Thạc Sĩ Comparison of motor deficits in autism spectrum disorder and developmental coordination disorder

Abstract
Autism Spectrum Disorder (ASD) is an umbrella term for disorders involving deficits
in social interaction, stereotyped behaviours and communication difficulties. A growing
area of research has recently focused on motor deficits in ASD, which have been noted
in clinical observations and diagnostic criteria since autism was first described. How-
ever, motor deficits have traditionally carried little weight in the diagnostic procedure.
Until recent changes to diagnostic criteria (Diagnostic and Statistical Manual 5th edi-
tion: DSM-5), a comorbid diagnosis of Developmental Coordination Disorder (DCD: a
neurodevelopmental disorder affecting motor development) was not possible for those
with ASD and motor deficits. This exclusion criterion prompted an investigation of
the nature of motor deficits in ASD, questioning whether they are characteristically
different from motor deficits in DCD. Previous literature suggested a possible double
dissociation in the use of vision and proprioception to guide movement and perception
in ASD and DCD, with a reliance on proprioception in ASD, and an over-reliance on vi-
sion in DCD. Motor deficits were first investigated by looking at high-level motor skills,
and then more basic sensory processing associated with movement to investigate this
possible dissociation. There was no significant difference between ASD and DCD on a
standardised motor battery (Movement Assessment Battery for Children 2nd edition:
MABC-2), with 70% of children with ASD showing motor difficulties within the clinical
range on tasks such as timed manual dexterity tasks and balance. Similarly, children
with ASD and poor motor skills were indistinguishable from children with DCD on
a number of basic motor tasks manipulating visual and proprioceptive cues. These
tests included spatial location matching, reaching, goal-directed movements towards
proprioceptively-defined targets, and the rubber hand illusion. Children with poor mo-
tor skills with a diagnosis of either ASD or DCD seemed to either rely more heavily
on visual cues, or behaved in a similar way to typically developing (TD) children. In
the spatial location matching task, children with ASD and spared motor skills showed
a tendency to give more weight to proprioceptive cues, however too few children with
ASD and spared motor skills took part in other tasks to fully investigate cue weighting
in this subgroup. Mirroring the overlap in social and motor skills in the clinical groups,
a study of the relationship between perceived social and motor ability in a large sample
of TD children highlighted the related nature of these developmental domains in typical
development. It is concluded that motor deficits in ASD are not ASD-specific but are
instead indicative of an additional diagnosis of DCD. This is supported by the recent
change to diagnostic criteria.Acknowledgements
Thank you to Rob for all his help along the way, and for the motivational mp3 rewards
during write-up. Thanks also to Bonnie for her feedback on draft chapters. Thank you
to Anne O’Hare, Sue Davidson and the OT department for all of their help with NHS
recruitment, and thank you to all of the schools, the Skool’s Out after school club,
hospitals, clinics, families and children who helped with and took part in the studies.
Thanks to Alasdair, Mum and Dad for listening to more than their fair share of ethics-
and recruitment-related moans along the way, and thanks Dad for building all of the
apparatus for me! Finally, thank you to the Kerr-Fry Bequest for funding my PhD and
the Patrick Wild Centre for funding one of the studies.Contents
1 Introduction 1
1.1 Developmental Coordination Disorder . 1
1.1.1 Identifying and diagnosing DCD 2
1.1.1.1 Origins of the DCD diagnosis . 2
1.1.1.2 DSM and ICD diagnostic criteria for DCD . 4
1.1.1.3 Examining the diagnostic criteria 5
1.1.1.4 Diagnostic tools 6
1.1.1.5 What exactly is DCD: Is everyone on the same page? . 7
1.1.2 Literature review of studies investigating motor skills in DCD 9
1.1.2.1 Basic visuomotor and fine motor skills 9
1.1.2.2 Pointing 9
1.1.2.3 Action planning 10
1.1.2.4 Gross motor skills . 11
1.1.2.5 Balance, postural control and postural knowledge . 11
1.1.2.6 Catching 12
1.1.2.7 DCD summary . 13
1.2 Autism Spectrum Disorder . 13
1.2.1 Recognition of motor deficits in ASD in early accounts of the
disorder 14
1.2.2 Diagnosing ASD: The role of motor impairments across the spec-
trum 14
1.2.2.1 DSM-IV-TR criteria 14
1.2.2.2 DSM-5 criteria . 16
1.2.2.3 ICD-10 criteria . 16
1.2.2.4 Criteria summary . 17
1.2.3 How prevalent are motor deficits in ASD? . 17
1.2.3.1 Do motor deficits differentiate AS from HFA/AD or do
they unite the spectrum? . 17
1.2.3.2 Prevalence rates across the autistic spectrum 18
1.2.4 Literature review of studies investigating motor skills in ASD 20
1.2.4.1 Studies using standardised motor batteries . 20
i1.2.4.2 Fine motor skills 22
1.2.4.3 Gross motor skills . 22
1.2.4.4 Action planning 23
1.2.4.5 ASD summary . 24
1.3 Comorbidity between ASD and DCD 24
1.3.1 Comparing ASD and DCD directly . 24
1.3.2 Comorbidity or coincidence? 25
1.4 Chapter 1 conclusions 26
1.5 Outline of thesis . 27
2 Profiling motor skills in ASD and DCD 28
2.1 Aim 1: Profiling motor skills and drawing comparisons between subject
groups . 28
2.1.1 MABC-2 . 29
2.1.2 Previous findings using the MABC with ASD and DCD groups . 29
2.1.3 Can the MABC be a true gold standard? . 32
2.1.4 cKAT: a future gold standard? . 33
2.2 Imitation . 34
2.2.1 Understanding imitation . 34
2.2.2 Can people with ASD imitate? . 35
2.2.2.1 Spontaneous versus elicited imitation 36
2.2.2.2 Meaningful versus meaningless: does meaning aid imi-
tation? . 36
2.2.2.3 Imitating kinematics 37
2.2.2.4 Social motivation . 38
2.2.2.5 Imitation in ASD summary 38
2.2.3 Imitation in DCD 39
2.2.4 Comparing imitation in ASD and DCD 39
2.3 Methods 40
2.3.1 Subjects (adults) . 40
2.3.2 Procedure (adult and child) . 41
2.3.2.1 Questionnaires . 41
2.3.2.2 Behavioural overview . 41
2.3.2.3 cKAT 42
2.3.2.4 Imitation 42
2.4 Results (adults) 44
2.4.1 AQ and SRS questionnaire measures 44
2.4.2 MABC-2 . 44
2.4.2.1 Overall percentile rank 46
2.4.2.2 Performance in each test component . 47
2.4.2.3 MABC-2 summary . 47
ii2.4.3 cKAT . 48
2.4.3.1 cKAT summary 50
2.4.4 Imitation . 50
2.4.4.1 Measures 50
2.4.4.2 Hypothesis . 50
2.4.4.3 Is motor output modulated by stimulus properties? 51
2.4.4.4 Constant error . 51
2.4.4.5 Variable error . 53
2.4.4.6 Imitation summary 53
2.5 Discussion (adults) 54
2.6 Subjects (children) 56
2.7 Results (children) . 56
2.7.1 SRS and DCDQ-07 questionnaire measures 57
2.7.2 MABC-2 . 57
2.7.3 MABC-2 summary 58
2.7.4 cKAT . 60
2.7.5 cKAT summary 62
2.7.6 Imitation . 62
2.7.6.1 Is motor output modulated by stimulus properties? 62
2.7.6.2 Constant error . 65
2.7.6.3 Variable error . 67
2.7.6.4 Imitation summary 67
2.8 Discussion (children) . 69
2.9 General discussion 72
3 Vision and proprioception in perception and action 73
3.1 Comparing the roles of vision and proprioception in perception and ac-
tion in ASD 73
3.1.1 Altering proprioception . 74
3.1.2 Altering visual feedback to assess visual/proprioceptive weighting 75
3.1.2.1 Prismatic displacement 76
3.1.2.2 Vision for postural control 76
3.1.3 Assessing visual and proprioceptive benefit and acuity 77
3.1.4 A counter argument . 78
3.2 Comparing the roles of vision and proprioception in DCD 79
3.2.1 Altering proprioception . 79
3.2.2 Altering visual feedback . 80
3.2.2.1 Vision for postural control 80
3.2.2.2 Reaching tasks . 80
3.2.3 Assessing visual and proprioceptive benefit and acuity 81
3.3 Vision and proprioception in ASD and DCD: a double dissociation? 82
iii3.4 Visual-proprioceptive matching . 83
3.4.1 Perceptual matching to assess visual and proprioceptive benefit . 83
3.4.2 Perceptual matching using prismatic displacement 85
3.5 Experiment 1: Visual-proprioceptive spatial location matching . 86
3.6 Methods 86
3.6.1 Subjects 86
3.6.2 Apparatus . 87
3.6.3 Procedure . 87
3.7 Results . 91
3.7.1 Recording responses . 91
3.7.2 Measures . 92
3.7.2.1 Plano measures 92
3.7.2.2 Prism measure: visual weighting . 92
3.7.2.3 Hypotheses . 93
3.7.3 The effect of target on error . 93
3.7.4 Plano conditions . 93
3.7.4.1 Absolute error . 93
3.7.4.2 Proprioceptive and visual benefit . 95
3.7.4.3 Plano conditions summary 95
3.7.5 Prism condition 97
3.7.6 Plano conditions: MABC-defined groups 97
3.7.6.1 Absolute error . 98
3.7.6.2 Proprioceptive and visual benefit . 98
3.7.7 Prism condition: MABC-defined groups 99
3.8 Discussion (Experiment 1) 100
3.9 Experiment 2: Vision and proprioception in action (mirror reach) 103
3.10 Methods 105
3.10.1 Adult pilot study: Methods, results and discussion 105
3.10.1.1 Design . 105
3.10.1.2 Subjects 105
3.10.1.3 Apparatus . 106
3.10.1.4 Procedure 106
3.10.1.5 Results . 107
3.10.1.6 Discussion . 108
3.10.2 Child study 109
3.10.2.1 Subjects 109
3.10.2.2 Procedure 109
3.11 Results . 110
3.12 Discussion (Experiment 2) 111
3.13 General discussion 112
iv4 Proprioceptive feedback in action 114
4.1 The nature of a goal-directed actions 114
4.2 Reaching to proprioceptively-defined targets 115
4.3 Online proprioceptive guidance in the posting and matching task 116
4.3.1 Present study . 117
4.3.2 Hypotheses 118
4.4 Methods 118
4.4.1 Subjects 118
4.4.2 Apparatus . 118
4.4.3 Procedure . 119
4.5 Results . 122
4.5.1 Measures . 122
4.5.1.1 Terminal orientation 122
4.5.1.2 Speed of movement measures . 122
4.5.1.3 Planned analyses 123
4.5.2 Vision-only matching . 123
4.5.3 Vision-only posting 123
4.5.3.1 Choosing clockwise or anticlockwise rotations 123
4.5.3.2 The time-course of visually-guided movements . 126
4.5.3.3 Other measures 127
4.5.4 Posting main analysis 129
4.5.4.1 Orientation absolute error . 129
4.5.4.2 Orientation constant error 130
4.5.4.3 Orientation variable error . 130
4.5.4.4 Posting summary . 131
4.5.5 Matching . 131
4.5.5.1 Orientation absolute error . 132
4.5.5.2 Orientation constant error 132
4.5.5.3 Orientation variable error . 133
4.5.5.4 Matching summary 133
4.6 Discussion . 133
4.7 Posting using vision and proprioception in children with ASD, DCD and
TD . 134
4.8 Methods 134
4.8.1 Subjects 134
4.8.2 Apparatus . 135
4.8.3 Procedure . 135
4.9 Results . 136
4.9.1 Vision-only 136
4.9.2 Experimental conditions . 136
4.9.2.1 Absolute error . 136
v4.9.2.2 Constant error . 138
4.9.2.3 Variable error . 139
4.9.2.4 Comparing MABC-defined groups 141
4.10 Discussion . 141
4.11 General Discussion 145
5 Proprioception and susceptibility to the Rubber Hand Illusion 146
5.1 The rubber hand illusion . 146
5.1.1 What can explain individual differences in susceptibility to the
RHI? 147
5.1.2 Variations in stimulation duration and type 149
5.1.2.1 Stimulation duration . 149
5.1.2.2 Type of stimulation 150
5.1.3 Methods of measurement 151
5.2 Measuring proprioceptive acuity 152
5.3 Study 1: The relationship between proprioceptive acuity and RHI sus-
ceptibility in neurotypical adults 153
5.4 Methods 153
5.4.1 Subjects 153
5.4.2 Procedure . 153
5.4.3 Rubber hand illusion . 154
5.4.3.1 Apparatus . 154
5.4.3.2 Procedure 154
5.4.4 Proprioceptive postural matching 155
5.4.4.1 Apparatus . 155
5.4.4.2 Procedure 155
5.4.5 Proprioceptive location matching 156
5.4.5.1 Apparatus . 156
5.4.5.2 Procedure 156
5.5 Results . 157
5.5.1 RHI 157
5.5.1.1 Effect of estimate number . 157
5.5.2 Proprioceptive shift . 159
5.5.3 Postural matching 161
5.5.4 Spatial location matching 161
5.5.5 Correlational analysis 163
5.6 Discussion . 163
5.6.1 RHI 163
5.6.2 Postural matching and Spatial location matching . 164
5.6.3 Correlational analyses 164
5.7 Study 2: RHI susceptibility in ASD, DCD and typical development . 165
vi5.7.1 RHI in autism 165
5.7.2 RHI in typical development . 167
5.7.3 Using the RHI with children and clinical groups . 167
5.7.4 Hypotheses 168
5.8 Methods 168
5.8.1 Subjects 168
5.8.2 Procedure . 168
5.9 Results . 169
5.9.1 Effect of estimate number 169
5.9.2 Hypothesis 1 analysis (diagnostic groups) . 170
5.9.3 Hypothesis 2 analysis (MABC-defined groups) 174
5.9.4 The effect of proprioceptive acuity in RHI shift 175
5.10 Discussion . 176
5.11 General discussion 177
6 Investigating the related nature of motor and social skills in typical
development 179
6.1 Motor deficits in ASD and social deficits in DCD: What separates these
two disorders? . 179
6.2 The interrelated nature of social, motor, attentional and educational
aspects of typical development . 180
6.2.1 The relationship between social and academic skills 180
6.2.2 The relationship between motor development and academic achieve-
ment 181
6.2.3 The relationship between social and motor development . 182
6.2.4 Summary . 183
6.3 Methods 183
6.3.1 Subjects 183
6.3.2 Materials . 185
6.3.3 Procedure . 186
6.4 Results . 186
6.4.1 Preliminary analyses . 187
6.4.2 Correlational analysis 192
6.5 Discussion . 192
7 Conclusions 197
7.1 Research question . 197
7.1.1 Why do motor skills matter? 197
7.2 Working with children and clinical groups . 198
7.3 Working in schools 200
7.4 Strengths and weaknesses of the present studies 201
vii7.5 Future research 203
7.6 Chapter summaries 204
7.6.1 Chapter 1 . 204
7.6.2 Chapter 2 . 204
7.6.3 Chapter 3 . 205
7.6.4 Chapter 4 . 205
7.6.5 Chapter 5 . 206
7.6.6 Chapter 6 . 207
7.7 Conclusions 207
A Additional non-significant main and interaction effects: Chapter 2 209
B Additional non-significant main and interaction effects: Chapter 3 212
C Additional non-significant main and interaction effects: Chapter 4 213
D DCDQ-07 214
E Baseline questionnaire 216
F Familial risk questionnaire 217
viiiList of Figures
2.1 Screenshots/illustrations of each cKAT task 43
2.2 Stills from each condition in the imitation task 45
2.3 Spread of MABC-2 percentile ranks for each (adult) group. A total rank
at or below the 15th percentile is outwith the typical range. Total scores
for ASD and DCD are significantly worse than TD. Within the DCD
group, the difference between AC and balance is significant 48
2.4 Mean correlation coefficients for each (adult) group across each imita-
tion condition and measure. Error bars show SE. There is a significant
condition*measure interaction 52
2.5 Mean constant error for each imitation condition and measure (adults).
Error bars show SE. There is no significant effect of group, condition, or
measure and no interaction effects 52
2.6 Mean variable error for each imitation condition and measure (adults).
Error bars show SE. There is a significant condition*measure interaction. 53
2.7 Percentage of children in each group passing and failing the MABC . 59
2.8 Spread of MABC-2 percentile ranks for each (child) group. MD=manual
dexterity, AC=Aiming and catching. A total rank at or below the 15th
percentile is outwith the typical range. TD scores are significantly higher
than both ASD and DCD for all but MD. In TD scores in the MD
component were significantly lower than AC and balance . 59
2.9 Mean correlation coefficients for each condition in the imitation task
between diagnosis-defined groups. Error bars show SE. Coefficients in
ASD and DCD are significantly lower than TD, and there is a significant
condition*measure interaction 64
2.10 Mean correlation coefficients for each condition in the imitation task
with groups split according to MABC-2 performance. Error bars show
SE. Coefficients in the clinical motor deficit group are significantly lower
than TD 64
2.11 Median constant error across each condition and the three diagnostic
groups. Error bars show SE. There is a significant group*measure inter-
action 66
ix2.12 Median constant error across each condition and the MABC-defined
groups. Error bars show SE. There are no significant effects 66
2.13 Variable error across each condition between diagnosis-defined groups.
Error bars show SE. Variable error in the DCD group is significantly
higher than ASD and TD. There is also a significant condition*measure
interaction . 68
2.14 Variable error across each condition between MABC-defined groups.
Variable error in the clinical motor deficit group is significantly higher
than ASD and TD. There is also a significant condition*measure inter-
action 68
3.1 Front view of the apparatus, with the viewing aperture in the centre, two
curtained entry points either side for access to the target, and two open
entry points at the bottom for access to the slider and bead. A right-
handed subject would use entry points A and D, a left-handed subject
would use B and C . 88
3.2 A right-handed subject completing the VPP condition with normal vision 89
3.3 Recording sheet for spatial location matching . 91
3.4 Range of median absolute errors in each plano condition for each target.
Target 1 is on the subject’s right, 2 is central and 3 is left. There is no
clear effect of target on error in any condition or group 94
3.5 Absolute errors in each condition between groups. ASD are significantly
less accurate than TD in the PP condition . 95
3.6 Mean proprioceptive and visual benefit. ASD show a significantly larger
proprioceptive cost than TD. Groups are not differentiated by visual
benefit . 96
3.7 Visual weighting for each target in each group. There is no clear effect
of target and no apparent interaction with group 97
3.8 Visual weightings for each group. There is no significant effect of group. 98
3.9 Visual weightings for MABC-defined groups 100
3.10 Mirror reach apparatus from above. The mirror is between compart-
ments 2 and 3, with the reflective side facing into compartment 2. The
left hand is placed to the left of the mirror and lid 2 is removed to allow
for a view of the mirror. The right hand is placed in the right compart-
ment and reaches to directly underneath the target bead seen here on
the slider 106
x4.1 Posting and matching apparatus. a) The posting apparatus as viewed by
the subject. The letter is posted through the top slot. During testing the
lower slot is covered. b) The back of the posting apparatus: The subject
holds the back of the slot at the top (direct) or the bottom (indirect). In
indirect conditions both slots are set to the same orientation. Orientation
is set by inserting a peg into one of 18 holes around the circle. c) The
matching apparatus as viewed by the subject. Subjects move the top
handle to match the proprioceptively-defined handle at the back of the
board (either at the top or bottom), or visually match the front lower
handle. During testing the lower handle is covered in proprioception
conditions. d) The back of the matching apparatus. The top is held for
direct trials, the bottom for indirect. Orientation is set as per posting 120
4.2 Absolute, constant and variable error for each target in the vision-only
matching condition. Error bars show SE. Target 0 is vertical, and 9 is
horizontal 124
4.3 Absolute, constant and variable error for terminal orientation for each
target in the vision-only posting condition. Error bars show SE 125
4.4 Orientation error over normalised time for two subjects approaching the
horizontal slot . 127
4.5 Mean absolute orientation error across normalised time. By 60% MT
large wrist rotations have been completed and the rest of the movement
involves smaller adjustments . 128
4.6 Pearson correlation between target orientation and each measure for each
subject in the vision-only condition . 128
4.7 Orientation error in each condition at 60% and 100% MT. Error bars
show SE. There is a significant vision*proprioception interaction at 100%
MT . 129
4.8 Mean constant error in each condition at 60% and 100% MT. Error bars
show SE. At both time points there is a significant effect of vision: at
60% MT error is lower when vision is removed, although the removal of
vision significantly adversely affects accuracy at 100% MT 130
4.9 Mean variable error in each condition. Error bars show SE. At 60% MT
there is a significant main effect of vision, and at 100% MT there is a
significant vision*proprioception interaction . 131
4.10 Mean error between conditions for absolute, constant and variable error.
Error bars show SE. There is a significant effect of vision and propri-
oception on absolute error and variable error. There is a significant
vision*proprioception interaction for constant error 132
4.11 Pearson correlation between target orientation and each measure for each
subject in the vision-only condition. Red, green and blue represent ASD,
DCD and TD respectively . 137
xi4.12 Mean absolute orientation error across normalised time. Data from all
groups have been combined for each target due to insufficient numbers
in the DCD and TD groups. As with the adult study, by 60% MT
large wrist rotations have been completed and the rest of the movement
involves smaller adjustments . 137
4.13 Median absolute orientation errors collapsed across targets for each group.
Errors are shown across normalised time (from 0-100% movement time.) 138
4.14 Mean absolute orientation error at 60% and 100% MT for each condition
in each group. Accuracy significantly decreases when vision is removed.
Group and group*vision effects are not significant . 139
4.15 Mean constant orientation error between groups and condition at 60%
and 100% MT. Error bars show SE. There is a significant effect of vision
at 100% MT 140
4.16 Mean variable orientation error at 60% and 100% MT for each condition
in each group. Precision is significantly lower when vision is removed 140
4.17 Constant error at 60% and 100% MT for MABC-defined groups. Note
that the ASD pure group was not included in analysis due to small
sample size. There is a significant effect of vision at 100% MT 142
4.18 Posting errors in MABC-defined groups. Note that the ASD pure group
was not included in analysis due to small sample size . 143
5.1 RHI apparatus showing the four lids, slider and response bead. The real
hand is placed under lid 2 and the rubber hand is placed under lid 3.
The areas under lids 2 and 3 are separated by a wooden divider . 154
5.2 Postural matching board . 156
5.3 Mean constant error across trials for synchronous and asynchronous con-
ditions. Negative drift is towards the rubber hand and zero corresponds
to the veridical location of the real hand. (Error bars show SE.) . 157
5.4 Each subplot shows constant error for each subject across trials for syn-
chronous and asynchronous conditions. Negative drift is towards the
rubber hand 158
5.5 Effect of condition on subjects’ proprioceptive drift (median constant
error). Drift towards the rubber hand is coded as negative. Error bars
show SE 160
5.6 Median constant error for synchronous versus asynchronous conditions
for each subject. The line shows slope 1, intercept 0 (no illusion).
Subjects who completed asynchronous trials first (red) tended to show
greater drift in synchronous than asynchronous trials, compared to sub-
jects who completed synchronous trials first (blue) . 160
xii5.7 Effect of target on median absolute error (significant difference between
120 and 60, and 120 and 90). All target angles are relative to horizontal:
a 90
◦
target is vertical . 162
5.8 Distribution of average shift for diagnosis-defined groups. Data to the
left of the red line is in the expected direction for the illusion . 170
5.9 Proprioceptive dift across trials (ASD). There is no clear pattern over
time and there does not appear to be a strong illusion as synchronous
and asynchronous drift overlap to a large extent 171
5.10 Drift across trials (DCD). Again there is no clear pattern over time and
there does not appear to be a strong illusion as only one child shows
consistently greater drift in the synchronous condition . 172
5.11 Drift across trials (TD). As with ASD and DCD there is no clear pattern
over time. There is still some overlap between synchronous and asyn-
chronous, however some children show consistently greater drift following
synchronous stimulation 173
5.12 Average drift for asynchronous against synchronous conditions. Line
shows slope 1, intercept 0 (no illusion) 174
5.13 Mean drift in each condition between developmental groups. Error bars
show SE. There is a significant effect of condition but no group effect or
group*condition interaction 175
6.1 Distribution of DCDQ-07 and SRS total scores. The red line shows the
mean score, and the blue line shows the median score. The average score
is within the typical range for both measures 190
6.2 SRS/DCDQ-07 correlation. Higher scores on the SRS are indicative of
more ASD symptoms, and lower scores on the DCDQ-07 are indicative
of more DCD symptoms 193
xiiiList of Tables
1.1 Terms denoting DCD, compiled by Polatajko (1999) . 3
1.2 Studies using motor batteries to assess motor skills in ASD . 21
2.1 Manual dexterity subtests for each age bracket 30
2.2 Aiming and catching subtests for each age bracket 30
2.3 Balance subtests for each age bracket 31
2.4 Types of imitation, as defined by Sevlever & Gillis (2010) 35
2.5 Average scores for autistic trait measures . 46
2.6 Results from post hoc analyses of AQ scores 46
2.7 Mann-Whitney U analyses of group differences in each MABC-2 component 47
2.8 cKAT variables 49
2.9 cKAT group effects 49
2.10 Pearson correlations between MABC-2 total score and each cKAT com-
ponent . 49
2.11 Mean correlation coefficients split by condition and measure . 51
2.12 Comparison of variable error for each condition and measure 53
2.13 Median SRS and DCDQ scores for each group (including any child who
successfully completed at least one battery) 57
2.14 Analysis of MABC-2 percentile rank differences in ASD and DCD . 58
2.15 Comparison of MABC components for each clinical group 58
2.16 A comparison of children with ASD who failed the MABC-2 and children
with DCD on each cKAT measure . 61
2.17 Spearman correlations for MABC-2 percentile rank and each cKAT mea-
sure 61
2.18 Significant post hoc comparison findings for cKAT tasks . 62
2.19 Mean (SE) z-transformed correlation coefficients for each condition and
measure 63
2.20 Mean (SE) z-transformed correlation coefficients for each condition and
measure (MABC-2-defined groups) . 65
2.21 Group*Measure mean (SE) for constant error . 65
2.22 Condition*Measure mean (SE) for variable error . 67
3.1 MABC, IQ and age demographics for each group . 87
xiv3.2 Wilcoxon pairs comparing each plano condition across all groups 93
3.3 MABC-defined groups’ mean absolute error for each plano condition 99
3.4 Mean (SD) response angle for each congruent condition and corrected
mean responses for each incongruent start position and condition 108
3.5 Subject demographics (excluding those children who either attempted
the task but did not complete it, children whose data were not recorded,
and TD children who failed the MABC-2) . 109
3.6 Mean response angle (SD) collapsed across target . 110
4.1 Instructions for experimental conditions in the posting and matching tasks121
4.2 Posting measures . 122
4.3 Percentage of clockwise and anticlockwise rotations for each target for
vision-only posting 126
4.4 Subject demographics (values shown are mean (SD)) . 135
4.5 Main effect of group for kinematic variables 136
5.1 Mean constant, absolute and variable error (degrees) for each of the three
target angles . 161
5.2 Mean (SD) constant and variable error, and median (range) absolute
error for each target in the spatial location matching task 162
5.3 Subject demographics (values shown are mean (SD)) . 169
5.4 Mean shift (mm), grouping subjects by clinical diagnosis . 174
5.5 Mean drift (synchronous and asynchronous) and mean shift (all mm) for
MABC-defined groups 175
6.1 School roll, percentage of pupils receiving free school meals, number of
parents giving consent, and number of completed questionnaire packs
returned 184
6.2 Age, gender and school demographics for the final data set 188
6.3 Details of the four main measures split by age . 189
6.4 Median scores for each measure according to school 191
6.5 Rotated component loadings for SRS and DCDQ-07 components 191
6.6 Age correlated with each main measure 192
6.7 SRS correlated with DCDQ-7 scores for each age group . 193
A.1 Analysis of constant error for ASD, DCD and TD (adult imitation) . 209
A.2 Analysis of variable error for ASD, DCD and TD (adult imitation) . 209
A.3 Non-significant group effect for cKAT measures (child cKAT) 209
A.4 Non-significant group effect for cKAT measures using MABC-2-defined
groups (child cKAT) . 210
A.5 Analysis of subject/model correlation for ASD, DCD and TD (child im-
itation) 210
xvA.6 Analysis of subject/model correlation for DCD and motor impaired ASD
(child imitation) . 210
A.7 Analysis of constant error for ASD, DCD and TD (child imitation) . 210
A.8 Analysis of constant error for DCD and motor impaired ASD (child
imitation) . 210
A.9 Analysis of constant error for ASD pure, clinical motor deficit and TD
(child imitation) . 210
A.10 Analysis of variable error for ASD, DCD and TD (child imitation) . 211
A.11 Analysis of variable error for DCD and motor impaired ASD (child imi-
tation) . 211
A.12 Analysis of variable error for ASD pure, clinical motor deficit and TD
(child imitation) . 211
B.1 Non-significant group comparisons for each plano condition (spatial lo-
cation matching) . 212
B.2 Comparison of ASD pure, clinical motor deficit and TD for each plano
condition (spatial location matching) 212
C.1 Analysis of constant error for DCD and motor impaired ASD (child
posting) 213
C.2 Analysis of absolute and variable error for DCD and motor impaired
ASD (child posting) . 213
C.3 Analysis of absolute and variable error for clinical motor deficit and TD
at 60% and 100% MT (child posting) 213
xviList of Abbreviations
AC-Aiming and Catching
AD- Autistic disorder
ADHD- Attention Deficit/Hyperactivity Disorder
APA- American Psychiatric Association
AQ- Autistic Quotient
AS- Asperger Syndrome
ASD- Autism Spectrum Disorder
BOTMP- Bruininks-Oseretsky Test of Motor Proficiency
cKAT- Computerised Kinematic Assessment Tool
CP- Cerebral Palsy
DCD- Developmental Coordination Disorder
DCDQ- Developmental Coordination Disorder Questionnaire
DCDQ’07- Developmental Coordination Disorder Questionnaire 2007
DN- Direct proprioception, no vision (Chapter 4: posting condition)
DV- Direct proprioception, vision (Chapter 4: posting condition)
DSM-IV- Diagnostic and Statistical Manual-4th edition
DSM-IV-TR- Diagnostic and Statistical Manual-4th edition-text revision
DSM-5- Diagnostic and Statistical Manual-5th edition
DT- Deceleration Time
GG- Greenhouse-Geisser
GMDS- Griffiths Mental Development Scales
HFA- High functioning autism
ICD-10- International Classification of Diseases-10th edition
IN- Indirect proprioception, no vision (Chapter 4: posting condition)
IV- Indirect proprioception, vision (Chapter 4: posting condition)
LD- Learning Disability
MABC- Movement Assessment Battery For Children
MABC-2- Movement Assessment Battery for Children 2nd edition
MD-Manual Dexterity
MGA- Maximum Grip Aperture
MT- Movement Time
OT-Occupational Therapy/ Occupational Therapist
xviiPA- Path Accuracy
PANESS- Physical and Neurological Examination for Soft Signs
PDD- Pervasive Developmental Disorder
PDD-NOS- Pervasive Developmental Disorder-Not Otherwise Specified
PL- Path Length
POS- Peak Orientation Speed
PS- Peak Speed
PP- Proprioception (Chapter 3: spatial location matching condition)
RHI- Rubber Hand Illusion
RT- Reaction Time
RTM- Repetitive Timed Movements
SRS- Social Responsiveness Scale
TD- Typically Developing/ Typical Development
TO- Terminal Orientation
TOMI-HR- Test of Motor Impairment-Henderson Revision
TPOS- Time to Peak Orientation Speed
VP-Vision (Chapter 3: spatial location matching condition)
VPP- Vision+Proprioception (Chapter 3: spatial location matching condition)
WASI- Wechsler Abbreviated Scale of Intelligence