Tone Deafness Study Yields Sweet Notes
JOE PALCA, host:
From NPR News, this is Talk of the Nation: Science Friday. I'm Joe Palca. For the rest of this hour, tune deafness or tone deafness, that's people who can't tell this...
(Soundbite of a tune playing)
PALCA: From this.
(Soundbite of a tune playing)
PALCA: Ooh, or what about this?
(Soundbite of a tune playing)
PALCA: From this?
(Soundbite of a tune playing)
PALCA: Now, if you couldn't tell the difference, give us a call at 800-989-8255. That's 800-989-TALK, because those are very distinguishable to about 90 percent or so of our audience, and if you're in that 10 percent, we would like to hear from you, and so would my next guest, because he's doing research on this very topic.
And that's Dr. Allen Braun, he's the chief of the Language Section in the Voice, Speech and Language Branch at the National Institute on Deafness and Other Communication Disorders. That's a part of the National Institutes of Health.
And the reason he's coming on the program, is he's just finished or he's just published a paper in the Journal Plus One(ph), that talks about people who can't hear, can't or who say, I mean I guess they say they can't hear the wrong notes in those two pieces we just played. But if you look at what their brains are doing, it's not so clear.
So, give us a call, even if you did hear the difference and we'll talk about this. It's 800-989-8255. That's 800-989-TALK and let me welcome you to the program, Dr. Braun.
Dr. ALLEN BRAUN (Chief, Language Section, Voice, Speech and Language Branch at the National Institute on Deafness and Other Communication Disorders): Thank you. Pleasure to be here.
PALCA: So, did I say that right? Is it about 90 percent of the people who hear those tones, will say, oh, yes, I - the first one is completely right, and the second one is completely wrong, or is it...
Dr. BRAUN: Yeah, probably even a little bit more.
PALCA: Right. But there are people who will say, problem? What problem?
Dr. BRAUN: Right, exactly. And these people just do not appreciate music, and that's fairly prevalent, not quite 10 percent, but we think between two and four percent of the population just can't do this.
PALCA: And so, why were you interested in studying this population?
Dr. BRAUN: Well, we're interested in what the brain abnormalities are that underlie these symptoms. We really were motivated by the fact that these - this study of these subjects - genetic study of these subjects, in order to identify the genetic variants that underlie this condition.
Dr. BRAUN: And we use some of these electrophysiological measures to provide quantitative, phenotypic markers as ways of quantitatively diagnosing the condition, which is necessary for reliable genetic studies.
PALCA: So, you say this is an abnormality? I mean, you say that a - I mean, for one of - for not wanting to put a qualitative word on it, but a normal person should be able to hear that - these errors clearly.
Dr. BRAUN: Yeah, well the inability to perform on the test we used, the distorted tunes test to identify these subjects, is fairly continuous. So, it's not that there is a group of subjects who can and a group who can't, but is a fairly continuous gradation of people from those that absolutely get everything right, to those that can't discriminate at all.
PALCA: So, what are you seeing in the brains of people who say, no, can't tell a single difference, that tells you that maybe there's - there is some difference that's being perceived.
Dr. BRAUN: Well, we used, as I said, these electrophysiological methods, EEG, vent-related potentials, to look at 2 markers of what - what's called, change detection. That is the ability or the brain's response to obvious differences in stimuli that are expected, that deviate from the expectations.
The two that we looked at are called the mismatch negativity, which is generated about 200 milliseconds after the deviant note is presented to the subject. And the P300, which is generated a little bit later. They are generated in different portions of the brain, but both are very unambiguous responses to change, to violations of expectation, and have been seen to be generated by these source of deviations in melodic structure in normal subjects.
And we expected both of them to be abnormal in the tune-deaf subjects.
PALCA: Right, and they weren't?
Dr. BRAUN: Well, the mismatch negativity was. The earlier one about 200 milliseconds was generated in the early auditory cortices, was not present. It was clearly present in control subjects, absent in tune-deaf subjects. That didn't surprise us, but we were sort of floored by the fact that the later response, the P300, which is very robust in control subjects in response to the deviations, was just as robust in the tune-deaf population.
PALCA: So, that's the question. What does it mean that the brains of these tune-deaf people were responding almost identically to the wrong notes as the brains of people who clearly heard the errors and yet, one group says, yes I heard it and the other group says, no I didn't?
Dr. BRAUN: Well, it means, just as you said, that they are clearly processing the differences. They are clearly discriminating - the brain is discriminating the differences between the deviant and the normal ending of these tunes. But they are absolutely unaware. So they're processing these differences outside of conscious awareness. They know the differences at some level, but they are unaware of them.
PALCA: OK. Let's take a call now and some listeners already rose to the challenge of telling us that they were having trouble discriminating the differences. And we have John from Minnetonka, Minnesota. John (ph), welcome to Science Friday.
JOHN (Caller): Hi, Joe. I laughed out loud when I heard the two songs, because I said to myself, they're playing the same one over trying to trick us.
PALCA: Well, Dr. Braun is that the kind of response that people who have this condition frequently have?
Dr. BRAUN: Absolutely, yeah. Those that are more severely affected that it sounds like your caller may be.
JOHN: Well, I could tell that within each song, the different notes. But when you played the first and the second, I - there was no difference at all.
PALCA: Wow. So John, I mean, do you think - I mean, do you like to turn on the radio and listen to music?
JOHN: I love music. I listen to music all the time.
PALCA: So, what's your favorite song?
JOHN: I know that I couldn't match the note when I sang it but to listen to it, it was fine.
PALCA: Yeah, and do you have a style of music or a favorite piece of music?
JOHN: I like almost anything, except gospel music.
PALCA: I see.
JOHN: For some reason, doesn't do much for me.
PALCA: So in other words, "Yankee Doodle" is not - I mean, you've heard that before. That wasn't a surprise to you?
JOHN: No, that wasn't a surprise.
PALCA: But you could identify it as "Yankee Doodle"?
JOHN: Yes, absolutely.
PALCA: Huh, so what - I mean, what are we to make of this, Dr. Braun? I mean, I just think it's so interesting that it's - there's clearly something that's normal and something that's sort of off normal in - or maybe you just don't have a good radio. I guess that's a possibility.
JOHN: Oh no, did you change key or something? Is that what happens?
PALCA: Then tell them nature of the errors, Dr. Braun.
Dr. BRAUN: Well, the errors in what you played are from the distorted tune test, they're a little more varied and a little more dramatic than the errors we used in our studies which were deviations about one or two semi-tones only at the end of the melody. But your caller is a little bit atypical in that most of these subjects don't really appreciate music. They don't tell us that they enjoy listening to music. So, that's a little atypical. But when your caller said that's important is that he heard all the stimuli, all of the notes, and that's an important part of this condition that auditory processing - primary auditory processing is intact. It's the ability - inability to recognized melodic structure that's what - that is the problem in these cases.
PALCA: Well, John. I don't want - I'll keep one more second because I'm just curious, have you - have you ever - I mean, are there any parts of your life like I don't know, you know, is there any time when you think, oh gosh, there's thing that I can't do that other people seem to do easily or you just...
PALCA: Like what?
JOHN: I'll never forget holding my infant son and singing to him at maybe six months and having him reach out and grab my mouth to...
(Soundbite of laughter)
PALCA: Well, clearly if it's genetic it's not a deeply penetrant chain in your family.
JOHN: It must not be, because he could tell I was not singing correctly.
PALCA: Yeah, all right. Well, John, thanks very much for your call.
JOHN: Thanks, Joe.
PALCA: It's really interesting issue. And we have another person who also claims to be in this boat. Let's go to Pam from St. Paul, Minnesota. Pam you say that you couldn't hear the differences in the tunes either?
PAM (Caller): Oh, no. I could tell they were similar but I could not tell, you know, I mean, I couldn't tell any vast difference but I have Meniere's Disease which is an inner ear disease and so I'm totally deaf in my right ear. But my hearing comes and goes. And right now it's really, really good. But a year ago, it wasn't so good, and if you were to play that it would have been absolutely - I couldn't have told any, any type of difference. And what's frustrating for me, is like, during that time when my hearing is so bad, I will be in church and I can't tell anything - any tones. And I could relate to that guy about that six-month-old, for me it's my 16 year old when I'm in church they absolutely will not let me sing because I'm so out of tune.
PALCA: Oh Pam, I'm sorry to hear that. Well, thanks very much for your call. I want to ask Dr. Braun. You said the subjects you were looking at, they were more mostly people who, like our first caller, he had good ear - good hearing.
Dr. BRAUN: Right. Yeah, we made sure that the patients we - the subjects we studied had no problems with hearing and clearly the woman that just called with Meniere's disease presents a different picture. And maybe the deafness associated with Meniere's that causes her problems.
PALCA: I got it. Lets listen to - actually we have another caller here. Steve from Nottingham, New Hampshire also says he had trouble discriminating any tones. Steve you couldn't tell the difference between those two.
STEVE (Caller): Hey, I'm getting really upset because I've been called - you said I'm abnormal. I want know about this because, like, in synagogue my kids and no one wants me to sing. In fact they asked me to sing far, far away. But I do love folk music, I do love music, but I could not tell the difference and found both sounded pretty damn good to me.
PALCA: I think abnormal maybe a little strong. Abnormal in the sense of - yeah - we're all abnormal Steve. It's just in different ways.
STEVE: OK, good.
Dr. BRAUN: (Unintelligible)
PALCA: But tell me a little more about that Dr. Braun. What is this continuum that you're talking about?
Dr. BRAUN: Well, if you just mark the scores the subjects have on this test, the distorted tunes test, it goes from a 100 percent down to 50, down to chance, as though they were selecting at random and a fairly linear fashion. So, the population - some of the population is modestly impaired, some as very impaired, and some as unimpaired.
PALCA: And you said, you're beginning to use these data to help look for genes. Have there been genes that seemed to be associated, in other words, is there a physical difference in the brains between people...
Dr. BRAUN: Well, there's nothing that we can see and there - we certainly can use the data we've generated as a phenotyping tool. But we are dependent upon sort of classical methods of gene mapping to try to identify what the gene or genes are that are abnormal, what the gene products are, where the structural regulatory proteins, which will give us a clue on as to what is going on in these brains.
PALCA: We're talking with Dr. Allen R. Braun about a new paper he's written about. What tune-deaf people - what's going on in the brains of tune-deaf people? He's at the National Institute on Deafness and Other Communication Disorders. I'm Joe Palca and this is Talk of the Nations from NPR News. I'm curious, you know, one of the things when I read this paper that it made me think about was there are other phenomenon where, like in other sensory systems where people will, you know, people who are so - are blind, are definitely blind, you can flash things in front of them and you say to them, well, did you see anything? They say, no, no, we didn't see anything. Well, think of the first word that comes in to your mind. And you've just flashed the picture of a shoe at them and they'll say, well shoe, you know. Is that a similar - they call it blindsight I think
Dr. BRAUN: Yes, that's blindsight.
PALCA: Yeah, is that a similar phenomenon?
Dr. BRAUN: Well, it's not similar in one important way and that is, there is structural damage to the brain in those subjects. So those subjects have damage to the primary visual cortex, V1, usually unilaterally, so you can test things in both visual hemifields. And as he said, you can ask them to make, force them to make a choice and they're often right, sometimes up to 90 percent correct. But they are absolutely unaware. So, it's the same phenomenon but it's based on a structural lesion in the brain. Which makes it difficult to study these conditions because there's a variability across subjects with - what's interesting to us about tune-deafness is that it occurs in an otherwise intact brain that is very common in two to the four percent of the population. And if we really are able to say that these subjects are perceiving, without being aware of these auditory stimuli, these auditory deviations, it allows us because it's a very heritable condition to use the tools of genetic research to study conscious awareness.
PALCA: Interesting. Let's take one more call now and go to Pierro (ph) in Montpelier, Vermont. Pierro, welcome to the program.
PIERRO (Caller): Hi. This is a great conversation for me because I'm a conductor and I work with singers all the time, and I've definitely had experiences where they don't know if what their singing is right or wrong. But I'm wondering if you had the experience - I definitely see progress, like you know, I might be working with a singer in the beginning of the season and they'll be singing a little out of tune or they'll be singing wrong notes, but by the end, it improves.
PALCA: Ah, interesting question. Now, I know you're not trying to train these subjects, Dr. Braun. But is it possible that if you, you know, you give them the test 100 times, they'll do poorly; but 500 times they'll get better at it or if you give them feedback about it each time?
Dr. BRAUN: If you give them this distorted tunes test, they reliably going to perform the same, it's a very reliable instrument. So, they're going to perform the same each time you give it to them. But that doesn't mean they get at the issue of training. Nobody has tried that and that's an interesting point. If they can process these things outside of conscious awareness, then perhaps they can be trained to recognize them, incorporate them into consciousness, and improve. I just don't know.
PALCA: That's an interesting point, Pierro. Thanks very much for that call.
PIERRO: My pleasure. Thank you, guys.
PALCA: Yeah, I'm wondering though. That's an interesting point, too. Is there any example where these kinds of unconscious or subconscious brain phenomenon are brought into consciousness through training, or can you think of one?
Dr. BRAUN: Not in the conditions we just talked about. Blindsight, or deaf hearing, or Prosopagnosia. There are certainly are instances in which things that are processed outside of conscious awareness have priming effects on things that occurs subsequently. So it's not out of the question.
PALCA: And are you extending this study or was this simply in the development of these testing purposes for the...
Dr. BRAUN: Well, no, we're extending it now because of what we found. We expected just to find the absence of these two markers and then use them. But in fact, we found this interesting phenomenon and we want now to use functional imaging methods, such us MRI in conjunction with EEG to get a better handle on where in the brain these processes are occurring.
PALCA: So, are you recruiting subjects?
Dr. BRAUN: Not currently, but we probably will be over in the next several (unintelligible).
PALCA: All right. Well, there are links on our website to your website so people can keep in touch and find out what's happening. Anyway, thank you very much for joining me this hour, Dr. Braun.
Dr. BRAUN: My pleasure. Thank you.
PALCA: Dr. Allen Braun is the chief of the Language Section in the Voice, Speech, and Language branch of the National Institute on Deafness and Other Communication Disorders. That's a part of the NIH. From NPR News in Washington, I'm Joe Palca.
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