lecture 10 - neuropsychology ADHD Flashcards
what is the purpose of neuropsychology
-to understand the relationship between the brain and the behaviour
what is clinical neuropsychology
-sub field of neuropsychology
-explains functional behaviour and relate this to any underlying neuropathology in order to inform treatment, rehabilitation and education
what are neuropsychological assessments used for
-clinical purposes
-research
what are test batteries
what do they assess
a collection of tests / assessments
-they asses
-cognitive functioning,
-emotional processing
-psychosocial skills,
-motor development
neuropsychological assessment
-how are they standardised
Assessments are typically standardized
* Undergoes rigorous reliability and validity tests
* Can only be used by trained individuals
* Administered in a standardized way
* Evaluated and interpreted by trained individuals
what is assessed in a neuropsychological assessment.
and what can they be tested with
-Sensory perceptual functions (tactile, visual, auditory, etc.)
* Motor functions related to speed and strength
* Attention and problem solving skills
* Language and communication skills
* Learning and memory skills
* Executive functioning
can be tested with
-a fixed battery
-a flexible battery at the discretion of the neuropsychologist (piece together different tests etc)
how are sensory/ perceptual functions (tactile, visual, auditory) assessed
-example boccia bilateral coordination
-video shows girl being instructed to touch nose with alternating arms when eyes are closed,
-relies on sensory input, where her fingers are in space
how are motor functions related to speed and strength assessed
-measure strength using a dynamometer,
-a machine you can rip and squeeze as hard as you can to figure out how strong your grip is
-eg finger tapping test to look at speed, you tap anytime you see a light (old method)
-hand eye coordination , place one hand behind their back, put these little peg into their holes, can sense deficit motor , hand to eye movement
how are attention and problem solving skills assesed
-trials making test
-child is asked to take their pencil and draw lines to cross dots , these dots have letters and numbers
-ask child why number 1 and they go 1a, 2b, 3c, they have to keep track mentally requiring attention
-an attention and processing speed task,
how are learning and memory skills assessed
-was the task we did in class which was looking at a complex picture with shapes and patterns, and then asked to draw it after class (to see how much we could remember )
how is executive functioning assessed
continuous performance task
-looking at ability to inhibit responses and shift attention etc
-task in class, you clap every time you see a letter apart from the letter ‘X’
CPT and other tests of executive functioning
-used clinicall to screen to challenges with attention etc ADHD
what is ADHD
-what types are there
attention deficit hyperactivity disorder
-ADHD I - inattention
-ADHD-HI - hyperactivity/impulsivity
-ADHD-C - combined
ADD is not a diagnosis (attention deficit disorder)
ADHD - DSM 5 definition
ADHD categorized as a neurodevelopmental disorder because symptoms are present in childhood
* Even if diagnosis only occurs in adulthood
what is ADHD
-criteria
-which conditions must be met (DSM5)
Criteria:
* At least 6 symptoms for at least 6 months → for ages 16 and under
* At least 5 symptoms for at least 6 months → for ages 17 and older
Must meet the following conditions:
* Symptoms present before age 12
* Symptoms present in two or more settings
* Evidence that symptoms interfere with functioning
* Symptoms cannot be better explained by another disorder (e.g., anxiety, dyslexia)
ADHD- I symtoms
-more inattention related
Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or with other activities.
* Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace(e.g., loses focus, side-tracked).
* Often avoids, dislikes, or is reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework).
* Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).* Is often easily distracted* Is often forgetful in daily activities.
ADHD-HI symptoms
-more hyperactive
Often fidgets with or taps hands or feet, or squirms in seat.
* Often leaves seat in situations when remaining seated is expected.
* Often runs about or climbs in situations where it is not appropriate (adolescents or adults may be limited to feeling restless).
* Often unable to play or take part in leisure activities quietly.
* Is often “on the go” acting as if “driven by a motor”.
* Often talks excessively.* Often blurts out an answer before a question has been completed.
* Often interrupts or intrudes on others (e.g., butts into conversations or games)
risk factors - genetic influences
-twin studies
-family studies
-twin studies
-genetic influences account for 70-90% of variance (if you have a twin with ADHD theres a 70-90% chance you may also have ADHD)
-family studies
-if you have an immediate family member with an ADHD diagnosis , you are 5x more likely to experience symptoms
Research has not established causative role for individual genetic variants yet
* There isn‘t one gene!
* Likely several genes with minor effects
risk factors - environmental influence
-factors in early development , prenatal, perinatal and postnatal
-genetics
Possible harmful factors in early development reliably associated with ADHD
* Prenatal association’s
:* E.g., Smoking, alcohol, illicit drug use
- Perinatal associations:
- E.g., Low birth weight, preterm birth
- Postnatal life:
- E.g., Inadequate diet, major vitamin B deficit, exposure to industrially contaminated areas, some artificial colorings, depriving institutional environment,medical illnesses…
- Genetic factors can influence exposure and susceptibility to environmental risks
risk factors - interacting factors
genetic x environmental factors
ADHD risk is made up of many interacting genetic and environmental factors with different individuals affected in different ways, at different times and to different degrees
* E.g., two siblings share 50% genetics and may grow up in the same household but can still present differently
ADHD theories
-Russel Barkley (1997)
-postulated that ADHD is a disorder related to executive function (EF)
-specifically inhibitory control- the ability to withhold a behaviour response
-believed that difficulties with attention were biproducts of inhibitory control deficits
i.e symptoms relate back to the same deficit
Russell Barkley theory evidence
-stop signal tasks
eg CPT children with ADHD performed worse
1, habituate a response
eg ‘press the button every time a letter appears on the screen’
-participant practices the response
- Measure commission errors
* e.g., “Refrain from pressing the button when the letter X appears”
* Count the number of times the participant made a response when they should have withheld it
criticisms with Russell Barkley’s theory
Stop Signal Tasks have high continuous demands:
* Child must continuously process information, remember instructions, prepare for their behavioural response
- Higher intra-individual variability in ADHD groups:
- Each participant’s performance is not consistent
- Participants vary greatly from one another
ADHD theories
-delay aversion theory
-the tendency to prefer smaller-immediate rewards instead of larger-delayed rewards
-eg marshmallow test of delayed on gratification
-but this could be worse for children who grew up poor ? they just learn to take what they get
delay aversion theory
evidence
and findings
and conclusion
Sonuga-Barke et al. (2003)
* 156 children (3-6 years)
- Given two tasks:
- EF test battery
- Choice delay task (tests delay aversion)
- Computer game with a points system
- Throughout the game, they had a choice:
- Small-immediate reward – green square = 1 point
- Large-delayed reward – blue square = 2 points
- Can we predict which children are diagnosed with ADHD based on their performance?
Findings:
* ADHD – not more likely to choose the green square (small-immediate reward)
* Combining tests was able to predict 90% of the children with ADHD
- Conclusions:
- At least two mechanisms contributing to ADHD behaviours
when can we see variability in ADHD
Variability in ADHD:
* Presentation of symptoms
* Onset of symptoms
* Development of symptoms
* Duration of symptoms
* Performance on different tasks (e.g., EF vs choice delay tasks)
What does variability look like in non-ADHD populations?
* Studying typical development is important for clinical research!
variability in brain development
-grey matter and white matter development
studying the natural development of the brain provides insights into the process that lead to several deficits that a child might show and grow out of
-the graphs show there is variability with white matter and grey matter through your lives
white matter -increases towards as you get mid aged and then decreases as you grow old
gray matter decreases through life
what age does white matter increase until and what does this mean
The brain is not yet done developing.
* White matter increases till mid-30s
* Could be due to myelination
* Frontal regions develop more slowly, which has control over attention and impulsivity.
variability in frontal lobe development of children
variability in
-cortical thickness
-surface area
-volume
The inter-individual differences in development are large between children.
how does variability cause concerns about diagnosing ADHD at a young age
-it causes concerns as we may not capture child’s individual trajectory
ADHD across the lifespan
study
method and basic findings
Since children are still developing, can they grow out of symptoms? Shaw et al. (2013)
* Longitudinal study (childhood adulthood)
* All participants were diagnosed with ADHD as children
* Evaluated neural correlates of symptoms across time
method
Two groups:
* Diagnosis with ADHD vs non-ADHD controls
* Evaluated neural correlates of symptoms across time
findings
-Inattentive symptoms were more like to be persist than hyperactive /impulsive symptoms
* 60% of patients no longer met criteria for ADHD
ADHD across the lifespan
study
findings: variability in brain development causing the changes in adhd diagnosis
conclusion
Changes in cortical thickness in right and left hemispheres detected differences between groups
* Typical and Persisters – maintained the same developmental trajectory from childhood adulthood
* Remitters – significantly different trajectory across time
Conclusions:
* ADHD can persist into adulthood(but not always)
* Inattention tends to persist
* Brain development might explain some inter- and intra-individual variability
* But 22-years-old may be too young to capture the full trajectory of ADHD
how is ADHD being researched today
-brain networks
-looking at frontal lobe
-associated with executive functioning and adhd symptoms
how is ADHD being researched today
-assessments and diagnosis
Despite brain imaging data, diagnosis doesn’t use neuroimaging information(yet)
* Reliance on:
* EF tests
* IQ test batteries
* Self-report questionnaires
* Issues with over-diagnosis of ADHD:
* Meta-analysis reports increased reports of ADHD (Kazda et al.,2021)
* Widens the ambiguity of symptoms
* Reliance on self-report alone leads to over-diagnosis
how is ADHD being assessed today
maternal health
Maternal post-partum mental health challenges (after giving birth)
:* Related to ADHD symptoms when child is 8-9 years
* (Mulraney et al., 2019)
- Maternal anxiety and sleep difficulties during pregnancy
:* Related to ADHD symptoms when child is in preschool - (Vizzini et al., 2018)
how is ADHD being researched today
-gut biome
Gut biome:
* Based on the gut-brain axis
Lower diversity of gut bacteria leads to:
*reduced production of neuroprotective factors
* higher likelihood of ADHD symptoms
* (Bull-Larsen & Mohajeri, 2019)
how is ADHD being researched today
-cross cultural
Are there cultural aspects to symptoms reporting of ADHD?
* Do ADHD symptoms present similarly across countries?
* Small differences between cultures might be due to parenting differences
