9A. Childhood Disorders Flashcards
What percentage of people with autism have normal or above-average intelligence?
Over 40%
By which two criteria is autism diagnosed?
Impaired social communication and repetitive behaviours or narrow, obsessive interests
How many times more boys are diagnosed with autism than girls?
Four to five
Environmental factors that contribute to autism
Parents having children later in life, fever and infection during pregnancy, premature birth
Genes/mutations implicated in autism
FMR1: codes for fragile X mental retardation protein. Non-mutant form needed for normal cognitive development
PTEN: codes for tumor suppressor enzyme
TSC1 or TSC2: code for proteins controlling cell division
NF-1: children with variant of this gene develop tumors in childhood
What percent of people with FMR1 mutation have ASD, and what problem does the mutation cause?
50-60% of people with fragile X syndrome have ASD
What percent of people with TSC1 or TSC2 mutations have ASD, and what problem does the mutation cause?
40% of people with tuberous sclerosis complex have ASD
What percent of people with NF-1 mutations have ASD, and what problem does the mutation cause?
10% with neurofibromatosis (childhood tumors) have ASD
What pathway do the genes implicated in autism affect, and what is its function?
mTOR pathway, major pathway for regulating cell metabolism, growth, and proliferation
When are developmental issues involved with autism usually noticed?
Before first birthday
When can autism be reliably diagnosed?
Age 2
When is autism usually diagnosed
4 and a half
What is the apparent cause of autism?
Unusual cellular development within cerebral cortex. Both white and grey matter show alterations. Some have abnormally large brains and faster brain growth
Drugs used to treat autism
No cure. Some symptomatic relief from drugs designed for other uses like anxiety. Social benefits from oxytocin. Behavioural therapies still only proven treatment
What percentage of American parents report a child with ADHD?
11%
What percentage of those with ADHD carry the disorder into adulthood?
30%
Environmental risk factors for ADHD
Extreme early adversity, exposure to lead, low birthweight
Abnormalities in brain associated with ADHD
Unusual activity in neurons that release dopamine
Treatments for ADHD
Stimulants (methylphenidate), behavioural interventions
Distinctive features of Down Syndrome
Flattened face and bridge of nose, eyes slanted upward, small ears, small hands and feet, short, poor muscle tone, intellectual disabilities, hearing loss, heart defects
Key factors in intellectual disabilities of Down Syndrome
Poor connections among nerve cells in hippocampus, disfunction in mitochondria
Biological features of dyslexia
Brain areas involved in language are less well connected. E.g., word-form area, region on left side of brain, involved in recognition of printed words. Less brain activity in left occipitotemporal cortex, essential for skilled reading.
How do people with dyslexia compensate for reduced activity on left side of brain?
Rely more on right side
Which system is impaired in people with dyslexia?
Visual magnocellular system. Dominates visual control of eye movements. Plays part in pointing eyes steadily at letters to determine their order
Early indicator of dylsexia
Inability to rapidly and automatically name things
How is epilepsy diagnosed?
If someone has two or more seizures that can’t be explained otherwise
Biological cause of epilepsy
Increase in firing of action potentials followed by period of reduced excitability. Progress modulated by GABA (inhibitory) and glutamate (excitatory)
What technique is used to distinguish between different types of epilepsy?
EEG
Types of seizures
Generalized seizures: affect both sides, normal alpha rhythm replaced by large, slow, synchronous waves of activity
Absence or petit mal: part of generalized. causes rapid blinking or staring into space
Tonic-clonic or grand mal: part of generalized. can make someone fall, have muscle spasms, cry out, lose consciousness
Focal or partial: localized
Simple focal seizure: causes twitching or change in sensation
Complex focal seizure: begins in one part and spreads
Factors that can provoke seizures in epilepsy
Fatigue, missed meals, low blood sugar, alcohol, flickering lights
Possible causes of epilepsy
Premature birth, brain trauma, abnormal development for genetic reasons
Treatments for epilepsy
Medication and diet. Most of the time, single medication is enough. Ketogenic diet (high fat, low carbs). Surgery can be used when medicine doesn’t work. Split-brain surgery - cutting of corpus callosum
In which sex are anxiety disorders more common?
Women
SSRIs
Medication for anxiety disorders. Selective serotonin reuptake inhibitors. Raise serotonin levels
Benzodiazepines
Medication for anxiety disorders. boost levels of GABA. Used to be standard but cause dependence. E.g., diazepam, Valium.
Significance of basal ganglia to OCD
Helps conduct routine behaviours (habit centre). Disrupted signalling between BG and cortex could cause OCD
Medications for OCD
SSRIs, tricyclic antidepressant clomipramine, neuroleptic (tranquilizing) drugs
Treatments for OCD
Cognitive behavioural therapy, deep brain stimulation
Treatments for panic disorder
Psychotherapy, medications, or combination. SSRIs are primary choice, benzodiazepines in emergencies
Most effective treatment for PTSD
Cognitive behavioural therapy
Physiological changes to people with PTSD
Increased heart rate, heightened electrical sensitivity in response to triggers, shallow seep with increased periods of RED, which can lead to sleep deprivation. Altered levels of hormones like cortisol and norepinephrine.
Treatments for PTSD
Drugs that block norepinephrine (blood pressure medicine prazosin, beta-blockers like propranolol). SSRIs. Neurotransmitter neuropeptide Y
Neurological changes in people with PTSD
Smaller hippocampus, smaller PFC, overactive amygdala
Diagnosis for major depression
Minimum of four of the criteria must be met for over two weeks: feeling sad, loss of appetite, irritability, sleep issues, changes in appetite/weight
In which sex is major depression more common?
Females
Neurological basis of depression
Disrupts hypothalamus. Secretes hormone that tells adrenal cortex to produce more cortisol. Monoamine neurotransmitter systems (dopamine, serotonin) disrupted. Smaller hippocampus and PFC
Treatment for depression
Antidepressants raise norepinephrine, serotonin, and dopamine levels. SSRIs most common. CBT used in combination
Treatment for bipolar disorder
Hard to treat. Separate drugs for highs and lows. Mania: anti-epilepsy drugs (lithium, atypical antipsychotics). Depression: antidepressants, CBT. Third of people don’t respond, significant side effects.
Positive symptoms of schizophrenia
Hallucinations, delusions, confused thinking
Negative symptoms of schizophrenia
Inability to experience pleasure, lack of motivation
When does schizophrenia usually appear?
15-25, corresponds to development of PFC
Drugs used to treat schizophrenia
Chlorpromazine used to calm people down. Antipsychotic drugs dampen dopamine response, which drives positive symptoms. May cause tremors and Parkinson’s-like things (low dopamine activity). Drugs that suppress serotonergic activity help with negative symptoms. Nicotine may be helpful
Cause of migraine
Muscle tension usually
Biological features of migraine
Starts in part of brain that processes pain coming from cerebral blood vessels. In response, brief increase in local blood supply (causes flashing lights) immediately followed by reduced blood flow (causes temporary weakness)
Drugs for migraines
Drugs that activate serotonin (5-HT) receptors, class of drugs called triptans.
