week 9 Neurodevelopmental disorders Flashcards
- outline the features of attention deficit/hyperactivity disorder;
2-3 times more likely in boys than girls. May first be differentiated from peers at 3-4 years of age. At such an age, often described as active, slow to toilet train, oppositional. In school years, signs of impulsivity, inattention and hyperactivity become clearer. Appox 5.2 % of children. 11% of children in US.
2 subtype of symptoms: a) problems of INATTENTION , don’t listen to others, lose things, don’t pay attention to detail, careless mistakes.and
b) HYPERACTIVITY/IMPULSIVITY; hyperactivity is fidgityness, constantly being on the go. Impulsivity includes blurting answers before question finished, cannot wait turn.
May be diagnosed with ADHD due to either subtype, or may have both.
approx 50% have ongoing difficulties throughout life.
During teens more likely to have problems with teen pregnancy, sexually transmitted diseases, driving problems etc due to the impulsivity. Later, tend to have lower positional jobs, increased risk of divorce, substance use disorders, antisocial personality disorder and more emergency department admissions.
Commmon comorbidities include oppositional Defiant Disorder, conduct disorder, bipolar
- discuss the biological and psychological factors thought to cause attention deficit/hyperactivity disorder;
More common in families. Highly genetically influenced.Sometimes genetic mutations are involved. Multiple genes involved.Some specifically implicated genes include those for dopamine d4 receptor, dopamine dat1 transporter and dopamine d5 receptor.
Other environmental factors such as mother smoking, maternal stress or alcohol use or low birth weight may also increase the risk in those susceptible.
Overall brain volume is on average 3-5% smaller.
Allergens and food toxins and colourants may have some small influence also.
Negative responses repeated over years by teachers and parents to undesrrable behaviours displayed by the child may also long term contribute to child’s depression/low self esteem, lack of effort etc etc.
- describe the biological and psychosocial treatment of attention deficit/hyperactivity disorder
Typically psychosocial tx focus on improving academic performance, decreased disruptive behav and improved social skills. typically employ reinforcement strategies.
Biological tx aims to reduce impulsivity/hyperactivity and improve concentration. Biological treatments include stimulants such as ritalin or adderall to improve concentration and focus, and non stimulants such as atomoxetine and guanfacine to reduce hyperactivity and impulsivity. Currently selection of drug is somewhat trial and error but studies are working on tayloring solutions to individuals.For those with ADHD and a specific gene defect at adrenergic alpha-2a receptor gene (ADRA2a), the drug methylphenidate has good effect, but not for those with ADHD without that particular gene defect. in general, meds help most to improve attention but does not improve academic preformance or social skills. Sometimes side effects of drowsiness or irritability.
Typically try behavioural therapy before biological but often use both together. Both together has some evidence of better response but not definite.
- discuss the clinical features and prevalence of specific learning disorder;
Specific learning disorder-performance substantially below expected given age, intelligence and opportunity. is not due to sensory issues such as blindness or deafness. Many variants but most often described by specifiers such as disorder of reading, written expression or mathematics. traditionally formally recognised when their is 2 standard deviations difference b/n performance and what iq says should be capable of. Argue that this method less helpful as takes while to show. Therefore better to recognise based on eg failure to respond as peers do to a a reading program. Then when recognised can try to help.
Typically affects 5-15% of youth. difficulty with reading is the most common. Increased dropout of school rates, , more risk of unemployment and increased suicide risk.
- describe the genetic, neurobiological and environmental factors associated with the aetiology of specific learning disorder;
There is some genetic influence as disorders tend to run in families butseems genes generally affect learning and not specific genetic issues for specific areas of learning difficulty.
Environmental influence is also there eg with family’s reading habits etc.
Sometimes there are brain structural/neural issues for a variety of reasons.
Personal determination due to sociocultural/psychological factors also play a part in whether the difficulty will be overcome or not.
- outline the major approach for treating individuals with specific learning disorder;
drug tx rare-usually only used if have comorbid adhd.
Needs educational intervention programs. Such programs either target specific skills or work out specific strategies. Such behavioural interventions can actually change the way the brain works, to approach their normal peers.
- describe the clinical features of autism spectrum disorder
Affects one’s perceptions of others and how one socialises with others. Includes previous dx’s of Asberger’s (milder form of autism) Childhood disintegrative disorder and Rettt disorder.
2 main symptom classes (both aspects must be present for dx): impairments in social interactions, and restricted repetitive behavioural patterns (typically hours of stereotypic behaviour).. Symptoms arise in early childhood. Requirements for support levels are listed in dsm 5 but are somewhat subjective. Fail to develop age-appropriate relationships.
Milder forms may lack appropraite facial expression or tone (prosody) but still manage some communication.
Approx 25% of those with Autism Spectrum disorder never sufficiently achieve speech level required for communication of their needs.
- outline the prevalence of autism spectrum disorder
Prevalence appears to be increasing although changes to dx have occurred. Currently estimated as 1 in 68 in US.Male to female ratio usually 4.5 : 1.
31% of those with ASD have intellectual disability, with IQ score less than 70. (higher IQ= far less likely to need extensive support).
There are many frequent comorbidities with ASD, including approx 30% with ASD also have epilepsy.
Savant ability of some sort might be present in up to 30% with ASD but certainly not if has more severe forms of the disease.
- discuss the psychological, social and biological theories of autism spectrum disorder;
Previous theories of parents typically being higher socioeconomic but emotionally cold have been debunked.
Many with ASD have not mastered the concept of self eg might say “he wants a drink of water” but meaning “I”. So some theorized the issue of asd was an issue of self identity, but it seems more because some have not advanced beyond the typical development of a 2 year old. Their is a spectrum here.
Is quite a genetic influence on ASD, with multiple genes thought to be involved, and each gene having a very small contribution. Oxytocin levels in the brain are thought to influence our social relations and some preliminary research indicates a possible issue with oxytocin receptors in the brain of those with Asd.
A family who has 1 child with asd has a 20% chance of having another (which is more than 100x the general risk). Increased risk if father over 40, and also if mother over 40.
Post-mortem studies have looked at the amygdala (as is involved in emotion). Those with asd had amygdala of similar size but with fewer neurons. Other research has shown in early life those with asd have an enlarged amygdale, theorising excessive anxiety and fear have contributed to their social withdrawal.
Some researchers have found decreased levels of the neuropeptide oxytocin in blood, and treatment with, has improved ability to process emotional displays of others.
A form of mercury (thimerosal) previously used in vacc’s as a preservative is speculated by some to have caused increased prevalence. Modern vacc’s do not contain this and some large studies have found no association with vacc and asd. However because children are commonly vacc’s for measles, mumps and rubella at 12-15 months which is the same time asd is becoming apparent, some still think vacc a cause.
- outline the various interventions for autism spectrum disorder
Tx with medication rarely helps social aspects, sometimes used to help against more severe behaviours such as tantrums and anxiety/agitation, eg tranquilisers and ssri’s.
Intensive educational programs required to improve socialization and behaviours. Many first require some intensive speech training. Some show that milder forms if started with psychosocial programs early enough, might approach normalcy. Some programs also focus (in later life) on improving independence and possibly having a job.
- define intellectual disability
Significant deficits when cf peers, re intelligence and adaptive functioning. wide spectrum. defined as mild, through to profound, and on level of assistance required. present prior to being 18 years of age.
Below iq of 70. 1-3% of population, and 90 % of those are mildly affected, and therefore with help can live independent lives.
Iq in general population has been increasing (Flynn effect) and so occasionally iq tests and standards are upgraded. One study found that the number of people testing with mild disability was tripled when given a revised iq test.
IQ 50-70 mild, 35-50 moderate, 35-50 severe, 20-35 profound.
- discuss the biological, genetic and psychosocial causes of intellectual disability;
Large numbers of possible causes. Causes include genetic (sometimes single gene), sometimes de novo mutations, chromosome defects, environmental/toxic influences on parents, during pregnancy and dystocia, infections and head trauma.. 30% of cases are unknown aetiology. Sometimes there is also profound neglect as a cause.
A few dz’s include:
PHENYLKETONURIA-recessive gene affecting 1in 10000, inability to break down phenylalanine. Now routinely screened for and this can be 100% averted with diet.
DOWN’S syndrome-extra chromosome. easy to detect in gestation but unable to predict degree of impairment which may be mild to severe. Much greater risk if mother older when pregnant.
LESCH-NYHAN syndrome , x-chromosome linked disorder, female carriers normal, males affected,
FRAGILE-Xsyndrome, mainly males, but occsionally females with learning disability too. Typically the affected males have moderate-severe learning disability, greater hyperactivity, poor attention span, avoid eye contact, larger ears, testicles and heads. estimate 1 in 4000 males and 1 in 8000 females.
- outline the treatment options for individuals with intellectual disability
Mainly as per Autism Spectrum disorder. Treatment is assistance and learning basic skills, with the hope of independence, being able to hold a job , and communicate needs. learning life skills might need to be broken down into its components (task analysis) and repeated, with rewards/positive reinforcers etc.
