Why Does Grandpa Ignore Grandma? A Case Study in Hearing Loss by Benjamin F. Timson and Scott D. Zimmerman Biomedical Sciences Department Missouri State University, Springfield, MO
	Scanning electron micrographs showing a human sensory hair cell (left) and a hair bundle (right).

Part I—Introduction

Carla Marie Jackson, a first semester graduate student in Audiology, was having difficulty staying awake in her early afternoon class. “I knew I shouldn’t have eaten such a big lunch,” she thought to herself as her head jerked up for the third time in the past 15 minutes. She glanced at the clock and groaned when she realized 45 minutes still remained in the period—Professor Wilson would take every bit of that, plus more! Her mind began to drift to the upcoming spring break that would begin next week, when suddenly something Professor Wilson said took her back to an experience she had while visiting her grandparents the previous Christmas.

Carla was named for her maternal grandparents, Carl and Marie Wojahowski. She loved them both dearly even though there couldn’t have been two more different people in the world. Grandpa Carl was a calm and loving man who spent his working career as an auto mechanic in the small northeastern Wisconsin town of Marinette. Grandma Marie was a 5-foot-1-inch ball of fire with a high-pitched shrill voice who always wanted to accomplish more than was physically possible in a day. The only time she relaxed was when she slept. Grandma and Grandpa lived eight miles west of town in a two-story house with a wrap-around porch on a 160-acre farm. Carla’s mother, Kathy, the youngest of Carl and Marie’s six children, had married Bob Jackson, who she met in college, and they had raised their family 12 hours away in St. Louis. Carla was the oldest of their five children.

Many of Carla’s favorite childhood memories were of times she spent on the farm in the summers and at Christmas. She loved sitting on the porch with Grandpa Carl and working with him in his garden and orchard. He had tremendous patience with her as he showed her how to till the soil and care for the plants. She also loved working with Grandma Marie in the kitchen, although the pace and intensity was much greater than working with Grandpa in the yard. Preparing Christmas dinners was hectic as Grandma barked orders for six hours. Everything had to be perfect and if she did something wrong Grandma was “on her case” immediately. Carla smiled to herself when Grandma’s shrill voice cut the air, “Didn’t I tell you to cut those potatoes a quarter inch thick!” Grandma always meant well. She just got too excited, Carla always reminded herself. Besides, Grandma didn’t yell at her nearly as much as she yelled at Grandpa.

Professor Wilson now had Carla’s attention as he discussed age related problems affecting the auditory system. Carla thought back to a specific event the previous Christmas as she and her Mom prepared dinner under the watchful eye of Grandma Marie while Grandpa Carl and her Dad sat in the living room watching the Green Bay Packers play the Chicago Bears on TV. Carla almost laughed out loud in class as she remembered the situation.

Questions

1. What is the general purpose of the sensory nervous system and the specific purpose of the auditory system?
2. Trace the path of sound from the outer ear to interpretation by the brain, detailing what happens at each step in the pathway.
3. What are the environmental factors that might have prevented Grandpa Carl from hearing Grandma Marie?
4. Why was Bob able to hear Grandma Marie when Grandpa Carl could not?

Image Credit: Photos courtesy of Carole M. Hackney and David N. Furness, MacKay Institute of Communication and Neuroscience, School of Life Sciences, Keele University, Staffordshire, ST5 5BG, UK. Used with permission.

Date Posted: 01/13/06 nas.

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