Studies on Hearing Loss

In the discussion lead by Dr. Yu the topic of how cells arrange themselves tonotopically in the cochlear nucleus in relation to their birthdate was evaluated.The background knowledge for the study was that the cells in the cochlear are organized by the frequency that they process. For example, the cells found in the apex process a lower frequency and the cells found in the base process a higher frequency. This knowledge is important in our understanding of how the ear is able to recognize and respond to different sounds. Dr. Yu's research was taking this knowledge a step further and asking whether the time period in which the cells develop determine where they are located in the cochlear and therefore what frequency they would respond to. The research was done with BrdU staining to determine the birthdate of the individual cells. The result found were cells in the AVCN formed in order from dorsal to ventral. These results hinted at the idea of the birthdate of the cells determining the location of them as well. This discovery is important in the field of hearing loss from the aspect of being closer to pinpointing where the hearing loss may be occurring or at least in which cells.

A study focused in this direction can be seen in the article, Scientists Restore Hearing in Animals Using Human Stem Cells. The study was focused on introducing stem cells into mice that had their auditory nerve cells damaged. The role of the stem cells were to replace the damaged cells in the auditory nerve and in turn improve hearing in the mice. 10 weeks into the treatment the mice showed about 50% improvement in their hearing. By the end of the treatment some of the mice were able to regain most of their hearing function. By being able to control and use the stem cells as a treatment, the researchers were able to repair what was causing the hearing loss and for this study it was the auditory nerve cells. The knowledge that was gained from this stem cell research however may be able to be combined with the results found in Dr. Yu's study. By being able to know more about the location in which the cells need to be produced, stem cells may be able to be introduced in that location based on the time period in which they develop. By combining the two studies it could help pinpoint where the damage is that is creating the hearing loss and the stem cells introduced could be the solution to repairing those specific cells.

Sifferlin, Alexandra. "Scientists Restore Hearing in Animals Using Human Stem Cells." New York Times. 13, Sept. 2012. http://healthland.time.com/2012/09/13/scientists-restore-hearing-in-animals-using-human-stem-cells/

Shepard, Austin. Scheffel, Jennifer. Yu, Wei-Ming. "Relationship between neuronal birthdates and tonotopic positions in the mouse cochlear nucleus." Wiley. 11 Sept. 2018