DeafBlindness

Demographics

Between 0.2% to 2% of the world's population is DeafBlind.

Medical Details

Range of Presentation

DeafBlindness is a spectrum. Most people who are DeafBlind are not completely Deaf and completely Blind, but rather are placed somewhere on the spectrum of Deafness (hard of hearing to total hearing loss) and Blindness (low vision to total vision loss).

For example, a person who has vision loss in one eye and one ear might identify themself as DeafBlind.

Children who are born DeafBlind and adults who become DeafBlind will have different challenges. Notably, in the development of language and capacity for navigating spaces physically. For example, a DeafBlind adult who was raised Deaf and lost vision at a later time is more likely to use tactile signing than a DeafBlind adult who, as a Blind child, went through Blind education and learned written communication skills through Braille.

Causes of DeafBlindness

According to Barbara Miles' Overview of Deaf-Blindness, a linked BoK resource, DeafBlindness can be caused by Usher Syndrome, and developmental conditions like Down's Syndrome, Trisomy 13, CHARGE, and fetal alcohol syndrome. A person can become DeafBlind after bad cases of encephalitis and meningitis, after a stroke, and after they are asphyxiated or suffer head trauma.

According to Deafblind International, a linked BoK resource, some cases of DeafBlindness are caused when a person is a fetus. When a fetus develops their eyes and ears, those are actually in a common area during the first 12 weeks of pregnancy. A gestating parent who has rubella, cytomegalovirus (CMV) or toxoplasmosis during this time might produce a DeafBlind child.

For example, in the case of CMV, a common virus that is spread primarily by asymptomatic carriers, the rate of serious disability for the fetus is only about 5%.

Toxoplasmosis is a parasite that comes primarily from cat dung. Gestating parents have a 40% chance of passing it to the child through the placenta. The toxoplasmosis may cause deafness and damage to the retina that might not actually start causing issues with vision until the affected person is in their late teens.

DeafBlindness can also result in very rare disease profiles like Goldenhar Syndrome (facial deformity) and Alstrom Syndrome (life threatening, degenerative, and hereditary condition).

A Communication Disorder?

According to Barbara Miles' Overview of Deaf-Blindness, a linked BoK resource, DeafBlindness interferes most strongly on one's ability to develop language skills. Cut off from sound and sight, traditional approaches from Blind education and traditional approaches from Deaf education are typically not sufficient enough to have 'comparable language stimulation.' Children born DeafBlind will have trouble navigating physically through spaces.

The emerging trend of DeafBlind education through the Protactile approach is a new emerging paradigm that the BoK doesn't touch on. DeafBlind children have historically been taught ASL (a visual language) or English (a sound language). By teaching a tactile language like American Protactile, perhaps we'll see an increasing institutional capacity to meet the language needs of DeafBlind children.

Accommodating DeafBlindness

DeafBlind individuals each have unique solutions to the barriers they encounter in the world. As the severity and progression of symptoms differ so widely, there really isn't a single approach that will be appropriate for everyone.

Let us address the range of solutions that might be used for the biggest barrier: the communication barrier.

Communicating while DeafBlind

People with total DeafBlindness have two modes for communication:

• Tactile sign. There are different strategies here. I am most familiar with what happens in the Northern part of North America. Some will use very slightly adapted ASL. By holding the other person's hand as you sign, a Blind person can perceive a lot of ASL information tactilely. But ASL also relies on facial expressions and other things that aren't so natural to a tactile-only world. Therefore, some will use the new tactile-first language, American Protactile. While it descends from tactile ASL, Protactile isn't afraid to part ways with the visual nature of ASL when needed and increases the amount of touch that is socially considered as being appropriate. There are also tactile cues and orientational systems that a support person (typically referred to as a DeafBlind Intervenor) might use to describe the layout of a room, the responses of people in an audience to a DeafBlind individual. DeafBlind people with additional developmental disabilities might rely on less complex tactile communication systems developed by the people who support them.
• Braille. Texts can be accessed through Braille and the internet can be accessed through a refreshable Braille display. Face to face communication can be accomplished nowadays by two people sitting together, using the computer to type and read Braille as needed. A range of fancy Braille contraptions have been released that realize this setup in different ways. A DeafBlind person can directly connect a refreshable Braille display to the output of a live-captionist or transcriber to access the content of an real-time event.

Considerations in ICT

Descriptive transcripts are the only meaningful way a person with no functional vision or hearing can access time-synchronized media. Not captions.

In order to access a computer, a person might hook up a refreshable Braille device to a computer with screen-reading software installed. There are also Braille computers specifically designed for these kinds of use cases. Material can be printed into Braille for a person to read.

Haptic alerts and feedback are preferred to audio-visual alerts and feedback.

There are lots of specialized devices that arise, but some low-tech solutions also exist. For example, use of a communication card or booklet to use during small predictable interactions. A person might offer a small card that has their coffee order and informs the worker that they are DeafBlind, so please tap them when the order is ready.

Amy Mason, a linked Body of Knowledge source, reports that sometimes screenreaders are not really designed to be operated by DeafBlind people. A DeafBlind person requires assistance to pair a refreshable Braille display with a computer like a screenreader. The advantage of specialized devices is that this step can perhaps be circumvented. Speaking in 2024, Mason noted that 'BrailleBack,' the version of TalkBack optimized for Braille output, was 'badly hampered' and that one should 'steer far clear of Android.'

Physical Navigation

Like a Blind person, a DeafBlind person may use a cane or guide dog to navigate independently. They benefit when the environment is designed with tactile navigation aids. They also may use a support person or DeafBlind intervenor to navigate.