atypical 3 - diagnosis Flashcards
diagnosing William’s syndrome
physical and cognitive features
cause = deletion at 11.2 - impacts ELN gene
use genetic test - blood test for ELN gene (elastin)
test = fluorescent in situ hybridization (FISH) - detects ELN gene
diagnosing down syndrome prenatally (2)
in week 10-14 of pregnancy (12 week scan)
offered a combined test:
- blood test - maternal blood contains DNA from foetus
- nuchal translucency scan - checks build of fluid at back of baby’s neck - larger = greater chance of chromosomal abnormality
finding high risk = mother offered amniocentesis to confirm - voluntary, take sample of amniotic fluid to test
diagnosing down syndrome postnatally
physical characteristic check
can follow up with blood test - presence of extra chromosome
comorbidity of ASD and ADHD
potential 70% comorbidity between ADHD and ASD - many overlapping traits
ADHD is one of most commonly comorbid conditions with ASD
DSM-IV (2000) - prohibited dual diagnosis of ADHD and ASD
DSM-V (2013) - two separate conditions
diagnosing ADHD: referral, care levels, screening
referral often by school (SENCO) to:
- primary care - GP / social worker / educational psychologist
- secondary care - psychiatrist / CAMHS psychologist
base diagnosis on:
- behaviour in different settings
- developmental and psychiatric history and observer reports
- asses mental state - comorbid with anxiety
screening instruments - supplement diagnosis:
- conner’s rating scales
- strengths and difficulties questionnaire
diagnosing ASC
ASC and ASD are often used interchangeably
referral by parents / school / GP
referral to secondary care - e.g. CAMHS
autism assessment:
- questions about parent/carer concerns - can also be child / young persons concerns
- details of experience of home life, education, social care, developmental history - focussing on ones in line with ICD-X or DSM-V#
- medical history - prenatal, perinatal + family history, past + current health
- physical examination
2 diagnostic manuals
DSM-V (2013) - diagnostic and statistical menual (5th edition)
ICD-XI - international classification of diseases (11th edition)
DSM-V ADHD criteria - inattention symptoms
6 or more symptoms for <16 y/o
5 or more symptoms for >17 y/o
symptoms for at least 6 months which are inappropriate for developmental level
symptom examples:
- lack close attention to details
- careless mistakes
- trouble holding attention on tasks
- doesn’t seem to listen when directly spoken to
- no follow through on instructions e.g. school, chores, work duties
- trouble organising tasks and activities
- avoids / dislikes / reluctant to do mental effort tasks over long time periods (e.g. homework)
- loses things
- easily distracted
- forgetful in daily activities
DSM-V ADHD criteria - hyperactivity and impulsivity symptoms
6 or more symptoms for <16 y/o
5 or more symptoms for >17 y/o
symptoms for at least 6 months which are inappropriate for developmental level
- fidgeting
- doesn’t remain seated when should
- feel restless
- cannot play quietly
- driven by motor - on the go
- excessive talking
- says answer before question finished
- can’t wait their turn
- interrupts others
DSM-V criteria for ASD - social communication deficits (3)
Persistent deficits in social communication and social interaction across multiple contexts:
- socio-emotional reciprocity deficits
- non-verbal communicative deficits
- developing, maintaining + understanding relationships deficits
Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
Deficits in developing, maintaining, and understand relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to absence of interest in peers.
have to show from all 3 of these categories
DSM-V criteria for ASD - restricted, repetitive patterns of behaviour
at least two of these:
- stereotyped/repetitive motor movements, use of objects, or speech
- insistent on sameness, inflexible with routine, ritualized verbal and non-verbal behaviour
- highly restricted, fixated interests that are abnormal in intensity or focus
- hyper or hypo - reactivity to sensory inputs
Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypes, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat same food every day).
Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests).
Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment (e.g. apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).
standardised tool for ADHD diagnosis
Conner’s scale
questionnaire, used as initial evaluation
likert scale - 0-3
3 forms - for parents, teachers, and self-report from child
t-score calculated from results - standardised
can be used also in follow-up to monitor how medication/intervention are helping
standardised tool for ASD diagnosis - ADOS
autism diagnostic observational schedule (ADOS)
- semi-structured interview
- very interactive tasks for individuals - monitor behaviour
- for presence/absence of key behaviours e.g. eye-contact, reciprocal interaction, turn-taking, imaginative play, non-verbal communication
5 modules:
- toddler: 12 – 30 months (no consistent speech)
- module 1: 31 months + (no consistent speech)
- module 2: Children any age (not verbally fluent)
- module 3: Children & young adolescents (verbally fluent)
- module 4: older adolescents & adults (verbally fluent)
becomes more question based with older age - unless person is not verbally fluent - then go to module 2 regardless of age
need formal training for this - costs money to complete to - due to subjectivity so guidelines need to be maintained
standardised tool for ASD diagnosis - ADI
autism diagnostic inventory (ADI)
- parent / caregiver interview focusing on developmental milestones and social behaviour
- focus on age 4 / 5
need formal training - costs money to complete too
at what age is ASD typically diagnosed
mean ages:
autism:
diagnosis = 5.5 years
parents first concerns = 18 months
aspergers:
diagnosis = 11 years
parents first concerns = 30 months
(based on sample of 614 parents of kids with autism and 158 of kids with aspergers)
ASD is rarely diagnosed before age 2 - especially in UK - even in other countries with screening
growing numbers diagnosed in adulthood
autism and aspergers
DSM-IV = split into autism and aspergers
DSM-V = aspergers no longer a thing
ASD screening - M-CHAT
M-CHAT = modified checklist for autism in toddlers
everyone in america takes the m-chat
for 16-36 months
one study showed children who screened positive on M-CHAT were 114x more likely to get ASD diagnosis than those who screened negative
M-CHAT limitations
finds possible red-flags, but not sensitive for detecting only autism in this age group
e.g. detects developmental delay, not necessarily ASD
therefore researchers start to study infant-siblings of older children with ASD diagnosis
infant siblings approach to ASD diagnosis
diagnosis typically around 4 years old (can be later)
1 in 5 chance that a child with an older sibling with ASD will also be diagnosed with ASD
therefore look for early markers in these children
techniques used in infant-sibling approach (3)
functional near infrared spectroscopy (fNIRS)
electroencephalogram (EEG)
eye-tracking
fNIRS
functional near infrared spectroscopy
optical imaging method - like how smartwatches measure heart rate
shine light in to cortex of brain and measure light coming out - light than doesn’t exit cortex has been absorbed
haemoglobin is main absorber of near-infrared light, therefore use near-infrared light to measure haemoglobin
measuring absorption can tell about blood flow - more Hb in brain areas that are more active
fNIRS to investigate ASD early markers
Lloyd-Fox et al (2013)
4-6 month olds:
- infant siblings of older child with ASD
- infant siblings of older child without ASD
show videos of social and non-social stimuli
results:
infants with higher chance of ASD showed reduced activity over temporal cortex in response to social stimuli compared to those with reduced chance of ASD
EEG
electroencephalography
measures electrical signals through electrodes on the scalp
signals are produced by cortical field activity and are measured as changes in voltage, recorded at the scalp, over time
analysis of signals can be task dependent or independent
EEG data analysis - coherence
connectivity between brain regions - how well they communicate = coherence
difference in EEG connectivity between high and low risk infants at 12 months (not really seen at 6 months)
LOOK AT SLIDE 42 FOR CHART
eye-tracking and ASD diagnosis
Pierce et al (2011)
measure difference in looking behaviour
neurotypical toddlers spend more time looking at social videos than geometric videos
some ASD toddlers spent more time looking at geometric videos (some only really did, variation within those with ASD)
if they spend more than 69% of their time fixating on geometric, have positive predictive value for ASD diagnosis of 100% ( in this study)
challenges of infant-sibling and early detection approach
differences seen at group level, not individual
most studies don’t follow up on at risk infants to confirm whether they do or not get an ASD diagnosis later
–> therefore differences between high and low risk infants could be reflecting a broader autism phenotype rather than specific biomarkers for ASD
ASD is heterogeneous - lots of individual variability in its expression - therefore trying to identify a single neural/behavioural construct for ASD is difficult/impossible
prevalence of ASD and ADHD
increase over time
centre for disease control - USA:
ASD prevalence in 8 year old children:
2008 = 1 / 88
2010 = 1 / 68
2012 = 1 / 69
2014 = 1 / 58
ADHD in US children and adolescents
1997-98 = 6.1%
2015-16 = 10.2%
reasons for increasing rates of ADHD (5)
- greater awareness
- reduced stigma
- better recognition (esp in girls)
- environmental factors (socioeconomic status, exposure to lead)
- prenatal risk factors (premature birth, exposure to tobacco)
reasons for increasing rates of ASD (4)
- greater awareness
- reduced stigma
- evolution of diagnostic criteria / diagnostic substitution
- environmental factors - maybe?
diagnostic substitution and ASD
children who would now meet diagnostic criteria for ASD were previously diagnosed with other conditions
therefore shows as increased prevalence - actually from change in diagnosis
Bishop et al (2008)
- followed up on those who did language studies between 1986 and 2003
- those who were told they had specific language impairment (SLI) or pragmatic language impairment (PLI)
- test these people for ASD
- 11 out of 20 with SLI and 2 out of 18 with PLI met ASD criteria
discussion:
- direct evidence of diagnostic substitution
- many children who were diagnosed with severe language disorders in the 1980s and 1990s displayed behaviours that would be regarded as meriting a diagnosis of ASD according to contemporary criteria
- appears to be a direct result of changing diagnostic criteria from DSM-III through to DSM-IIIR and DSM-IV
