing sample page layouts and user setups will be provided at the presentation.
Angelo J (1997). Access Methods. In J Angelo (Ed), Assistive Technology for Rehabilitation Therapists. Philadelphia: Davis.
Cook AM and Hussey SM (1995). Assistive Technologies: Principles and Practice. St. Louis: Mosbey-Year Book.
Glennen SL and DeCoste DC (1997). Handbook of Augmentative and Alternative Communication. San Diego: Singular Publishing Group.
Reichle J, York J, and Sigafoos J (1991). Implementing Augmentative and Alternative Communication. Baltimore: Paul H. Brooks Publishing.
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