This is my paternal grandmother, who I helped get to an audiologist appointment recently.
For those with an elderly relative who is experiencing dementia and s/he refuses to keep hearing aids in the ears (as she was), there may be a different way to go about helping your person maintain connection to the outside world.
G'ma's audiologist commented that many people in this situation have increasingly sensitive ear canals so putting a hearing aid in there can cause them discomfort (which they very sensibly avoid by removing the hearing devices!). Under the advisement of the audiologist I paid a worthwhile visit to Radio Shack to buy a little pocket-sized device called an audio amplifier. You can plug in an external headset and talk at normal range into the amp. The whole setup (pocket amp, headphones, a pack of AAA batteries) cost under $60 and after I took it back to the assisted living facility to see if she'd tolerate this new thing the RAs and I delighted in-
1.)not having to yell (hollering to communicate is not done with an angry tone yet feels too much like mean-yelling!), and
2)seeing G'ma actually HEAR the vacuum cleaner that someone was using in the building.