For most people listening to music or playing an instrument is a great way to relax, unwind, have fun, and express themselves. But not everybody is able to perceive, appreciate or memorize music, to sing or to dance. Monica is one such person, and to her, any kind of music is just a bunch of noise that makes her head ache and feel stressed. It might come as a surprise to learnt hat Monica was involved in a church choir as a child and played in the school band in high school. But she participated in these activities because of social pressure, not because she liked to, she says.
So why can't she understand, even worse why can't she enjoy music, the way she sees everyone around her do? Puzzled, she got in touch with a group of researchers at the University of Montreal in Canada, who examined her case and diagnosed her with congenital amusia -- a disorder that left her brain unable to process music since birth. In her 2002 study published in Neuron, the team reports that while the condition can be acquired as a result of brain damage, they believed that her condition is genetic, as she had no trauma that might explain it and her mother and brother also report suffering from amusia.
When they examined Monica's musical characteristics, they found no proof of hearing loss that might muddy her perception of music, -- she was able to normally perceive and recognize voices, spoken lyrics and common environmental sounds. Lack of exposure to music couldn't explain her difficulties either, as she had plenty of experience with the medium as a child. They ruled out cognitive impairment too; Monica was completing a Master's degree after working as a nurse for many years and her overall cognitive and memory skills were above average.
"The musical disorder appears as an isolated deficit in an otherwise fully normal cognitive and affective system," the authors wrote in the case report.
A notable problem
After extensive testing, the team started to suspect that Monica's deficit seems to have something to do with pitch discrimination, and she perceives it as monotonous because she can't detect small variations in pitch. This may prevent her from hearing the basic building blocks of music in most cultures, like the tone and semitone.
While the general characteristics of amusia have been described pretty thoroughly by scientists, its neural mechanisms are still being investigated, said Benjamin Rich Zendel of the University of Montreal. In a study published in March 2015 in the Journal of Neuroscience, Zendel and his colleagues found clues to some potential neural mechanisms that could be involved in amusia.
Previous research had suggested that amusics might actually have some tonal knowledge, but they might not be able to access it like non-amusics do, so Zendel's team decided to look into it a bit more. For the study, they recruited nine people with amusia and 11 people without the condition and monitored their brain responses during certain tasks.
In the first task, the people were asked to respond to a click embedded in a melody. Here, all the participants were able to detect the clicks, and both groups showed the same brain responses. But, in the second task, where they were asked to detect incongruous notes in a melody, the difference became apparent. While the people without amusia were able to consciously differentiate between incongruous and in-key notes, the people in amusia were not.
This suggests that amusics have tonal knowledge, but it is disconnected from conscious experience. The researchers aren't exactly sure how this translates into brain functions, but suspect that the cause lies with connectivity issues between the different parts of the brain. More exactly, amusics may have a deficit in connectivity between the primary auditory cortex — an area that is the first to receive any auditory information — and an area of the frontal cortex that is thought to be related to consciousness and awareness in general, Zendel explained.
Zendel and his colleagues have been trying to figure out the neural mechanisms of amusia because, ultimately, they would like to improve pitch perception in people with the condition.
"The long-term goal is really to understand the brain mechanisms well enough so that we can create programs or systems to improve pitch perception in these people and give them access to music," Zendel said.
"Music is one of the very few things that is universal to every known human culture, like language," he said. "Not having access to music limits your ability to participate in human culture."