Diagnosis Flashcards
1
Q
diagnosing William’s syndrome
A
- physical and cognitive features
- confirmed with a genetic test
–> blood test to identify absence of the ELN (elastin) gene - the lab test used to detect the elastin gene is called fluorescent in situ hybridization(FISH)
- very straightforward
2
Q
Down syndrome: prenatal diagnosis
A
- screening test available between 10-14 weeks of pregnancy
–> typically carried out at the 12 week scan - ‘Combined’ test =
–> blood test (Mother’s blood contains DNA from the foetus)
–> nuchal translucency scan (checks the build of fluid at the back of the baby’s neck, the larger it is the greater the chance of a chromosomal abnormality) - if this test shows a ‘high risk’ then the mother would be offered an amniocentesis to confirm:
–> take a sample of the amniotic fluid
–> voluntary
3
Q
down syndrome: post-natal diagnosis
A
- check physical characteristics
- if unclear, follow up with a blood test
–> check for the presence of an extra chromosome
4
Q
comorbidity (ADHD and Autism)
A
- ADHD and autism frequently co-occur, with comorbidity rates potentially as high as 70/80%
- ADHD is one of the most commonly comorbid conditions with autism
- the previous edition of the DSM (DSM-4, 2000) prohibited dual diagnosis of autism and ADHD
- listed as two separate conditions in the DSM-5, hence why we discuss as two separate conditions throughout these lectures
- many traits associated with ADHD overlap with traits associated with autism
5
Q
diagnosing ADHD
A
- initial referral often made in school (e.g. by SENCO)
–> primary care
(GP, social worker, educational psychologist)
–> secondary Care
(psychiatrist, psychologist working within CAMHS) - diagnosis based on:
–> discussion about behaviour in a range of different settings (e.g. school, home)
–> full developmental and psychiatric history and observer reports
–> assessment of the person’s mental state - screening instruments can be used to supplement diagnosis (but not on their own)
–> Conner’s rating scales
–> strengths and difficulties questionnaire
6
Q
diagnosing ASC (autism)
A
- initial referral often made by parents, school, GP
- referral made to secondary care (e.g. CAMHS)
- autism assessment:
–> detailed questions about parent’s or carer’s concerns and, if appropriate, the child’s or young person’s concerns
–> details of the child’s or young person’s experiences of home life, education and social care
–> a developmental history, focusing on developmental and behavioural features consistent with ICD-10 or DSM-5 criteria
–> a medical history, including prenatal, perinatal and family history, and past and current health conditions
–> a physical examination
7
Q
DSM-5 criteria for ADHD (inattention)
A
- six or more symptoms of inattention for children up to age 16 years
- five or more for adolescents age 17 years and older and adults
- symptoms of inattention have been present for at least 6 months
- they are inappropriate for developmental level
8
Q
DSM-5 criteria for ADHD (hyperactivity and impulsivity)
A
- six or more symptoms of hyperactivity-impulsivity for children up to age 16 years
- five or more for adolescents age 17 years and older and adults
- symptoms of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for the person’s developmental level
9
Q
DSM-5 criteria for Autism
A
- persistent deficits in social communication and social interaction across multiple contexts
1. socio-emotional reciprocity
2. non-verbal communicative behaviours used for social interaction
3. developing, maintaining and understanding relationships - ALL 3 NEEDED
10
Q
diagnostic criteria for ASD
A
- restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the categories
–> e.g. want for sameness and routine, repetitive behaviour, fixated interests and hyperactivity or hyporeactivity in response to sensory stimuli
11
Q
ADHD diagnosis: standardised tests
A
- The Conner scale for assessing ADHD
–> Questionnaire screening for behaviours associated with ADHD, used as initial evaluation when
ADHD is suspected
–> three forms:
1. one for parents
2. one for teachers
3. self-report to be completed by the child - can be used during follow-up appointments to help doctors and parents monitor how well certain medications or behaviour-modification techniques are working
12
Q
scoring of the Conner scale
A
- psychologist will total the scores from each area of the test
- they will assign the raw scores to the correct age group column within each scale
- the scores are then converted to standardized scores, known as T-scores
13
Q
Standardised Tools Used in the Diagnosis of ASC
A
- autism diagnostic observational schedule (ADOS)
- autism diagnostic inventory (ADI)
- both require formal training before use
14
Q
autism diagnostic observational schedule (ADOS)
A
- semi- Structured Interview
–> give individuals lots of tasks (observe and monitor behaviour) - code interaction for presence / absence of certain key behaviours
–> e.g. eye-contact, reciprocal interaction, turn-taking, imaginative play, non-verbal communication - five modules
1. toddler: 12 – 30 months (no consistent speech)
2. module 1: 31 months and older (no consistent speech)
3. module 2: children any age (not verbally fluent)
4. module 3: children & young adolescents (verbally fluent)
5. module 4: older adolescents & adults (verbally fluent)
15
Q
scoring on the ADOS
A
- each behaviour has its own code
- you add certain codes together to get an overall score for each domain of the DSM-5 criteria
- the participant’s score on the two domains determines if they would be classed as autistic
- raw scores turned into t-scores (standardised)
16
Q
autism diagnostic inventory (ADI)
A
- parent / caregiver interview focusing on developmental milestones and social behaviour
- focus on age 4 / 5
17
Q
how early can autism be diagnosed?
A
- Autism:
–> mean age of diagnosis = 5.5 years
–> mean age when parents first had concerns = 18 months - Asperger’s syndrome (not a separate diagnosis anymore)
–> mean age of diagnosis = 11 years
–> mean age when parents first had concerns = 30 months - ASC is very rarely diagnosed before age 2 (especially in the UK)
–> some countries carry out ASC screening, and the youngest age at which a child is diagnosed with ASC is ~ 2 years old - there are a growing number of people being diagnosed with ASC in adulthood
18
Q
ASC screening: The M-CHAT
A
- not done in the UK, every child in the US takes it
- a questionnaire used for screening toddlers for ASC is the M-CHAT (modified checklist for autism in toddlers)
- this has been shown to be very useful in children aged between 16 and 36 months in terms of flagging up issues in development
- in one study, children who screened positive on the M-CHAT were 114 times more likely to receive an ASC diagnosis than children who screened negative
19
Q
issues with the M-CHAT
A
- it is not particularly sensitive for detecting ONLY autism, in this age group
- for example, it also picks up cases of children who may have developmental delay, but not necessarily ASC
- for this reason, researchers who are aiming to develop tools for early-identification of ASC, have started to study the “infant-siblings” of older children with a diagnosis of ASC
20
Q
the infant siblings approach
A
- ASC diagnosis typically made at around 4 years old (but can be a lot later)
- because of the genetic association with ASC, there is an increased chance (1 in 5) that a child with an older sibling who has a diagnosis of ASC will also go on to be diagnosed with ASC
–> therefore, looking for early markers for ASC in these children is considered a fruitful approach
21
Q
3 methodologies used in the infants siblings approach
A
- Functional Near infrared spectroscopy (fNIRS)
- electroencephalogram (EEG)
- eye-tracking
22
Q
Functional Near Infrared Spectroscopy (fNIRS)
A
- optical imaging method (like a fit-bit measuring your heart-beat)
- shine light in, measure light coming out (light that doesn’t exit the cortex has been absorbed)
- the main absorber of near-infrared light is haemoglobin
–> therefore shining in near-infrared light allows us to measure haemoglobin - measuring absorption can tell us about blood flow
23
Q
Using fNIRS to investigate early-markers of ASC
A
- recruited infants between 4-6 months of age:
–> infant siblings of an older child with ASC (increased chance of having ASC)
–> infant siblings of an older child without ASC (lower chance of having ASC) - showed videos of social and non-social stimuli
- the infants with a higher chance of having ASC were found to show reduced activity over temporal cortex in response to social stimuli compared to infants with reduced chance of ASC
24
Q
electroencephalography (EEG)
A
- EEG measures electrical signals generated by the brain through electrodes placed at the scalp
- EEG signals are produced by cortical field activity and are measured as changes in voltage, recorded at the scalp, over time
- analysis of EEG signals may be task dependent or task independent
- EEG data can be analysed in many different ways
- connectivity between different brain regions (coherence)
25
Q
eye tracking
A
- difference in looking behaviour (measured with eye-trackers) in toddlers with a diagnosis of ASC (identified during an earlier screening study)
- majority of neurotypical toddlers spent more time looking at the social videos than the geometric patterns.
- some of the toddlers with ASC spent more time looking at the geometric videos
- if a toddler spent more than 69% of his or her time fixating on geometric patterns, then the positive predictive value for accurately classifying that toddler as having an ASD was 100%
26
Q
challenges of the infant-sibs / early detection approach
A
- while differences can be seen at a group-level, the work has not yet yielded clear biomarkers that are useful at an individual level
- most of the studies do not follow up the ‘at-risk’ infants in order to confirm whether or not they do receive a later ASC diagnosis
- group differences between high and low risk infants could be reflecting the “broader autism phenotype” rather than specific biomarkers for autism
- ASC is a very heterogeneous condition, and there is a lot of individual variability in the way that ASC is expressed
–> aiming to identify a single neural or behavioural construct that can classify ASC is a difficult (impossible?) challenge
27
Q
Bugha et al. (2011) - ADHD and ASC diagnosis
A
- ADHD and ASC diagnoses have increased over time
- 7,461 households completed an autism screening questionnaire
- 5,102 people eligible for phase two (AQ20 score >5)
- phase 2 = face to face diagnostic evaluation
- number of people meeting diagnostic criteria for autism = 9.8 per 1,000 (~1 in 100)
28
Q
reasons for increased ADHD diagnosis
A
- environmental factors
–> socioeconomic status
–> exposure to lead - greater awareness
- reduction of stigma
- better recognition
–> better recognition in girls - prenatal risk factors
–> premature birth
–> exposure to tobacco
29
Q
reasons as to why ASC diagnosis has increased
A
- greater awareness
- reduction of stigma
- evolution of diagnostic criteria / diagnostic substitution
- environmental Factors (?)
30
Q
diagnostic substitution
A
- children who would now meet the diagnostic criteria for ASC were previously diagnosed with other conditions
–> e.g. language disorders
31
Q
Bishop et al. (2008) method
A
- people who had previously participated in studies on language (between 1986 and 2003) were re-contacted to take part in a new study (in 2008)
- in the original studies, none of the participants had a diagnosis of ASC, but they all had a diagnosis of either specific language impairment (SLI) or pragmatic language impairment (PLI)
- During the new study, the participants were tested for ASC using the ADOS and the ADI
32
Q
Bishop et al. (2008) results
A
11 out of 20 participants with a diagnosis of SLI, and 2 out of 18 participants with a diagnosis of PLI met criteria for ASC on both the ADOS and the ADI
