I know that this is a subject that comes up fairly regularly. My other half (who has the PD) has been getting quite frustrated trying to keep up with his emails, etc. He’s been having issues with tremor and some difficulty in focus, attention and memory (specifically remembering the processes for doing routine things like attaching a document in an email).
Just to say, before you spend money on special keyboards and mice, it is worth playing around with the accessibility features that come pre-packaged. We have a PC with Windows 10, but I’m assuming there will be same for Macs.
For the tremor, we’ve had some success with slowing down the mouse speed (Settings>Devices>Mouse) and enlarging the pointer to the largest size (Settings>Ease of Access>Mouse Pointer).
Also, bumping up the screen display to the maximum size has helped with focus (Settings>Ease of Access>Display).
We had a go with the Speech setting (also under Ease of Access) which allows you to dictate commands and text. The OH just found it irritating, but others may find it useful. It takes a bit of patience and practice. Cortana was absolutely hopeless.
I made some prompt sheets for using Outlook, etc and we found what worked best was brief instructions – briefest possible in larger text and double spaced – using Shortcuts https://support.microsoft.com/en-gb/windows/keyboard-shortcuts-in-windows-dcc61a57-8ff0-cffe-9796-cb9706c75eec Initially I made lots of screenshots annotated with instructions, but this was too much information and not very helpful. Short and sweet worked best.
Hope this is helpful, and keen to hear anyone else’s tips.