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Autism and Asperger's Disorder: Neurology and Diagnosis Author: Dr Shari Au - Honolulu, Hawaii, USA Shari Au, Ph.D. has worked in mental health since 1986. She works with children on the autism spectrum aged 2-13. She has a background in neuropsychology, learning disabilities and EEG biofeedback. An interest in leading edge interventions influences her therapeutic approach. She is an adjunct professor for Chaminade University and also teaches for Phoenix University. She lives in Honolulu, Hawaii. Abstract: Autism is thought to affect one person in 500. Four out of five autistic individuals are male, three out of four are thought to be mentally retarded, a third suffer from epilepsy and most are in institutions by age 13. The number of children in California receiving state services for autistic disorders has nearly quadrupled since 1987. Nationally, such services rose by 556 per cent during the 90s. It is seen as either a growing epidemic or a new awareness of an existing problem. Only 10 per cent of the autistic children entering the celebrated Princeton Child Development Center after the age of five go on to enter mainstream schools; yet half of those recognised earlier make that transition (Cowley, 2000). These reports indicate the importance of early diagnosis and intervention. Dr Marie Bristol Power, of the National Institute of Child Health and Human Development, describes autism as 'not a rare disorder, but a pressing public-health problem' (Cowley, 2000). Full Paper: Definition Autism is a syndrome known as mindblindness. The implicit perceptual knowing that thoughts and feelings are revealed in gestures, facial expressions, and voice tones eludes an autistic child. The most brilliant Asperger’s individuals are easily flummoxed by facial expressions. Asked to match pictures of people’s eyes to words like 'grateful' or 'preoccupied”', they are lost. They cannot perceive the world through other’s eyes. Unable to perceive mental states, they cannot empathise, distinguish a joke from a threat or make friends. Sharing is difficult when its effects on others are imperceptible and conversation loses meaning without its non-verbal components, which provide its cohesive intentions. The terms 'Asperger’s Disorder' and 'Pervasive Developmental Disorder' describe mild variants of autism. Asperger’s patients are somewhat autistic but capable of functioning at a fairly high level. They have quick verbal responses, sharp minds, and may speak eloquently about pet interests. The Asperger’s cognitive style enables excelling at certain mental tasks: 1) Their “weak central coherence” or blindness to contextual cues helps them resist optical illusions; 2) Their tendency to view the world as an array of discrete particulars helps them find a simple shape hidden in a complex design (embedded figures test) and excel at telling similar objects apart. Where others see forests, they see trees from the start. They view the world as an array of discrete particulars (Cowley, 2000). Autism differs from PDD in that children diagnosed with PDD fall into two groups: 1) very mild autistic symptoms, or 2) some autistic symptoms in a child with other severe neurological problems. Some children diagnosed as PDD may be almost normal while others have severe neurological problems as epilepsy, microencephaly or cerebral palsy. Autism and PDD diagnosis are not precise; they are based on behaviour only (Grandin, 2000). Asperger’s syndrome describes patients with normal IQs and no evidence of language delay (Rodier, 2000). Epidemiology Some environmental risk factors are known to increase the chances that autism will develop. In utero exposure to rubella (German measles) or birth defect-causing substances such as ethanol, valproic acid or thalidomide. Certain genetic diseases such as phenylketonuria and tuberous sclerosis have a greater chance of developing autism. However, none of these factors isconsistent enough to be causal. Suspected causes of autism range from genetic mutations to viruses and toxic chemicals. However, most exposures to diseases or hazardous substance would be likely to affect both members of a pair of twins, rather than just one (Rodier, 2000). Miller and Stromland observed that 5% of thalidomide victims had autism, which is 30 times higher than the general population rate. To identify autism’s causes, researchers needed to pinpoint exactly when the disorder begins. Its connection with thalidomide suggested that autism originates in the early weeks of pregnancy when the embryo’s brain and nervous system are just beginning to develop. The biological basis of autism enabled research to identify the leading risk factors and possible treatments for the condition. Because science knows which embryonic organs develop at each pregnancy stage, they can pinpoint exact days when a malformation can be induced. The thumb is affected 22 days after conception, the ears from days 20-33, the arms and legs from days 25-35. Thalidomide victims with autism had anomalies in the external part of their ears but no malformations of the arms or legs, indicating very early injury in gestation, 20-24 days after conception (Rodier, 2000). Few neurons form as early as the fourth week of gestation; most are motor neurons of the cranial nerves, which operate the muscles of the eyes, ears, face, jaw, throat, and tongue. The cell bodies of these neurons are located in the brain stem, between the spinal cord and the rest of the brain. Miller and Stromland confirmed that all subjects with autism had abnormalities of eye movement or facial expression, or both (Rodier, 2000). It is speculated that an early brain injury affects the cranial nerves and has secondary effects on later brain development in people with autism. Injury to the brain stem may interfere with the proper development or wiring of other brain regions. Neurobiologists associate the brain stem with the most basic functions such as breathing, eating, balance, motor co-ordination, etc. Language, planning and interpretation of social cues are believed controlled by higher-level regions of the brain such as the cerebral cortex and the hippocampus in the forebrain. Lack of facial expressions, hyper-sensitivity to touch and sound, and sleep disturbance are believed to originate in the brain regions associated with basic functions, the brain stem. A gene known as Hoxa1 plays a central role in the development of the brain stem. Hoxa1 is not active in any tissue after early embryogensis. Hoxa1 produces a type of protein called a transcription factor, which modulates the activity of other genes. Active only during development, Hoxa1 may explain a congenital disability like autism, which seems stable after childhood. Hoxa1 is a highly conserved gene; this means it is not commonly found in multiple versions (polymorphic alleles or allelic variants). Deviations from the normal sequence in any part of a gene can affect its performance. However, the majority of disease-causing variations are in the protein-coding regions. If a variant allele of Hoxa1 could be found, it may be a trigger for the development of the disorder. Most genetic disorders result from many different deviant alleles of the same gene. Two variant alleles of Hoxa1 were identified. The allele doubles the risk of developing the condition but other genetic factors must contribute to the disorder. In 60% of people with autism, the allele is not present. Hoxa1 is one of many genes which could be involved in the spectrum of autism disorders (Rodier, 2000, p.61-63). Neurology Brain Stem The brain stem is the region just above the spinal cord. In people with autism, it is shorter than in a normal brain stem. The brain stem of an autistic person lacks the superior olive and has a smaller-than-normal facial nucleus, appearing as though a band of tissue were missing. These changes occur only in early gestation (Rodier, 2000, p.58). In an autopsy examination of the brain stem of a woman with autism, the facial nucleus, which controls the muscles of facial expression, and the superior olive, a relay station for auditory information, were nearly absent. Both structures are from the same segment of the embryo’s neural tube, the organ that develops into the central nervous system. About 400 facial neurons were evident in the autistic brain, compared to 9,000 facial neurons in a control brain (Rodier, 2000,p.61). Cerebellum The cerebellum, a large processing centre of the hindbrain that has long been known to have critical functions in the control of muscle movement, is a relatively large portion of the brain located near the brainstem. It is primarily responsible for motor movements and partially responsible for speech, learning, emotions, and attention. In the late 1980s, Dr Eric Courshesne used magnetic resonance imaging (MRI) to examine structural brain abnormalities in autistic individuals. Two areas of the cerebellum were significantly smaller in autistic individuals compared to non-autistic individuals, lobules VI and VII. This abnormaility is called hypoplasia. In a small group of autistic individuals, lobules VI and VII were much larger than normal, a condition called hyperplasia (Edelson, 1995). It is thought that hypoplasia in lobules VI and VII are a result of lack of development in utero, rather than due to atrophy or damage post-natally. Researchers speculate that it may be due to oxygen deprivation, infection, toxic exposure and/or may be genetically transmitted (Edelson, 1995). Autopsy studies have shown a dramatic reduction in Purkinje cells in the cerebellum. These cells are responsible for inhibition and are rich in the neurotransmitter, serotonin. Abnormal levels of serotonin are well-documented in individuals with autism and may be linked to faulty arousal and difficulties in mood regulation (Edelson, 1995). Autism is a brain-based developmental disorder, and autopsies show that cells in the limbic regions are often small and densely packed. Autopsies of five autistic brains indicated that cerebellar abnormalities occur during foetal development, as many areas of the limbic systems were immature and abnormal. Because the limbic system does not fully mature until two years after birth, Dr Grandin suggests that secondary neurological damage may be caused by disordered sensory reactions as withdrawal from touch in those born with sensory problems (Grandin, 2000, p.7). An autistic individual’s speech resembles the speech in young children who have had tumors removed from the cerebellum. Rekate, Grubb, Aram, Hahn and Ratcheson, 1985, found that surgeries that lesioned the vermus, deep nuclei and both hemispheres of the cerebellum caused temporary speech loss in normal children (Grandin, 2000, p.1). Courshesne, Yeung-Courshesne, Press, Hesselink and Jernigan, 1988, reported that 14 out of 18 high- to moderate- functioning autistic individuals had undersized cerebellar vermal lobules VI and VII (Grandin,2000, p.1). The most consistently observed abnormality in the brains of people with autism is a reduction in the number of neurons in the cerebellum (Edelson, 1995). Amygdala and Hippocampus Dr Margaret Bauman found neurological evidence that indirectly supports the relationship between brain-functioning and social-emotional age. In numerous autopsies on the brains of autistic children and adults, she consistently found immaturities in the amygdala and hippocampus; both are parts of the limbic system (Edelson, 2000). Amygdala means almond-shaped. The amygdala is responsible for many aspects of behaviour, including emotions, aggression and sensory processing. Animal experiments indicate that, when the amygdala is removed or damaged, animals exhibit behaviours similar to autistic individuals, such as social withdrawal, compulsive behaviours, failure to learn about dangerous situations, difficulty retrieving information from memory and difficulty adjusting to novel events or situation. The amygdala is responsive to sensory stimuli as sounds, sights, smells and emotional or fearrelated stimuli. Autistic children often have problems with each of the senses (Edelson, 2000). The hippocampus, shaped like a seahorse, is responsible for learning, memory and the integration of sensory information. Damage to, or removal of, the hippocampus leads to an inability to store new information into memory. Dr Bernard Rimland theorised in his 1964 awardwinning book, Infantile Autism, that autistic children have difficulty relating new information to previously stored information. When the hippocampus is damaged or removed, animals display stereotypic, self-stimulatory behaviours and hyperactivity (Bauman & Kemper, 1994). According to Dr Bauman, the amygdala and hippocampus are less developed functionally in autistic individuals. Those with Asperger's syndrome and high-functioning autism have abnormalities in their amygdala but little to no abnormalities in the hippocampus. Intellectual functioning (hippocampus) is mildly or not impaired while emotional functioning (amygdala) is impaired and responsible for immature emotional reactions in social situations (Edelson, 1995). Assessment Physical Anomalies A few physical anomalies characteristic of autism disorder include: the corners of the mouth are low compared with the centre of the upper lip, the tops of the ears flop over and the ears are lower than normal and have an almost square shape (Rodier, 2000, p.59). Subjects with autism have abnormalities of eye movement or facial expression, or both (Rodier, 2000, p.59). A large number of these children are visual learners. They require increased time with spatial orienting of attention, making eye tracking difficult (Kashman, Mora, Glaser, 2000). Sensory System Autistic individuals may have dysfunctional sensory systems. One or more senses are either over- or under-reactive to stimulation. These sensory problems may underlie behaviours as rocking, spinning and hand-flapping. Though sensory receptors are located in the peripheral nervous system (everything but the brain and spinal cord), the problem is believed to stem from neurological dysfunction in the central nervous system, the brain. Sensory integrative dysfunction is a disorder in which sensory input is not integrated or organized appropriately in the brain. Varying degrees of problems in development, information processing and behaviour may occur (Hatch-Rasmussen, 2000). Sensory Integration focuses primarily on three basic senses: tactile, vestibular and proprioceptive. Interconnections formed prior to birth continue to develop based upon environmental interaction (Hatch-Rasmussen, 2000, p.1), because the limbic system does not fully mature until two years after birth ((Grandin, 2000, p.7). These interconnected senses are connected with other brain systems. The inter-relationship among these three senses allow us to experience, interpret and respond to different environmental stimuli; they are critical to basic survival (Hatch-Rasmussen, 2000). Tactile System The tactile system includes nerves under the skin’s surface, which inform the brain of light touch, pain, temperature and pressure. The tactile system is important in environmental perception and protective survival reactions. Tactile system dysfunctions are evident in withdrawing when touched, refusing to eat certain textured foods, to wear certain textures clothing, complaints at hair- or face-washing, avoiding touching certain textures. A dysfunctional tactile system may lead to touch misperception, hyper-or hypo-sensitivity to pain, self-imposed isolation, irritability, distractibility and hyperactivity (Hatch-Rasmussen, 2000). Tactile defensiveness is a condition of being extremely sensitive to light touch. When the tactile system is immature and working improperly, abnormal neural signals are sent to the cortex in the brain. This can interfere with other brain processes, which causes neural over-stimulation leading to excessive brain activity, which can neither be halted nor organised. This over-stimulation in the brain can make it difficult for an individual to organize behaviour or concentrate, and may result in negative emotional response to touch sensations (Hatch-Rasmussen, 2000). Vestibular System The vestibular system refers to structures within the inner ear (semi-circular canals) that detect movement and changes in the position of the head. The vestibular system senses whether your head is upright or tilted with your eyes closed. Vestibular system dysfunction manifests in two different ways: 1. Hypersensitivity to vestibular stimulation may result in fearful reactions to ordinary movement activities as swings, slides, ramps, inclines. Difficulty climbing or descending, walking or crawling on uneven or unstable surfaces may be observed. A general fearfulness in space may appear as clumsiness. 2. Hyposensitive individuals may actively seek very intense sensory experiences as excessive body whirling, jumping, spinning. They are trying continuously to stimulate their hypo-reactive vestibular systems (Hatch-Rasmussen, 2000). Proprioceptive System The proprioceptive system refers to components of muscles, joints and tendons that provide one with subconscious awareness of body position. In efficiently functioning proprioception, one’s body automatically adjusts in different situations. The proprioceptive system provides the body with signals to sit properly and step off a curb smoothly; to manipulate objects using fine motor movements as writing with a pencil, using a spoon, buttoning a shirt. Common signs of proprioceptive dysfunction are clumsiness, tendencies to fall, lack of awareness of body position in space, odd body posturing, minimal crawling when young, difficulty manipulating small objects and resistance to new motor movement activities (Hatch-Rasmussen, 2000). Praxis, the ability to plan and execute co-ordinated movement (Tabers, 1985), is another dimension of proprioception. This ability to plan and execute different motor tasks relies on obtaining accurate information from the sensory systems, then organizing and interpreting the information efficiently (Hatch-Rasmussen, 2000). Dysfunction within these three systems manifests in over- or under-responsivity to sensory input. Activity level may be unusually high or low, a child may be constantly in motion or fatigue easily. Some fluctuate between these extremes. Gross and fine motor co-ordination problems are common and may result in speech language delays and academic under-achievement. A child may be impulsive, easily distractible, and show a general lack of planning. Some have difficulty adjusting to new situations and may react with frustration, aggression, or withdrawal (HatchRasmussen, 2000). Dr Temple Grandin has suggested that autistic individuals, overwhelmed by incoming auditory and tactile stimulation, create self-imposed sensory restriction by withdrawing from too-intense input. Animals in environments that severely restrict sensory input develop autistic symptoms such as stereotyped behaviour, hyperactivity, and self-mutilation. Tactile input is required for normal development. Animal studies show that sensory restriction in puppies result in hyper-excitability; their brain wave EEGs contain signs of over-arousal six months after removal from a barren kennel environment. Many autistic children have a desynchronised EEG, which indicates high arousal or overactive brain metabolism (Grandin, 2000, p.6). An EEG or electroencephlagram provides a record of the continuous electrical activity of the brain by measuring the voltage changes generated by large numbers of neurons below an electrode placed onto the scalp (Kellogg, 1995, p. 22). Diagnostic Criteria 1. The DSM-IV (APA, 1994) (appendix 1). 2. Gilberg’s Criteria (Freisleben-Cook, 2001)(appendix 2). A diagnosis of autism requires that the patient exhibit abnormal behaviours in three categories and have especially notable deficits in the category of social interaction: 1. Impairment of Social Interaction a. Failure to use eye contact, facial expression or gestures to regulate social interaction. b. Failure to seek comfort. c. Failure to develop relationships with peers. 2. Impairment of Communication a. Failure to use spoken language, without compensating by gesture. b. Deficit in initiating or sustaining a conversation despite adequate speech. c. Aberrant language as repeating a question versus replying. 3. Restricted and Repetitive Interests and Behaviours a. Abnormally intense preoccupation with one subject or activity. b. Distress over change c. Insistence on routines or rituals with no purpose. d. Repetitive movements as hand flapping (Rodier, 2000). Diagnosis There are no medical tests for autism presently. Diagnosis is based on the child’s behavior; it is not precise. In the future, brain scans may be used for precise diagnosis (Grandin,1998). The rating scales for Autism include: 1. Checklist for Autism in Toddlers Screening Tool (CHAT) 2. The Childhood Autism Rating Scale (CARS) 3. The Profile-Revised (PEP-R) (University of North Carolina, 2001) There are three rating scales specifically for Asperger's syndrome: 1. The Australian Scale for Asperger Syndrome 2. The Asperger Syndrome Diagnostic Scale (ASDS) 3. The Gilliam Asperger’s Disorder Scale (GADS) (OASIS, 2001) Behavioural Observations for Asperger's In toddlers and young children, idiosyncratic or odd-like behaviours emerge in language, cognition and behavioir: 1. In Language a. Lucid speech before age 4 years, grammar and vocabulary are usually very good. b. Speech is sometimes stilted and repetitive. c. Voice tends to be flat and emotionless. d. Conversations revolve around self. 2. In Cognition a. Obsessed with complex topics, as patterns, weather, music, history, etc. b. Eccentric. c. I.Q. ranges are full spectrum, but many are above normal in verbal ability and below average in performance ability. d. Many have dyslexia, writing problems, and difficulty with mathematics. e. Lack of common sense. f. Concrete versus abstract thinking. 3. In Behaviour a. Movements tend to be clumsy and awkward. b. Odd forms of self-stimulatory behaviour. c. Sensory problems appear not to be as dramatic as those with other forms of autism. d. Socially aware but displays inappropriate reciprocal interaction (Edelson, 2001). Awareness of Self In older children, adolescents, and adults, defective self-awareness may occur tovarying degrees and is multi-faceted (Lezak, 1995, p. 652). Requesting a human figure drawing and inquiries into an older child’s future plans can reveal their level of self-awareness. (Lezak, 1995, p. 652). Self-knowledge reveals an individual’s insightfulness regarding their personal strengths and limitations and ability to function in the world. An Asperger's adolescent or adult may have an impaired appreciation of his or her strengths and weaknesses. Awareness of Environment and Situational Context Use of environmental and situational cues reflects an awareness of context. The extent to which an individual is aware of and responsive to surrounding activities is reflected in their use of environmental clues. Situational circumstances can be deduced when an individual is attentive to situational clues. The 'Problems of Fact' items of the 1973 revision of the Stanford-Binet scales require an individual to use cues to interpret a situation. The Cookie Theft picture from the Boston Diagnostic Aphasia (absence or impairment of the ability to communicate through speech, writing, or signs due to dysfunction of brain centres) Examination, or any of five Picture Interpretation pictures of the Cognitive Competency Test, tests one’s ability to infer a story from a picture. Such testing may reveal a bit by bit unrelated description, which raises the question of visuo-perception or inability to integrate, to disregard of all but one or two items due to impaired capacity to attend systematically or to persevere in an activity (Lezak, 1995, p.653) Social Awareness Astute observation of social awareness can provide early evidence of autism. High-functioning toddlers reading sentences at ages two or three, with obsessive interests and peculiar behaviours as averting direct eye contact and interaction are displaying symptoms suggestive of Asperger's syndrome. High-functioning children unable to establish peer relations, repeatedly demonstrating a lack of awareness of inappropriate social behaviours, with perseverative speech and obsessive interest in a few specific subjects are displaying characteristics suggestive of Asperger's. Especially notable deficits in the category of social interaction is the first of six categories of diagnostic criteria for Asperger’s syndrome (Friesleben-Cook, 2001). Simple Motor Tests Walking the straight line, as done by police on drunken drivers, is a simplemotor test for cerebellar dysfunction. Requesting smooth. co-ordinated movements is another simple motor test most people can execute (Grandin, 1998). Two-year-old toddlers should be able to run well without falling, walk up and down stairs holding a railing, and kick a large ball on request. They should be able to turn a single page at a time in a book and hold a pencil shaft between thumb and index finger. Three-year-old toddlers should be able to jump in place on two feet, go up stairs using alternative feet, go down stairs one foot at a time, ride a tricycle, stand on one foot, throw overhand, and catch by over-extending arms and hugging the body. The gross motor achievements of normal child development are useful to test for age-appropriate development. Small Motor Tasks Drawing tasks have achieved a central position in neuropsychological testing because they are sensitive to many kinds of organic disabilities. The Bender-Gestalt designs, a pencil and paper drawing task requiring manual dexterity, are well-suited to the purpose of use of space in drawing to provide concrete demonstration of an autistic adolescent or adult’s ability to organise visuoperception into a sensible acceptable construct. Beaumont and Davidoff, 1992, stress the need to consider visual impairments when evaluating performances involving visuoperception (Lezak, 655). Small motor difficulties are observable in Asperger's children with difficulty co-ordinating hand movements for drawing or writing, tossing or catching a handball, or manipulating lego or tinker toys. The small motor achievements of normal child development are useful for age-appropriate developmental comparison. Spatial Relations Tests The Woodcock-Johnson Spatial Relations test is a timed speed test challenging processing speed as well as spatial relations. Comparing scores of a standardardised administration to an untimed administration can reveal spatial relations abilities in an individual with slow processing speed. People with autism require increased time with spatial orienting of attention, as eye tracking may be slower than normal. (Kashman, Mora, Glaser, 2000). The Hiskey Nebraska Spatial Reasoning Test is an untimed spatial reasoning measure (Grandin, 2000). Visual testing Specialised visual testing for abnormal retinal activity, reliance on peripheral vision, tunnel vision, hypersensitivity to light or scotopic sensitivity, perceptual stress which leads to various perceptual distortions, may be useful. Scotopic sensitivity is triggered by various components of light: fluorescent or sunlight, reflection or glare, brightness, colour and color contrast. Colour transparencies/overlays used to reduce contrast of a dominant overtaking white background have improved perception by reducing perceptual stress. Diagnostic discrimination of distortion reduction with different transparency colors and hues is suggested in Irlen testing for scotopic sensitivity (Edelson, 2001). Contructional Performance Constructional performance combines perceptual activity, motor response and spatial relations in testing. In people with more than very mild perceptual disabilities, visuo-perceptual dysfunctions become evident on constructional tasks. Because constructional disturbances can occur without concomitant impairment of visuo-perceptual function, observation is needed to distinguish between perceptual failures, apraxias (inability to perform purposive movements despite absence of sensory or motor impairment), spatial confusion and attentional or motivational problems (Lezak, 1995, p.559-564). Intervention Scientific studies and practical experience have shown that the prognosis is greatly improved if a child is placed into an intense, highly structured educational programme by age two or three. Children may engage in repetitive (seemingly obsessive) behaviours to shut out confusing, overwhelming, or painful sounds and sights. However, doing so reduces stimuli necessary for normal development. Autistic and PDD children need many hours of structured education continually to engage with the world, to be kept interacting in a meaningful way with an adult or another child. Caregivers and service providers must simultaneously be sensitive to sensory overload. Both children diagnosed with autism and PDD will benefit from education programmes designed for autistic individuals (Grandin, 1998). Structured behaviour modification methods that work with small children are often useless with a high-functioning older child. Intervention approaches include behaviour modification, auditory integration training, sensory integration training, visuoperception adaptation, music, small and large motor activities including skating, swinging, painting, building. Creative, unconventional interventions need to emphasise a gradual transition from the world of school to the work world. The importance of transition training cannot be over-emphasised for autistic individuals who need gradual introduction to a job before they graduate. A variety of activities and use of more than one approach including flexible behaviour modification, speech therapy, exercise, sensory treatment with activities that stimulate the vestibular system and tactile desensitisation, musical activities, contact with normal children and extra affection are therapeutic. Effective intervention in one case may be less effective with another due to the uniqueness of individuals with autism (Grandin, 2000), and by virtue of the imprecision of diagnostics and treatment. Bibliography American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders ((4th ed.). Washington, DC. Bauman, M.L. and Kemper, T.L. (Eds.). (1994). The Neurobiology of Autism. 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