Neurodevelopmental Disorders PDF

Neurodevelopmental Disorders Prepared by: Prof. Trixia Anne A. Reyes, MAP-CP, CHRA Neurodevelopmental Disorders ▪ Condition that begins in childhood. (Usually starts before the child starts schooling) ▪ Impairment of growth and development of the Brain or CNS ▪ Has major impact on social...

Neurodevelopmental Disorders Prepared by: Prof. Trixia Anne A. Reyes, MAP-CP, CHRA Neurodevelopmental Disorders ▪ Condition that begins in childhood. (Usually starts before the child starts schooling) ▪ Impairment of growth and development of the Brain or CNS ▪ Has major impact on social and cognitive functioning. ▪ Frequently co-occur. Neurodevelopmental Disorders ▪ Intellectual Disabilities ▪ Intellectual Disability ▪ Global Developmental Delay ▪ Unspecified Intellectual Disability (IDD) ▪ Communication Disorders ▪ Language Disorder ▪ Speech Sound Disorder ▪ Childhood-Onset Fluency Disorder ▪ Social Communication Disorder ▪ Autism Spectrum Disorder ▪ Attention-Deficit/Hyperactivity Disorder ▪ Specific Learning Disorder Intellectual Disabilities Intellectual Disability Global Developmental Delay Unspecified Intellectual Disability  Intellectual Disability is a disorder evident in childhood as significantly below-average intellectual and adaptive functioning Note: Term changed to Intellectual Developmental Disorder in DSM 5 TR 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: ▪ A. Deficits in intellectual functions. Confirmed by both clinical assessment and individualized, standardized intelligence testing. ▪ B. Deficits in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence and social responsibility. ▪ C. Onset of intellectual and adaptive deficits during the developmental period  Specifiers Severity Category Prevalence DSM V (Daily skill basis) AAIDD Mild 85% Able to live independently Intermittent with minimum support Assistance Moderate 10% Independent living may be Limited Assistance achieved with moderate level of support. Severe 3.5% Requires daily assistance Extensive Assistance with self-care activities and safety supervision Profound 1.5% Requires 24-hour care Pervasive Assistance Prevalence and Risk and Prognostic Factors ▪ overall general population prevalence of approximately 1%, and prevalence rates vary by age. Prevalence for severe intellectual disability is approximately 6 per 1,000. ▪ Environmental: Deprivation, abuse, and neglect ▪ Prenatal: Exposure to disease or drugs while still in the womb ▪ Perinatal: Difficulties during labor and delivery ▪ Postnatal: Infections and head injury Differential Diagnosis Major and mild neurocognitive disorders Intellectual Disability Categorized by loss of cognitive Categorized as a Neurodevelopmental functioning Disorder. May occur with ID (e.g., DS who develops Alzheimer's Diseases etc) Communication disorders and specific learning disorder Specific to Communication and learning Shows deficits in Intellectual and domains. Adaptive behavior. May co-occur with ID Both diagnosis are made if full criteria are met for ID and CD or SLD Autism spectrum disorder Common with people with ID Typically “behind” their same-aged Categorized by challenges with age- peers in intellectual skills appropriate social communication and/or repetitive behaviors Global Developmental Delay Reserve for individual under 5 years old when clinical severity level cannot be reliably assessed during early childhood. Unspecified Intellectual Disability (IDD) Reserve for individual over 5 years old and standardized testing is unable to be completed due to physical, motor, behavioral, or mental health factors but there is a suspicion of ID. Re- evaluation is necessary to confirm a diagnosis. Communication Disorders Speech Language Communication Language Disorder someone having difficulty with: Getting their meaning or message across to others (expressive language) Understan ding the message coming from others (receptive language) Diagnostic Criteria ▪ A. Persistent difficulties in the acquisition and use of language across modalities due to deficits in comprehension or production that include the following: ▪ 1. Reduced vocabulary ▪ 2. Limited sentence structure ▪ 3. Impairments in discourse ▪ B. Language abilities are substantially and quantifiably below those expected for age, resulting in functional limitations in effective communication, social participation, academic achievement, or occupational performance, individually or in any combination. ▪ C. Onset of symptoms is in the early developmental period. ▪ D. The difficulties are not attributable to hearing or other sensory impairment, motor dysfunction, or another medical or neurological condition and are not better explained by intellectual disability or global developmental delay. Risk and Prognostic Factors ▪ Children with receptive language impairments have a poorer prognosis than those with predominantly expressive impairments ▪ Language disorders are highly heritable, and family members are more likely to have a history of language impairment. Differential Diagnosis ▪ Normal variations in language ▪ Difficult to make before 4 years old. Regional, social or social/ethic variations must be considered when being assessed for language impairment ▪ Hearing or other sensory impairment ▪ Needs to be excluded as the primary cause of language difficulties, though language deficits may be associated with hearing, sensory or speech motor deficits. When language deficits are in excess of those usually associated with these problems, a diagnosis of language disorder may be made. ▪ Intellectual disability (Intellectual Developmental Disorder ▪ Diagnosis may not be made until the child is able to complete standardized assessments. A separate diagnosis is not given unless the language deficits are clearly in excess of the intellectual limitations. Differential Diagnosis ▪ Neurological Disorders ▪ LD can be acquired in association with neurological disorders ▪ Language Regression ▪ Less than3 years old – ASD (with developmental regression) ▪ Older than 3 years old - Specific neurological condition (Landau-Kleffner syndrome) ▪ May be a symptom to seizure.  Speech Sound Disorder a child has trouble saying certain sounds and words past the expected age. Diagnostic Criteria ▪ A. Persistent difficulty with speech sound production that interferes with speech intelligibility or prevents verbal communication of messages. ▪ B. The disturbance causes limitations in effective communication that interfere with social participation, academic achievement, or occupational performance, individually or in any combination. ▪ C. Onset of symptoms is in the early developmental period. ▪ D. The difficulties are not attributable to congenital or acquired conditions, such as cerebral palsy, cleft palate, deafness or hearing loss, traumatic brain injury, or other medical or neurological conditions. Differential Diagnosis ▪ Hearing or other sensory impairment ▪ Hearing impairment or deafness may result in abnormalities of speech. May be associated with a hearing impairment, other sensory deficit, or a speech-motor deficit. ▪ Dysarthria ▪ May be attributable to a motor disorder (Cerebral Palsy). Not applicable to under 3 years old. ▪ Selective Mutism ▪ Anxiety disorder. May develop in children with speech disorder due to embarrassment from the impairment.  Childhood- Onset Fluency Disorder (Stuttering) Speech condition that disrupts the normal flow of speech. Diagnostic Criteria ▪ A. Disturbances in the normal fluency and time patterning of speech that are inappropriate for the individual’s age and language skills, persist over time, and are characterized by frequent and marked occurrences of one (or more) of the following: ▪ 1. Sound and syllable repetitions. ▪ 2. Sound prolongations of consonants as well as vowels. ▪ 3. Broken words (e.g., pauses within a word). ▪ 4. Audible or silent blocking (filled or unfilled pauses in speech). ▪ 5. Circumlocutions (word substitutions to avoid problematic words). ▪ 6. Words produced with an excess of physical tension. ▪ 7. Monosyllabic whole-word repetitions (e.g., “I-I-I-I see him”). Diagnostic Criteria ▪ B. The disturbance causes anxiety about speaking or limitations in effective communication, social participation, or academic or occupational performance, individually or in any combination. ▪ C. The onset of symptoms is in the early developmental period. (Note: Later-onset cases are diagnosed as adult-onset fluency disorder.) ▪ D. The disturbance is not attributable to a speech-motor or sensory deficit, dysfluency associated with neurological insult (e.g., stroke, tumor, trauma), or another medical condition and is not better explained by another mental disorder. Risk and Prognostic Factors ▪ Risk of stuttering among first-degree biological relatives of individuals with childhood-onset fluency disorder is more than three times the risk in the general population. Differential Diagnosis ▪ Sensory deficits ▪ Dysfluencies of speech may be associated with a hearing impairment or other sensory deficit or a speech-motor deficit. When the speech dysfluencies are in excess of those usually associated with these problems, a diagnosis of childhood- onset fluency disorder may be made. ▪ Normal Speech dysfluencies ▪ Disorder must be distinguished from normal dysfluencies that occur frequently in young children. ▪ If difficulties increase in frequency or complexity as the child grows older. diagnosis of childhood-onset fluency disorder is appropriate. ▪ Medication side effects ▪ Adult-onset dysfluencies ▪ If during or after adolescence, it is an "adult-onset dysfluency“ ▪ Tourette’s disorder ▪ Vocal tics and repetitive vocalizations of Tourette's disorder should be distinguishable from the repetitive sounds of childhood-onset fluency disorder by their nature and timing. Social (Pragmatic) Communication Disorder persistent difficulties with the use of verbal and nonverbal language for social purposes. Diagnostic Criteria ▪ A. Persistent difficulties in the social use of verbal and nonverbal communication as manifested by all of the following: ▪ 1. Deficits in using communication for social purposes ▪ 2. Impairment of the ability to change communication to match context or the needs of the listener ▪ 3. Difficulties following rules for conversation and storytelling ▪ 4. Difficulties understanding what is not explicitly stated (e.g., making inferences) and nonliteral or ambiguous meanings of language (e.g., idioms, humor, metaphors, multiple meanings that depend on the context for interpretation). Diagnostic Criteria ▪ B. The deficits result in functional limitations in effective communication, social participation, social relationships, academic achievement, or occupational performance, individually or in combination. ▪ C. The onset of the symptoms is in the early developmental period (but deficits may not become fully manifest until social communication demands exceed limited capacities). ▪ D. The symptoms are not attributable to another medical or neurological condition or to low abilities in the domains of word structure and grammar, and are not better explained by autism spectrum disorder, intellectual disability (intellectual developmental disorder), global developmental delay, or another mental disorder. Risk and Prognostic Factors ▪ A family history of autism spectrum disorder, communication disorders, or specific learning disorder appears to increase the risk for social (pragmatic) communication disorder. Differential Diagnosis ▪ ASD ▪ Can be differentiated by the presence in autism spectrum disorder of restricted/ repetitive patterns of behavior, interests, or activities and their absence in social (pragmatic) communication disorder ▪ autism spectrum disorder may only display the restricted/repetitive patterns of behavior, interests, and activities during the early developmental period, so a comprehensive history should be obtained ▪ ADHD ▪ Primary deficits of ADHD may cause impairments in social communication and functional limitations of effective communication, social participation, or academic achievement. Differential Diagnosis ▪ Social Anxiety Disorder (Social Phobia) ▪ The symptoms of social communication disorder overlap with those of social anxiety disorder ▪ The timing of the onset of symptoms ▪ Intellectual Disability ▪ separate diagnosis is not given unless the social communication deficits are clearly in excess of the intellectual limitations. Autism Spectrum Disorder  Autism Spectrum Disorder is a neurodevelopmental disorder that, at its core, affects how one perceives and socializes with others Diagnostic Criteria ▪ A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history: ▪ 1. Deficits in social-emotional reciprocity ▪ 2. Deficits in nonverbal communicative behaviors used for social interaction ▪ 3. Deficits in developing, maintaining, and understanding relationships, ▪ Specify current severity: Severity is based on social communication impairments and restricted, repetitive patterns of behavior Note: Changes in DSM 5 TR “as manifested by the following” was revised to read “as manifested by all of the following” Diagnostic Criteria B. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history 1. Stereotyped or repetitive motor movements, use of objects, or speech 2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior 3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests). 4. Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment Specify current severity: Severity is based on social communication impairments and restricted, repetitive patterns of behavior Diagnostic Criteria C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities or may be masked by learned strategies in later life). D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level. Diagnostic Criteria Note: Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder. Specify if; With or without accompanying intellectual impairment With or without accompanying language impairment Associated with a known medical or genetic condition or environmental factor Associated with another neurodevelopmental, mental, or behavioral disorder  Specifiers Severity Level Social Communication Restricted, repetitive behaviors Level 3 Severe deficits in verbal and non Inflexibility of behavior, extreme “Requiring very verbal social communication skills difficulty coping with change, or other substantial support” cause severe impairments in restricted/repetitive behaviors markedly functioning, very limited initiation interfere with functioning in all spheres. of social interactions, minimal Great distress/difficulty changing focus response to social overtures from or action others. Level 2 Marked deficits in verbal and non Inflexibility of behavior, difficulty coping “Requiring verbal social communicative skills. with change, or other substantial support” Social impairments apparent even restricted/repetitive behaviors appear with support. frequently enough to be obvious to the Limited initiation of social casual observer and interfere with interaction. functioning in a variety of context. distress/difficulty changing focus or action  Specifiers Severity Level Social Communication Restricted, repetitive behaviors Level 1 Without support in place, deficits in Inflexibility of behavior causes “Requiring social communication cause significant interference with functioning support” noticeable impairments in one or more context. Difficulty initiating social Difficulty switching between activities. interactions and clear example of Problem with organization and planning atypical or unsuccessful responses hamper independence. to social overtures of others. May appear to have decrease interest in social interactions To use the specifier "with or without accompanying language impairment," the current level of verbal functioning should be assessed and described The specifier "associated with a known medical or genetic condition or environmental factor" should be used when the individual has a known genetic disorder or a history of environmental exposure Risk and Prognostic Factors ▪ Environmental. ▪ advanced parental age ▪ low birth weight ▪ fetal exposure to valproate ▪ Genetic and physiological ▪ Heritability estimates for autism spectrum disorder have ranged from 37°/^ to higher than 90%, based on twin concordance rates Differential Diagnosis ▪ Rett syndrome ▪ Disruption of social interaction may be observed during the regressive phase of Rett syndrome (typically between 1-4 years of age); thus, a substantial proportion of affected young girls may have a presentation that meets diagnostic criteria for autism spectrum disorder. ▪ Most individuals with Rett syndrome improve their social communication skills, and autistic features are no longer a major area of concern after 1 – 4 years. Consequently, autism spectrum disorder should be considered only when all diagnostic criteria are met. ▪ Selective mutism ▪ Early development is not typically disturbed. ▪ The affected child usually exhibits appropriate communication skills in certain contexts and settings. ▪ Language disorders and social (pragmatic) communication disorder ▪ specific language disorder is not usually associated with abnormal nonverbal communication, nor with the presence of restricted, repetitive patterns of behavior, interests, or activities Differential Diagnosis ▪ Intellectual disability (intellectual developmental disorder) without autism spectrum disorder. ▪ A diagnosis of autism spectrum disorder in an individual with intellectual disability is appropriate when social communication and interaction are significantly impaired relative to the developmental level of the individual's nonverbal skills (e.g., fine motor skills, nonverbal problem solving) ▪ Stereotypic movement disorder ▪ Motor stereotypies are among the diagnostic characteristics of autism spectrum disorder, so an additional diagnosis of stereotypic movement disorder is not given when such repetitive behaviors are better explained by the presence of autism spectrum disorder ▪ Attention-deficit/hyperactivity disorder. ▪ Should be considered when attentional difficulties or hyperactivity exceeds that typically seen in individuals of comparable mental age. ▪ Schizophrenia. ▪ Hallucinations and delusions, which are defining features of schizophrenia, are not features of autism spectrum disorder Attention- Deficit/Hyperactivity Disorder A condition that affects people's behavior.  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: Note: The symptoms are not solely a manifestation of oppositional behavior, defiance, hostility, or failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), at least five symptoms are required. ▪ a. Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or during other activities ▪ b. Often has difficulty sustaining attention in tasks or play activities ▪ c. Often does not seem to listen when spoken to directly ▪ d. Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace ▪ E. Often has difficulty organizing tasks and activities  Diagnostic Criteria ▪ F. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort ▪ g. Often loses things necessary for tasks or activities ▪ h. Is often easily distracted by extraneous stimuli ▪ i. Is often forgetful in daily activities  Diagnostic Criteria ▪ 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: Note: The symptoms are not solely a manifestation of oppositional behavior, defiance, hostility, or a failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), at least five symptoms are required. ▪ a. Often fidgets with or taps hands or feet or squirms in seat. ▪ b. Often leaves seat in situations when remaining seated is expected ▪ c. Often runs about or climbs in situations where it is inappropriate. ▪ d. Often unable to play or engage in leisure activities quietly. ▪ e. Is often “on the go,” acting as if “driven by a motor” ▪ f. Often talks excessively. ▪ g. Often blurts out an answer before a question has been completed ▪ h. Often has difficulty waiting his or her turn ▪ i. Often interrupts or intrudes on others  Diagnostic Criteria ▪ B. Several inattentive or hyperactive-impulsive symptoms were present prior to age 12 years. ▪ C. Several inattentive or hyperactive-impulsive symptoms are present in two or more settings ▪ D. There is clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning. ▪ E. The symptoms do not occur exclusively during the course of schizophrenia or another psychotic disorder and are not better explained by another mental disorder (e.g., mood disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication or withdrawal). Specifier ▪ Specify whether: ▪ Combined presentation: If both Criterion A1 (inattention) and Criterion A2 (hyperactivity-impulsivity) are met for the past 6 months. ▪ Predominantly inattentive presentation: If Criterion A1 (inattention) is met but Criterion A2 (hyperactivity-impulsivity) is not met for the past 6 months. ▪ Predominantly hyperactive/impulsive presentation: If Criterion A2 (hyperactivity-impulsivity) is met and Criterion A1 (inattention) is not met for the past 6 months ▪. Specifier ▪ Specify if: ▪ in partial remission: When full criteria were previously met, fewer than the full criteria have been met for the past 6 months, and the symptoms still result in impairment in social, academic, or occupational functioning. ▪ Specify current severity: ▪ Mild: Few, if any, symptoms in excess of those required to make the diagnosis are present, and symptoms result in no more than minor impairments in social or occupational functioning. ▪ Moderate: Symptoms or functional impairment between “mild” and “severe” are present. ▪ Severe: Many symptoms in excess of those required to make the diagnosis, or several symptoms that are particularly severe, are present, or the symptoms results in marked impairment in social or occupational functioning Prevalence ▪ 5% in children and 2.5% of adults Risk and Prognosis Factors ▪ Temperamental ▪ associated with reduced behavioral inhibition, ▪ effortful control, or constraint; ▪ negative emotionality; and/or elevated novelty seeking. ▪ Environmental ▪ Very low birth weight (less than 1,500 grams) ▪ Smoking during pregnancy ▪ history of child abuse, neglect, multiple foster placements, neurotoxin exposure (e.g., lead), infections (e.g., encephalitis), or alcohol exposure in utero. ▪ Generic Differential Diagnosis ▪ Oppositional defiant disorder. ▪ Intermittent explosive disorder. ▪ Specific learning disorder. ▪ Intellectual disability (intellectual developmental disorder) ▪ Autism spectrum disorder. ▪ Anxiety disorders. ▪ Depressive disorders. ▪ Bipolar disorder. ▪ Disruptive mood dysregulation disorder. ▪ Personality disorders  Specific Learning Disorder characterized by performance that is substantially below what would be expected given the person’s age, intelligence quotient score, and education Diagnostic Criteria ▪ A. Difficulties 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: ▪ 1. Inaccurate or slow and effortful word reading ▪ 2. Difficulty understanding the meaning of what is read ▪ 3. Difficulties with spelling ▪ 4. Difficulties with written expression ▪ 5. Difficulties mastering number sense, number facts, or calculation ▪ 6. 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. For individuals age 17 years and older, a documented history of impairing learning difficulties may be substituted for the standardized assessment. Diagnostic Criteria ▪ 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 (e.g., as in timed tests, reading or writing lengthy complex reports for a tight deadline, excessively heavy academic loads). ▪ D. The learning difficulties are 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. Note; The four diagnostic criteria are to be met based on a clinical synthesis of the individual’s history (developmental, medical, family, educational), school reports, and psychoeducational assessment. Specifier ▪ With impairment in reading: ▪ Word reading accuracy ▪ Reading rate or fluency ▪ Reading comprehension Note: Dyslexia is an alternative term used to refer to a pattern of learning difficulties characterized by problems with accurate or fluent word recognition, poor decoding, and poor spelling abilities. Specifier ▪ With impairment in written 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 ▪ Note: Dyscalculia is an alterative term used to refer to a pattern of difficulties characterized by problems processing numerical information, learning arithmetic facts, and performing accurate or fluent calculations. If dyscalculia is used to specify this particular pattern of mathematic difficulties, it is important also to specify any additional difficulties that are present, such as difficulties with math reasoning or word reasoning accuracy. Specifier ▪ Mild: Some difficulties learning skills in one or two academic domains, but of mild enough severity that the individual may be able to compensate or function well when provided with appropriate accommodations or support services, especially during the school years. ▪ Moderate: Marked difficulties learning skills in one or more academic domains, so that the individual is unlikely to become proficient without some intervals of intensive and specialized teaching during the school years. Some accommodations or supportive services at least part of the day at school, in the workplace, or at home may be needed to complete activities accurately and efficiently. ▪ Severe: Severe difficulties learning skills, affecting several academic domains, so that the individual is unlikely to learn those skills without ongoing intensive individualized and specialized teaching for most of the school years. Even with an array of appropriate accommodations or services at home, at school, or in the workplace, the individual may not be able to complete all activities efficiently. Prevalence ▪ The prevalence across the academic domains of reading, writing, and mathematics is 5%-15% among school-age children across different languages and cultures. Prevalence in adults is unknown but appears to be approximately 4%. Risk and Prognostic Factors ▪ Environmental. ▪ Prematurity or very low birth weight increases the risk for specific learning disorder, as does prenatal exposure to nicotine. ▪ Genetic and physiological ▪ The relative risk of specific learning disorder in reading or mathematics is substantially higher. ▪ first-degree relatives of individuals with these learning difficulties compared with those without them ▪ There is high heritability for both reading ability and reading disability in alphabetic and nonalphabetic languages, including high heritability for most manifestations of learning abilities and disabilities Differential Diagnosis ▪ Normal variations in academic attainment. ▪ Intellectual disability ▪ Attention-deficit/hyperactivity disorder. ▪ Psychotic disorders