Prenatal Exogenous Factors Affecting Neurodevelopment Lecture Slides PDF

LECTURE 9 (Oct. 9th) Prenatal Exogenous Factors Affecting Neurodevelopment The internal and external environment of the mother during the developmental stages of the fetus affects the offspring’s health. According to the developmental origins of health and disease (DOHaD) theory, environmenta...

LECTURE 9 (Oct. 9th) Prenatal Exogenous Factors Affecting Neurodevelopment The internal and external environment of the mother during the developmental stages of the fetus affects the offspring’s health. According to the developmental origins of health and disease (DOHaD) theory, environmental factors influence the offspring and also affect health in adulthood. Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD) and attention- deficit hyperactivity disorder (ADHD) can be caused by exposure to certain prenatal environments during pregnancy The DOHaD theory is various environments during development induce predictive adaptive responses that anticipate later environments, and that the degree of adaptation between these environments and later environments is related to future disease risk. An epidemiological study reported by Baker et al. has proposed the fetal programming hypothesis, which states that future health conditions are destined based on the early environment during prenatal and/or postnatal developmental periods. The DOHaD theory suggests that the characteristics acquired in early fetal developmental periods due to a certain environment become health risk factors in adulthood. Based on the DOHaD theory, it is possible to predict and identify high-risk groups for various diseases, therefore it is gaining attention in the field of preventive medicine, early intervention, and therapeutic treatment. In the prenatal environment, maternal immune activation (MIA), stress, undernutrition, and drug exposure are well-known as the environmental factors that affect the future health of the offspring. These environmental factors are associated with various NDDs and psychiatric disorders such as ASD, ADHD, schizophrenia, and depression Prenatal Environment & NDD In the prenatal environment, maternal immune activation (MIA), stress, undernutrition, and drug exposure are well-known as the environmental factors that affect the future health of the offspring. These environmental factors are associated with various NDDs and psychiatric disorders such as ASD, ADHD, schizophrenia, and depression. ASD is a NDD characterized by social communication deficits, repetitive behaviors, and hyperesthesia/hypesthesia. The prevalence of ASD has been reported as a one in 54 (1.85%) in the US. ASD can be caused by both genetic and environmental factors. ADHD is characterized by hyperactivity, attention deficits, and impulsivity. The worldwide prevalence of ADHD is 5.29%. ADHD is also caused by genetic and/or environmental factors.  The prenatal environment impacts the offspring’s health. Maternal immune activation (MIA), exposure to specific drugs, maternal stress, and undernutrition during the fetal period are potential risk factors for the onset of neurodevelopmental disorders (NDDs). ASD, autism spectrum disorder; ADHD, attention-deficit hyperactivity disorder; SLD, specific learning disorder; ID, intellectual disabilities; CD, communication disorders; and MD, motor disorders. What do “Prenatal” and “Perinatal” mean? Prenatal: Occurring before birth Preconception factors Exposure to toxins Maternal infections/illness Perinatal: Occurring during or just after birth Labour/delivery complications Prematurity/low birth weight Advanced Maternal Age Controversial topic – many articles say yes, many say no 2016 meta-analysis of 17 studies (> 55,000 patients) found link between advanced maternal age (> 35 years) and intellectual disability 1.53 times higher likelihood of ID Before 2000, advanced maternal age: >30 years No confirmed relationship between maternal age >30 and risk of ID Confounds? Huang, Zhu, Qu, & Mu, 2016 Gestational Factors - Exposure to Toxins, Maternal Infection/Illness The Gestation Period The Embryonic Period Weeks 3 to 8 of gestation Critical period for organ development Highly vulnerable to environmental influences and toxins Teratogen: any agent that can disturb the development of an embryo or fetus CNS (brain, spinal cord) development Known Human Teratogens Alcohol Tobacco Chemotherapy Caffeine Cocaine Androgens Lead Mercury Radiation Prescription Drugs Accutane Anticonvulsants Antithyroid medications Lithium Tetracycline Thalidomide Anticoagulants Common Teratogens that Can Affect Fetal Development Alcohol - associated with 1.63 times higher risk of ID Fetal Alcohol Spectrum Disorder Tobacco - associated with 1.10 times higher risk of ID irritability poor self-regulation lowered reactivity to sensory stimulation deficits in information processing behaviour problems Cornelius & Day, 2009; Huang, Zhu, Qu, & Mu, (2016) Maternal Illness Infection = type of teratogen Urinary tract infection: associated with 1.83 times greater risk of mild-moderate ID, and 1.41 times greater risk of severe ID Maternal diabetes - 1.15 times greater risk of ID Maternal hypertension - 1.33 times greater risk of ID Maternal asthma - 1.48 times greater risk of ID Maternal epilepsy - 2.76 times greater risk of ID Huang, Zhu, Qu, & Mu, 2016; Ikonomidou, 2010; Langridge et al., 2013 ; Lin et al., (2009) Developmental Stages of the Human Embryonic Brain The human embryonic brain are divided into three periods. In the first trimester (0–13 weeks of gestation), the neural tube is formed in the ectoderm, and the neuroepithelial cells that form the neural tube produce neural progenitor cells and neurons. These neurons migrate to the cortical layer and eventually begin to form synapses during the late first to second trimesters (14–27 weeks of gestation.) In the third trimester, neuronal axons and glia are produced from the glial progenitor cells such as astrocytes and oligodendrocytes, and are integrated into neural circuits. Brain morphology and plasticity continually develop after birth. Courchesne et al. reported that ASD associated genes continuously expressed in all trimesters first to third. However, the specific period of risk factors such as maternal infection, exposure to certain drug, and stress in the onset of ASD is reported. Neurodevelopmental abnormalities may occur in the prenatal period (first to third trimesters), when the brain is particularly sensitive and fragile to the surrounding environment, subsequently results in NDDs - The blue bars indicate neurodevelopmental events during fetal brain development. - After neural tube formation in the ectoderm (neurulation), brain vesicles are formed and neuroepithelial cells produce neural stem cell progenitors and neurons (neurogenesis). - Neural progenitor cells also produce astrocytes and oligodendrocytes (gliogenesis). The developing neurons migrate, differentiate into specific subtypes, and form synapses and myelin. The orange bars indicate the risk periods for NDDs. - MIA during pregnancy can cause NDDs; in particular, the risk of ASD onset increases in the first half of pregnancy. Maternal stress and drug exposure during pregnancy can also cause NDDs. - For example, thalidomide and valproic acid exposure are known risk factors for ASD onset Preterm Birth Birth before 37 weeks Leading cause of perinatal mortality in developed countries Frequency is 12–13% in USA, but lower in some other developed countries Main causes: Spontaneous labour with intact membranes (45%) Preterm premature rupture of membranes (PPROM) (25%) Labour induction/C-section for maternal or fetal indications (30%) Goldenberg et al., 2008 Low Birth Weight (LBW) Defined as < 2500 g at birth (5 lbs 8 oz) LBW can be preterm, but don’t nec. have to be. Some full term babies are born LBW. Maternal hypertension, smoking, drug use, & poor maternal weight gain are all risk factors for LBW Preterm Birth & LBW Preterm Birth According to meta-analysis of 17 studies, preterm birth (< 37 weeks) is associated with a 2.03 times higher likelihood of intellectual disability. 12-point IQ score difference between preterm and full term babies Linear relationship: IQ decreases as gestation shortens Low Birth Weight (LBW) According to the same meta-analysis, low birth weight is associated with a 3.56 times higher likelihood of intellectual disability. Higher risk for very low birth weight (< 1500g) than moderately low birth weight (1500-2499 g) Huang, Zhu, Qu, & Mu, 2016; Kerr-Wilson et al., (2011) Prenatal vs. Perinatal PRENATAL Preconception factors Maternal age >35 Exposure to toxins Teratogens most dangerous during embryonic period Alcohol, tobacco associated with ID Maternal infections/illness UTI, diabetes, hypertension, asthma, epilepsy PERINATAL Labour/delivery complications Breech presentation,  placenta previa, very tight nuchal cord Meconium aspiration Cephalopelvic disproportion Hypoxic ischemic encephalopathy Prematurity/low birth weight Preterm: < 37 weeks Low birth weight: < 2500g Both associated with ID LECTURE 10 & 11 (Oct. 21st & 23rd) Some Common Labour/Delivery Complications BREECH PRESENTATION - Frank Breech - Complete Breech - Footling Breech = risk of mild/mod DD PLACENTA PREVIA = risk of mild/mod DD MECONIUM ASPIRATION = unclear, but likely little risk NUCHAL CORD = unclear, but likely little risk of DD CEPHALOPELVIC DISPROPORTION = unlikely to lead to DD Langridge et al., (2013) Hypoxic Ischemic Encephalopathy Any complication that interrupts the flow of oxygenated blood to the brain can result in hypoxic ischemic encephalopathy (HIE) “Hypoxia” – a shortage of oxygen in the blood “Ischemia” – a shortage of blood flow to the brain “Encephalopathy” – the resulting brain damage Cerebral Palsy Affected Areas of the Brain: Spastic (constitutes 75% of cerebral palsy cases; 80-90%) - arises from Motor Cortex damage - the affected area is the brain cortex - the body movements are stiff and jerky - the limbs are rigid - Spasticity refers to extra stiffness in muscles associated with increased reflexes and may be bilateral or unilateral (one or both sides of the body) Bilateral: Spastic quadriplegia: Quadriplegia, or bilateral CP, affects all four limbs and occurs in about 23% of cases. Spastic diplegia: Diplegia affects both legs and occurs in about 38% of cases. Unilateral: Spastic hemiplegia: Hemiplegia, or unilateral CP, affects one side of the body and occurs in about 39% of cases. Dyskinetic (6%) Athetoid cerebral palsy can also be known as dyskinetic, dystonic or choreoathetoid cerebral palsy (constitutes 20% of cerebral palsy cases) - arises from damage to the Bascal Ganglia - the affected area is the central part of the brain - affects coordination and body posture - Dyskinetic CP is characterized by involuntary movements and consists of two subtypes: dystonic and Choreoathetotic Dystonic relates to fluctuations in muscle tone and stiffness of movement Choreoathetotic CP is seen in excessive or increased activity involuntary movements. Ataxic (5%) - constitutes 5% of cerebral palsy cases - arises from Cerebellum damage - the affected area is the cerebellum, located at the back of the brain - results in balance probl. and a hypotonic body. Hypotonic infants can sometimes be described as “floppy”, due to decreased muscle tone. Some signs of hypotonia include floppy head, feeling limp when held and flaccidity at joints, among others. - Ataxic CP is associated with poor balance and decreased muscle tone. Mixed Types - a # of childr. w CP will have two motor types present Cerebral Palsy is a term used for a group of motor disorders It is a group of “permanent” disorders of the development of movement and posture resulting in limitations of activity that are attributed to non-progressive disturbance in the developing fetal or infant brain to the developing brain. Rosenbaum et al. (2007) There may be accompanying disturbances in sensation, perception, cognition, communication and behaviour Epilepsy or secondary musculoskeletal problems can be present. Brain dev. during gestation and first weeks after birth (adapted from Dr. Jan Willem Goder) Type of CP and symptoms depend on site, extent and location of the lesion (Here in full term infants w perinatal stroke) Main Features of CP: Onset that is before, during, or after birth (usually before 2 years of age) Motor difficulties that are secondary to brain injury or an abnormality of the developing brain Decreased control of movements with poor motor coordination or balance, muscle stiffness, or abnormal movements (or a combination of these features) A condition that is non-progressive but permanent Prenatal, Perinatal (birth), & Postnatal Risk Factors Prenatal factors include congenital malformations of the brain, congenital infections (e.g., rubella), exposure to chemical toxins (alcohol) prematurity/low birth weight, stroke, toxemia (high blood pressure) Perinatal (during birth) factors premature separation of placenta from the uterus, neonatal encephalopathy, cord prolapse, brain hemorrhage or infarction (stroke). Postnatal (after birth) factors include asphyxia (secondary to choking or near drowning), head injury, or brain infections (meningitis or encephalitus). Diagnosis, prevalence, & causes of cerebral palsy - Cerebral palsy is the most common cause of childhood physical disability. - Generally diagnosis is made by paediatrician when motor milestones are not achieved, examining muscle tone - Prevalence is 2.0 in every 1000 children in developed countries (Anderson et al., 2008). - The prevalence of cerebral palsy has remained very stable despite improvements in obstetrical care. - Only a small percentage of CP children have had difficult births. - Other conditions other than asphyxia are present. What causes cerebral palsy? A combination of factors leads to cerebral palsy: Prematurity is a significant risk factor for cerebral palsy but, majority of children with cerebral palsy were born at term; Similarly, children born preterm do not have cerebral palsy. It is likely that a combination of genetic vulnerability interacting with environmental stressors leads to its development  The presence of multiple risk factors markedly increases the risk. Some Early Signs of CP may include: - Increased or decreased muscle tone - Arching of the back - Poor head control - Inability to sit up by 8 months - Seizures/epilepsy - Random or uncontrolled body movements - Balance and coordination problems - Eating/swallowing impairment - Learning diff. - Beh. problems - Visual/hearing problems - Sleeping problems  - The severity of CP mobility limitations can also be categorized into five different levels according to the Gross Motor Function Classification System – Expanded and Revised (GMFCS – E & R).8 Each level clearly describes the child’s current physical abilities and whether equipment or mobility aids are or will be needed in the future. The Gross Motor Function Classification System Levels (GMFCS): 1. Childr. walk at home, school, outdoors and in the community. They can climb stairs w/out the use of a railing. Childr. perform gross motor skills such as running and jumping, but speed, balance and coordination are limited. 2. Childr. walk in most settings and climb stairs holding onto the railing. They may exp. diff. walking long distances and balancing on uneven terrain, inclines, in crowded areas or confined spaces. Childr. may walk w physical assistance, a hand-held mobility device or used wheeled mobility over long distances. Childr. have only minimal ability to perform gross motor skills such as running and jumping. 3. Childr. walk using a hand-held mobility device in most indoor settings. They may climb stairs holding onto a railing w supervision or assistance. Childr. use wheeled mobility when traveling long distances and may self-propel for shorter distances. 4. Childr. use methods of mobility that require physical assistance or powered mobility in most settings. They may walk for short distances at home w physical assistance or use powered mobility or a body support walker when positioned. At school, outdoors and in the community childr. are transported in a manual wheelchair or use powered mobility. 5. Childr. are transported in a manual wheelchair in all settings. Childr. are limited in their ability to maintain antigravity head and trunk postures and control leg and arm movements 1. Youth walk at home, school, outdoors and in the community. Youth can climb curbs and stairs w/out physical assistance or the use of a railing. Youth perform gross motor skills such as running and jumping, but speed, balance and coordination are limited. 2. Youth walk in most settings but environmental factors and personal choice influ. mobility choices. At school or work they may require a hand held mobility device for safety and climb stairs holding onto a railing. Outdoors and in the community youth may use wheeled mobility when traveling long distances. 3. Youth are capable of walking using a hand-held mobility device. Youth may climb stairs holding onto a railing w supervision or assistance. At school they may self-propel a manual wheelchair or use powered mobility. Outdoors and in the community youth are transported in a wheelchair or use powered mobility. 4. Youth us wheeled mobility in most settings. Physical assistance of 1-2 people is required for transfers. Indoors, youth may walk short distances w physical assistance, use wheeled mobility or a body support walker when positioned. They may operate a powered chair, otherwise are transported in a manual wheelchair. 5. Youth are transported in a manual wheelchair in all settings. Youth are limited in their ability to maintain antigravity head and trunk postures and control leg and arm movements. Self- mobility is severely limited, even w the use of assistive technology. Implications & Impact of CP Cerebral palsy can affect many aspects of an individual’s life, including the ability to move, the ability to complete activities of daily living, cognitive and language abilities, and physical health Movement – controlling and motor planning are affected Most individuals with CP have some mobility Those with spastic quadriplegia or dyskinetic CP may require a wheelchair. There is a 5-level classification system used with children (see Table 3) The amount of independence is based upon the degree of hand control they possess. Some individuals with CP can have developmental disabilities (anywhere from 30 to 60%). There may be difficulties with articulation, some may be unable to communicate verbally and so other systems such as picture of symbol displays are used Table 3: Gross motor function classification system (GMFCS) for childr. ages 6-12 years 1. Walks w/out restrictions; limitations in more advanced motor skills” such as speed of running 2. Walks w/out assistive devices; limitations walking outdoors and in the community, such as difficulties w changes in terrain 3. Walks w assistive mobility devices, such as a walker or cane 4. Self-mobility w limitations; childr. are transported or use power mobility outdoors and in the community 5. Self-mobility is extremely limited even w the use of assistive technology People w cerebral palsy often have medical complications. The main medical complications are as follows: Seizures (seen in approximately 20%–30% of people with CP) Visual impairment Strabismus (turning in or out of the eye) Hearing loss Dental cavities Drooling Swallowing difficulties Poor growth/nutrition Aspiration pneumonia Gastroesophageal reflux disease (GERD) Constipation Orthopedic complications Treatment of rehabilitation focuses on health and wellness as well as participation The goal is to achieve developmental potential Learning and developmental disabilities People with cerebral palsy can have typical intellectual functioning, but some people also have developmental delays, or learning disabilities. Reported rates of intellectual disability in people with cerebral palsy range from 30% to 60% (Evans, Evans, & Alberman, 1990). Speech and language Many people with cerebral palsy are able to speak fluently and clearly. Some have difficulty with articulation, which can make speech difficult for a listener to understand. Others may be unable to speak because of motor problems and require alternate strategies to communicate, such as picture or symbol displays, or they may use a computer voice out put system. Difficulty with articulation is common for people with dyskinetic cerebral palsy Interventions & Therapies Interventions focuses on promoting health, wellness, & participation with the goal of achieving their developmental potential Numerous professionals may be involved including nurses, OTs & PTs, orthopedic surgeons, orthotists, pediatricians, psychologists, recreation consultants, SW, SLPs, & teachers. Providers utilize the WHO International Classification of Functioning, Disability and Health (ICF) as a framework. ICF emphasizes interactions between body functions & structures (impairments affecting body structure and function), activities, participation, and contextual factors (e.g., personal and environmental factors). e There are many different treatments available for people with cerebral palsy (see Table 4)  Advances in pharmacologic management have fostered an evolution in interventions. The use of botulinum toxin type A, a neurotoxin that blocks the synaptic release of acetylcholine from cholinergic nerve terminals to help manage spasticity (stiff muscles). When Botulinum toxin type A is injected into a stiff muscle, it causes partial temporary Paralysis of this muscle thereby decreasing muscle tone & treatment last for approximately 3 months. For individuals with hemiplegic cerebral palsy, hand function can be *** Developmental Area Example of Treatment Health Professional Involved Gross Motor Function Physical therapy to teach Physical therapist stretching to maintain flexibility, improve muscle strength, and Orthotist work on functional movements (i.e., walking, sitting, rolling) Physician Use of special equipment such as walkers to help promote indep. in walking Use of wheelchairs (manual and electric) to help promote mobility Use of splints, braces (e.g., an ankle-foot orthosis that helps the indiv. put his or her heel on the floor) Spasticity management, such as the use of botulinum toxin type A injections (Delgado et al., 2010) Fine Motor Function/Activities of Stretching and strengthening Occupational therapist Daily Living activities to promote hand control, splinting (e.g., a Writing aid clinics (staffed neoprene hand splint that helps occupational therapists) to keep the thumb out of the palm to make grasping objects easier) Assessment for equipment to make activities of daily living easier (e.g., grab bars near toilets and baths, commode chairs, seating w trays to create a stable work or play area, lifting systems) Home renovations to promote wheelchair accessibility Computer-assisted writing aids Training of the affected limb via constraint of the unaffected limb Speech and Language Parent training on encouraging Speech-language pathologists young childr. language dev. (e.g., the Hanen Program) Augmentative communication clinics (staffed by speech- Speech-language therapy to language pathologists and improve articulation and promote occupational therapists) language dev. Augmentative and alternative communication systems used for indiv. who are not able to speak effectively (e.g., a communication book w picture symbols that the indiv. looks at or points to, voice output computer systems) Learning/Cognitive Development Infant stimulation programs for Early childhood educators childr. younger than 2 years of age School boards, teachers, psychologists Preschool programs for childr. ages 2-4 years that include Teachers, occupational therapy consultation therapists, psychologists Special educ., including indiv. education plans and accommodations for motor and learning diff. Psycho-educational assessment to eval. learning strengths and weakn. in order to assist w school and vocational planning] Vocational programs to provide training and support to indiv. w special needs to enter the workplace Psychosocial Development/ Support to family and siblings Social worker Wellness Participation in recreational and Recreational therapist extracurricular activities Promotion of peer interactions  Will CP Ever be Preventable? Preterm birth is a significant risk factor for cerebral palsy. There is evidence that treating women who are in preterm labour (prior to 31 weeks) with magnesium sulfate substantially reduces the risk of cerebral palsy in infants (Doyle, Crowther, Middleton, Marret, & Rouse, 2009). A second strategy is the use of cooling (either head or total body cooling) for 72 hours for treatment in the immediate new- born period if an infant born at term has neonatal encephalopathy. Studies have shown that cooling may reduce both the frequency and severity of cerebral palsy (Schulzke, Rao, & Patole, 2007). Other treatments for the prevention of cerebral palsy are melatonin, with research being done to supplement pregnant mothers who are carrying a growth-restricted baby to reduce oxidative stress. Research studies evaluating stem cells or erythropoietin (a protein produced mainly by the kidneys that helps produce red blood cells) given to infants with or at risk for cerebral palsy Breaking the Stereotype https://www.kveller.com/speechless-is-abcs-new-show-starring-a-teen-with-cerebral-palsy/ LECTURE 12 & 13 (Oct. 28th & 30th) Language Development & Language Disorders (LD) Rudiments of language development & functioning.... The first 3 years of life, when the brain is developing and These skills develop best in a world that is rich with sounds, sights, and consistent exposure to the speech and language of others. There appear to be critical periods for speech and language development in infants and young children when the brain is best able to absorb language. If these critical periods are allowed to pass without exposure to language, it will be more difficult to learn. Language Development Infants selectively attend to parental speech sounds By age 1, a child can recognize several words as well as say a few words to express needs and emotions Over the next two years, language development increases exponentially along with the ability to formulate complex ideas and express new concepts Perceptual maps are formed in the brain when children hear phonemes (basic sounds) repetitively By 6 months---infants differentiate their own language from other languages By age 1---the map is complete and infants have lost the ability to discriminate sounds not important to their own language Phonological Awareness Language development Early language problems are highly predictive of subsequent communication and learning disorders and should not be ignored Phonology Deficits in phonology are a chief reason that individuals develop communication and learning disorders About 80% of children can use phonemes properly by the age of Phonological Awareness Broad construct that includes recognition of the relationship that exists between sounds and letters Detection of rhyme and alliteration Awareness that sounds can be manipulated within syllables What is the difference b/w a speech disorder and a language disorder? - Children who have trouble understanding what others say (receptive language) or difficulty sharing their thoughts (expressive language) may have a language disorder. - Specific language impairment (SLI) is a language disorder that delays the mastery of language skills. Some children with SLI may not begin to talk until their third or fourth year. - Children who have trouble producing speech sounds correctly or who hesitate or stutter when talking may have a speech disorder. - Apraxia of speech is a speech disorder that makes it difficult to put sounds and syllables together in the correct order to form words. Communication Disorders Diagnostic subcategories in DSM-5 - language disorder - speech sound disorder - childhood-onset fluency disorder - social communication disorder Language Disorder (LD) Characterized by deficits in expression despite normal comprehension of speech LD occurs when a child’s language matures at least 12 months behind his or her chronological age Children with LD often have: Delayed/slowed speech development, limited vocabulary, and speech marked by short sentences and simple grammatical structure Linguistic abilities vary significantly among those with LD Children with LD may have difficulty understanding particular types of words or statements Speech sound disorder—difficulty with articulation or sound production Diagnostic Criteria for Language Disorder Table 7.1 Diagnostic Criteria for Language Disorder A. Persistent difficulties in the acquisition and use of language across modalities (i.e., spoken, written, sign language, or other) due to deficits in comprehension or production that include the following: 1) Reduced vocabulary (word knowledge and use). 2) Limited sentence structure (ability to put words and word endings together to form sentences based on the rules of grammar and morphology). 3) Impairments in discourse (ability to use vocabulary and connect sentences to explain or describe a topic or series of events or have a conversation) 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 (intellectual developmental disorder) or global developmental delay. Prevalence and Course of Language Disorder - Language disorder affects 7% of younger school-age children - Communication disorders are identified twice as often in boys than girls - Most children acquire normal language by adolescence - 50% fully outgrow the problems - LD is associated with higher-than-normal rates of negative behaviors Causes of Language Disorder Genetics - Temporal processing deficits Brain - Circular feedback loop in the left temporal lobe - Probl. in connections b/w brains areas and less brain activity in left temporal region Areas of the Brain involved in Language Functions Neurons: form a vast, miniaturized informational network that transmits info. in the form of electrical signals. When electrical signals move thru- a neuron, the cell ejects chemicals called neurotransmitters into the synapses (spaces b/w neurons). The neurotransmitters then cross the synapses and act like switches to turn adjacent cells on or off. Cortex: a thin layer of cells that essentially covers the entire surface of the forebrain. A well- developed cortex allows a person to read, understand, talk about, and remember the concepts in this text. The vast majority of our neurons are located in the cortex. Frontal Lobe: involved w personality, emotions, and motor beh. Parietal Lobe: involved w perception and sensory experiences Occipital Lobe: involved w processing visual information Temporal Lobe: involved w hearing and speaking Treatment of LD LD and other similar communication disorders usually self-correct by age 6 and may not require intervention Strategies for parents to stimulate language development: Enrol child in a specialized preschool Using a combination of computer-and teacher-assisted instruction to teach early academic skills Build on the child’s existing strengths Childhood-Onset Fluency Disorder The repeated and prolonged pronunciation of certain syllables that interferes with communication Prevalence and course Gradual onset between ages 2 and 7; peaks at age 5 About 3% of children are affected Affects males about three times more often than females 80% of those who stutter before age 5 stop after a year in school Causes and Treatment of Childhood-Onset Fluency Disorder Genetic factors account for 70% of variance in causes Environmental factors account for remaining influences Possible treatments Parental changes---speak to the child slowly in short sentences Contingency management procedures Habit reversal procedures Social (Pragmatic) Communication Disorder New addition to DSM-5 Persistent difficulties in pragmatics (social use of language and communication) Diagnostic Criteria of Social Communication Disorder Diagnostic Criteria for Social (Pragmatic) Communication Disorder 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, such as greeting and sharing information, in a manner that is appropriate for the social context. 2. Impairment of the ability to change communication to match context or the needs of the listener, such as speaking differently in a classroom than on a playground, talking differently to a child than to an adult, and avoiding use of overly formal language. 3. Difficulties following rules for language and storytelling, such as taking turns in conversation, rephrasing when misunderstood, and knowing how to use verbal and nonverbal signals to regulate interaction. 4. Difficulties understanding what is not explicitly stated (e.g., making inferences) and nonliteral or ambiguous meanings of language (e.g., idioms, humour, metaphors, multiple meanings that depend on the context for interpretation). 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 early in the 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 development disorder), global developmental delay, or another mental disorder Other Aspects of Pragmatic Difficulties using appropriate greetings; changing language and communication style based on setting or partner; telling and understanding stories; engaging in conversation (e.g., initiating or entering a conversation, maintaining the topic, taking turns); repairing communication breakdowns (e.g., rephrasing when misunderstood); using appropriate verbal (e.g., prosodic) and nonverbal (e.g., gestures) signals to regulate an interaction; interpreting the verbal and nonverbal signals of others during an interaction understanding ambiguous or figurative language; understanding information not explicitly stated (inferring); and making and keeping close friendships. What is AAC? Augmentative and alternative communication (AAC) includes all forms of communication (other than oral speech) that are used to express thoughts, needs, wants, and ideas. Everyone uses AAC when they make facial expressions or gestures, use symbols or pictures, or write. People with severe speech or language problems rely on AAC to supplement existing speech or replace speech that is not functional. Special augmentative aids, such as picture and symbol communication boards and electronic devices, are available to help people express themselves. This may increase social interaction, school performance, and feelings of self-worth. AAC users should not stop using speech if they are able to do so. The AAC aids and devices are used to enhance their communication AAC Populations Individuals who use AAC have severe expressive communication disorders that are characterized by impairments in speech, language, reading, and writing. The list of populations below includes those who may have a temporary or permanent need for AAC to augment or replace other more traditional means of communication. It is not intended to be an exhaustive list of individuals who may benefit from AAC intervention. AAC users fall into two broad categories—those with congenital disabilities and those with acquired disabilities. Congenital Disabilities autism spectrum disorder (ASD); cerebral palsy; developmental disabilities; intellectual disability; developmental apraxia of speech; and genetic disorders. Individuals with congenital disabilities are acquiring language while using AAC strategies. For this population, AAC not only represents existing language but also is a tool to aid in expressive and receptive language acquisition and literacy development. Acquired Disabilities cerebrovascular accidents; traumatic or acquired brain injuries; neurodegenerative diseases (e.g., amyotrophic lateral sclerosis [ALS], supranuclear palsy, primary progressive aphasia, and apraxia); disability following surgeries (e.g., glossectomy, laryngectomy); and temporary conditions (e.g., intubation) for patients in critical care settings.  AAC needs for individuals with acquired disabilities will vary and may change over time, depending on the intactness of their language and cognition at the time of injury as well as on disease onset and progression. Incidence and Prevalence It has been reported that approximately 12% of preschoolers who were enrolled in special education services in Pennsylvania required AAC, and this was thought an underestimate. The majority of children in this report had a primary diagnosis of developmental delay, autism, or pervasive developmental disorder (PDD). It was reported that students used a variety of different types of AAC systems (often, more than one), including gestures (62%), sign language (35%), objects (31%), pictures (63%), and high- tech devices or SGDs (15%). An AAC Assessment An AAC system is an integrated group of components used to enhance communication and include forms of AAC (aided or unaided), symbols, selection techniques, and strategies. The AAC system incorporates each individual's strengths and needs. It may include existing speech, vocalizations, gestures, languages spoken, and/or some form of external system (e.g., SGD). Individual may use multiple modalities or many systems of AAC in combination, allowing for change based on context, audience, and communicative intent. A well-designed AAC system is flexible and adaptable The goal of an AAC assessment is to determine the AAC user's communication potential. AAC assessment is an ongoing process; ongoing evaluation and decision making are required, even after an AAC system has been selected. Exposing individuals to symbols and systems prior to assessment may ensure more accurate assessment results. This can be accomplished by providing core vocabulary supports in the home and classroom and by introducing visually represented language using a variety of communication display forms and sizes prior to the formal assessment process. It is difficult to estimate the prevalence of AAC users due to wide variability across this population in terms of diagnosis, age, location, communication modality, and extent of AAC use. The number of AAC users is growing, most likely as a result of increases in access to technology and AAC awareness and increases in the number of individuals with complex communication needs. 1.3% of people (or roughly 4 million Americans) are unable to reliably communicate using natural speech to accomplish daily communication needs. The National Survey of Children With Special Health Care Needs (2005–2006), estimates prevalence of children with special health care needs who have a speech difficulty is 2.9%. Of these children, 7.6% were estimated to require a communication aid or device; however, an estimated 2% did not receive one.  The assessment is conducted in the language preferred by the AAC user and takes into account unique characteristics, linguistic background, and cultural variables that affect communication style and use. Interpretation services may be needed. If the individual (and/or communication partner) wears hearing aids or prescription eyeglasses, these should be worn during the assessment. Hearing aids should be inspected prior to the assessment to ensure that they are in working order. Environmental modifications are made to accommodate vision or hearing deficits and any other physical difficulties. These modifications may include special lighting, physical positioning of the individual relative to his or her communication partner; volume of the SGD if the communication partner has a hearing impairment; additional personal amplification if needed; and modifications of physical space to *** *youtube video Components of an Assessment Primary, secondary, and tertiary components of the AAC system are also considered during assessment. Primary components are those that perform the functions of natural language and have the greatest impact on communication performance (e.g., symbols, vocabulary, methods of utterance generation). Secondary components relate to the way the individual uses and interacts with the system (e.g., user interface, selection method and output). Tertiary components are often external to the system itself but affect long-term use and ongoing success with the system (e.g., switches, portability, mounts, training and support Assessment takes into consideration the needs of the individual, which may include one or more of the following: Augmentative means of communication to facilitate natural speech Alternative means of communication to replace natural speech or writing Temporary or permanent need for AAC Means of communication to facilitate more appropriate alternate behaviors Forms of AAC Unaided Aided Aided No-tech Low/Light Tech High-Tech - Gestures - Pictures - Speech generating devices - Manual signs - Objects (SGD)* - Facial expressions - Photographs - Single-message devices and - Vocalizations - Writing recordable/digitized devices - Verbalizations - Communication boards/books - AAC software that enables - Body language dynamic symbol/language representation and that is used w some form of technology hardware (e.g., computer, tablet, smartphone) Forms (Unaided or Aided) AAC is typically divided into two broad categories—unaided and aided. Unaided forms of AAC do not require an external tool. Unaided forms require some degree of motor control. Aided forms of AAC require some form of external support—either electronic or non- electronic. Non-electronic aided forms are often referred to as "light-tech" or "low-tech.“ Electronic forms are referred to as “high-tech." Examples are listed in the table below. Table 2: Considerations when selecting an AAC system 1. Does the person have the fine and gross motor skills necessary for fluent use of the AAC system? 2. Will the AAC system be effective across environments (the person’s home, school, vocational, and community environments)? 3. Will the AAC system be effective w familiar and unfamiliar listeners? 4. Will the AAC system be easily transported by the user? 5. Can the AAC system be easily expanded in order to meet the changing needs of the user over time? 6. What symbol options can be used w the AAC system? Do these symbol options match the person’s vision, hearing, and cognitive abilities? 7. Does the person have the skills necessary to use the AAC system, or can he/she be taught the required skills? 8. Does the person demonstrate a preference for one system over another following training to use more than one system? Digital Speech Digitized speech (also called "waveform coding") consists of natural speech that has been recorded, stored, and reproduced. Non-speech sounds, such as laughter or the sound of a car horn, can also be recorded. Through message banking, an individual can use his or her own voice or a proxy voice to digitally record and store words, phrases, sentences, and sounds using natural voice, inflection, and intonation. Those messages are then stored on, and reproduced by, the AAC device *speech sample “Steve Gleason’s synthetic voice” youtube An AAC Assessment - Speech Output Comparison of Synthesized and Digitized Speech Output Synthesized Digitized - Less natural-sounding speech - More closely resembles natural speech - Requires less memory storage than digitized - Requires more memory storage than speech synthesized speech - Allows for generation of speech in multiple - Allows for recording of messages in a given languages language or dialect and in the individual's own - Allows for novel message generation via text to voice speech - Number of possible utterances is limited to recorded items Symbols Symbols are used in AAC to represent objects, actions, concepts, and emotions. They can include drawings, photographs, objects, facial expressions, gestures, auditory symbols (e.g., spoken words), or orthography (i.e., alphabet-based symbols). Iconicity refers to the association made between a symbol and its referent. Iconicity varies along a continuum, based on how easily the meaning of the symbol can be guessed. Transparent symbols are at one end of the iconicity continuum and are readily guessable in the absence of the referent. Opaque symbols are at the other end of the continuum and are not readily guessable, even when the meaning of the symbol is known. Translucent symbols lie between the two extremes of the continuum. The meaning of the referent may not be obvious, but the relationship between symbol and referent is more obvious when additional information is provided. There are three common ways that symbols are used to represent language; these are known as language representation methods (LRMs). May use a single LRM or a combination of LRMs, depending on preference and the functionality of the system. The following are commonly used in AAC systems: Alphabet-based methods use traditional orthography (spelling) and rate enhancement techniques such as word or phrase prediction. Single-meaning messages use graphic symbols (e.g., photographs, drawings), each of which represents one word or message (e.g., touching the picture of the toilet indicates one's need to go to the bathroom). Semantic compaction (Minspeak *) is based on the concept of multiple-meaning iconic encoding; it combines picture symbols (icons) in various prescribed sequences to form words or phrases. Because a single icon can be associated with multiple meanings, a relatively small set of icons can be used to create many words and phrases. For example, frog can refer to the following concepts: "frog," “green," "jump," and "water." Pairing frog with different symbols can communicate these various concepts—Frog + Rainbow = Green; Frog + Arrow = Jump; Frog + Cup = Pond (Glennen, 1997). A Minspeak system uses multiple meaning icons in short sequences following simple, easy to learn patterns. With only a small set of icons used in short sequences, a person can say hundreds, even thousands of words. Symbol Display Types Static/Fixed Dynamic Hybrid - Symbols remain in a fixed - Electronic—selection of one - Static/fixed display with location. symbol automatically activates dynamic component (e.g., - Most common in change in symbol set. alphabet board or keyboard communication board or low- - Often arranged by large with word prediction; grid tech SGDs. category first, then broken display that opens new page - There is a finite number of down to more specific following user selection of a symbols/messages. vocabulary items. symbol) - User may have multiple fixed - With use of multiple-meaning displays (e.g., multiple pages icons, selection of one icon in a communication book) may prompt display of other related icons. Symbol Display Organization Semantic–syntactic displays organize vocabulary based on parts of speech and syntactic framework. Symbols are laid out according to spoken word order and print orientation, and they vary depending on the language used (e.g., left-to-right or right-to-left). Useful for adults with relatively intact language (e.g., individuals with ALS) or language learners. Taxonomic displays group symbols according to semantic category (e.g., people, places, feelings, actions). Children begin to find this type of grouping helpful at around age 6–7 years. Need to consider developmental level Activity grid displays organize vocabulary by event schemes, routines, or activities. Each page or display includes activity-specific vocabulary and may be further organized by part of speech (e.g., nouns, verbs). Activity grid displays increase participation by euraging use of multiword combinations. Context-based displays are similar to activity grid displays but are designed for a particular (usually frequent) context or environment, allowing for greater generalization than vocabulary designed around a single, specific activity Selection Techniques Comparing Direct and Indirect Selection Techniques Direct Selection Indirect Selection - More efficient - Less efficient - Less load on working memory of user and - Greater demand on listener's and user's working listener memory - Can be used with high-tech or low-tech systems - Can be used with high-tech or low-tech systems - Requires more precise and accurate motor - Requires less fine-motor control movements - Requires intermediary steps between motor act - One-to-one relationship between the motor act and message generation and message generation - Can be used by individuals with significant - Requires greater visual or auditory acuity visual or auditory deficits