Has anyone tried using a bidet seat for better hygiene with the elderly?

Most emphatically YES! We are involved in many caregiver groups in our retirement area and the bidet seats are a life changer for many of their patients and clients.

I would point out that bidet sprayers are usually hooked up to the COLD water supply, and require a certain amount of cognition and/or dexterity to operate properly as they are hand held devices.

Here's a recent thread about this issue:
www.agingcare.com/questions/bidets-and-incontinent-alzheimers-patients-184692.htm