ALS - Amyotrophic lateral sclerosis

The disease & symptoms

It is currently assumed that a certain molecule does not function properly in the muscle disease ALS.
This molecule normally breaks down damaged proteins in the motor nerve cells in the brain.

In ALS, proteins are deposited in the nerve cells and interfere with the transmission of brain commands to muscles.
Over time, muscle strength decreases and even seemingly simple movements such as pressing the buttons of the computer mouse become difficult.

First symptoms and problems

At first, ALS is usually noticed by muscle twitching and decreasing strength in the arms and hands or legs.
The diagnosis is usually made at this time.
The patients are usually very inventive at this time and help themselves as good as possible with tricks over the disability.
Since most patients use a computer, they notice the first serious limitations.
Suddenly it is difficult to lift your hands to the computer keyboard and press down your fingers on the keys.
Double clicks are particularly frustrating. You have to press the mouse button quickly one after the other.
Especially this fast muscle movement is difficult for ALS patients.

Many ALS patients therefore use the popular OnScreenKeys on-screen keyboard.
This screen keyboard was specially developed for people with motor disabilities.
OnScreenKeys can be operated completely via the computer mouse, so that the patient does not have to hold his hands laboriously over the normal computer keyboard.
It is sufficient to hold the mouse pointer over a key on the on-screen keyboard. The key is automatically clicked after a settable time.
OnScreenKeys can also be used to "simulate" mouse clicks.
The user no longer has to laboriously press the buttons of the real computer mouse.

Head instead of arms

As the disease progresses, the patient's mobility decreases.
Even small movements of the hands become more and more difficult.

In some cases, however, head movements are even more possible than arm movements.
A so-called "head mouse" is a good choice here.
With a head mouse, the patient moves the mouse pointer across the screen by movements of his head.
If the user moves the head to the left, the mouse pointer on the screen also moves to the left.
This way, for example the OnScreenKeys on-screen keyboard can still be operated.

At this time, however, many users switch to the larger "OnScreenCommunicator" communications software.
OnScreenCommunicator offers additional functions specially designed for the operation of a head mouse.


An alternative to a head mouse is the so-called "scanning".
In some cases, despite severe movement restrictions, the patient can still operate a particularly easy-going switch by minimal body movements (e.g. via a finger or toe).
In "scan mode", a selection box in OnScreenCommunicator moves from top to bottom through the cells of the surface.
The patient stops the selection box by pressing the switch. The selection box then moves from left to right.
By pressing the switch again, the patient now triggers a click. This allows the patient to select a cell in OnScreenCommunicator.
This way, the patient can either click on ready-made sentences and have them spoken by the computer voice.
Or the patient can select letters on the keyboard interface in OnScreenCommunicator to write new sentences, which he can then of course also haven spoken by the computer voice.
More about scanning

Eye tracker

As the disease progresses, the use of the hands or head to control the mouse cursor becomes too strenuous.
The solution to this problem is the use of so-called eye control:
A special camera is directed at the patient's eyes. This camera observes the patient's viewing direction and controls the mouse pointer exactly where the patient is looking.
OnScreenCommunicator shows the patient a keyboard that can be controlled via the eyes.
If the patient looks at a letter on this keyboard for a while, this letter is clicked and written.
In this way, the patient can write whole sentences with his eyes. The sentence can then be pronounced via the computer voice.
Thus communication is only possible via the eyes.
In order to make writing texts as fast and convenient as possible, a "double word prediction" has been integrated into the OnScreenCommunicator.
The OnScreenCommunicator offers the most likely next word after writing a word.
In addition, a sentence prediction and freely assignable text fields make writing even easier and faster.

Environmental control

Via a so-called "environment control", the patient can operate his technical equipment, such as the television set, windows, blinds, radio, etc.
The environment control is operated via the OnScreenCommunicator.
Thus via the OnScreenCommunicator interface, the patient can open and close his windows, lower and raise blinds, operate his television and much more.