Congenital amusia york 2012

The Musical Mind: Insights from Congenital Amusia Dr. Vicky Williamson http://www.gold.ac.uk/music-mind-brain/ http://www.gold.ac.uk/psychology/staff/victoria-williamson/

Overview
What is amusia? How is it diagnosed?
Behavioural studies – what is difficult?
How music overlaps with other cognitive processes
Neurological studies; structural and functional
How their abilities and brain structure inform about typical music processing

We are born ‘musical’
Preference for consonance at 2 days (Deaf parents: Masataka, 2006).
Notice changes to contour (ups and downs) but not intervals (Trehub et al,1997)
Respond to phrase structure in Mozart (Krumhansl & Jusczyk, 1990)
Can distinguish different rhythm deviations at 2 days (Winkler et al. 2008)

Natural musical development
Newborn – perceive and remember pitch sequences, sensitivity to contour, preference for consonance
4-6yrs – Respond to tonal more than atonal music
7yrs – Sensitive to the rules of implied harmony
10yrs – Understand finer aspects of key structure
12yrs – Begin to develop tastes and recognition of definite styles

What is amusia?
People are born with the ability to internalize the music of their own culture (Hannon & Trehub, 2005)
Amusia: Lifelong difficulties with music perception (production)
Not acquired
Estimated ~4% of the population (Kalmus & Fry, 1980)
No hearing loss, lack of exposure to music, social or cognitive impairments (Peretz et al., 2002; Ayotte et al., 2002)

If you were amusic…
You report having the condition for as long as you can remember
Typically unaware when music, including your own singing, is off-key
Only ~50% have difficulties with rhythm
Difficulty discriminating or recognizing melodies without lyrics
May dislike musical sounds and even avoid public places and situations where music occurs.
Significantly less likely to “use” music in everyday life or experience reactions such as chills, relaxation or mood enhancement
( Ayotte et al, 2002; Peretz et al, 2003; McDonald & Stewart, 2008 )

Psychological Functions McDonald & Stewart, Music Perception (2008)

Some (possible) examples
Milton Friedman – Nobel prize winning economist
President Theodore Roosevelt
Che Guevara
Florence Foster Jenkins
King Alfonso XIII of Spain - (Anthem servant)

Why is amusia interesting?
Sheds light on cognitive, neural and potentially genetic basis of normal musical processing
Can address questions concerning the extent to which musical capacities are associated with other capacities (language, spatial awareness)
May shed light on possible origins of other developmental (congenital) disorders such as dyslexia, prosopagnosia and dyscalculia

Diagnosis - MBEA The Montreal Battery for the Evaluation of Amusia Hear 2 melodies and say same or different Subtests: Scale, Contour, Interval, Rhythm, Meter (Memory)

1) Pitch Perception Deficits
What is the smallest difference in pitch that can be detected? ( Pitch Change )
What is the smallest difference in pitch that can be discriminated? *
( Pitch Direction )
What type of test to use?

Based on Loui et al. (2008) Testing pitch direction 0

Problem: Really excessive thresholds!

An alternative – AXB tasks Pitch Detection Pitch Direction The advantage of this task is that it is ''criterion free'' (Macmillan & Creelman, 2005)

AXB thresholds Williamson et al. 2012 Neuropsychologia

Conclusions: Pitch Perception
Many amusics can detect pitch changes but have problems discriminating direction
Right Heschl’s gyrus lesions (Johnsrude et al. 2000), bilateral lesions of AC (Tramo et al. 2002) , and ‘direction poor’ listeners (Mathias, Micheyl & Bailey, 2010)
Affects the small changes which are often used in ( western ) music (e.g. semitones)
Amusic thresholds are sensitive to task demands

2) Pitch memory problems
Williamson & Stewart (2010) – Memory
N = 28 (14 amusics)
Tone span (how many tones can you remember?)
Digit span (similar test)
Both tasks use a list probe recognition paradigm, and a 2up 1down adaptive tracking staircase procedure.
Working memory span (Operation span – Professor Randall Engle)

Amusic’s tracks Digits Tones Span = Average of last 6 reversals

Findings
Amusics have lower spans for tones but not digits

Conclusions: Memory
Significantly reduced tone span but comparable digit span
No general short-term memory problem
Influence of pitch perception (direction) problems only arguable in two extreme cases.
Supporting evidence: Inability to maintain pitch sounds in memory (Williamson et al. 2010, Advances in Cognitive Psychology )
Around 20% may have reduced working memory = poorer attention?

3) Speech problems?
Pitch is important to audible speech
Especially if we are apart.
Tone languages (65%)
Intonation: Question to statement, convey attitude.
Speaker Identity
Do amusics have trouble hearing speech?

Liu et al.(2010) Brain
Statement-question discrimination with SUBTLE pitch changes:
Natural speech
Gliding tones
Nonsense speech

Natural speech Gliding tones Nonsense speech * * * amusic control Most amusics have difficulties with all 3 tasks amusic control amusic control

Conclusions: Speech
Difficulty with subtle speech prosody
No difficulty with ‘natural’ sentence stimuli (Patel et al. 2008)
Not a huge problem in real life:
Large pitch leaps (5-12 semitones)
Semantic and sentence context
But important processing overlap

4) A spatial problem?
Pitch has a spatial association
“ Lower” or “Higher”
The musical stave
SMARC effect (Rusconi et al., 2006)
Musicians better on spatial tasks (Brochard et al., 2004)
Amusia as a failure to implement a spatial representation of pitch?

Supportive evidence NB. No overall difference in reaction times

Visuo-spatial tasks Williamson, Cocchini & Stewart (2011) – Brain and Cognition
MBEA
Pitch detection and direction discrimination thresholds
Mental Rotation
– Shepard & Metzler figures
Visual Patterns Test (VPT)
– visual memory
Corsi Blocks
– spatial sequence memory

Results

Conclusions: Wider cognition
Amusia is associated with wider pattern of difficulties than just pitch perception...but...
All difficulties have a pitch basis
Spatial difficulties in amusia have not been replicated in two published studies
Unique view of processes that underlie music cognition

Neurological underpinnings
No difference in structure of PAC
Hyde et al. (2006) measured white matter density between the right frontal and temporal lobes.
Amusics white matter was thinner, suggests a weaker connection.
Severity of Amusia = Thinner white matter.

Diffusion tensor tractography studies
Loui et al. (2009) – A rcuate fasciculus (AF).
“ Disconnection” in the temporal-frontal pathway
Abnormal migration of proteins along tract
Underdev of higher order musical processing

In 9/10 Amusics the right superior AF (red) was unidentifiable

EEG study of melodic expectancy (Omigie, Pearce, Williamson & Stewart, in revision)
Task: Detection of expected or unexpected notes in a melody (Pearce and Wiggins, 2006; Pearce et al. 2010) using an implicit (timbre) and explicit task
Previous finding: Amusics were comparable in the implicit task but significantly worse at explicit recognition of unexpected notes
Present study: EEG while listening to real melodies . ERPs associated with the recognition of an unexpected musical event (ERAN/N1; 150ms)
Hypothesis: Amusics will show attenuated responses
N = 30 (15 amusics): 58 hymns in electronic piano (32 or 64 notes long), all but first 2-4 notes divided into 3 ‘bins’ of low, medium and high expectancy
Listen to the melodies and detect any deviation in timbre

Results
Less expected notes = ERAN/N1 in controls that was diminished in amusics
Amusics have internalised the regularities of music but have less robust representation
Supported by studies of musicians (Koelsch et al. 1999; 2007)
Early pre-attentive mechanisms increase probability that change will be consciously perceived (Teemu Rinne et al. 2006)
Scalp maps showing voltage and illustrating the negativity in the N1 time window for low, medium and high expected notes, and the difference in voltage between the low and high IC conditions. Amusics Controls

Conclusions
Congenital Amusia is a neurodevelopment disorder that impacts on music listening (and production)
Pitch perception problems; discriminating pitch direction
Pitch memory weaknesses
Carry over into subtle speech difficulties
But no spatial difficulties
Most likely brain origin is a breakdown in pathways that carry pitch-based information to higher centres (role in other ND disorders)
Diminished explicit awareness of change alongside intact implicit knowledge – links back to task sensitivity issues in pitch perception
Insight into the organisation of musical mind .

Thanks for listening

Congenital amusia york 2012

by vickywilliamson

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