Is Hearing the Last to Go?

New research shows that the brain processes what we hear at the end of life.

Posted Aug 26, 2020

A significant percentage of professional music therapists in the United States provide end-of-life care, often through working for a hospice agency. This is an area of practice where music therapists can positively impact the quality of life for patients and their families by addressing various physiological, social, emotional, and spiritual needs (Fiore & Masko, 2018).

Though I have little personal clinical experience in hospice and end-of-life care, I have many friends and colleagues who do. These hospice music therapists love their work, and for good reason. They talk about the unique privilege it is to be with their patients and their families during this transitional period in life, how it offers perspective and reminds them of what it means to connect, live, and feel.

Sometimes, too, these hospice music therapists are called in to provide music during the last minutes and hours of someone’s life. Why? Well, it’s thought that hearing is one of the last senses to go.

But is that true? Researchers in Vancouver, Canada who examined just that published their findings this summer in Scientific Reports. They analyzed three different EEG-measured brain responses to auditory patterns in 17 conscious, healthy young participants, 8 hospice patients who were conscious, and 5 hospice patients who were actively dying and unresponsive. 

Participants in all three groups listened to a series of five-tone auditory patterns while an EEG tracked their neural responses. These responses were selected as they indicate a person is able to perceive auditory information (MMN), and focus their attention on the auditory signal either voluntarily (P3b) or automatically (P3a).  

The researchers analyzed neural activity as participants heard tone changes and pattern changes. Their results covered a range of findings outlining similarities and differences in neural responses to auditory patterns between the three groups of participants. But what did they find specific to understanding whether or not hearing is in fact one of the last senses we hold? Here is the evidence they presented for the five participants in the unresponsive, actively dying hospice group:

  • All showed evidence of neural MMN (auditory perception) and P3a (automatic attention) responses to tone changes.
  • Some showed evidence of P3a and P3b (voluntary attention) responses to pattern changes.
  • When averaging neural responses from all five participants in the group, the researchers reported weak, but observable, P3a responses to tone changes, but not pattern changes, and no P3b responses to tone or pattern changes.

So what does this all mean? In short, these results provide evidence that for at least some individuals their brains continue to process auditory information, even if they don’t respond in a noticeable way through a turn of the head, a change in eye gaze direction, or toe taps to the beat. Additionally, they reported that some of the neural response patterns in these participants were similar to those seen in the younger, healthy controls, indicating their brains were processing what they were hearing in (perhaps surprisingly) typical ways. 

Thus, there may indeed be something to the notion that gets passed down between professional hospice workers and shared with recipients of hospice care—in those final moments of life, go ahead and keep talking and singing to your loved one. Include them in the conversation (even if they don't respond), play music, and accept that music therapist’s offer to support you and your loved one during this time of transition. 

References

Blundon, E.  G., Gallagher, R. E., & Ward, L.M. (2020). Electrophysiological evidence of preserved hearing at the end of life. Scientific Reports, 10(10336). https://doi.org/10.1038/s41598-020-67234-9

Fiore, J., & Masko, M. (2018). Music therapy in hospice, palliative care, and bereavement. In A. Knight, B. LaGasse, & A. Clair (Eds.), Music therapy: An introduction to the profession (pp. 395-414). American Music Therapy Association, Inc.