Hi! My name is Taylor, and I am seven years old. I am deaf, and I use American Sign Language to communicate.

This is my twin sister, Isabelle. She can hear and talk, even though we were born three minutes apart.

Although our ears work differently, we are still very close and do everything together!

Today our mom is taking us to the doctor to have our ears checked. We go there once a year.

This time, we have some questions that we want to ask Dr. Banner. Why do we hear differently? Why don't I hear like Isabelle?

Mom says Dr. Banner will be able to explain it very clearly. He is my favorite doctor because he knows sign language.

"Hello Taylor and Isabelle! How are you both doing today?" Dr. Banner asked and signed at the same time.

"Good!" I signed.

"Are you ready for your ear checkup?" Dr. Banner asked.

"Yes! But we have some questions," Isabelle said.

"Of course, let's take a look while you ask."

"I'm going to use this light to look into your ear, Taylor. Do you girls remember what I look for?" Dr. Banner asked.

"Yes, you look at our eardrums, right? That's where all the sounds come in. And you see if anything is inside," I signed.

"That's right, Taylor. Now, what did you girls want to ask about?"

"Well, why am I able to hear and my sister can't?" Isabelle asked.

Dr. Banner smiled. "Well, I'm glad you asked. Here's my otoscope. I use it to look in your ear. Take a look in Taylor's ear with me."

Of course, Dr. Banner signed if that was okay with me. Yes!

"Right now, Isabelle, this is what it looks like to us. We can't see very much, but I want you to take a look at this poster," Dr. Banner said.

"You too, Taylor, let's see what's going on in your ear," he signed to me.

"Wow," I signed. "Is this what it really looks like in our ear?"

"Yes, Taylor. For both of your ears, you have something called the external ear. This is on the very outside. This tube inside your ear is called the ear canal. This is where sound waves enter."

"Dr. Banner, what's this? The tym...panic membrane?" Isabelle asked.

Dr. Banner smiled. "You both actually know this part of the ear. This is the ear drum! It's where the sound waves become louder so that the rest of the ear can receive it."

"Cool!" I signed.

"Now, here is where it is different for the two of you. Isabelle, you can hear. If I tell you to jump when I say go, you will process the sound waves from my voice when I say the word go, which is called a stimulus.

There are tiny hair cells in the cochlea, right over here, the part that looks like a snail."

Isabelle and I laughed.

"These hair cells in your cochlea are where the stimulus goes. They are called receptors. The stimulus, the message, then goes to your brain through a cochlear nerve to the brain. Your brain is very complex and can process the message that a word has been said. We call this the afferent pathway, because it goes up."

"Now, Isabelle, in order for you to jump, the brain will tell your legs to move. This happens through the efferent system. Not afferent, but efferent, with an e.

Let's look at a new poster."

I was surprised. "Dr. Banner, what's next to those bones in the legs?"

"These are called muscles. They help you move all the parts of your body. They're even found in your arms!

For a minute, let's look closer at the brain. This part next to the ear is called the frontal lobe. This is where the stimulus is processed and understood by the ear.

Now, the efferent system. This moves through this spinal cord in the picture. Can you point to where it is?"

I pointed to the bottom right of the picture.

"Yes, Taylor, that's right! The message now goes down this spinal cord to the motor nerves in your legs. What do you think of when you think of the word motor?"

"A motorcycle?" I said.