Aphasia

Claire Ceriani's picture

 Neural and Behavioral Sciences Senior Seminar

Bryn Mawr College, Spring 2010

Aphasia

Aphasia is a language disorder caused by brain damage, and may appear suddenly (as the result of a stroke or trauma) or gradually (as in Alzheimer's or primary progressive aphasia).  The most common forms are typically classified as either fluent (Wernicke's aphasia) or nonfluent (Broca's aphasia), with fluent affecting a person's ability to understand speech and put words together meaningfully, and nonfluent affecting a person's ability to articulate and express words verbally.  Studies of sufferers has led to a better understanding of how and where the brain processes language, but has also opened up some questions about how language use may be integrated with other skills within the brain.  Attempts to "reteach" spoken language to aphasics has given us greater insight into neuroplasticity and the integration of the left and right hemispheres.

Background readings:

Videos:

Some continuing conversation from  last week:

I do think that a part of the popularity of astrocyte research currently, and part of the reason why any particular area becomes a hot topic in a scientific field is the degree to which the extent of the influence of astrocytes upon the function of the nervous system is unknown.  Astrocytes are something of a blank canvas right now and researchers are able to ascribe all sorts of potential incredible breakthroughs to them (again things like significance in HIV/AIDS treatment).  Because it seems possible that the established understanding of the function of astrocytes was wrong we are allowed to hope ... there is tremendous potential in astrocyte research, and those who are involved in that research are happy to have the publicity ... Jeremy Posner

It may be true that astrocytes may be receiving so much attention because they are the new frontier of neuroscience that young scientists are trying to become famous for, but aren't there other great discoveries that were made because some young scientist wanted to make a name for themselves? It may be true that scientists will later find that astrocytes are not a significant contributer to the function of the nervous system, but I think it is important to at least research them and learn about them until this conclusion is reached ... Bo-Rin Kim

Whether or not we include them in our undergraduate neuroscience classes, I believe the research in the field has adapted to incorporate the wealth of new information and the contradictions to old assumptions in the field.  A journal called Neuron Glia Biology was launched in early 2004 and another journal called GLIA, described as the journal that launched the field of glial research, was launched in 1988 ... VGopinath

an emerging field of research and probably does belong in entry-level courses ... rdanfort

I do think it is something that should at least be mentioned at some point before med school because if the goal is to spark interest for figuring out something that we do not entirely know everything about than that interest starts well before med school ... vpina

the average person learns about terms that are reported by the press, the press reports scientific data that are interesting to people, that which is most interesting to people is often that which is most relevant to them, and astrocytes do not seem to have any relevance to who we are or what we care about. The second we find out that astrocytes play a role in curing a disease, or housing our deepest thoughts in a manner that does not require neurons, then people will know about them ... David F

The only problem then comes from the gap between what scientists know and what the general public knows. The question is  ... how do we inform the general public about astrocytes when the people researching astrocytes can't pinpoint their exact functioning? ... meroberts

As scientists, we know that the field is constantly changing and that scientists often make new discoveries that contradict contemporary theories; part of being a scientist is using the data that you have to determine the truth, even if it goes against what you already know.  But to the public, this back-and-forth can discredit science.  Yesterday, eggs were bad for you, but today, eggs are good for you.  Cell phones cause brain cancer.  Cell phones do not cause brain cancer.  At the same time, it would be both unethical and almost impossible to hold back all information until we were sure that it was 100% correct.  We know that neurons don't work without astrocytes, but it has not been deemed important enough to explain to the public.  Just as most laypeople know that bones are made up of calcium, but they don't know how the calcium gets to their bones, scientists have decided that astrocytes aren't basic enough for the public to need to know.  And frankly, if we don't know what astrocytes are doing, why would the public want to know about them?  Once they become important enough that we can make some definitive statements about what they do and what processes they effect, that information will surely be shared with the public.  And then refuted. ... aliss

An interesting issue sparked by our astrocyte discussion is that there is only so much science that can be communicated from scientists to others ... Each and every day, there is an increasing amount of scientific facts/information/theories being discovered or clarified. It is impossible for all these to be conveyed not only to the general populace, but from one scientist to another. Who, or what decides what we should learn about from TV, newspapers, or a 200 level biology class?  In the case of Neurobiology and Behavior, it is Paul who directly decides. But ultimately, he makes his decision with consideration of the amount of attention being given to astrocytes in the scientific community, and whether this amount of attention is enough to carve a place for astrocytes in his course.  So in essence, it is whether or not the person who disseminates the information chooses to listen to what the "loudest voice" in scientific research is saying. Do we trust the NY Times to make the decision as to what the population should learn about science? Or Scientific American? Or our professors? .... It seems that with astrocytes, although they are "under the spotlight" in the academic/research worlds, that people not involved in science do not know much, if anything, about astrocytes. Why is this? Is it because we as scientists do not think that astrocytes will be interesting to a lay audience so we don't discuss them? Or is it because the public holds so strongly to the idea of the neuron as the core of the nervous system? I'm inclined to think it's the former, because it seems to me that if scientists could make a big splash and get publicity by claiming that astrocytes have an important role just like neurons, they would - but without an interested public, there would be no big splash ... sberman

the more that I learn about the process of sifting through data as well as the politics of publishing papers, the more skeptical I become about the objectivity of the entire research process ...  science should be a constant back and forth dialogue .... demonstrates the importance of considering the influence of scientific journals in shaping the information that we are exposed to as well ... unlike articles in the NYT that cater to the general public – articles published in scientific journals will influence what scientists chose to research in the future ... lmccormick

We have truly become acolytes of science, ready to defend our ideology from all who attempt to weaponize science and use its seeming objectivity to influence the un-learned masses. It is interesting (and certainly supports the notion of science as religion) that we can so ravenously defend science but leave the intra-scientific debates about what science should be (rather than what it is not) to the “church elders”, the journal editors and well-published professors ... dshanin

If indeed all understanding (scientific and otherwise) is brain construction,  and so there are only "subjectivities" and "shared subjectivities," then, as Alison put it in her introductory posting, "How does the brain decide what is important"?  Or, expanding a bit: how do brains, individually and collectively, decide what is important?  are we comfortable with how it is done or do we want to change it, to create a new shared subjectivity? ... While some people legitimately can and should work on astrocytes, maybe its at least as important that others be doing research on what motivates particular constructions in particular brains and how these interact to yield shared subjectivities?  With an understanding that the business of science is as much to open new possibilities as it is to account for the current state of "reality"?  .... Paul

Discussion summary (Bobby)

Claire opened with the Seeley paper, which delineates an attempt to connect the progression of a woman’s degenerative aphasia to changes in her painting style and subject material.  The paper’s major contention was that the artist’s move towards transmodal expression and visual realism indicated that her lost brain tissue and speaking ability were concurrent with functional gains in polysensory integration of stimuli.  Some note was made of the ambiguity of the patient’s diagnosis and difficulty in connecting paintings to discrete brain phenomena, although David pointed out that the nature of a case study is such that causative assertions cannot be made anyway.  Some discussion regarded the appropriateness of the term, “gain of function,” applied to brain damage.  A brain “unlocked” by trauma is a prevalent cultural myth, but can it be justified?  One prominent example in favor was the gain in tactile and auditory ability by the blind, among similar examples for other sense deficits.  I asked if “becoming more visual” were a proper hypothesis for the artist, as it seemed to conflate a loss of expression with sensory loss in order to appeal to this notion.  It was also asked- why is this woman painting houses if this is her way of speaking?  Respondents noted the lack of clear connection between observed increases in grey matter in particular regions and painting behavior, given the other pronounced changes in behavior and thinking that would come with aphasia.  Perhaps the artist changed as she spent less time talking, and more time looking at leaves.  Conceptualization of the “usefulness” of the article was difficult.  Perhaps it helped us to understand the jargon and concepts used by psychologists to attempt to analyze difficult subjects such as “creativity,” or perhaps it was just an interesting read.

The next paper addressed retention of singing abilities in some aphasia patients, and attempts to re-learn speech through singing-oriented therapy.  Few were surprised by the singing/speaking differentiation, although it was very difficult to pin down exactly what about the rhythm and cadence of song was not found in speech.  As in our recent talks on stroke and EMDR, watching the video had a striking impact on our understanding of the process.  The man presenting his success in re-learning speech was intelligible, but lacked what Paul called the “fluent” quality of speech, making him difficult to listen to.  It was still a fairly impressive accomplishment, and the noted development of the right hemisphere in response to therapy was interesting.  We were fairly curious about the integration of hand-tapping into the therapy program, and disappointed in the lack of control or justification for this protocol.  On the notion of language “centers” and multiple “centers”, people were not fundamentally opposed but had some questions.  It turns out that senses adapt quickly, as demonstrated by temporary blindness experiments, and Paul wanted to know “who decides” how/if/why changes occur in this fashion.  David talked about the importance of input upstream of a disabled region in promoting new connections, and I suggested that some process (potentially our own higher cognition) notices that something is seriously wrong (I’m blind!) and that this initiates adaptation.  Paul noted that words were once thought to be stored in Broca’s area, but that violence has since been done to that exclusive model and that word “templates” may be diffuse, degenerate, or otherwise difficult to pin down.  Billingual-raised and acquired-language brain differences were invoked to illustrate features that separate “word” from “concept” in such an investigation.  We still could not find a clear distinction between language and singing, but realized that singing in a group does carry a measure of correction from auditory feedback.  On that note, the study’s use of folk songs with predictable rhyme and tone schemes was thought to be highly relevant to its success, and it was agreed that atonal or unpredictable music would be far more difficult for aphasia sufferers to reproduce.  Paul noted the use of a relatively new form of brain imaging, Diffusion Tensor Imaging, and suggested these would in general yield  future new insights into the long connections that make up white matter and how they relate to these associative functions.

Comments

mrobbins's picture

Feel the beat of life

 
In class, I was very intrigued by the power of music to render speech to the speechless and the ability to walk to those who never thought they would take another step again. The fascinating healing properties of music seem endless. Research has suggested that music is helpful for aphasia, Alzheimer’s, Parkinson’s, treating asthma, ulcers, hypertension and even the common cold! These findings prompted me to research more about the healing powers of music, as a magical elixir of health. One of music’s strengths is its ability to reach our emotions. This quality has made music therapy of great use to those suffering from Alzheimer’s. People with this disease often experience a state know as sundowning. Sundowning is excessive agitation that occurs in the late afternoon when certain expectations are not met, such as returning home for work etc. Playing music before this time of day not only soothes many people, but also prevents sundowning from even occurring in some people. Exposure to a certain song, or piece of music establishes a sense of predictability which enhances memory, object recognition, and other cognitive functions. It is astounding that such a small establishment of predictability has such a profound effect on function. What is it about music and our emotional states and abilities that hit the right note every time?
Research has shown that musicians have a larger motor cortex than do non-musicians. Years of practice, exposure, and repetition of music can strengthen existence of synapses and even form new ones. Musicians with absolute pitch have even more pronounced differences in this area of the brain than do other musicians. Therefore, it seems that there are endless research opportunities for scientists to delve into the ability of music to combat neurological disorders. Furthermore, music may have an important effect on psychoimmunology. The ways in which our emotional states impact our overall health and immune system is promising area of study. Psychosomatic illnesses could stand to benefit exponentially from further research into this area. Other disorders and diseases related to emotional disorders such as peptic ulcers, IBS, hypertension, muscle pain, and headaches among others would greatly benefit from music therapy. What is it about the rhythm of music that matches the beat of our lives?
 
 

Claire Ceriani's picture

I was especially interested

I was especially interested in our discussion of creativity and the idea of gain of function.  We so rarely discuss conditions like aphasia in terms of functions gained, rather than just functions lost.  I'd be interested to know how many people with aphasia have some sort of "unlocked" cognitive ability.  This story was the only example of this sort of thing I've found.  I'm assuming that it's an unusual case, but there must be other people with similar experiences where the function gained is less remarkable, but no less obvious to the patient.  As I mentioned in class, I think this article tries too hard at times to draw neat parallels between this woman and Ravel, and to somehow quantify something as subjective as a person's level of creativity, but I think it also makes some very interesting points.  The creative mind is often associated with mental illness.  Is it possible that we find something creative because it is the product of a mind radically different from our own?  Many of the most famous artists (visual or otherwise) are known to have suffered from some sort of mental disorder.  It's certainly not true of every great artist, but many of the most enigmatic and intriguing works of art come from people who likely think very differently compared to most people.  Perhaps deteriorating language ability is one of the ways in which thought might shift enough to create something that other people will find interesting.

kenglander's picture

The difference(s) between

The difference(s) between talking and singing were certainly a point of contention during class last week. I've thought a bit about the differences, specifically the role of pitch. In speech, pitch gives meaning to what is said. Granted, how pitch is used (i.e. inflection) varies across cultures, but within the same culture people tend to speak with similar pitch patterns. In singing, however, pitch is more closely tied to the melody rather than the meaning of the words. For example, if you read the lyrics of a song aloud, your pitch probably differs from the pitch of the song.

Interestingly, if you take a fragment of speech and repeat it multiple times, it can start sounding like a song (http://philomel.com/phantom_words/play.php?fname=Track_22&s=0). I'm not really sure what to make of this except that maybe our brains search for rhythmic patterns within speech. However, these patterns may not become apparent in normal dialogue because there is not usually a repetitive element in speech like there is in song.

 

Bo-Rin Kim's picture

common underlying area storing general language concepts?

I think one interesting article that we didn’t really get to discuss during class last week was the article about the case study on the bilingual man who was only able to improve one of his languages after rehabilitation from aphasia. The patient was fluent in both Arabic and Hebrew pretty equally, but Arabic was his mother tongue and it improved significantly more than Hebrew during rehabilitation. This raises the very interesting question of how different languages are stored in our brains and if there really is just one center for language.


Megan mentioned in her post that just because Broca’s area is commonly known to be THE language production center, this not does necessarily mean that it is the only path the brain can use to produce language. I remember learning in Psychology of Language that some researchers of bilingualism propose that there is shared database of information that can be processed and accessed by both languages. Thus, it is as if each language is a unique pathway in which to interpret and express in the information in this common database of general language concepts. This theory, along with Megan’s comment about the possibility of many language pathways, got me thinking about how aphasia could just damage one or a couple of these pathways of language processing/expression, but not all of them. Within this idea, singing may also be another “language” another form of accessing and expressing language concepts (as well as other musical concepts…_). Perhaps this is why aphasics can still sing, but not produce speech and can recover one language more than another even though they were fluent in both before.
 

meroberts's picture

Link between consciousness, speech and music?

http://www.sciencedaily.com/releases/2010/04/100408111313.htm

This article came out Saturday and it has some pretty interesting implications to our discussion of aphasia and the recuperative power of music as it relates to a loss of speech-production ability. The article says there is no link between amusia, lack of musical ability, and dyslexia. This implies that the processes that govern musical ability are different from those that govern speech production.

I particularly enjoyed this explanation of the difference between musical ability and the ability to produce speech:

"Music and speech do overlap, but musical sounds and phonemes are not the same, the researchers explain. Musical tones are simply sounds, however, they are produced and can be heard without recourse to complex auditory analysis. Phonemes, in contrast, whether spoken or read, are abstractions of the units into which language might be broken down. They are purely symbolic and require significantly more interpretation to understand than simply hearing a sound."

The researchers go on to say that phonemes are consciously studied and learned. This conscious learning process distinguishes speech production from musical ability because the amount of interpretation (or amount of neurons involved in interpreting process) that is required to understand speech is greater than that required to produce music. This makes sense to me. I often notice that I'll sing along to songs on the radio without actually paying attention to the words. Therefore, more consciousness is required for speech production making it a more complex process than musical ability. This could change future treatments for dyslexia, which used to base considerable emphasis on music therapy.

EB Ver Hoeve's picture

  Even though it seems no one

 

Even though it seems no one else decided to post about the beginning of last week’s conversation, I thought I would because, honestly, the discussion on Intro classes kind of bothered me. The basic question posed by Paul, was, should we do away with introductory level classes/what’s the point of introductory classes? Honestly, I feel that the class was overall pretty apathetic to the entire discussion. And, I mean, understandably so. The issues facing the field of pedagogy are not really on the minds of graduating seniors, trying to finish up their theses. But I would just like to say that I feel that we need “the basics” to build from. I think about it like development. In the beginning, an organism is comprised of simple pathways, but as new connections are built on and other connections are strengthened, the organism develops into something complex and functional. I’m not trying to be a cookie-cutter in this system of standardization and conformation; I’m just saying that I think there is a reason/benefit that the introductory classes have lasted this long. Also, I really like learning.  And yes, I learned a lot of detailed information in intro bio that I probably can’t fully recall now, but to me, the fact that I can’t remember all of it doesn’t mean it wasn’t useful to have learned it. And Paul, I think I would agree with you that there are serious issues concerning how students are being evaluated in these intro classes. For instance, I agree that the old school rationale behind the standard multiple choice exam is probably not the most useful way to test for comprehension. Learning is a process and I would prefer to first take in “the basics” in order to ultimately achieve (what I believe to be) a more complete understanding.    

 

Paul Grobstein's picture

learning as process: "basics" first?

Glad you picked up on this.  I do indeed think there are "serious"issues here, not only about evaluation but also about curriculum and "learning" in general.   For more along these lines, see Subjectivities and objectivities in classrooms and beyond and Evolution of science education as story telling and story revising.  Does one really have to "first take in 'the basics'"?  Mightn't one be better off trying to construct understandings for oneself from the beginning?  Much the way we learn language? 

Jeremy Posner's picture

The neuroplastic adaptations

 that the brain has been shown to be capable of in cases of aphasia but also generally in response to prolonged deficits in a particular sense are really incredible.  The degree to which the brain seems capable of reorganizing itself to deal with problems that may arise in its function amazes me.  I am still wowed by the idea that the effects of Parkinson’s Disorder are only really evident after a person has lost a huge percentage of the cells in their dopamine pathway (off the top of my head that number is north of 80%).  Of course the reorganization and repurposing of the visual cortex in response to blindness is another often dramatic example of neuroplasticity; I recall a television special in which it was demonstrated that activity in the visual cortex in response to tactile stimuli increased significantly after a volunteer with normal vision went without using their eyes for a week.  Amputees have reported feeling their lost limbs when their faces are touched because of a blending between two areas of the sensory cortex as a result of their injury; there are a huge number of examples of this but I really am amazed by how easily the brain seems to bend but not break when faced with an injury or disruption of function. 

 

At the same time I am absolutely confused by some of the neuroadaptive processes that the brain seems to be capable of and some that it does not.  I wasn’t able to add a lot to the discussion of being able to adapt to an inability to speak by learning to speak through song, and the implication that speech and song depend upon different neural processes because I really do not understand why that would be, either in the exact nature of speech and song and what difference between the two distinguishes them functionally and from an evolutionary perspective why such a distinction would develop within the brain.  Back on the general topic of neuroplasticity it is interesting to me that the brain is apparently capable of a fair amount of adaptation and adjustment in response to injury but that damaged neurons are generally not capable of a significant amount of regeneration.

meroberts's picture

Primitive Brain Structures

 

“If people who we consider blind actually have "blind sight" - the term refers to a native ability to sense things using the brain's subcortical and primitive visual system- who knows what other capabilities we have missed in people with losses of function.” -VGopinath

The idea of primitive brain structures is an interesting addition to most of the topics discussed in class and I’m glad that Vidya mentioned it. I was actually thinking of the role that these primitive brain structures play in our discussion about the experience of stroke a few weeks ago. The evolution of the human brain has allowed for very complex brain functions. But it also enables secondary pathways to take over should there be damage to a more localized structure. I agree with Paul that the oversimplified ‘localizationist’ viewpoint often ascribes specific functions to structures and misses the big picture of the entire neural network and its ability to reorganize: “"function" isn't so much "recovered" as reconstructed from surviving functions” (Paul).

I believe that music and speech are two very closely-related, complex forms of communication. There must be considerable overlap in the ability to produce speech and the ability to sing. But if the ability to sing is maintained in people with certain types of aphasia while the ability to speak is lost, there must be some differentiation between the two processes. Thus, there might be some truth to the localizationist perspective if, for example, damage to Broca’s area routinely causes similar deficits in speech production in all Broca’s area aphasics. At some point in the evolutionary process, this area became a dominant area of speech production. The neurons in this area became so adept at speech-production that the network crystallized as THE speech-production site of the modern human brain. That doesn’t mean that it is the only neural path that can create speech, but it is probably the most evolved method. How is it that certain primitive pathways can be forgotten with the advent of new, perhaps more efficient pathways? What secondary neural activity do these primitive pathways engage in when there is no primary need for them? Is it safe to assume that these forgotten primitive neural pathways are ‘taken over’ by other functions?

 

LMcCormick's picture

Aphasia and music

I am intrigued by the notion that it is the social aspect of singing that improves language in aphasics.  In class some people suggested that this may be because singing in a group provides auditory feedback.  However, I feel like this is an unlikely explanation: I doubt that reading an unknown passage in a group would have any therapeutic effect for someone with aphasia.  Instead, I am inclined to believe that the social benefit has more to do with a combination of the predictability aspect of music and the emotional experience.  As many people have mentioned, it seems important that music is familiar/predictable.  It is possible that music functions as a sort of muscle memory for language – with enough practice aphasics strengthen connections that improve their speech.  However, I imagine that it is also this predictability that fosters an emotional experience while singing in a group.  As I mentioned above, I doubt speaking an unknown passage in a group would conjure an emotional experience or improve language in a person with aphasia.  However, what about a familiar passage, such as reading prayer in a group?  For many people this is a very emotionally charged experience that fosters unity as a group in a similar way as singing in a group.  It would be interesting to study whether reciting group prayers might help a person with aphasia that is religious.  If it does, it might suggest that it is the emotional charge and familiarity of group singing that helps aphasics rather than music’s tonality or rhythm. 

I am also curious about the question of how this phenomenon might manifest differently in people who speak different languages.  Might different languages have different types of connections with the music center in the brain?  And how might this change if a person is bilingual?  Would music therapy in one’s mother tongue improve their linguistic abilities in another language, or are the two languages represented completely separately in the brain?

 

Paul Grobstein's picture

Aphasia rethinking methodology/localization/rehabilitation

I too was interested in the speaking/singing distinction as it turns up with brain damage, and the difficulty in distinguishing between the two in other terms.  I'm intrigued by the possibility that in the present context singing should be seen as more "structured"/"predictable" than speaking, and so the speech problems classically associated with aphasia may relate less to words or language per se and more to brain processes involved in integrating novelty/unpredictability/individual intentionality into structured sequences.  Its worth thinking more as well about the social dimensions of singing along these lines. Maybe the social character facilitates structured outputs like singing in a way that is missing in speech?

On a more general level, the conversation made me think more about brain/behavior methodologies as discussed earlier in connection with imaging in comparison to older methods, in particular lesions.  That behavior can be immediately "released" by brain damage clearly indicates that simple localizationist interpretations of brain organization based on deficits following lesions are not reliable.   That deficits can also not be reliably interpreted as indicating that particular functions reside in particular brain regions (cf my Strategies for analyzing complex organization in the nervous system. I. Lesion experiments, the old revisited (available as .pdf).   To this we should add the caution that experimenters are always looking for particular functions as they understand "function," and so may impute functions to brain areas other than those actually performed there.

I wonder to what extent the entire literature on brain organization in relation to language may need some significant reinterpretation because of these problems.   There is no question but that damage to Broca's and to Wernicke's areas produce disturbances in linguistic behavior.  It is though, I suspect, at least an entertainable proposition that the disturbances don't relate to language per se but rather to as yet uncharacterized brain functions that play some role in language, and may play some role in other "functions" as well.  There are abundant other reasons to suspect that "language" isn't actually localized in the brain as well but is instead an emergent characteristic of a number of different brain regions, none of them performing itself the function of language. 

And this in turn suggests one may want to think somewhat differently about "recovery of function."  From a naive localizationist perspective, the reappearance of a function after loss of the brain region "responsible" for that function is taken as evidence that some other brain region has "taken over" that function.  An alternate perspective is that most functions are the resultant of a distributed variety of as yet to be described functions and so "function" isn't so much "recovered" as reconstructed from surviving functions.  This would change somewhat how one thought about rehabilitation (along the lines of our earlier discussion of stroke recovery).  And might help to explain my sense of a persistant deficit (and somewhat ironic) deficit in the Music therapy and aphasia speaker.   

vpina's picture

Aphasia was a very

Aphasia was a very interesting topic that I recall going over in my intro class. I do remember that there are many different types of aphasia’s that affect different portions of the brain and make it so that a person has a more difficult time with life. The two stories that we talked about in class on the happy stories of people overcoming these issues or having a positive come from it, which is rare from my knowledge. I recall an aphasia where even though the person can understand spoken word their response comes out as gibberish.

At first I thought that the idea of a part of the mind being “locked” was something more out of a sci-fi than hard science but the conversations we had and the video seen makes me more of a believer.   At least in the sense that even though someone loses a sense it doesn’t mean that they can not find another way to get threw it. It also brings to my attention that this is a sensitive situation and I’m guessing the man in the video did not speak like that prior to the accident. Though there is a lose there may not be a total loss whenever these things happen and the two stories do keep hope alive for those of who have not found the alternative to their aliment.   

rdanfort's picture

This was a cool talk

I really like cross-sensory stuff.  One thing that I don't think was really addresed, though, was the question of whether or not sensory language is a good fit for observed changes in how patients express themselves.  Aphasic patients can hear fine, and so the general classification of AA as becoming "more visual" struck me as an oversimplification and a too-convenient reference to the more solid theory of the deaf being more vision-oriented and the blind developing keen processing of sound.

Speech, and the processes that feed into speech, are heavily reliant on hearing for feedback, so it is foreseeable that damage to a speech-processing region would reduce the firing of some sensory neurons and promote expression in terms of other sources of input.  I couldn't say whether this would be expected to affect the quality of sensory perception, or how I would go about trying to find out.  Do people with aphasia find themselves unable to think in words?  If not, do they gradually stop thinking in words over time?  I can think of a lot of ways in which cognition might change independent of sensory readjustment, which is part of what made me suggest that cognition - realizing that the sense or the motor/expressive functions are not quite 100% - might play a role in restructuring how sensation is perceived in a blind or deaf person.

aliss's picture

During our discussion of

During our discussion of aphasia, I wondered what the difference between English and tonal languages would be in terms of aphasia treatments.  From what I know about some Asian languages (which is admittedly not much) there are some languages in which the same words can have different meanings depending on the tone.  Do people who speak these languages have more overlap between the "singing" and "speaking" centers of their brains?  In this case, would injury to Broca's area have less of an effect in this population than in the English-speaking population?


Like Sara, I've been trying to decide what about singing makes it different from speaking, and why there would be two separate areas in the brain that deal with both - especially because lyrics to a song are not a problem for aphasics although they are words.  I think we hit on something when we discussed the predictability of music, and the way that a musical phrase can prompt lyrics when it is hard to come up with the next word.  Another possibility that I have considered is that in the healthy brain, singing does activate Broca's area just like speaking does, but it also activates this separate area in the right brain.  Therefore, the activation of the right brain in left-hemisphere damaged patients helps to recall speaking (since they are usually activated together).  This could also help explain why speaking could be recoded onto this specific area: if they are usually activated together, and the two areas also activate similar functions, then it might make sense for speaking to be recoded onto the "singing" area in the right brain.

sberman's picture

singing vs. speaking and music therapy

I've been thinking a lot about the difference between singing and speaking --> in class, we discussed that signing and speaking vary only by degree. Both singing and speaking share rhythm, tonality, and beats, but these characteristics are just more pronounced in singing. Initially, the fact that I could not come up with something distinct that singing has that speaking does not have confused me in terms of how singing could be helpful for aphasiacs. Why would singing help people learn to speak if it didn't require anything but an enhancement of speaking characteristics? After thinking about it more, however, I think that the extreme similarities between speaking and singing is the reason why music therapy must be so helpful for aphasiacs. The portion of the brain responsible for singing has the capabilities for speech (rhythm, tonality, fluency), so singing therapy might help aphasiacs by training the portion of the brain previously used for singing to be used for speech as well. 

Vidya brings up an interesting point in her post though re that music therapy has been used for Parkinson's. I also am aware of a lot of other disorders that employ music therapy for treatment (autism, for example). Is the way music therapy is helping this large variety of conditions through the same mechanism for each (a social, positive group mentality one)? Or is it that singing is associated with language (which helps aphasiacs) and music is associated with movement (which helps Parkinson's patients)? Is there any way to tease apart the mechanism by which music therapy helps sufferers of vastly different diseases? Does it even matter if music therapy is just helping because it is social, because it does helps aphasiacs speak and can reduce Parkinson's tremors? Is it important for us to know a mechanism other than that "music is social" to increase the legitimacy of music therapy? (at least in terms of funding for it, I think yes).

VGopinath's picture

Unlikely Connections

     The knowledge that aphasics can still sing even when they can't speak was actually completely new to me.  I find the evidence of singing as therapy for aphasics one of the most compelling aspects of our reading and it got me thinking about other cases in which losses of function are so specific to the point that very related skills are not affected. One example that I have heard about is the fact that Parkinson's patients can dance.  Some individuals whose condition is so severe can't walk but they can still dance.  A study by the University of Calgary found that in some patients, music can "freeze the effects of Parkinson's" and stop tremors for minutes after dancing.  Another group is studying the positive effects of singing on people with Parkinson's to prevent the progressive loss of speech and vocal capabilities.  These are both examples of the growing music therapy movement and a great emphasis has been placed on the positive effects of music therapy on neurological conditions but perhaps this can be extended.  

     One of the possible contributors to the positive effects of music therapy is psychological- Parkinson's and other neurological disorders can be alienating thus being in big, positive groups can improve morale.  Exercise in general has numerous biological benefits and this is a fun way to keep individuals active.  The social aspect could also account for how singing in a choir is more beneficial than singing alone.  Therefore, the benefits of music therapy can potentially be felt by other patients.  

     I found this an impetus for us to be creative in looking at which capabilities are impaired and which aren't in other disorders to find unconventional therapies.  A very remarkable study I found was published in Biology and it demonstrated that a man who is blind due to two successive strokes was actually able to navigate a cluttered hallway.  If people who we consider blind actually have "blind sight" - the term refers to a native ability to sense things using the brain's subcortical and primitive visual system- who knows what other capabilities we have missed in people with losses of function.  

 

The article on "blind sight:" http://www.nytimes.com/2008/12/23/health/23blin.html?_r=1

David F's picture

A minor point regarding the re-localization of function

We briefly touched on a point tonight that has confused me in the past and continues to confuse me. When someone suffers damage to their language center (e.g., Broca's area), some have an ability to "re-locate" their language abilities to different parts of the brain. For example, the study on white matter plasticity showed that language abilities could be recuperated in former music-related circuitry. This is not an isolated instance, as we also discussed that blind people, youth, and people who experimentally wear blinding goggles can develop occipital activation in response to auditory and tactile stimuli. It can also work in reverse, such as when a monkey whose motor cortex is hooked up to a brain-computer interface realizes he no longer has to move his arm in order to move the cursor on the computer screen (representing motor cortex activation while eliminating the connection of that activation to efferent motor neurons). In our discussion of this plasticity, Paul asked "what" decides to perform this relocation of circuitry. This appears as an odd question at first, as it seems to imply the existence of some external, non-material entity or consciousness that can dictate physical processes. However, it need not imply this sort of conclusion, and rather indicates to me a much more complicated and real question. Since I assume we all believe in necessary causality, we can reasonably conclude that there must be some "upstream" input that encodes the desire to speak and causes activation in Broca's area, which ultimately results in speech. When someone relocates their speech circuitry to, say, their musical circuitry, it seems equally reasonable to conclude that the upstream input that represents the desire to speak now causes enhanced activation in the musical circuitry. Now: why is this? One possibility is that the upstream input always had a connection to that musical circuitry, but after the loss of Broca's area, these connections were strengthened or "unveiled". By why would that be? The musical circuitry should be receiving an equal amount of synaptic input before and after the insult to Broca's area, so why would there be a strengthening of these connections afterwards? What force would allow for this reinforcement? A second possibility is that the fibers that originally connected the upstream input to Broca's area must now find other dendrites with which to form synapses, or else they will die. These fibers form new synapses with the musical circuitry, thereby strengthening the connection between the upstream input and the musical circuitry. But then how would the fibers be able to find the musical circuitry versus any other available synapses? Moreover, what would reinforce these connections while eliminating errant connections (e.g., perhaps the upstream input fibers might synapse on the somatosensory cortex, causing a tactile sensation whenever we wanted to speak)? A potential answer to either of these questions is that we receive perceptual data that can feedback and reinforce or eliminate new instances of plasticity. In other words, we can perceive ourselves communicating musically when we desired to speak and think "Good! I want more of these kinds of connections!" or perceive ourselves feeling a tingling sensation in our arm whenever we we desired to speak and think "Bad! Get rid of these connections!" But how would we go about identifying the physical underpinnings of this reinforcing/eliminating feedback force? Another possible answer that I can think of is that the neurites of fibers from the upstream input express receptors that specifically respond to neurotrophic factors released from Broca's area and the musical circuitry, with more signalling coming from the former. When the former Broca's area is damaged, the now available wandering fibers are attracted to the weaker neurotrophic signal coming from the musical circuitry, and find new connections there, thereby strengthening the connection between the upstream input and the musical circuitry. But does that mean every connection in the brain is established by its own particular set of neurotrophic factors and receptors? Moreover, how can this story account for loss of input without damage (e.g., blindness goggles) or the reverse instance of plasticity (e.g., when a monkey eliminates its own efferent connections)?

Anyway, I realize that I've rambled to some extent, but this is a question that's bothered me for some time. I feel like I'm missing a simple but critical piece of the puzzle.

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