You
will need:
* A table with a large surface.
* Lighting that is similar to that of the patients
classroom or office.
* Overlay Assessment Pack, including Visual Materials 1 and 2, and 20 A5-sized
overlays.
* Overlay Score sheet, including Chart
Setting
up
There are ten different colours of overlays,
two A5-sized overlays for each colour. Arrange the two overlays of each colour
in 10 piles on the surface of the desk where you can reach them easily.
NOTE that each overlay is matte on one side
and gloss on the other.
NOTE that the Chart refers to single overlays
and combinations of two overlays. The outer ring in the Chart and the lower
half of the central circle refer to double overlays. Double overlays are formed
by placing one overlay on top of the other (it does not matter which overlay in
the pair goes on top).
There are 18 colours formed from double
overlays (19 including the double grey). These colours are darker and stronger
(more saturated) than those provided by single overlays.
NOTE that the 19 combinations of overlays
shown in the Chart are the only combinations that need to be tested. Other
colour combinations are possible, in fact there are 90 possible combinations of
the 10 overlays, but the combinations shown in the Chart are sufficient to
sample colours systematically and efficiently. You do not need to try other
combinations. The chances of any of these other combinations being preferable
are very slight.
There are two passages of text labelled
Visual Material 1 and Visual Material 2. Use Visual Material 2 (the smaller
text) unless the child finds the text very uncomfortable to look at, or cannot
see the letters or the spaces, in which case use Visual Material 1 (the large
text).
Stage
1. Identifying good overlays
* Take a single overlay and place it over
half the page of text. Start with Number 1, which is Rose. Cover the left side
or right side of the page with the overlay, choosing the side at random. Ask
which side is clearest and most comfortable to see. (Comfort is more important
than clarity.)
* Mark the Chart box with a +, 0 or -. If the
side on which the overlay is placed is chosen as the clearest, then place a +
in the box in the Chart corresponding to that overlay. If the overlay makes
little difference to the clarity or comfort of the page, enter a 0 in the
Chart. If the overlay makes the text more difficult to look at, enter a -.
* Chose which way up. If the overlay makes
the text clearer or more comfortable, check which way up (matte or gloss
uppermost) is best. Use this orientation subsequently for all overlays.
* Repeat the process. Continue until you have
tried each of the 10 single overlays once.
* Check. If none of the overlays has been
marked + then stop testing now.
* Continue with the double overlays. If any
of the overlays has been marked +, then try each of the double overlays, shown
in the outer ring. If you present them in the order shown you will reduce the
confusing effects of colour adaptation. To save time, you need only try double
overlays with boxes that touch those of boxes already marked +.
Stage
2. Finding the best of the good overlays.
*Compare good overlays beside one another.
Take one of the single overlays marked with a + and place it over half of the
text (left or right side). Take another of the single overlays marked with a +
and place it over the other half of the text. The overlays should be placed
side by side, so that they abut one another and there is no gap between the
two. One overlay should cover the left side of the text and the other the
right. Vary which one goes on the right and which on the left from trial to
trial.
NOTE During testing you may need to compare
single overlays with a pair of overlays of the same colour You do not need
three similarly coloured overlays to do this. Simply place one overlay over the
entire text, then place the other overlay on top so that it covers just one
side of the text (the left or the right at random). For example, simply by
placing the Rose overlay over the entire text, and placing the appropriate
overlay on top, over one half of the text, you can compare a Rose overlay with:
1. a combination of two Rose overlays, one on top of the other; 2. a Rose
overlay with a Rose and Orange combination; 3. a Rose overlay with a Rose and
Pink combination.
* Annotate the chart. Ask the child which
side is the clearest and most comfortable to look at, as before. Then take all
overlays off the page, replacing them in their piles, and put an oblique line
(/) through the box in the Chart corresponding to the colour that was not
preferred. If the child was uncertain, leave both boxes unmarked, and return to
them later.
* Repeat the process. Take another pair of colours (single overlays or
combinations of overlays) marked with a +, place them side by side as before,
and ask the child to choose the better of the two. Then replace the overlays in
their piles and put a / through the box of the colour that was not preferred.
Repeat this process, until there is only one box that has not been lined
through. By successive elimination you have chosen the best overlay colour.
NOTE that it is advisable to vary at random
the side of the text on which the overlays are placed.
* Prepare the overlays for the patient. If
the patient consistently prefers a particular combination of two overlays
rather than a single overlay, the overlays should be adhered to one another by
adhesive tape along both short sides. This will ensure that they are used as a
pair, and the tape does not mask the overlay.
Stage
3. Confirmation of choice
It is a good idea to check the consistency of
the choice if there is any doubt. You can do this by taking the overlay or
overlay combination that has been selected as best in Stages 2 or 3, and
comparing it in turn with all the overlays you originally marked +.
A childs responses
may be equivocal. They may appear to be inconsistent. If you are uncertain, it
is helpful to arrange for a weeks trial usage of the
best overlay or combination of overlays to see whether the child spontaneously
uses the overlay.
You can assess whether the overlay has a
beneficial effect on reading speed using the Rate of
Reading Test (IOO Marketing Ltd). Individuals who use the overlay without
prompting and continue to do so long-term usually read faster with the chosen
overlay.