Keyguard

Also called Key guard, Screen guard, Grid overlay

A rigid frame with holes that sits over the screen, so a sliding hand stops at the edge of a cell instead of on the wrong one.

What it is

A keyguard is a plate, usually clear acrylic or laser-cut plastic, with a hole for every cell on the screen. It clips or sticks over a tablet. The finger goes into the hole and the walls of the hole keep it there.

It is the oldest access aid there is, and still one of the most effective. It turns a flat, frictionless screen into something with edges.

Who it can help

People whose hand reaches the right area but slides, drags or rests on the screen. It suits a fist, a knuckle, a stylus, a head pointer and a tired finger. It is the classic fix when touch settings alone are not enough.

It is not for a person who cannot get into a hole (a very weak, flat press may not reach the glass through a thick guard), and it fixes the grid size: a keyguard cut for 20 cells is useless the day the page set moves to 36. Every keyguard is also a lump on the device that makes it harder to swipe between pages and, on a phone, awkward to carry.

How it works

A keyguard has to match three things exactly: the device model, the case, and the cell layout of the app. Suppliers cut them to order from a template for each popular AAC app and grid size. Thickness matters (thinner for a light touch, thicker for a resting hand), and so does the rest area: a raised border where the heel of the hand can sit without touching glass.

Some guards have a small cut-out for the message bar and page navigation; others cover only the grid. A keyguard is often paired with select on release, so a finger can slide down into a hole and fire when it lifts.

Getting started

Before spending money, make one. Draw the grid on stiff card, cut the holes with a craft knife, and tape it over the screen for a day. If the person's hits go up, you know a keyguard is worth buying and you know which thickness and rest area to ask for.

Then measure carefully: device, case, app, grid size. Ask the supplier whether they will re-cut it when the grid grows, because it will. And write the grid size on the guard in marker so nobody at school or the care home changes the page set without knowing they have just broken it.

Where to get help

Ask your AAC service or occupational therapist; most order keyguards routinely. The ACE Centre and CALL Scotland publish guides on choosing one, and Smartbox and Tobii Dynavox supply guards for their own products. Communication Matters lists UK suppliers.