Switch access

Also called Switch control, Single-switch access, Switch use

Operating a whole device with one or two buttons, placed wherever the body is most reliable. Slower than touch, but it needs so much less.

What it is

Switch access means the person operates the device through one or two switches instead of touching the screen. A switch is just a button, though it might be pressed by a hand, a head, a knee, a foot, a cheek, a breath or an eyebrow. The device then does the work of offering choices, one at a time or in groups, until the person presses to pick.

It is an indirect method. The person never points at the cell; they say yes when the device gets to it.

Who it can help

People without a movement accurate enough for direct selection but with at least one movement they can make on purpose, repeatedly, without pain. That covers a large number of people with cerebral palsy, later-stage motor neurone disease, spinal muscular atrophy, muscular dystrophy, brain injury and locked-in syndrome.

It is a poor fit where a faster method is available. Switch access asks for patience and attention over long stretches, and a person who could point should point. It is also not the right first step for someone who has not yet learnt that pressing does something; cause-and-effect toys and single-message buttons come before scanning.

How it works

The switch plugs into the device by a cable, Bluetooth or a small interface box. The device runs switch scanning, moving a highlight through the choices by row-column, linear or group patterns, either on a timer (auto scan) or with each press.

The two decisions that make or break it are the switch site (which movement) and the type of switch (which button suits that movement), followed by switch mounting so it stays put. Everything else is settings.

Getting started

Borrow a switch before you buy one. A cheap wired switch and a toy or a single-message button shows within a week whether the person understands press-means-something, and which movement is reliable.

Then, on a tablet, turn on the built-in switch access (Switch Control on iPhone and iPad, Switch Access on Android) with a Bluetooth switch or even the screen itself as the switch. Pick the largest grid the person can tolerate, set a slow scan speed, and let them choose something real. Note what tires them and when.

Where to get help

Ask for an AAC assessment through your speech and language therapist; switch users with complex needs are eligible for the specialised AAC services. The ACE Centre publishes free switch-access resources, CALL Scotland runs courses, and the Barnsley Assistive Technology Team is an NHS specialist centre. Communication Matters lists suppliers who lend switches for trial.