4 - 2 - Audition

Archiwum

• Index
• 4 - 5 - Video 3.5 The Effectiveness of Task Shifting & Task Sharing (10 55), Childbirth A Global Perspective
• 4 - 4 - Video 3.4 Task Shifting vs. Task Sharing (8 47), Childbirth A Global Perspective
• 5 - 6 - Video 4.6 Challenges to EmOC Implementation in Developing Country Contexts (8 26), Childbirth A Global Perspective
• 5 - 3 - Video 4.3 United Nations Process Indicators for Monitoring EmOC (8 52), Childbirth A Global Perspective
• 4 - 1 - Video 3.1 Health Care Workforce Shortages (6 01), Childbirth A Global Perspective
• 5 - 5 - Video 4.5 Quality Improvement in EmOC (3 05), Childbirth A Global Perspective
• 5 - 2 - Video 4.2 EmOC Signal Functions (6 52), Childbirth A Global Perspective
• 5 - 4 - Video 4.4 EmOC Monitoring and Assessment (5 22), Childbirth A Global Perspective
• 4 - 2 - Video 3.2 Maldistribution & Migration (6 07), Childbirth A Global Perspective
• 4 - 10 - Pros and cons of 'labeling ', Childbirth A Global Perspective
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4 - 2 - Audition, Childbirth A Global Perspective

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So, another part of the dyslexiaconstellation is the area of audition.And ... we've referred tothis a bit in previous weekswe've talked about the fact thatone of the primary issues indyslexia is a phonological deficit.And ... this is a sound-based problem.So adults give the hint, that maybe otheraspects of audition may be impacted.But this is in fact ... a very mixed area of research,the findings are not conclusive.And so we're going to talk a bit aboutwhat we're seeing and why this might be.And I think one of the issues here is that... audition is actually an incrediblybroad area of processing.And just to be clear as well,when we're talking about audition,we're not necessarily talkingabout peripheral hearing per se,so whether there's something going onwith the actual ears themselves, butit seems that if there isan issue with audition,it is going to be more atthe level of of the brain, andhow the brain is making sense ofthe sounds that the ears transmit.So (as I said)there has been a lot of research butwhen we think about how the brainprocesses sound it actually haslots of different areasdoing different types of processing.And this makes sense because speech isjust such a complex signal thatwe're actually trying to process.And so ... ... ...as a mature adult,we hear very clearly a 'b','d', those sounds have somany different elementsthat discriminate them from each other.So for example, one dimension on whichspeech sounds differ is DURATION.So for example,you can have the vowel sound 'eh' andthen you can have the vowel sound 'air'and those two sounds ... can createdifferent meanings if in a word.Also, speech sounds different (in) FREQUENCY,... sometimes called 'pitch'.And ... this is due to how air actuallytravels through our vocal tracts.So when we're producing a soundthe air comes up ... throughthe vocal tract, out though the mouth.And it's actually,it's kind of bouncing around as it goes.It ... can't go in a straight linebecause our vocal tracts aren't ...purely straight.So the air bounces around, andthis actually causes multiple resonances.So ... actuallymost speech sounds have pitches ofdifferent levels, as a result of these ... various courses the air is taking.And so, so we need the brain to compute,not just one frequency, butactually multiple frequencies,... and then work out the soundidentity from that pattern.And actually ... ... youcan get a sense of this with -especially with old telephones,because old telephones often chop offthe highest frequencies,this can sometimes make it ... ...difficult to hear the distinctionbetween sounds such as 'ff' and 'ss',which have quite a lot of highfrequency elements to them and so,by chopping out the higher frequencies,those sounds can become difficultto distinguish, and so ... ...something a telephone can't quite masterour brain is doing all the time.Another element where sounds canvary is in their LOUDNESS andtheir loudness patterns.So, whenever we produce a syllable,what's happening isthe sound is going from a very lowloudness or amplitude and then whenthe vowel comes; a vowel is a veryopen sound; usually our articulators,our tongue and things, kind of get out the wayand just let the air come through.And this ... makes vowels a more,resonant, higher amplitude sound.All syllables have a vowel.So so typically, the peak of the loudnessin any syllable, is that vowel point.And people need to be ableto distinguish the rate atwhich the loudness gets to its maximumamplitude, what that amplitude is.And when you think about Englishit's ... what we calla stressed-based language.So ... some syllables have a greaterdegree of stress than others.And, although what constitutesstress is actually quite complex,one of the clear, most salient, factorsin a stressed syllable is actuallyit's just louder thanan unstressed syllable.So, for example, in the word'binoculars' when I'm saying the 'nock',... you can hear that'sa more salient, louder syllable.When I'm saying ... the following syllable, so'(nock)-culars', the 'l is just a veryindistinct syllable, less loudness.And this is in children a key gateway in talking andlearning a language -hearing the syllables andthen working out what's within them - stressed syllables can be more informative.So there's lots going on here.And then... we can add more layers ofcomplexity, because actually, although wecan come up with the prototypicalqualities of anyone's speech sound,... .... when we're linking soundstogether they actually influence eachother and the speech stream is a bitof a 'mush' when it comes to it.So for example,if I'm making the 'r' sound, that... sound will have a certain,group of frequencies, a certain duration.But then if I put a 'm' at the end,so 'arm', then actually, I'm really... altering the quality ofof the 'r' in my preparation tomake that 'm' sound, ... ...so the vowel is actually gettinginfluenced by the nasal quality of the 'm'.And yet our brains just makes sense ofthis; they extrapolate, they work out,'okay, that's still an 'r' even thoughit's being a bit intruded on by the 'm'.So... it's an epic featthat our brains are doingin distinguishing sounds at all.And so, this suggests that then actuallythere's multiple levels at whichthe system could also go wrong.And I think this is the conundrumaround the relationship betweenauditory perception and phonologicalprocessing difficulties in dyslexia,because lots and lots of researchershave been looking at this area, butthey've all taken a slightly differentaspect of the perceptual task.They've perhaps ... looked at children with different ages anda different dyslexic profile potentiallygiven the heterogeneity ... of dyslexia.So, I often think about... the story of the blind men andthe elephant,when trying to kind of make sense of this.Because it feels like auditoryperception is this elephant, andus researchers (are) blindly holding on to adifferent aspect of it andthinking 'oh, ... this is may be ... the thing that's going wrong.And ... then (other)people are thinking 'oh,well I'm finding different things to you'.But actually we're probably alllooking at aspects of the same issue.So ... ... to summarize wherethe research is at in this area:What we seem to find is that when peopledo studies of different aspects ofauditory perception, andseeing if these are impacted in dyslexia,we're finding that typically ... moststudies find that a sub-group of childrendo struggle with say, durationdiscrimination or loudness discrimination.But it's never typically seen inall the children with dyslexiain a research sample.So this suggests to us thatauditory perception does sometimesseem to be compromisedbut... it's not a consistent link.We can't clearly say the phonologicalproblem is (in)controvertibly coming from aa kind of lower level auditory cause.But this doesn't mean that that'sactually not what is happening.And if you remember in week one,when I was talking about a longitudinalstudy in Finland where they'd actuallyfollowed children at genetic risk fromdyslexia from the first week of lifeand by playing the infants Finnishspeech syllables and lookingat the neural responses to those syllables,they were finding strong correlations tolater language development,and later reading development.So this suggests that ... potentially,audition really and speech perception isquite key to the, the profile, but it mayjust be that we're actually not capturingthis trajectory very sensitivelyin our current measures inour piece-meal approach which is whenaudition is such a complex thing.It's actually hard forus to do otherwise, buthopefully in a few decades we're going tobe closer to what's really going on here.So, that's quite a long and complex storyif we're talking about how auditionmay link to phonological processing.But there's real interventionimplications here,which is really ... the motivation here.And that is, if we can find aspectsof speech perception, or even ...lower level perception andnot just localized to speech,this could give us another strategywith which to help people with dyslexia,if we could actually maybework on improving andtuning these earlier aspectsof speech perception.And this is actually something duringmy doctoral work with Professor Usha Goswami we werelooking at aspects of amplitude orloudness discrimination.We were looking to see if this wasrelated to reading difficulties,which we found for many children it was.But then we asked, 'well if we try andfine tune amplitude discrimination,can we see knock-on effects on literacy?'And this was with some older primaryschool children where ... ...we saw some positive effects,but they weren't actually as... as significant as the effectsof actually working on literacy itself.So I think, taking the study asan example and looking at others,we're not in a position where wecan say that any aspect of auditoryintervention should take the place ofactually just working on the literacy.But it could be a useful supplement.And I think especially whenI reflect on this, forchildren who are sodisaffected with reading,I'm hoping that this could ultimately bea useful way to help them ... ...almost within a new approach where they'renot actually having to face lots of textsbut where we can see somekind of indirect gains.So hopefully that'swher... 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