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Flashcards in Neurodevelopmental Disorders Deck (27)
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Neurodevelopmental disorders are

neurologically based


Normal and abnormal development

Why is developmental delay problematic?


  • Critical developments occur during childhood
  • Relatively standard, typical progression of development as child ages
  • Develop one skill before the next

Why is developmental delay especially problematic?

  • Because it implies that any disruption in the development of early skills will, by the very nature of this sequential process, disrupt the development of later skills
  • Although, there are times when people believe normal development are actually symptoms of abnormality such as echolalia which involves repeating the speech of others
  • Disorders here are typically diagnosed in infancy, childhood, or adolescence
  • Often persist into adulthood


Attention Deficit/Hyperactivity Disorder (ADHD): Diagnostic Criteria

  • A. A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development, as characterized by (1) and/or (2):
  • 1. Inattention: Six (or more) of the following symptoms have persisted for at least 6 months to a degree that is inconsistent with developmental level and that negatively impacts directly on social and academic/occupational activities
    • Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or during other activities
    • Often has difficulty sustaining attention in tasks or play activities
    • Often does not seem to listen when spoken to directly
    • Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace
    • Often has difficulty organizing tasks and activities
    • Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort
    • Often loses things necessary for tasks or activities
    • Is often easily distracted by extraneous stimuli
    • Is often forgetful in daily activities
  • 2. Hyperactivity and impulsivity: Six (or more) of the following symptoms have persisted for at least 6 months to a degree that is inconsistent with developmental level and that negatively impacts directly on social and academic/occupational activities:
    • 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 inappropriate
    • Often unable to play or engage 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 has difficulty waiting his or her turn
    • Often interrupts or intrudes on others
  • B. Several inattentive or hyperactive-impulsive symptoms present prior to age 12 years
  • C. Several inattentive or hyperactive-impulsive symptoms are present in two or more settings
  • D. Clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning
  • E. Symptoms do not occur exclusively during the course of schizophrenia or another psychotic disorder and are not better explained by another mental disorder
  • Specify whether:
    • Combined presentation
    • Predominantly inattentive presentation
    • Predominantly hyperactive/impulsive presentation


ADHD: Clinical Features

  • Primary characteristics: pattern of inattention (disorganized, forgetful) and/or hyperactivity and impulsivity
  • Symptom presentation
    • Inattention
    • Hyperactivity
    • Impulsivity
  • Impairment on functioning
    • Academic performance
    • Comorbid learning disorders
    • Unpopular with and rejected by peers
    • Some research shows that having a specific genetic mutation and a low birth weight predicts later behaviour problems in children with ADHD


ADHD: Demographics and Course

  • Overall prevalence: 5.2% children worldwide
  • Male-to-female ratio: 3:1
    • Sex differences in presentation externalizing (acting out and being more aggressive) for boys vs. internalizing (anxiety and depression) for girls
  • Course
    • Typically identified as “different” at ages 3-4
    • Symptoms more obvious during school years
    • Teens with ADHD are at higher risk for teenage pregnancy and contracting sexually transmitted infections, they are also more likely to having driving difficulties, such as speeding, crashing or being suspended
  • Problems continue into adulthood
  • 50% Impact on adult life
  • Disorders similar to ADHD in children are oppositional defiant disorder, conduct disorder and bipolar disorder


ADHD: Aetiology


Environmental factors

Substance ingestion?

  • Genetics
    • Highly influenced by genetics
    • Smaller brain volume (3-4%)
  • Environmental factors
    • Maternal prenatal smoking, stress, and alcohol use
    • Parental relationship instability and discord
  • Substance ingestion?
    • Little evidence to support contribution of allergens
    • May be a small impact of artificial food colours and additives, pesticides
    • ADHD is much more influenced by genetics than environment 


ADHD: Treatment

psychosocial interventions

biological interventions

  • Psychosocial interventions
    • Behavioural interventions
    • Social skills training
    • Adults: CBT
  • Biological interventions
    • Documented effectiveness of stimulants (ritalin, adderall)
    • Concerns?
      • Potential for abuse of stimulants such as Ritalin and Adderall for their ability to create elation and reduce fatigue
      • Some unpleasant side effects such as insomnia, drowsiness or irritability
      • The ethical issue of psychopharmacogenetics
  • Combined approach recommended if medication is indicated


Specific Learning Disorder: Diagnostic Criteria

  • A. Difficulty learning and using academic skills, as indicated by the presence of at least one of the following symptoms that have persisted for at least 6 months, despite the provision of interventions that target those difficulties:
    • Inaccurate or slow and effortful word reading
    • Difficulty understanding the meaning of what is read
    • Difficulties with spelling
    • Difficulties with written expression
    • Difficulties mastering number sense, number facts, or calculation
    • Difficulties with mathematical reasoning
  • B. The affected academic skills are substantially and quantifiably below those expected for the individual’s chronological age and cause significant interference with academic or occupational performance, or with activities of daily living, as confirmed by individually administered standardized achievement measures and comprehensive clinical assessment
  • C. The learning difficulties begin during school-age years but may not become fully manifest until the demands for those affected academic skills exceed the individual’s limited capacities
  • D. The learning difficulties not better accounted for by intellectual disabilities, uncorrected visual or auditory acuity, other mental or neurological disorders, psychosocial adversity, lack of proficiency in the language of academic instruction, or inadequate educational instruction
  • Specify if:
    • With impairment in reading
      • Word reading accuracy
      • Reading rate or fluency
      • Reading comprehension
    • With impairment in expression
      • Spelling accuracy
      • Grammar and punctuation accuracy
      • Clarity or organization of written expression
    • With impairment in mathematics
      • Number sense
      • Memorization of arithmetic facts
      • Accurate or fluent calculation
      • Accurate math reasoning


Specific Learning Disorder: Clinical Features


  • Major defining feature: academic performance that is substantially below what would be expected given the person’s age, IQ, and education
  • Should not be caused by a sensory difficulty, such as poor sight or hearing and not be the cause of poor or absent instruction
  • Response to intervention criterion is being used now instead of identifying when someone has a discrepancy of more than 2 standard deviations from achievement and IQ (because this may only show up later in life)
    • Response to effective intervention significantly inferior to performance by peers
    • Provides an early warning system, and focuses on providing effective instruction


Specific Learning Disorder: Demographics

  • Prevalence statistics
    • Impairment in reading: 4% - 10%
    • Impairment in mathematics: 1%
    • Impairment in written expression: unknown
  • Male-to-female ratio: relatively equal
  • Potential long-term consequences
  • Communication disorders
    • Childhood-onset fluency disorder (stuttering)
    • Language disorder (expressive and mixed receptive-expressive language disorders)


Specific Learning Disorder: Aetiology


Brain Impairment


  • Genetic
    • Runs in families
  • Subtle brain impairment
    • Present particularly for reading and word problems
    • Brain impairment in:
      • Broca’s area (articulation and word analysis)
      • Left parietal temporal area (word analysis)
      • Left occipital temporal area (recognition of word form)
  • Environmental
    • Reading habits of families
    • Specific learning disrders are more often diagnosed in English-speaking countries (english very complex language to learn as a possible reason)
  • Also take into account: socioeconomic status, cultural expectations, parental interactions and expectations, and child management practices (in combination with existing neurological deficits and support available in schooling)

The outcome of children with specific learning disorders seems to be effected by socioeconomic status, cultural expectations, parental interactions and expectations and child management practices together with existing neurological deficits and the types of support provided in schools


Specific Learning Disorders: Treatment

  • Educational intervention
    • Specific skills instruction
    • Strategy instruction (improves cognitive skills through decision making and critical thinking)
  • Behavioural interventions
    • Direct Instruction
      • Systematic instruction (using highly scripted lesson plans that place children together in small groups based on their progress)
      • Teaching for mastery (teaching students until hey understand all concepts)
    • Efficacy in improving academic skills

Studies show that behavioural interventions can change the way the brain works (to be more similar to normal functioning) and that we can use such interventions to help individuals with significant problems


Autism Spectrum Disorder (ASD): Diagnostic Criteria

  • A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history:
    • Deficits in social-emotional reciprocity; ranging, for example from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, and affect; to failure to initiate or respond to social interactions
    • Deficits in nonverbal communicative behaviours used for social interaction, ranging for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication
    • Deficits in developing, maintaining and understanding relationships, ranging for example from difficulties adjusting behaviour to suit various social contexts; to difficulties in sharing imaginative play and in making friends; to absence of interest in peers
  • B. Restricted, repetitive patterns of behaviour, interests, or activities, as manifested by at least two of the following, currently or by history:
    • Stereotyped or repetitive motor movements, use of objects, or speech
    • Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behaviour
    • Highly restricted, fixated interests that are abnormal in intensity or focus
    • Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment
  • C. Symptoms must be present in the early developmental period
  • D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of functioning
  • E. Disturbances not better explained by intellectual disability or global developmental delay. Intellectual disability and ASD frequently co-occur; to make comorbid diagnosis of both, social communication should be below that expected for general developmental level


ASD: Clinical Features

  • Essentially a neurodevelopmental disorder that affects how one perceives and socializes with others
  • Two major characteristics:
    • Impairments in social communication and interaction
    • Restricted, repetitive patterns of behaviour, interests, or activities
  • Degree of impairment rated for social/communication interaction and restricted/repetitive behaviours separately
    • Level 1: requiring support
    • Level 2: requiring substantial support
    • Level 3: requiring very substantial report


ASD: Demographics

  • Current estimates: 1/50 children
    • Increasing prevalence?
  • Male-to-female ratio: 4.4 : 1
  • Over 1/3 have associated intellectual disabilities
    • Language performance often predicts prognosis
  • 38% of people with ASD have intellectual disabilities
  • Estimated that 1/3 of those with ASD have savant abilities (superior working memory and highly focused attention) although they are only present in those who do not have a severe form of ASD

Usually, language abilities and IQ scores are reliable predictors of how children with ASD will fare later in life: the better the language skills and IQ test performance, the better the prognosis


ASD: Impairment in Social Communication and Social Interaction

  • Social communication and interaction problems:
    • Problems with social interaction
    • Problems with nonverbal communication
    • Problems initiating and maintaining social relationships
  • Social interaction deficits:
    • Evidence suggests that persons with ASD may have no interest in social interaction
  • Deficits in nonverbal communication
    • Range from complete lack to deficits in nonverbal communication
  • All affect ability to maintain social relationships
  • Speech deficits common and may impact communication ability



lacking in appropriate facial expressions or tone of voice


ASD: Restricted, Repetitive Patterns of Behaviour, Interests, Activities

  • “Maintenance of sameness”: often have intense preference for status quo
  • May engage in stereotyped and ritualistic behaviours for hours (e.g., hand flapping, head banging)
    • Less severe ASD may evidence obsessive interests in certain, very specified subjects


ASD: Biological Aetiology



  • Genetic influences
    • Clear that ASD has significant genetic component
    • Families with one child with ASD have 20% chance of having another child with ASD
    • Increased risk of having child with ASD with older parents
  • Neurobiological influences
    • Association between ASD and oxytocin receptor gene (oxytocin is an important social neurochemical that influences bonding and is found to increase trust and reduce fear) resulting in lower levels of oxytocin in their blood
    • Amygdala with fewer neurons?
      • Theory is that children with ASD have a larger amygdala early in life which contributes to excessive worry and fear (perhaps contributing to their social withdrawal)
    • Mercury in vaccinations?
      • No evidence that vaccinations cause ASD
      • The perception may be found in the correlation of age when child is vaccinated for measles, mumps and rubella (12-15 months) and when the symptoms of ASD first become apparent (before 3 years)


ASD: Psychological and Social Aetiology

  • Issues with self-awareness and theory of mind
    • May be lacking because of associated cognitive disabilities or delays
  • Savant skills?
    • Only evident in 1/3 of individuals with ASD
    • Not evident in persons with severe ASD
    • Attributed to superior working memory and highly focused attention


ASD: Treatment

  • Primarily behavioural psychosocial treatments focused on skill building and treatment of behavioural problems
  • Treatment of communication problems
    • Shaping
    • Naturalistic training strategies
  • Social skills training
    • Early intervention targeting joint attention and play skills
  • Integrated treatment
    • Early intervention holds most hope
    • For older children, treatment more driven by specific needs/deficits
    • Ideal outcome is community integration

Medication has little impact on the core symptoms of language and social difficulties of ASPD

Early intervention holds the most hope for very young children with ASD for significant changes in the core symptoms of this disorder


Intellectual Disability (Intellectual Developmental Disorder): Diagnostic Criteria

  • Intellectual disability is a disorder with onset during the developmental period that includes both intellectual and adaptive functioning deficits in conceptual, social, and practical domains. The following three criteria must be met:
    • Deficits in intellectual functions, such as reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience, confirmed by both clinical assessment and individualized, standardized intelligence testing
    • Deficits in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence and social responsibility. Without ongoing support, the adaptive deficits limit functioning in one or more activities of daily life, such as communication, social participation, and independent living, across multiple environments such as home, school, work, and community
    • Onset of intellectual and adaptive deficits during the developmental period


Intellectual Disability: Clinical Features

  • Primary presentation: evident in childhood, significantly below average intellectual AND adaptive functioning
  • Range of impairment
    • Severe may need assistance with basic day-to-day care
    • Less severe may be able to live somewhat independently
  • Functional impairment:
    • Communication, self-care, home living, social and interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health, safety
  • Degrees of disability
    • Mild: IQ between 50 – 55 and 70
    • Moderate: IQ between 35 – 40 and 50 – 55
    • Severe: IQ between 20 – 25 and 35 – 40
    • Profound: IQ below 20 - 25


Intellectual Disability: Demographics

  • General prevalence: 2%
    • 90% of those fall in the mild category
  • Course is chronic
  • Prognosis will depend on level of impairment and disability
    • Mild: can live relatively independently
    • Profound: will require much assistance
  • Flynn effect: IQ scores have risen consistently over past century
    • Tests must adjust for this


Aetiology of Intellectual Disability

  • Hundreds of known causes
  • Main categories:
    • Environmental (deprivation, abuse, neglect)
    • Prenatal (exposure to disease or drugs in the womb)
    • Perinatal (difficulties during labour or delivery)
    • Postnatal (infections or head injury)


ID: Biological Aetiology


chromosomal mutations


  • Genetics
    • Multiple genetic influences appear to contribute to ID
    • Includes PKU and Lesch-Nyhan syndrome
  • Chromosomal mutations
    • Down syndrome (trisomy 21)
      • Characteristic facial features
      • Linked to maternal age
    • Fragile X syndrome
      • Primarily affects males
      • Associated physical characteristics


ID: Treatment and Prevention

  • Behavioural skills training and shaping
  • Communication training
    • Persons with severe ID may be taught how to use augmentative communication strategies (picture books, sign language, computers etc.)
  • Training for caretakers to help support them in community
  • Prevention
    • Early intervention to target and assist at-risk children
    • Prenatal gene therapy?
      • Where a developing foetus has been screened for a genetic disorder may be the target of intervention before birth