Augmentative and


Alternative Communication




Karl Dean
(BSC Computing)



Humberside & Lincolnshire









Humberside & Lincolnshire University


Frederick Holmes School


Prentke Romich Company


Barry Taylor (Clinical Scientist)


Julie Adams






























Introduction…………………………………………………………………………… 6

Background……………………………………………………………………………. 7

Chapter one…………………………………………………………………………… 9

Social and interactive implications

Children with AAC Systems 1.1…………………………………………….. 9

Speech improvement with an AAC 1.2………………………………….. 11

Adult users with an AAC system 1.3…………………………………… 14

Reducing behaviour problems 1.4……………………………………….. 17

Using the AAC system in the real world 1.5………………………. 18


Chapter two………………………………………………………………………….. 20

Different ways of scanning icons

Introduction on scanning with different displays 2.1…… 20

Operating switches 2.2………………………………………………………  22

Different scanning methods 2.3…………………………………………. 24

Scanning patterns 2.4………………………………………………………… 26

Making selection process more rapidly 2.5…………………….  28

Special requirements for users 2.6…………………………………. 30

Children and scanning 2.7…………………………………………………. 32

New scanning method 2.8………………………………………………………… 33

Summary of Chapter 2   2.9…………………………………………………….. 34


Chapter three…………………………………………………………………………. 35

Comparing previous speech synthesizers with the updated models

Introduction 3.1……………………………………………………………………… 35

Investigating the first AAC 3.2 …………………………………………… 35

Investigating the latest AAC 3.3 ………………………………………… 40

First AAC’s vs Pathfinder 3.4 ………………………………………………... 43

Pathfinder vs Pc 3.5  ………………………………………………………………  44

The pros and cons for a AAC system 3.6 ………………………………  45

Pros and cons on a laptop 3.7 ………………………………………………. 45

Future for AAC system 3.8……………………………………………………… 46


Conclusions ……………………………………………………………………………… 48


List of figures…………………………………………………………………………. 51


References …………………………………………………………………….52






Booklets…………………………………………………………………………………. A

Users questionaires………………………………………………………………. B

Designers questionaires……………………………………………………….. c

Letters…………………………………………………………………………………….. d


















Introduction 0.1

Many people with disabilities can benefit from technology.

Microcomputers, in particular, have provided people with the opportunity to lead more independent and “normal” lives.  Just as any able-bodied person in areas of vocation, education and leisure can do. In some cases, there are distinct applications that augment people’s abilities, such as allowing communication for those who have difficulty with speaking.   In the past people with these difficulties could only communicate with people that were close to them i.e. parents, brothers, sisters and friends they had known for a while, as these would be the only people who could understand them.  If they were to meet new people then it would take a considerable amount of time for them to understand what was been said, because it would take a while to get tuned in to there speech pattern. 


This project is about Augmentative and alternative communication (AAC) devices; these electronic AAC devices are for people with severe communication impairment. The AAC devices are similar to a laptop computer in size and weight. (If you are not familiar with them, you should read the booklet in the appendixes before reading on!) Mainly the AAC equipment will be for people with physical disabilities. This will be mainly people who have Cerebral Palsy with little control over their body movements. For instance, physical disabilities are relevant to both the adaptive and prosthetic use of information technology.  People with impaired manual function may not be able to use conventional input devices such as keyboards, and mice, while some people are unable to carry out such everyday operations as walking and may use a computer controlled wheelchair.


The main point of convergence is to investigate the social and interactive implications on the AAC equipment.


Secondly, I will be looking at the interactions that arise with a number of strategies that apply switch-based scanning to text selection in a task transparent fashion. The results should provide valuable insights regarding the design of access systems that enable users of indirect scanning access methods to achieve not just equal access, but to achieve equal productivity. Basically, selecting text with an emphasis on reducing user strain, errors, and time. Also to try to find out which is the best method on scanning.


Finally, I will also be investigating whether or not the current equipment is keeping up to date with the state of the art technology. For instance, I will be investigating and asking questions like; is the IT equipment available currently, adequate or inadequate to meet the needs of disabled people? Are the needs of disabled people met in terms of IT provision?


Background 0.2

In the mid 80s the Prentke Romich Company developed 2 AAC speech synthesiser devices called the Touch Talker and Light Talker. The synthesisers are like the boards but are electronic with icons to press. The icons are laid out in rows. There are eight lines, which contain 16 icons on each row. There is a storage device to store words and sentences. For example, supposing the person wishes to say, “what time is it please?” the sentence would be stored under the clock icon, and the user would go to the clock icon and click on it, then the speech synthesiser would say “what time is it please?”  And also the talker will write this message in the speak display LSD on the top of the machine.

This was the biggest improvement in people who had a speech problem because for many years disabled people with poor speech or even without any speech have been using paperboards with words/icons on it for communicating with people.  The disabled person would point to an icon if he/she wanted to communicate with a person. This method was slow and limited to a few words.  Supposing the disabled person was trying to tell another person a sentence, and then 90% of the listeners would have forgot the first part of the sentence when the speaker had finished, even more so, if the person didn’t have a word on the board, then he/she would have to spell the word out by each letter.  This is very confusing for them both, as you can imagine spelling a word by only pointing to each letters and remembering how to spell it, unless the opposite had a pen and paper to write the message down.  The bliss board did not really work in the real world.





Chapter 1

Children with AAC Systems 1.1

The social and interactive implication is a very important topic, which hasn’t been fully explored as yet.  Tens of thousands of people worldwide have AAC systems and are enjoying the benefits of these developments, but no – one knows the social impact of the user. For most AAC users, personal achievement is an essential role of the ability to

Communicate. The children in the first year at school have the potential for high personal achievement that far exceeds what was possible even a few years ago.

Therefore, the child with speech impairment should have an AAC from the first day at school. There is some research done by Laura F. Meyers Ph.D. at the university of California Los Angeles, Linguistics. From Closing the gap – Computer technology in special education and rehabilitation, February / March, 2000. Volume 18 – Number 6.

She says, “The AAC with Minispeak can be learned in the same natural way as spoken and written language is normally learned. As in the normal processes of spoken and written language learning, meanings comes first.

During active participation in conversations about personally meaningful topics, the device user constructs an internal grammar for minspeak. These methods make it natural to switch between minspeak and written language.”


Minspeak strictly speaking is not a language but essentially an index system for retrieving words\sentences by means of mapping sequences of keystrokes to stored phrases. Each key can have any icon or character written on the keys.


There are accommodations that expand selections through a mapping process as suggested by Vanderheiden and MacDougall et al. Three primary methods of input

Mapping are commonly used:

One-to-one mapping: characters, words, phrases or sentences are entered as displayed:

Macro or abbreviation-expansion mapping: one or a few letters or symbols are displayed and a complete message or command string is entered when selected (Roa & Riley, 1981; Vanderheiden, 1984; Beukelman & Yorkston, 1984; Stum & Demasco, 1992); and

Predictive mapping: a list of predictions of what the user intends to select is displayed following one or a few initial selections; a selection enters the predicted word (Swiffen, Alm and Newell, 1987; Darragh, Witten and James, 1990).


Therefore, Minspeak is essentially a translator from symbol sequences to phrase. For instance, pressing a key with “drink icon” in it, followed by a key with an icon of a pointing-finger on it, might result in the retrieval of the sentence “Please will you go to the bar?”  Whereas “drink icon” plus a person icon might retrieve “Do you want a drink?”  Here is the icons layout   illustrated in the figure 1.1.

(Figure 1.1.)For more information about minspeak refer to the booklet on AAC in the appendixes (A).


The children should come full of spontaneity – with theirs feelings, with their questions, with their creativity, with their risk to create, getting their own words “into their own hands” in order to do beautiful things with them. (Paulo Freire, 1985)


I feel that if children were provided with AAC from the beginning of their education, even pre school, then they would benefit socially and academically. 


Speech improvement with an AAC 1.2

There have been many research studies on the natural speech increasingly used by AAC, as parents are worried about their child giving up on attempting to talk. The research shows that not only was natural speech not inhibited by AAC systems but also that natural speech was likely to increase. Examined were 25 research studies published in 1998 that reported on individuals who used AAC systems, but had some natural speech, they coded each study and looked for reports about natural speech. Overall, they found that the majority of the individuals in the studies showed that natural speech either stayed the same or increased.

It increased because the AAC user has a backup device to communicate, unlike before when the user didn’t have an AAC system, they would get tired of trying to say something and after a few attempts he/she would have given up or would revert to the bliss board. This was a very long-winded process so you couldn’t really put a sentence together without thinking about having a conversation. However, in my research, I have found 60% of the AAC users prefer to have a sentence composed and speak it.  This is because they don’t like having someone looking over their shoulder reading what the user is trying to say. Because they said, most of the time, the person guesses, wrongly, what the user wants to say and this causes frustration.

You can see this in figure 1.2.

(figure 1.2.)

The other 40% of the AAC users I questioned proffered the person reading the screen as they typed.  This is because they say it saves time when explaining something. The person listening can then pre-empt what the user is trying to say as it becomes pretty obvious.

As an AAC user myself, it really depends on the situation. For instance, I might want to compose the first sentence to start off the conversation, then let the person read the screen as the person will know what topic of conversation I’m talking about.

I think at this point, the natural speech kicks in to gear. As we become deeper into the conversation, the user will only use the AAC for the main keyword if the other party cannot understand the users natural speech.  An example could be that if the user is trying to say, “please will you get me a bag of chips” with the natural speech

The person might decode the sentence as,

“Please will you get me a bag of ?????”    Without understanding the last word.  So therefore, the AAC user will write chips on the display, this would save the user time and energy, without writing out all of the sentence.  This means no embarrassment on both parts.


This is the natural speech increase.  I have a theory - more time using the AAC equals more improvement in the users natural speech.  I will use myself as an example, as I didn’t have time to research this area, I had just thought of it a few weeks ago myself.

The longer the user uses the AAC system the shorter time it will take for their new friends to understand them with their natural speech. For example, when I received my AAC system at school, three months later I went to college and I was provided with a personal helper who I have not met before in my life. It took the helper 3 months to understand my natural speech. 11 years later, it takes my new helpers on average 3 weeks to get to understand me.

I’m not saying the helpers fully understand what I’m saying as there is always words they cannot decode, but there will be approximately 75% of words they will understand.  Will my AAC be redundant? No, as it will limit myself to the people who I be able to talk to, (like the old days) and the probability of decreasing my natural speech as well.


Adult users with an AAC system 1.3

In my research I have found a lot of the adults users do not know how to communicate with people using their AAC systems.  This means they cannot have a conversation or even say a sentence.   This is because they only have been communicating with a few words in their lifetime, like yes, no, toilet, drink, eat etc. Some of these people have not had a conversation unless someone else was able to understand what they were saying.  However, when the adult user received an AAC system, some of the users did not know how to communicate with people, like putting a sentence together with their AAC.  These people will have to re-learn how to talk, basically, the learning process is a bit like teaching a baby to talk. Some adults users will not touch their AAC system and, consequently there is a danger they will be reluctant to get to know and use the AAC.  The user will not know how to communicate and will therefore be isolated from the “real world” which could lead to frustration and misunderstandings.

 I personally have known a few users who, still cannot communicate by having a conversation or even a saying a small sentence with somebody after eight years of using a machine.  The learning process can differ from just one week to over 10 years, or maybe not at all in the users lifetime.  However, the progress depends on an individual persons learning span.


Or it may be lack of support on teaching the adults how to use AAC systems because there are only few adults with an AAC system.

From my questionnaires, Nick Lyth says “I wish these talking machines were more simple and quicker for us disabled people and not so expensive so we could purchase extra things to make life that bit easier.”

In my investigation, I wanted to find out why the old fashioned “bliss boards” are still been used and see what is the age range of these people.

 I actually interviewed some people who still communicate with these boards in some of these so-called homes for the disabled.  I asked them a few question like; have you tried a speech synthesiser? Would you swap your board to a speech synthesiser? How long have you used one of these boards?

All the disabled users, which communicate with these boards, were over 40 years old and didn’t go out to work or college. They haven’t tried a speech synthesiser or some of them have not even heard one. Before I asked them questions with my speech synthesiser in the American accent they hadn’t even heard one speak.  Half of them said they would swap the board to a speech synthesiser straight away, before I told them the price of them. Well, £6,500 is a lot to pay for a few chips! The other half thought the machine would be too complicated for them to operate. I received the impression, that because they haven’t been in contact with computers in their lifetime they were totally apathetic to using one.

They have only ever known how to communicate with a bliss board, so they have not known any better, or are aware of up to date devices, but I feel these older generation are missing out on the technology and their quality of life is suffering because no-one has bothered introducing them to the new information technology or, as is usually the case they are too expensive.

From my research and experiences, the new technology is going to the age ranges of 4 to 16 years old, as the schools buy the new speech synthesisers from the school charities funds.  Especially the special schools as they receive a lot of funds from such areas as firms to individual charity events. When the schools receive the donations the fundraisers like to come and watch them working through the classroom door window. It is really hard to carry out fund raising for adults, (unless they are dying) however, why should disabled people have to rely on charity?


Regrettably, the adults are basically missing out on the AAC technology because it is a fact that all too often people are being restricted rather than enlightened with the AAC systems. Further, they may not even know of the availability and effectiveness of other options and features. There can be many reasons why users are not comfortable with all the potential AAC system options. These reasons can be funding, lack of professionals and service resources, and lack of awareness of the options available and their relative performance.


Another reason why disabled adults are still in the dark ages in the communication area is they don’t get regular speech therapists unlike when they were at school. Nowadays speech therapists are trained to teach the AAC systems to the users. Therefore, the adults don’t obtain any support on their AAC. Furthermore, if the adult hasn’t had one he/she might not know about them. Here is the answer from Barry Romich (The Boss) from Prentke Romich Company who manufactures the AAC, from my publicity questionnaire:

“Customers pay for all publicity.  Our primary marketing efforts are directed toward speech therapists since they are typically the gatekeepers to service provision.  Further, they are a reasonably well-defined lot, allowing targeted promotion.  This still is costly and we try to be judicious in spending our customers' money.”


Reducing behaviour problems 1.4

Supposing an user has a behavior problems, for instance, throwing objects, biting, head banging, attacking people, yelling etc… The AAC systems might decrease the aberrant behavior, as it is about 85% this kind of behavior is due to lack of understanding of the disabled person. For instance, if the user wanted something but other people cannot understand what they are saying, they will get angry, especially if that person already has a short fuse.  The AAC could bridge the time between the request and the providing the requested help.


However, those high achievers who rely on AAC systems have a clear vision of their aim in life. Providing they have the best systems and professionals, such as speech therapists, available, for full achievement.

For speech-language pathology professionals providing services in AAC, this consistent with the ASHA Code of Ethics (ASHA, 1994) as articulated in the introductory statement to Principe of Ethics 1:


“Individuals shall honour their responsibility to hold paramount the welfare of persons they serve professionally.”


This message is quite clear. Professionals are bound by their code of ethics to provide quality standards of care and service. Nothing is more important than acting in the highest interest of the person who relies on AAC, no matter what the presumed potential for achievement. If circumstances preclude behavior that is compliant with the Code, then a full disclosure to all involved is in order.

Using the AAC system in the real world 1.5

The AAC can make users much more independent. For example, they could go to purchase a take-away meal without any assistance. By storing a few orders in the memory, they will only need to press the right icon, to order the food.  If that person was in a wheelchair, the AAC user could also tell the shop assistance to hang the take away on the back of the wheelchair before going home, thus enabling them to lead a “normal” every day life. In my own experiences, carrying out my research I found that after had I used a certain take away a few times the assistants became familiar with me, the AAC user, and they also got the money out of my pocket and hung the food on the back of the wheelchair without me, the AAC user, asking them.  The process was that they asked me first, and got to know my special requirements and then, I, the AAC user would only have to say yes, thank you! Basically, the take-away shop assistance will treat the user as a “normal” customer.  Basically the conversation would go something like this, “good evening, what would you like to order tonight, Sir?” The AAC user will press an icon to order the food by a programmed phrase.


The key point to this scenario is the AAC can be more actively involved in a variety of experiences like ordering independently in a fast-food take away or going to the pub with mates. The AAC makes it easier for people to associate with others and on equal’s terms. People are sure to respond when a user tells a joke or initiates an interaction like “are you coming for a beer?” or tell a person “I love you” (this is probably when the user had too much beer”. The speech output allows individuals more opportunities for meaningful inclusion in activities with friends or with tutors and presentations. 


Finally, through daily experiences, using an AAC will give users many opportunities to practice important communication skills like turn taking, cause and affect, and that language is reinforcing and has meaning.

It might take a user a long time to learn how to effectively communicate using speech output. Therefore, if they never start, they will never learn.




































Chapter 2


Introduction on scanning with different displays 2.1


The chapter is about alternate access and scanning solution that emulate the

input device(s) of an AAC, such as keys.

When users have severe physical limitations, and cannot directly access any alternate or modified keyboard, an indirect means of access is usually indicated.


The scanning procedure encourages the user to consider different control options, for instance, direct selection versus scanning, and control movement (head, hand, foot, toe, etc) and to include in this decision process other influential factors such as proper seating and appropriate stabilizers.


An example of indirect access is switch-based scanning with an on-screen or virtual keyboard (Anson, 1991). An on-screen keyboard displays a representation of a keyboard on the computer screen and contains keys that inject keystrokes transparently into the target application when selected.

Here in figure 2.1. is an example of WIVIK software-:


(figure 2.1.)

Alternatives can be icons on the screen, as the AAC system operates under a system called Minspeak. Minspeak uses icons to which the user assigns meanings. Icons can have multiple meanings and can be combined in sequences.

Scanning involves the successive lighting up of icons displayed in the AAC. The user selects desired icons by activating a switch when that icon is lit. It is considered indirect because a switch action does not directly correspond to a keystroke. Similarly, when users are unable to use the standard mouse or some alternative-pointing device, an indirect scanning solution is often considered. This generally involves some form of scanning screen pointer. To control the direction of movement, the screen pointer rotates in a scanning fashion, or a specific direction is chosen by scanning the on-screen keyboard. Then the screen pointer scans across the screen and along the chosen heading. 

Emulating a pointing device is considered necessary because pointing is an integral component of current graphical user interfaces (GUIs).

It is also a fundamental concept of transparency that all keyboard keys and mouse functions must be available within the access system. These new AAC systems emulate the keyboard and type into the AAC and it will be displayed on their pc by infra-red link. The advantage of an infra-red system is that any selection method can be used and the access system is independent of any computer manufacturer and operating system.


Operating switches 2.2

There are a variety of switches widely available for individuals to use with these scanning methods (Closing The Gap Hardware and Software Resource Guide, 1996). These switches vary in contact surface area, property sensed (pressure, change in orientation, motion, relative positioning of components, degree of change), shape, contour, texture, and feedback (auditory, tactile, visual, kinesthetic) (Shein and Lee, 1983; Shein, Lee, Pearson, Milner and Parnes, 1985;


 Lee and Thomas (1990) describe the following user actions to operate switches that vary with scanning method

A timed momentary activation (i.e., activate at a critical instant with automatic scanning);

A non-timed momentary activation (i.e., activate at any time with step and direct scanning);

A continuous activation with timed release (i.e., release time is critical with inverse and directed scanning when selection is by release);

A continuous activation with a non-timed release (i.e., release time is non-critical with inverse and directed scanning when there is a separate selection switch).


These separate actions, differ in movement speed, direction, or positioning and do not affect the outcome of activation with a separate switch. Endurance becomes a critical concern with these actions because of the large number of repetitive actions to accomplish most tasks. Excessive repetition of movements may lead to fatigue and strain injury (Cantor, 1995).

One through five switches is not commonly used for scanning. Single switches are most frequently used for timed activation in an automatic scanning system, typically a row/column array. Occasionally they are used for inverse scanning on the new AAC systems nowadays. In the latter case, the user selects an icon by releasing the switch for a pre-set period of time. A second switch is often used to augment single-switch scanning techniques. In automatic scanning, the second switch often provides an ‘escape’ or ‘cancel’ function, and in step or inverse scanning it acts as a selection switch while the first switch is used to move the light. 


Three switches are not very common, although they can provide some additional control. For example, momentary activation or timed release of one switch may advance the cursor from left-to-right, while similar movements of a second switch may move the cursor from top-to-bottom.  Releasing and reactivating one of these switches reverses the scanning direction. Momentary activation of a third switch signals selection. This approach has the advantage of enabling users to back up quickly if they accidentally scan past a desired icon, instead of having to wait through

another scanning pass. Five switches provide a high degree of discrete switch control for directed scanning. Momentary activation or timed release of four switches, such as a micro switch joystick, directs the cursor within a two-dimensional scanning array. A momentary activation of the fifth switch selects the item under the cursor.


Different scanning methods 2.3

Indirect access through scanning can be intense and demanding on the remaining abilities of the user. However, in my research from the AAC road show at Frederick Holmes School, I have found much advancement has been done to reduce scanning time and switch activations through icon arrangement and rate enhancement techniques.


Nowadays there are 4 basic techniques.


The first one is automatic scanning  - it is a very basic scanning method.  The mechanism is that the lights automatically move across an array of icons. The light pauses at each icon for a pre-set time called a scan interval, momentarily activating a switch, it usually stops the lights over a row of icons and initiates scans across the row on an individual icon. If the switch is activated when an individual icon is lit, that icon is selected. Timing of the switch activation is a critical factor. Rather than track the moving light, users are taught to focus on the target icon and activate the switch whenever the target is lit. They continue with this until the target is selected and scanning begins from the top. This is an old method, which was used on the first AAC device in the mid 80s called the Light Talker. This method is still widely used today especially for beginners as it is very simple to use.


The second method is step scanning, rather than the system control the speed of presentation, the user is in control with step scanning, although more switch activations are required. Here, repeated momentary activation of a switch advances the highlight. The advantage of this method is that there is less time pressure on the user. Icons are selected when lit, by activating an additional selection switch, or by dwelling (i.e., pausing without selecting any switch). Disadvantage is that there are more switches; consequently it will mean more movements for the user.


Third method is the inverse scanning technique, this is for the advanced users. The mechanism is the cursor or light manually, maintaining switch activation. While the switch is activated, the light pauses at each icon for a scan interval. Timing the release of the switch within a scan interval is important. Sometimes, step and inverse scanning are combined. This is a virtually new method on the new AAC systems. It can be a bit complicated until the user gets used to it


And the final method is directed scanning associated with separate switches, with directions of cursor movement. These switches are used in a step or inverse fashion. The switches are often housed in a gated joystick, allowing users to ‘direct’ the light, as they would drive a powered wheelchair. However it is much harder to control the lights on the screen with a joystick. For instance, in a chair it doesn’t matter if the user doesn’t go exactly in a straight line as the footpath or corridor will be larger then the width of the chair, however, it does matter on an AAC system because if you cannot go in straight line on the row, you will jump rows. Another direct switch is a laser or a light pen.  Icons are selected by activating a selection switch.  Vanderheiden (1985, p. 23) describes this scanning method as a hybrid between scanning and direct selection because “the selection is based on the type of movement made as well as the point in time that the movement is made.”


It really depends on individual users to see which is the best scanning methods as some disabilities make one kind of input easier to use, while another disability may function better with an alternative choice. Similarly, differing output displays will benefit different users.  Many variations of these methods exist that depend upon the number of switches employed and scanning pattern.


Scanning patterns 2.4 

The connection with automatic, step and inverse scanning are particular patterns by which the scanning light moves across the format of keys/icons. These patterns include element, row/column, and block scanning. In an element scan, the cursor proceeds to light each icon of a medium in succession, usually from left-to-right and top-to-bottom. After a selection, the cursor generally returns to the first item and repeats scanning. Element scanning is typically limited to less than 15 items (Vanderheiden and Lloyd, 1986).   Illustration figure 2.2.






(figure 2.2)


 Here is an example of element scanning. Above, the black square indicates the current lit icon while the gray squares indicates the previous lights.


In the second example below is on row/column technique. Row/column scanning is a faster selection technique in which rows of icons are arranged in a two-dimensional matrix and are scanned row-by-row from the top down. A selection made

with the single switch stops the scanning at a particular row, which is subsequently scanned, column-by-column until the desired icon is reached and selected. As before, the cursor returns to the first row to repeat scanning after a selection, shown here in figure 2.3.


















(  figure 2.3.)


A third example is the block scanning approach, this is best used for large matrices. One variation of block scanning is quadrant scanning (Basacchi, 1982) which is used with a square matrix of icons. The matrix is divided into quadrants. Starting from the top left-hand quadrant, each quadrant in the board is lit in succession. When a ‘select’ switch is activated, the currently lit quadrant is selected and scanning is repeated within that quadrant until individual elements are scanned. This is a very efficient selection technique where one of 4 icons can be selected with n switch activations, shown in illustration figure 2.4.

















(figure 2.4.)


Treviranus (1994) described additional variations of this block scanning, involving successively expanding quadrants, halves, and diamond facets. For large matrices of other dimensions, blocks of items of irregular sizes may be scanned in a similar fashion. However, these blocks must be pre-defined for scanning or a special algorithm must be created.  A further variation of block scanning entails arranging items on different pages or windows that are then scanned.


Making selection process more rapidly 2.5

Appropriate presentation of the selection set is important to ensure effective and efficient interaction with the computer. Shein (1988a,b) suggested that there are two key issues in relation to the presentation that drive the design of scanning access: (a) locating the desired item within the set; and (b) getting to that item to select it. Physical characteristics of the items, such as size, font, boldness, colour, precision,

letter and line spacing are important for ensuring that the desired item can be quickly located. The total number, arrangement and placement of items facilitate scanning to a desired item.  Since scanning is inherently slow, techniques have been devised within the rehabilitation field to decrease delays between selections; and/or decrease the number of selections necessary to form a message. Delays between selections can be reduced through appropriate arrangement of icons.  Specifically, distances and the number of icons scanned can be minimized based upon knowledge of the frequency of occurrence of single letters, letter diagrams and trig rams, and word usage (Vanderheiden, 1985; Vanderheiden and Lloyd, 1986; Getschow, Rosen and Goodenough-Trepagnier, 1985). These frequency-of-use arrangements are organized in relation to the scanning pattern.

For example, consider row/column scanning with a single switch as the input device. Letters can be arranged according to their frequency-of-use starting from the upper left-hand corner and radiating down and across the display from the most to the least frequent (Foulds, Balesta and Crochetiere, 1975; Heckathorne, and Leibowitz, 1985).  Basically, the number of scans steps needed to select each icon in a matrix using row/column scanning. For example, the 2nd icon in the first row and the 1st item in the second row both require 3 scan steps (1 row and 2 icons, and 2 rows and 1 icon respectively). The time taken to scan to an item can then be

calculated by multiplying the number of steps times the scan interval. Here is an example figure 2.5.


















































(Figure 2.5.)


This row/column array indicating number of scans steps to select particular icons/letters.


This calculation can be used for arranging the alphabet for frequently used letters such as A E D T U O will be assigned to positions with lower number of switch activations or scan steps required.


Vanderheiden (1985) described a simple three-stages of selection-based AAC techniques that parallels computer input. The first stage involves interpreting signals from the user through some input transducer (e.g., switch). The second stage applies some selection algorithm to increase the number of available selections unless the user can directly select each icon. All scanning methods are applied at this stage, and

the third stage maps selections to messages that optimize output.


Vanderheiden’s method is useful and relevant for this discussion of AAC access because it suggests the independence between different levels of interaction are such that if the user has difficulty with one aspect then it can be replaced or augmented with another at that same level.

Further, very limited input can be used to access a large selection set for improved production.


Special requirements for users 2.6 

There are two basic input translators generally incorporated in an AAC system: one for the keyboard, the other for a pointing device. In the case of a scanning system a translator must also be available for switch activations. Input filters enhance the input signal; reducing or eliminating undesired input signals. A selection technique uses the filtered input signals to pick icons from a selection set. Selection sets can contain alphanumeric characters, words, phrases, and other data symbols as well as commands to the system; techniques include direct selection (as in typing or pointing) and various forms of switch-based scanning.


To improve user production, input mapping can be used where the selection set contains simplified labels that map onto more complex sequences of symbols and commands. These are then translated to the application through codes required by the target application.


There are control devices that also incorporate keys that provide mouse emulation because using a separate pointing device is often quite difficult. The main reason for this difficulty is that the region where a person has greatest control is often limited and positioning two input devices within this region is often not possible.

Expanding keyboards can be done on the AAC systems, extend the dimensions of the keyboard, the size of individual keys, and the spacing between keys. This may be necessary for someone who has poor targeting ability owing to a muscular disorder such as cerebral palsy.  Miniature keyboards are suitable for people with a

limited range of movement, such as those with Muscular Dystrophy (a condition that causes muscles to waste) To operate a miniature keyboard, users hold a stylus in their hands, pointing to and selecting keys through wrist action alone.  However, bigger keys reduce the amount of keys. For example, there are 128 keys on the AAC, therefore if the key size is doubled, the amount of keys will be reduced to 64 keys, and if these keys are not big enough for the particular user, the keys are capable of doubling the size again, but the user will be reduced to 32 keys and so on, reducing the keys 16, 8, 4, 2 on the AAC system. Every time you reduce the keys, the vocabulary will be slashed and sequences will also be decreased.


Children and scanning 2.7  

In chapter one I was discussing about the child should have an AAC at the first week at school. I have found some research on scanning with children. Shein et al (1985) demonstrated that children with severe physical disabilities could learn to program sequences of cursor movements to draw. The required knowledge and the many commands to be selected, however, make this approach too slow and difficult to be generally practical. Nonetheless, it had certain qualities associated with direct manipulation of the AAC systems. The programming of movement sequences for later reuse helps provide conciseness to some interactions. Semantic directness was partially achieved through the command selection approach, which was similar to delegating others to perform tasks on your behalf (Brownlow et al, 1990b), but the use of numbers detracted from the overall directness.


The scanning screen pointer in the drawing software achieves both semantic and articulator directness lacking in the Logo command approach. The scanning pointer require minimal and brief physical and cognitive effort, it follows the image of a child drawing, and it was accomplished through consistent scanning within the limited context of a drawing program.


New scanning method 2.8


Several scanning technique were discussed early on in this chapter in my scanning research. The block scanning combined with the efficiencies of icons movements resulted in faster and less demanding access. Secondly, scanning the icons offered a feeling of ‘directness’ to users, and many more methods.


In my rigoroures research I have discovered that on the new AAC systems there is a new scanning method called predictive selection. The mechanism for this new method is for selecting the first icon, for instance - the AAC will scan all the icons with 1 of the 4 basic scanning methods.  (Automatic scanning, step scanning, inverse scanning, directed scanning)

 The 2nd scan will only scan the icons, which are linked to the 1st icon without

scanning all the array of icons. The lights automatically move across an array of particular icons and leave out the irrelevant ones, which are not associated with the first icon. The light pauses at each particular icon, which is linked to the first icon for a scan interval, momentarily activating a switch, it usually stops the lights over the particular icon. If the switch is activated when an individual icon is lit, that icon is selected. There is very little research or literature on this method. As a result I cannot discuss the benefits and drawbacks to it. I’m assuming when the user has become familiar with the predictive selection, it will turn out to be a lot quicker selecting icons.


Summary of Chapter 2   2.9

This concept remains relevant in designing alternate access systems even if a pointing device cannot be used, and provides a basis for understanding user demands and difficulties. Particular difficulties arise when switch-based scanning access methods are employed.

Many permutations of scanning configurations are possible through various combinations of switches and patterns of scanning movements. Basically, the information regarding specific scanning methods theory is absolute hogwash as they must still rely on the users judgment and it will be on trial and error to obtain the specific input device.


Who knows, one day there may be a device that can be implanted in the brain to interact with a computer that will be able to decode messages from the brain, and put it onto the display screen.  However, I do think that will be a long way off.  But I do predict that within the next ten years that there will be a computer program that will decode what a person with speech difficulties is trying to say.  By talking into a microphone, the messages will come up straight away without any delay.













Third chapter


Introduction 3.1

In the third and final chapter I will be discussing about the latest AAC systems and comparing them with the early AAC’s. Which draws some conclusions that may help in the design of a new generation of AAC systems. I will be discussing the requirements of AAC for the user.  For instance, the requirements may not be meeting the needs of disabled people.  Perhaps - the able-bodied engineers are asked to design a system for “the disabled”, however, it is very clear to them that the users have characteristics different from their own.  In fact this can be such a powerful tendency that it produces an exaggerated view of the differences, which can lead to significant design fault.  Petitto and Marentette (1991) have shown that personal feedback is critical in the development of language, and specifically in sign language. It may be that the importance of feedback continues even after primary language concepts have been acquired.

The chapter will also be investigating whether or not the current equipment is keeping up to date with the today’s technology.


Investigating the first AAC 3.2

I have compared the light talker with the latest AAC systems (pathfinder, liberator II) The basics of the characteristics are surprisingly similar. For instance, here is the characteristics and an evaluation of the mid 80s AAC systems (Touch Talkers and Light Talkers) which are 5.25 and approximately 13 inches wide by 9 inches long and stands 3.75 inches high at the back of its sloping surface. It has 2 physical interfaces consisting of a 130 keys keyboard and 40 characters by 2 lines LCD (Liquid Crystal Diope) display. However, it is really 20 characters for the speech display as the second line is for the sequence codes of the Minispeak.  The LCD display is basically a secondary backup device as the listener to confirm what the speech synthesizer output says can use it.  Here is a photo of a touch talker-: Figure 3.1.


No Photo in this version


(figure 3.1.)

The mid 80s AAC systems surface is protected by a fairly transparent plastic keyguard through which keyholes have been cut for the Touch Talker to access the keys. Implications are that the keyguard holes keep the user from pressing on any key other then the intended one. However, on the Light Talker there is not any holes cut as this is a switch-based scanning AAC system (e.g. Switch, light pen etc) For scanning there are 128 red lights for each key. Red lights are great for inside usage. Although outside usage makes it very hard to be able to see the red lights, and totally impossible to see in bright sunshine. Here is a quote from my questionnaires by Gina McMaster in the USA

“It can be a problem.  I usually try to position myself so that direct

bright light is not on my Liberator.  My mom suggested using velcro to

attach a simple "bonnet" on the top of my Liberator to shade the lights.

We haven't really had this problem a lot so maybe she will work on it in

the future.”

On the right side of the Touch Talkers and Light Talkers are a serial communication port and a serial printer port; the light talker contains 2 RS232 jacks on the side of the machine for the scanning solutions. On both of these AAC systems (Touch Talkers and Light Talkers) there are two rotating controls on the left side, one to adjust volume of the synthesized speech, however, the user can adjust the volume by the keys on the keyboard as this is built into the software. The second knob on the side is for adjusting the intensity of the LCD display. In view of the fact that the LCD display does not use twisted or supertwisted LCD technology. Therefore, the angle of viewing and ambient light greatly affect the ability to see the 2 lines of the LCD display, subsequently it requires the intensity to be controlled to maximize contrast.  The disadvantage of the LCD display is that they cannot easily be seen at all angles of view, especially in dark places, and maybe obscured by their plexiglass display covering, which regularly becomes dirty and scratched. This is even more of a problem for the user than for the listener, in view of the fact that the user needs the LCD display to confirm the message he or she is composing.


Since the machine is portable, it has internal organs called batteries that offer a normal day’s use and after the days usage should be charged overnight with an AC adaptor plug. Consequently it can be disastrous as there is a danger of losing the programmed sentences, phrases and words in the internal battery, which operates the RAM (Random Access Memory).
These mid 80s ACC systems operate by means of the Minspeak language, which maps keystroke sequences to previously programmed phrases which are synthesized into speech. Programming of these machines occurs by means of an internal proprietary speech synthesis program, and by using built-in function for control of all the keys, and can be reprogrammed as the user desires, except for the “On” and “Off” keys which are in the upper right corner of the keyboard surface. As you will know from the first chapters the AAC systems uses minspeak to locate the phrases. The inventor of minispeak Bruce Baker can demonstrate how, with some simple paradigms, one can model a large constructs with a few keystrokes on a relatively few keys. (Baker & Schwartz 1986)

However, the difficulty remains the user must remember what each icon can stand for, and so it is incumbent upon the speech therapist to choose highly evocative icons that can serve a multitude of purposes. Even though there are only 128 programmable keys on these AAC systems, Minspeak key sequences may be any length as long as there is no sequence in the prefix of any other sequence. Consequently the only length limitation on sequences is the memory of the user. However, there is no browsing mechanism by which users can see what is available in the vocabulary.


The icons are written in the on a thin plastic overlay that lies between the rigid keyguard and the keys. There are two types of overlays in regular use. Swapping from one to another is accomplished by lifting up the keygaurd and then pulling off the current overlay then popping in a new one and not forgetting to put the keygaurd back on! The first overlay is built-in (Rom) called the Fixed overlay that allows access to all programming functions. Basically, it is a control panel to manage and regulate the machine. The second overlay is called custom, as this is a programmable overlay, meaning these are made by reassigning selected keys from the fixed overlay and by programming key sequences to have sentences, or phrases, or words stored with them. The AAC system remembers which overlay was in use when it is turned off. The advantage of this is that the customer overlay can be the one recognised by the AAC system when it is turned on without the user’s having to go through any preparatory key sequences for accessing a particular overlay.

These fixed overlays represent each of the device functions on a separate key. Therefore, these device functions include those necessary to generate custom overlays. Certain functions are usually kept on the fixed overlay, such as male or female speech option.  The user should not need to change this option in their lifetime. Anyway, the most important functions are those that control the mode of use of the custom overlay, and many of these are transferred to a ‘special’ key of the custom overlay so that they can be used by the user as well as by a speech therapist, or the person who programs the phrases into the machine. If the user is not capable of accomplishing this task for updating custom overlay phrases, keys (automatic keystroke prefixes), keys that allow entry of phonetic spelling to produce more accurate speech synthesis along with normal spelling for the speech display. For instance, if the user typed in ‘pint’ the speech output will be ‘pin’ as a result the user will have to phonetically spell the word pint as ‘pignt’ to get the correct sound. 

Keys allow selections of keystroke sequences for phrases to be stored, and most important is the keys to represent each letter of the alphabet as well as a few punctuation characters. Additional function keys control the user’s ability to type in words in the spell mode. Consequently, this is good for the users, especially for the young ones as it is good spelling practice, to select stored phases by using keystroke sequences in the communication mode.


From Winogred and flores 1986, consider the phenomenology of tool use and the effect of breakdowns when a tool becomes ineffective with respect to its intended goal and is no longer transparent to the user.



Investigating the latest AAC 3.3

So far we have discussed the characteristics of the first 2 models (Touch\Light talkers), which were manufactured by Prentke Romich Company. Now we are going to look at the Pathfinder (below), figure 3.2. as it only came on the UK market a few weeks ago.


(figure 3.2.)


Here are the characteristics of the Pathfinder. It is approximately 12 inches wide, by 9 inches long, and 3 inches deep it also weighs 4.5lb.

Therefore, all three of the dimensions are 1 inch less than the 80s AAC systems. In my questionnaires, I asked if they would like the AAC system smaller, and surprisingly the majority said no. Here is the pie chart, figure 3.3.


(figure 3.4.)

Here is a quote from Graham Clark “Not a must------remember the icons need space.”

However, the switch-based users did say yes! I think this is because they don’t have to press any keys, unlike the key users. Consequently, it would be problematical if the AAC was smaller – this will reduce the key size.

The Pathfinder surface is also protected by a fairly transparent plastic keyguard through which keyholes have been drilled to access the keys. However, it is a switched-base too, meaning that you can access the pathfinder by keyboard or accessing the keys from scanning with switches (single and double switch and joystick options) as the lights are at the top of each key. Or the user can even access the AAC system via the touch screen display. The parameters can also be adjusted to create the most effective access to the device. Auditory prompts aid individuals with visual impairments. Pathfinder is also compatible with many other input products.

The Pathfinder is a half of VGA display which contains active matrix touch screen with vivid 256 colour capabilities. There are fonts on the Pathfinder which can be displayed in three sizes and up to 10 lines of text 55 characters wide can appear on the screen.  At the bottom of the screen there is an 8 key activity row that appears at the bottom of the display, this is for getting to the noun icons straight away. Or if the user is trying to spell a particular word, this bottom row on the display will be a word prediction choice. The Notebook, Calculator and Clock will also appear at the bottom of the display.  Here is an example of the display, figure 3.5. 3.5.


The battery life will provide over 10 hours of continuous use, and the Pathfinder offers  a much improved synthesized speech than the first AAC systems, and those only had space for around 1,000 characters, compare this memory capacity to the Pathfinder memory capacity and it holds thousands of words totalling 20mb.

There are lots of speech options, from a range of age and gender to appropriate voice options.  There is  also a digitised speech option for adding fun sounds, songs or additional languages.


The pathfinder control panel previously known, as ‘fixed overlay’ is built-in the AAC system and the user can access the control panel through the matrix touch screen.  There is a notebook function which makes it simple to write letters or take notes, create lists or even write assignments. There is a second new function called the text editor, it lets the user add, delete, search, move or replace text. Added functions include calculator and clock, plus a computer emulation mode that allows Pathfinder to imitate a computer keyboard by infra-red. This infra-red device can operate Television, video, stereo, and any other devices that can be operated with an infrared remote control. The Codes are stored into the device in the same way vocabulary is, and when the appropriate keys are activated, it will send the signal to the TV, VCR, etc.

First AAC’s vs Pathfinder 3.4

Here is a summary table to compare the Pathfinder to the Touch\Light Talkers-: in the figure 3.6.



Price £6,500

Price £3,000

Size 12" x 9" x 3"

Size 13" x 9" x 3.75"

Weight 4.5 lbs

Weight 5.25 lbs

Half VGA Active Matrix Touch Screen

2 Lines LCD

Maximum 10x55 characters

Only 40 characters

256 colours display

Only Black

Three fonts sizes

Only one size

128 location is standard   with an extra 8-key Activity Row

128 location is standard

10 hours of battery continuous use

4 hours of continuous use

20 Mb memory card

1,000 Characters only

10 voices and over 15 minutes recorded digitised speech

Only 2 voices (male or Female)

Scanning Methods

Row/column and column/row
Quarter-row column
Directed or Automatic


Scanning Methods

Row/column and column/row
Quarter-row column

Macro capabilities
Memory saving/loading
Icon importing
Activity Row



(figure 3.7.)


As you can see the AAC technology has come a long way from the first AAC systems in 1986. There is one thing with that the light talker and Pathfinder have in common, they both have red lights for the scanning methods. At the road show at Frederick Holmes School, I asked one of the engineers from the company, why all AAC systems have red lights? He replied, by saying it could be that red lights are cheaper than other coloured lights. In my experiments, I have found green lights are visual in the sunshine. Maybe the next new AAC system will have green lights!


Pathfinder vs Pc 3.5 

However, if you compared a PC to the current state of the art PC of today, the AAC technology is clearly not keeping up to date with the current trends.

For instance, you can buy a state of the art Laptop Computer with up to date technology (AMD K6-2 450MHz processor, 32Mb SDRAM, 4Gb hard disk, 12.1" dual scan display, 24x CD-ROM, V.90 56k modem, 2.0Mb video memory, Plug 'n play BIOS, Built-in stereo speakers, Rechargeable lithium-ion battery) this is better technology and is a lot cheaper than pathfinder as the laptop is under £999.


However, the AAC systems are specially designed for a communication aid and there have been significant advances made in the quality of speech that is synthesized from text. A normal laptop would not be suitable for a communication aid unless a computer programmer wrote similar software to the AAC software in these systems, however over the last decade, there have been many different software packages which are currently available.

A dedicated communication aid  (AAC) is a device that has been purposely built for that job, and does nothing else. A computerised communication aid is a standard computer (Laptop etc.) running a piece of specialist software providing similar characteristics of the dedicated communication aid, with the added function of being a computer as well. From this basic acknowledgement of difference, I can point out some typical pros and cons.


The pros and cons for an AAC system 3.6

They are lighter to carry and a 10 hour battery life is normal. They do not require time to boot up, significantly, they are available immediately when you switch it on. The operating system seems a lot more stable than Windows. Windows CE includes an effective synchronisation system that lets you keep files on the AAC system in step with those on your main PC. This makes transferring files to the main computer and  printing very easy.  However, the AAC systems are not very flexible with fixed interface and not fit for any other purpose.


Pros and cons on a laptop 3.7

Normal laptop PCs are powerful with scope to upgrade, and they are typically fragile and not always suitable for harsh environments of a wheelchair user. They are flexible to change whenever necessary. However, laptops can be larger and heavier but have  better voices and clearer screens. But computers crash more! The biggest problems are the personalisation Battery life of only 3 hours and the time it takes to boot up.

Here is a statement from Barry Romich, at the Prentke Romich Company-:

First, our business is not focused on technology, but rather on language.  People can

talk faster and more fluently with our 1984 vintage Touch Talker than with

the latest Pentium computer.  This is because the power of communication

comes largely from the language representation method employed.  Semantic

compaction (Minspeak) has been demonstrated as being far more effective

than alphabet based systems or single meaning pictures.  The Liberator

continues to be the most powerful AAC system available today.  Virtually

every high performance user of AAC is on a Lib.  The Liberator was

introduced around ten years ago.  The latest product release, Pathfinder,

is based on a WindowsCE platform, so we're not far behind the technology



Future for AAC system 3.8

In my questionnaire, 80% of the users would like a mobile phone on the AAC system, to talk and to send text messages.  Figure 3.8.

(figure 3.8.)


On Kathy McMasters questionnaire it says, I would love to have a thesaurus in my Liberator to help me use different words when I am composing a letter.


In the questionnaires everyone thought it would be a good idea for two screens, one at the front and one at the back. Especially when the user is around a 

 table in a noisy room. For instance in a pub or disco? Here is two of the replies,” yes. I think it will be a good idea, because then I would talk more with my liberator.”

“Yes, because if I was writing something out and the person opposite could see what I was writing before I had finished, I would not have to carry on writing what it was I was  asking them, therefore saving me time.”




(figure 3.9.)



There is so much that could be done to improve the quality within the current technology for the AAC systems. I guess all improvements are related to the issue of money for research.






















·        In  chapter one we were discussing social and interactive implication of the AAC users. The AAC systems has fundamentally improved the quality of life of people with speech difficulties. It allows the person to communicate in the presence of a none translator and others, such as family members or close friend, who may able to decode the message. And for the people with a nonvocal impairment (100% no speech), the advantages are obvious. 
I believe that any person with speech difficulties should not be deprived of the use of an AAC system.


·        In the second chapter we discussed a problematical topic called scanning. The structure, design, and view of the text selection.  The task for each scanning strategy created a  different user demands that induced distinct performances. One of the drawbacks associated with scanning is that, in some circumstances, the user must wait as scanning proceeds across many items. An enhancement can be applied to all of the scanning strategies to reduce the scanning time. The individual motor, cognitive, and visual-perceptual abilities and their limitations due to disability, may have as much influence on the effectiveness of any scanning strategy, as the optimally used merits or disadvantages depending on the particular user.


·        In the final chapter, I discussed about the latest AAC systems and compared them with the early AAC’s  and with the current technology, as personal computers have become progressively more common in the area of communication over the last decade, and many different software packages are currently available. The benefits of a computerised communication aid are wide ranging, but probably the most notable is the flexibility. The ability to create and manipulate vast amounts of options makes it one of the more preferred choices for many communication specialists. A major drawback to date has been the portability of a computer-based system. Typically the weight, size and cost has made computer based aids available to the minority rather than the majority, but as technology improves we are finding more products appearing which are based on this technology, yet have the same physical characteristics of the more traditional dedicated communication aids.


·        This AAC system design principle has been improved since the first AAC models. They have validity as the end user inputs the design process. The PRC company now has a disabled person in their design process.  They pay attention to users nowadays as end users are the only ones who know best what they need.


·        Making AAC systems accessible to users with disabilities is a challenging problem requiring the co-operative efforts of the company.  The future seems brighter for communication all over the world, and the AAC systems should be accessible to all regardless of money, as I feel it should be free on the NHS because the machine is an aide to help the person communicate.


·        On the NHS a person can received hearing aids, glasses, special shoes, wheelchairs/sticks, etc….  So why not provide a speech synthesiser? I think speech synthesisers are essential to a person who requires them.  If a person was hard of hearing and also had a very poor speech, he/she would obtain a hearing aide to allow the person to help hear people talk to him/her, but he would find it very hard to reply back without a speech synthesiser! 


·        The speech synthesiser is important and essential to the quality of a  persons life, so I think it should be free on the NHS as it’s an aid for communicating!



































List of Figures


Icons layout, figure 1.1


Results from “Do you like to say your sentence/word after you have  composed it, or do you like the person to read it as you type?” figure 1.2.


WIVIK software, figure 2.1.


element scanning, figure 2.2.   


Rows of icons are arranged in a two-dimensional matrix and are scanned row-by-row from the top down. figure 2.3.


block scanning approach,  figure 2.4.


steps times the scan interval. figure 2.5.



Photo of a touch talker-: Figure 3.1.



Photo of a Pathfinder, figure 3.2.



Results from “Do you think the size of the talker needs to be smaller?”, figure 3.3



Display of the pathfinder, figure 3.5.



Comparing the Pathfinder to the Touch\Light Talkers, figure 3.6.


Results from, “Use a mobile phone for speaking and sending messages with the

talker?” Figure 3.8.


Results from, “Do you think it would be a good idea for two screens, one at the front and one at the back? Especially when you are around a table in a noisy room. For instance in a  disco.” Figure 3.9.












Adams, K. and Abbott, S. (1991). A model for designing an alternative access system for the Macintosh.


Beukelman, D. R., and Yorkston, K. M. (1984). Computer enhancement of message formulation and presentation for communication augmentation system users.


Bowe, F. (1985). Personal computers and special needs.


 Bowe, F. (1987). Making computers accessible to disabled people.


Brandenburg, S., and Vanderheiden, G. (1987). Communication, control, and computer access for disabled and elderly individuals.


Brownlow, N., Shein, F., Thomas, D., Milner, M., and Parnes, P. (1989a). Direct manipulation: Problems with pointing devices.


Alistair D.N. Edwards. (1995)Extra-ordinary human-computer interaction: interfaces for users with Disabilities.


Dermot Browne, Peter Totterdell, Mike Norman. (1990) Adaptive user interfaces.



Buxton, W., Scadden, L., Foulds, R., Shein, F., Rosen, M. J., and Vanderheiden, G. (1986). Human–Computer Interaction.


Cairns, A., Smart, W., and Ricketts, I. (1994). Alternative access to assistive devices.


Cantor, A. (1995). Repetitive strain injuries (RSIs) at the adapted keyboard:


Speech Synthesis Technology for Disabled People by Alistair D N Edwards


Gunderson, J. A., and Vanderheiden, G. C. (1988). On-screen multiplexed keyboard for transparent access to standard IBM PC software.


Horstman, H. and Levine, S. (1990). Modeling of user performance with computer access and augmentative communication systems for handicapped people.


Hutchins, E. L., Hollan, J. D., and Norman, D. A. (1985). Direct Manipulation Interfaces Augmentative and Alternative Communication.


Lee, K., and Thomas, D. (1990). Control of computer–based technology for people with physical disabilities


Lee, C. and Vanderheiden, G. (1988). Accessibility of OS/2 for individuals with movement impairments: Strategies for the implementation of 1-finger, Mousekeys, and software emulating devices using device drivers and monitors.


Marsden, R. and McGillis, G. (1991). An alternative approach to computer access: The ADAM interface for the Macintosh.



McDougall, J., Knysh, B., Sainani, D., Shein, F., Lee, K., Milner, M., and Parnes, P. (1988a). Computer-based technology for individuals with physical disabilities: A strategy for developers of microcomputer manufacturers


McDougall, J., Knysh, B., Sainani, D., Shein, F., Lee, K., Milner, M., and Parnes, P. (1988b). Computer-based technology for individuals with physical disabilities: A strategy for developers of alternate access systems


Moynahan, A., and Mahoney, R. (1995). Single-switch direct manipulation.


Closing The Gap Hardware and Software Resource Guide, 1996


Madison, WI: University of Wisconsin, Trace Research and Development Center.

Schauer, J., Novak, M., Lee, C., and Vanderheiden, G. (1990). Transparent access interface for Apple and IBM computers:

Websites (Prentke Romich Company main website) (Prentke Romich Company International website) (minspeak)   (Louisanna Assistive Technology Network)   (Augmentative Communication On-Line Users Group (ACOLUG))   (creative communicating)  (Ability net)   (Alliance For Technology Access)  (wivik) (Adaptive Computer Equipment for Kids with Special Needs) (Liberator) (Closing the Gap)  (Slater Software)  (Special Needs Equipment Co)  (Saskatchewan Abilities Council)   (United Cerebral Palsy) 





Closing the gap – Computer technology in special education and rehabilitation, February / March, 2000. Volume 18 – Number 6