From the other side of the scenario, I have had too many experiences with family members who are moderately hard of hearing to totally deaf. It's even more frustrating for the patient to be unable to communicate with the medical professionals! Walk a mile in your patient's shoes.
WRITE it Down
What ever happened to pen and paper? These patients are not blind and dumb! Use a pad of paper, your smart phone notes app, a white board, SOMETHING! Don't just give up and say you "just can't communicate with the poor guy!" Of course you can't if you think the only way to get your point across is to SHOUT so you can be heard 5 blocks away!
Indeed shouting may be required, but most times just ENUNCIATING clearly and speaking SLOWLY, especially if you rattle off words off at rapid fire speed. Try changing the pitch of your voice too. Tip your chin down, take a breath and speak slowly in a deeper voice. If that doesn't work, try raising the pitch towards a soprano level. Again, enunciate and speak slowly, and DON'T SHOUT!
Why Hearing Aids Don't Always Help
When human beings lose their hearing, one of the reasons hearing aids don't always work is that the person waited way too long to try them. By then the brain has forgotten what specific sounds are and the hearing aids only amplify sounds that are foreign to the brain. This causes more confusion than trying to eek out what little sound they can hear.
Think about a baby learning to speak. It has to hear sounds repeatedly and associate the sound with a person, object or action to learn to speak and understand speech. An adult who has lost their hearing doesn't usually understand they have to retrain their brain so their hearing aids will actually help them.
Consequently, many people choose not to use their expensive devices and sink into isolation. But they didn't forget how to read. So use some sort of written communication tool and see how much more you can accomplish without SHOUTING and becoming overly frustrated.
Pictures, videos, even charades or other visual cues can help when communicating with a person who is hard of hearing; and will work to enhance your written information.
Borrow a trick from trying to communicate on a very basic level with those who speak another language. Write out some of your frequently used questions, statements, directions, etc., on a sheet of paper or use 3X5 index cards. Keep them together and USE them when you have a patient who has diminished hearing. Laminate them to keep them clean and fresh.
Next time you have a patient who is hard of hearing, don't just write them off… WRITE IT DOWN! And teach your patients to ask others to do so. Feeling stigmatized, they don't always remember to suggest this solution.
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