Brain Bee Chapter 11 - Childhood Disorders

criteria for diagnosing autism

impaired social communication and interaction
repetitive behaviors / narrow, obsessive interests

no biochemical or other biomarkers of autism other than genes, based on behavioral analysis
tracking eye mvmt and functional neuroimaging later

can be reliably diagnosed at age 2, most diagnosed at 4.5

gene variants associated with ASD

rare ones are identified and studied →
FMR1 - codes for fragile X mental retardation protein, non-mutant needed for normal cognitive development
PTEN - codes for tumor suppressor enzyme, regulating cell division
TSC1 / TSC2 - tuberous sclerosis complex 1 and 2, code for proteins that control cell growth and size
NF-1 - variant = neurofibromatosis, associated with ASD

twin studies

compares diagnosis between twins → assesses for genetically driven diseases

mTOR pathway

major signaling pathway for regulating cell metabolism, growth, proliferation
ASD-related genes influence this (FMR1, PTEN, TSC1/2, NF-1)

drugs that inhibit mTOR pathway relieve or reverse ASD symptoms in mice (rapamycin, lovastatin)

ASD development

unusual cellular development within cerebral cortex (memory, attention, perception, language, etc.)
alterations in white and gray matter
minority = larger brain volumes, faster brain growth
older childhood to adulthood → atypical activity in cortex, information is not well integrated across distributed brain networks

ASD treatment

no medications to reverse
symptomatic relief from anxiety drugs / oxytocin (social bonding, mixed findings with this)
behavioral therapies are only proven treatment, early interventions are most effective

ADHD symptoms

attention deficit hyperactivity disorder
inattentiveness, hyperactivity, impulsive behaviors (extreme and longer lasting)
issues with executive function (remembering homework, multi-step directions, etc.)
symptoms must interfere with normal functioning and be present in multiple contexts (school and home, etc.)

ADHD diagnosis

no diagnostic test, requires comprehensive evaluation
tends to run in families

ADHD risk factors / indicators

extreme early adversity, exposure to lead, low birthweight
may have differences in brain cell structure and plasticity
unusual activity in dopaminergic neurons (dopamine = rewarding behavior)

ADHD treatment

drugs - stimulant (methyphenidate) and non-stimulant, dosage adjusted to child
behavioral intervention - organizational support, exercise, meditation

down syndrome

extra copy of all or part of 21 chromosome (trisomy)
facial features → flattened face and nose bridge, upward slanted eyes, small ears
short stature and poor muscle tone
low to moderate intellectual ability → poor connection among nerve cells in hippocampus
dysfunction in mitochondria (diabetes and Alzheimer’s more prevalent)

mosacisim

trisomy does not occur in every cell
mosaic down syndrome is less severe

down syndrome causes

maternal / paternal age
younger mothers can now be screened

down syndrome risks

heightened risk for Alzheimer’s → chromosome 21 has gene that encodes for amyloid precursor protein (APP)
mitochondria dysfunction → diabetes / Alzheimers (energy metabolism related)

down syndrome treatment

no proven treatments
research on gene that inactivates second X chromosome in female mammals → muted expression of genes on extra 21 chromosome

dyslexia symptoms

pronunciation issues
lack of fluency
difficulty retrieving words
poor spelling
hesitancy in speaking
persists lifelong, diagnosed in elementary

dyslexia diagnosis

use child’s ability to rapidly and automatically name things as early indicator → can be used in preschoolers and kindergarteners

dyslexia brain differences

areas involved in word recognition and sounds are less connected
→ word-form area
→ less brain activity in occipitotemporal cortex (essential for skilled reading)
rely more heavily on right side of brain due to reduced activity on left

word form area

involved in recognition of printed letters and words, less connected to other brain regions in dyslexic patients

dyslexia gene differences

susceptibility genes that affect cell migration
runs in families
wide range of genes and environmental factors

dyslexia treatment

behavioral and educational intervention
→ breaking words down into sounds, linking sounds to specific letter patterns

epilepsy

two or more seizures not explained by temporary or underlying medical condition

seizure

irregular activity in brain cells lasting five or more minutes at a time
EEGs used to distinguish types of epilepsy
accompany intellectual or psych problems (suppress growth of dendrites)

generalized seizures

affect both sides of brain, include absence (petit mal) and tonic-clonic (grand mal) seizures

petit mal seizures

absence seizures
cause rapid blinking or few seconds of staring into space

grand mal seizures

tonic-clonic seizure
causes falls, muscle spasms, crying out, loss of consciousness

focal seizures

partial seizures, localized to one area of the brain (vs. generalized)
simple → causes twitching or change in sensation
complex → leaves a person confused and unable to answer questions or follow directions

secondary generalized seizures

begin in one part of brain (focal / partial seizure) and spread to become generalized seizure

epilepsy causes

many possible causes (spectrum)
premature birth, brain trauma, abnormal development due to genetics
attributes include: head size, movement disorders, family history

epilepsy treatment

control seizures with medication or diet
diet = ketogenic, high-fat and low-carb
severe cases treated by surgery (inactivating or removing seizure-initiating part of brain) OR (split brain surgery)

split brain surgery

cutting corpus callosum
used in epilepsy patients where one side of brain triggers seizures on other side