I was asked what sort of lighting I would
recommend for the home of a child with Sensory Processing Disorder. People with
Sensory Processing Disorder process light differently than the general
population and all people with Sensory Processing Disorder will not process
light in the same way. What I offer here is my experience in the hope that it
can be…enlightening.
If you ask, I can certainly get into some detail or direct you to
sources of information with the details of things like mercury verses
electronic ballasts and binocular verses monocular vision and refraction verses
reflection of light. I find it interesting…and I find that most people find it
mind numbingly boring. So, for this post, I'll toss in some “Did You Know?”
references, but other than those I’ll try to stick to the basics of my
experiences.
Lighting issues, especially flickering
lights, intense light, contrasts, and certain colors, can cause in seizures, headaches,
nausea, dizziness, fatigue, blurred vision, eye strain, reduced visual task
performance, and a continuous level of distraction and stress in people without
sensory processing disorders. For people with Sensory
Processing Disorder, it is often best to assume these results are not just possible,
but likely and to proactively assess and address common lighting issues when
possible.
I’ll mention some of the issues that have had the
most noticeable effect on me and what I did to avoid or at least lessen the
source of the problem. Lighting issues that may not usually bother me will be more
likely to cause stress if I am tired, I have low blood sugar, or I am exposed
to the issue for an extended time. I suppose this is true of almost anyone and
anything, but I still need to remind myself from time-to-time, so I’ll mention
it here too.
Flickering/Flashing Light
Problem
Since flicker or flashing light is a problem
that many people know about and in some ways the most common, I’ll start with
this. Many people with some knowledge of autism and sensory processing issues
have heard the frequently repeated fact that people with sensory processing
issues (including most autistic children) can become stressed around bright
lights and the flicker of florescent lights. And many people accept that as the
full scope of the issue when, in fact, the issue is much more complex. Reactions
to flickering or bright lights may depend on the light’s brightness, the contrast
of the light or light source with the surrounding area, distance between the
individual and the light source, whether the person’s eyes are open or closed,
how often it flickers or flashes and the wave length of the light. I won't get into all of the factors. I mention them to make the point that it's just not that simple.
Often people will refer to the flicker of
fluorescent lights at the villain of light flickering. (And yes, I find it annoying
when someone just says this because they heard it or read it and not
because they have any experience or knowledge of the facts...because the facts are changing and so the truth is changing on this issue.) This is mainly
because older fluorescent lighting systems used magnetic ballasts that allowed
for varying electrical loads (and a humming noise that some people could hear)
and operated at a frequency that caused a flicker that many people could see. New fluorescent lamps usually use electronic ballasts that
operate the lights at a much higher frequency (and make much less noise). Although
the flicker may not be visible, it can still be detected by some people, which
can make for a frustrating time when trying to identify the source of stressors.
Some people think that they can avoid the
flicker problem by switching to LED lights. Not so. LED lights also flicker. Often the
flicker of LED lights is worse than the flicker of new fluorescent lighting
systems. Halogen lights can also flicker. Old bulbs and old or faulty light
fixtures tend to cause more flicker problems. However, sometimes it’s a technology
issue. As the technology gets better, the flicker problem is slowly going away
on fluorescent, LED, and halogen systems.
The combination of lighting fixtures and bulbs
is extremely complex. If someone in your home is particularly sensitive to
flickering, incandescent light, while not the choice of environmentalist, is an
option for a light source that does not flicker.
Flicker doesn’t just come from light bulbs. It also comes from some computer
monitors, televisions, and video games. It is caused by moving
water (aquarium, pet’s water dish, etc), light through leaves in trees, ceiling and other bladed
fans, and a myriad of other sources. I include light through window blinds with flicker because,
with an estimated 30 percent of people, patterns of alternating
dark and bright areas have the same effect as flickering/flashing light if
there are more than 5 pairs of stripes (if they are moving) and more than 8
pairs of stripes (if they are still). Look for and address these sources of flicker too.
Did you know?
Brightness enhancement, also known as the Broca–Sulzer phenomenon, refers to the fact that a flash of light of short duration may appear up to five times brighter than it looks when it is seen as a steady light. So the flicker/flash issue may be related to the brightness/intensity issue.
My Solution
I had new recessed lighting
fixtures with dimmer switches installed in my kitchen and living room. I use the
new compact fluorescent bulbs and I cannot see any flicker and do not observe
any stress from them. I tried LED lights, but they flickered when the dimmer is
set on low intensity. I use incandescent bulbs on a dimmer switch in my dining room chandelier and
in my bedrooms. I use LED lights in the bathroom as we do not have dimmers
there so the flicker is not a problem for me.
Cathode ray tubes in old
computer monitors were the cause of flicker. Now I have newer monitors
that do not use that technology (if you still have an older monitor, you can set the "refresh rate" higher to reduce the flicker) and flicker is not an issue. Same with
televisions. However, there is still the issue of what is showing on the screen
flickering. Some things that I have done that help with this issue are:
- sit far back from the screen (less of the visual field is
occupied by the flashing, so the brain is not as affected by the stimulus)
- reduce the brightness of the screen (there is a control
for this on most televisions)
- keep the lights on about the same brightness as the screen (to
reduce the contrast between the screen light and the background light)
Did You Know?
If you cannot
reduce the flicker, leave, or remove the source of the flicker, it usually helps to
cover (not just close) one eye if the flickering is of short duration; some people wear an eye patch when they know they will be around a flicker for a long time.
Placement of light sources
Problem
You can't see it from all angles unless you see it from all angles.The placement of your lights may be fine for you, but for someone of a different height, it can be a source of great discomfort. If you have small children in your home, this is an issue you may want to consider. For example, sometimes you will see a lampshade where a shorter person will be looking right at the bulb. You may have recessed lights or track lighting that is always above your line of sight, but when the children look up at you, they may then look right into the light. You may have your horizontal window blinds set so the sun does not go into your eyes, but it is directed into the shorter person’s eyes. They may not be able to tell you or may not even realize that this is affecting them.
Solution
Turn on all the lights, get at about the height of the people in your home you are concerned for, and go around your
home. Do this again for natural light by opening window coverings at different
times of the day and making the same exploratory trip in your home. See the sources from the point of view of the shorter (or taller) person. Make adjustments where needed. You can simply alter the placement of the light sources in some cases or use frosted light
bulbs, baffles, shades, and other items that are sold to reduce or eliminate these
problems.
Placement is also important
as it relates to contrast and reflection. I’ll address that in the corresponding
sections.
Intensity and Brightness of Light
Did You Know?
Problem
People with Sensory Processing Disorder often
experience light to be brighter than other people perceive it to be. For some, it
takes longer to become comfortable switching from a dark area to a light area. In
addition, bright lights may be more stimulating and being in a dimmer
atmosphere more relaxing. Of course, this may be true of most people, but it is
often especially true of people with sensory processing issues.
My Solution
Dimmer switches and night lights. I have dimmer
switches in the kitchen, dining room, and living room. This allows me to have a
lot of variation in the level of intensity of the light as various
times. When just getting up in the morning, I use dim light increasing gradually and
the opposite in the evenings. The lights
inside my home can vary in intensity depending on my mood and needs. I also have different lighting sources with different intensity bulbs in them, 3-way bulbs, and window coverings that allow for variable light entry.
Brightness is also a consideration under the topics of flicker, reflection/glare, and color.
For next time...
In Part II, I'll writing about color, contrast, reflection/glare, light sources and their relationship to each other, and how these topics relate to light and Sensory Processing Disorder.