Good morning dear reader. I realised yesterday that I still had one blog from the recent Music and Neurosciences conference that I had left to upload! So here you are:
I was particularly looking forward to the symposium entitled ‘Music: A window into the world of autism’. My friend Prof Pam Heaton was due to speak and I have always enjoyed her presentations, plus I was interested to hear about the other types of work going on in this area. The goal of the symposium was to present recent advances in research examining the neural underpinnings of musical processing in Autism Spectrum Disorders (ASD) and the therapeutic potential of experimental treatments in ameliorating some of the associated deficits.
1) Pam Heaton – Why are musical skills preserved in autism?
The first speaker was my friend Pam, who did a great job of outlining the symptoms and consequences of ASD for the audience. She pointed out that the first report of ASD from Kanner (1943) remains a very accurate description of the condition to this day, in particular in its emphasis on the language and social abnormalities that characterise a child or adult with ASD, and also the high incidence of heightened musical abilities. In Kanners original study 6/11 children displayed unusual music-related behaviours including one in particular who was able to identify 18 symphonies within the first two years of life.
The paradox of ASD in the auditory world seems to be a neglect of speech (Klin, 1991) combined with focused attention of the contour, syntax and even emotion of music.
Pam presented some pilot work she is conducting right now looking at ASD children and their reaction to different auditory sounds in their environment. She is looking at 10 children and age matched controls and coding a number of factors in their responses to different sounds: orientation co-ordination, positive affect, vocalisation, and anticipation/ increases in focus. She found that children with ASD showed more attention to music compared to either speech or environmental sounds.
In a second study she looked at emotion recognition of happy, sad and fearful states in vocal gestures (like laughing), vocal pseudo words and music. She has so far found no differences between ASD and control children in their ability to detect emotion in these stimuli. Interestingly however, while ability to detect emotion in all three types of stimuli is highly correlated in control children, the ASD children show no correlation between their identification of emotion in vocal gesture and music, and pseudo words. She concluded that speech processing may be less focused on semantic content in ASD and more focused on the finer perceptual aspects (so the more ‘music like’ aspects such as pitch and contour). An example of this is being able to recognise a word spoken by their mother but fail to recognise the same word spoken by their father.
2) Krista Hyde – Brain and behaviour correlates of auditory processing in ASD
I know Krista of course from her many years of work in congenital amusia. She now has her own lab and has moved into the area of studying auditory processing in ASD, in both children and adults. She talked about her work on high functioning adults with ASD. She pointed out that ASD has up to 90% heritability and is 4 times more likely in males. She also built on Pam’s introduction by describing the auditory processing features of ASD:
- Hyper/hypo sensitivity
- Hyper focus on the local sound source
- Diminished perception of speech
- Enhanced musical ability, including pitch perception and pitch memory. Absolute pitch is also much more likely in ASD than in a control population
She presented the Enhanced Perceptual Functioning (EPF) model of ASD, which is based on a similar model that was developed in the visual world. It is the equivalent of seeing the tree before the wood, rather than seeing the wood before the trees.
She also presented the Neural Complexity Hypothesis (NCH) in ASD (Bertone et al. 2003) which postulates that an over-activity in primary visual and auditory areas in ASD in response to simple stimuli is combined with an under-activity in the same areas for complex stimuli.
Her three studies (one behavioural, one brain structural, and one brain functional) presented data that nicely fitted with both the above hypotheses. In the first study, ASD adults show better perception of simple tones, especially when their speech onset is delayed. In the second study she found larger left planum temporal volume in adults with ASD (Foster et al. 2011 – Human Brain Mapping). Finally, simple tones elicit larger activity in primary auditory areas in adults with ASD compared to controls (reflecting their hyper sensitivity) while complex tones elicit less activity in the same area (reflecting their hypo sensitivity).
Her conclusion was that there is particular sensitivity in ASD to the processing of low level features, and pitch in particular. Next she intends to collect DNA samples to make a further link between genes, the brain and behaviour.
The final two talks were by Istvan Molnar-Szakacs and Catherine Wan (session chair). Both presented great brain data that supported the work of the previous two speakers.
Istvan has been working with Katie Overy on the Shared Affective Motion Experience (SAME) model of music perception, which holds that music is perceived not only as an auditory stimulus, but also as intentional, hierarchically organised sequences of expressive motor acts behind the signal.
They postulate that the human mirror neuron system allows for co-representation and sharing of affective musical experiences. With fMRI they have showed that children with ASD exhibit normal responses to emotional music in their mirror neurons and emotion areas of the brain, supporting their reliable ability to identify emotion in music (as showed by Pam earlier)
Catherine is working on a fascinating new intervention for nonverbal ASD children that is called Auditory Motor Mapping Training (AMMT). AMMT grew out of work on music therapy for stroke patients (Melodic Intonation Therapy) and in principle the method is very similar.
There is bimanual tapping on two drums that play a tone as you hit them (one high and one low) and children are taught words using the drums. Her pilot work, on 6 nonverbal ASD children has shown that in just 8 weeks children can learn some simple words, which is a big breakthrough when in some cases the children had not spoken for up to 8 years of their life. Using brain imaging of white matter tracts in the brain (Diffusion-Tensor Imaging) she has shown abnormalities in the language tracts of the brain that may be related to treatment outcomes. I will look forward to hearing more about her studies as they progress.