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Following are excerpts from Part I: "Characteristics of Disabilities and Implications for Mainstreaming in Science Classes"
The term "learning disabilities" (LD) refers to a cluster of problems of learning not caused by other handicapping conditions, or other factors such as cultural deprivation (although it has been argued that learning disabilities can co-exist with these other disability areas). It is therefore sometimes referred to as an "exclusionary" definition, because it describes what LD is by excluding alternative sources of learning failure. Nevertheless, the general presumption is that LD is often the result of some type of dysfunction of the central nervous system that allows normal functioning in general areas, but inhibits effective learning. Learning disabilities is generally considered an "umbrella" term for a variety of learning problems. It is the most common handicapping condition in schools. Other terms are given in the accompanying table.
ˇ Educational Handicaps
ˇ Minimal Brain Dysfunction (MBD)
ˇ Minimal Brain Injury
ˇ Perceptual Handicaps,
ˇ Dyslexia (reading disability)
ˇ Dyscalculia (mathematics disability)
ˇ Word Blindness or Strephosymbolia
Sometimes thought to include:
ˇ Attention Deficit Disorder (ADD), with or without hyperactivity.
In schools, students with learning disabilities are often identified by referral from the classroom teacher, and confirmation by the school psychologist and other members of the multidisciplinary team (the teachers and staff who work with the student). The student with learning disabilities exhibits serious academic learning problems in the face of normal intelligence' emotional stability, adequate sensory and physical ability, and reasonable previous opportunities to learn. Learning disabilities are often supported by the computation of a discrepancy, or mismatch, between academic achievement and general intelligence. That is, if a student has a standard score IQ of 100 (indicating 50th percentile in intelligence) and a standard score reading achievement of 70 (indicating 2nd percentile in reading), and no obvious alternative explanation can be found, the student may be characterized as "learning disabled," and provided with special education services. Although the extent of the discrepancy varies from state to state, most states mandate a discrepancy in the range of 15-20 standard score points.
Although estimates vary, students with LD comprise about 5% of the student population, or about 1-2 students in every "regular" classroom. Most students with LD are boys.
Students with learning disabilities are the students most likely to be "mainstreamed" in science classes, therefore most regular education teachers are likely to be familiar with at least some of the general characteristics of these students.
All students with LD exhibit some serious academic problems. These problems are generally thought to lie in the area of reading, but problems in math and language arts are common. Difficulties with spelling are very common among students with LD. It can be generally stated that most students are struggling to learn the basic skills, and are less able to use these skills to help them learn. In other words, most students with LD are "learning to read," not "reading to learn." They may frequently miss assignment completion dates, or turn in messy or sloppy papers, or fail to follow assignment directions.
Many (but not all) students with LD also have difficulty sustaining attention. Attention problems are thought to be at the heart of hyperactivity disorders, which are also found among populations of students with LD. Such students have difficulty staying quietly seated and academically focused during instruction.
In perhaps even greater numbers, students with LD exhibit problems with memory. Students with LD may have great difficulty remembering new vocabulary or terminology, important factual information, or directions presented in sequence. In some cases, memory problems may occur because reading disorders prevent studying or reviewing new information. It may also be that semantic memory problems are the cause of some reading problems.
Many students with LD have difficulty with organizational skills.
Many students with LD have difficulties making generalizations and applying previously learned information to new situations.
Finally, a subgroup of students with LD may exhibit problems with social behavior. These problems may be the result of an inability to read social cues, the result of problems brought on because of hyperactive or impulsive behavior, or inappropriate social behaviors which result from feelings of personal inadequacy which have arisen from school failure, or difficulties with problem-solving and generating effective alternative solutions.
Students with LD may get along well with other students on the playground or after school, but may appear frustrated and unhappy in your class. Whether the student admits it or not (or even cooperates particularly well), the student would very much like to improve his or her school functioning to the point where it is more like that of other students. With the right kind of attention and effort (including his or her own), this goal often can be achieved.
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The category "communication disorders" covers a variety of disability areas, all having to do with problems in interpersonal communication. As many as 10% of the general population have some problem with communication, and approximately 25% of all students identified for special education are characterized as having communication disorders. Further, many students from other categories of exceptionality (e.g., mental retardation, learning disabilities, hearing impairments) receive services in the area of speech and language.
According to the American Speech-Language-Hearing Association (ASHA), communication disorders include both speech disorders and language disorders.
Speech disorders include disorders of voice, articulation, and fluency. More than one of these disorders can occur together in one individual. The specific causes of most speech disorders are unknown. Different types of speech disorders and their causes are shown in the accompanying table.
Two factors contributing to speech disorders are cleft palate and neurological damage. Cleft palate can almost always be corrected by surgery, usually soon after birth. Speech disorders due to brain injury (e.g., dysarthria or apraxia) can be caused by oxygen deprivation, physical injury, disease, or stroke. Cerebral palsy (see Physical Disabilities/Other Health Impairments) is often associated with dysarthria and apraxia.
ˇ Voice disorders affect the pitch, volume, or quality of speech. Voice problems affect about 6% of the school population, and occur more frequently in younger children, and students with other handicapping conditions.
ˇ Articulation disorders involve errors in pronouncing individual words, and include such problems as lisping, or omissions or additions of word sounds. Articulation disorders characterize about 75% of the children characterized as having communication disorders.
ˇ Fluency disorders involve interruptions of the normal flow of speech. The most common type of fluency disorder is stuttering, which occurs in about one percent of the general population, more often in boys. Many children "outgrow" their disfluencies, but some do not. The specific cause of stuttering is unknown.
Over half of the students seen by speech-language pathologists have some type of language disorder. Language disorders are viewed as potentially more damaging than speech disorders because they are central to communication. Disorders of language are classified into five forms: phonology (sounds), morphology (the forms of words), syntax (word order and sentence structure), semantics (the meanings of words and sentences), and pragmatics (the social use of language).
Additional language disorders include elective mutism, in which the student, for emotional reasons, may refuse to speak in school, echolalia, where the student simply repeats the words he or she previously heard spoken, and the nonverbal student. Some students may be unable to speak, but can communicate with the use of speech synthesizers, picture communication boards, and personal computers.
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Students with mental retardation (MR) make up about 2% of the general population, and constitute about 15% of the special education population. Students who are suspected of having mental retardation are given intelligence tests and tests of "adaptive behavior" -- that is, tests of everyday living skills -- in addition to standardized achievement tests. The most commonly used definition of mental retardation is that of the American Association on Mental Retardation (AAMR): "Mental retardation refers to significantly subaverage intellectual functioning resulting in or associated with impairments in adaptive behavior and manifested during the developmental period." "Significantly subaverage" usually means an IQ score lower than 70 (about the 2nd percentile), although scores as high as 75 may be considered in some cases. Tests such as the AAMR Adaptive Behavior Scale or the Adaptive Behavior Inventory for Children are frequently used to assess adaptive behavior.
ˇ "Significantly subaverage" intellectual functioning (that is, IQ less than 70).
ˇ Impairments in adaptive behavior.
Mental retardation is also referred to as mental deficiency, mental disability, mental handicaps, and intellectual impairment.
Most students with mental retardation who are mainstreamed into regular classes are characterized as mildly retarded. This usually means that the intelligence test scores are between 50-55 and about 70. These students are often capable of acquiring academic skills up to about the sixth grade level, during their school years.
Students who score lower than 50 on intelligence tests are characterized as moderately, severely, or profoundly retarded. Students with moderate mental retardation usually can learn some relevant information about science, but it may be very difficult for them to learn at the pace and level of complexity found in the age-equivalent regular classroom. The regular classroom may not be the most appropriate environment for students with severe or profound mental retardation to learn science, although in some cases such mainstreaming may serve a socialization objective, and be used to broaden the experiences of nonhandicapped students, and their understanding of disability.
1. Mild (IQ 50-55 to 70-75); can be very capable of academic achievement.
2. Moderate (IQ 35-40 to 50-55); can learn some relevant science information, but may have difficulty with pace and level of regular classroom instruction.
3. Severe-profound (IQ below 35-40); will have great difficulty with typical classroom instruction.
Although many specific syndromes have been identified that cause mental retardation, most causes of mental retardation are unknown.
Students with mild mental retardation may be very similar in appearance to other students in the regular classroom, although in some cases they may be more careless in dress and general appearance. They typically have less well-developed language and communication skills than their peers, and have difficulty understanding complex concepts. Their academic skills will almost certainly be well below average, and they will probably exhibit memory deficits. Students with MR often become good at decoding words, but often experience great difficulties in comprehending the written material.
A particular problem with most students with mental retardation is in the ability to generalize what they have learned to other situations.
Many students with mild mental retardation are very eager to please teachers and classmates; however, social immaturity may cause them to go about seeking approval in inappropriate ways. Because of this, they may have more difficulty making and sustaining friendships than, for example, students with learning disabilities. In addition, students with mild mental retardation may have difficulty in sustaining attention, and exhibiting persistence of effort, especially on difficult tasks.
In some cases, motor coordination is delayed, and students may need some assistance on tasks requiring manipulation of laboratory apparatus.
Most students with mild mental retardation are very much aware that they are "different" from other students, and they frequently feel frustrated that they have so much difficulty with things that seem to come so easily to others.
Nevertheless, students with mild mental retardation, with appropriate educational support, can be very successful in science class, and find it an exciting and rewarding experience.
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Emotional disturbance (ED), as other disability areas, resists easy and precise definition, and is in reality an umbrella term for a group of disorders of social-emotional functioning. The federal government defined emotional disturbance as one or more social-emotional characteristics which are exhibited over an extended period of time and adversely affect school performance, including: (a) problems with learning or interpersonal relationships, (b) exhibiting inappropriate behavior under normal circumstances, (c) disorders of affect such as depression or pervasive unhappiness, or (d) exhibiting fears or physical symptoms in response to school or personal problems.
ED, according to the federal definition, is not intended to include "social maladjustment" unless it is accompanied by emotional disturbance (this issue is presently being debated). The federal definition does not now include (although it once did) students characterized as "autistic," but does still include students characterized as "schizophrenic."
ˇ A cluster of possible social-emotional characteristics.
ˇ Exhibited over time, adversely affecting school performance.
ˇ May include problems with affect as well as interpersonal relations.
ˇ Not intended to include social maladjustment.
Government officials have estimated that about 2% of the school-aged population are affected by ED, but other professionals feel the actual number is between 6 and 10 percent. Recent data indicate that only about 1% of the students with these disorders are identified for special education services, so you may find some students in your classes with social or emotional problems who are not receiving special services. Additionally, many students with other types of disabilities suffer some emotional distress as a consequence of coping with that disability.
Students with ED are among the least popular students with teachers. Most commonly, students with emotional disturbance exhibit acting out, aggressive actions toward their peers or their teachers. Students with these conduct disorders may display little or no obvious remorse for actions which may be hurtful toward others. (They may also be hurtful to themselves.) Often this behavior does not appear to be changed by discipline or consequences and students may appear to be noncompliant most of the time. Most (about 5 to I ) of the students with ED are boys. They may display affect inappropriate to the situation, such as anger or pleasure at inappropriate times. These students are usually not well liked by people they regularly come into contact with, and they often bring with them a history of criticism and punishment from others.
Another group of students with ED is characterized by withdrawal. They may be overly fearful of interactions or situations which appear nonthreatening to others. They may have a great deal of difficulty developing positive relationships with others. They may feel psychosomatic illnesses (illnesses with no obvious physical cause), or develop "real" illnesses as a result of personal stress. They may daydream and fantasize excessively and have severe anxieties. Students with ED may be prone to suicide.
The condition of emotional disturbance elicits less sympathy from other people than other disability categories do, partly because these students are often negative and aggressive toward others, and partly because others are less likely to believe the disability is beyond the individual's control (compared with, e.g., visual impairment). People often feel the student would do much better if he or she really tried to "get his (or her) act together," or "get on the ball." People often believe strict discipline alone will solve the problems, not realizing that many of these students have been punished continuously throughout their lives.
Emotional disturbance typically inhibits progress in basic academic areas, and as a consequence, many students with ED exhibit academic deficiencies, often as serious as students with learning disabilities, in such areas as reading, writing, spelling and mathematics. ED also inhibits learning from a variety of new situations, and can result in an impoverished knowledge base. New learning can be inhibited by lack of previous meaningful experience and the numerous mental distractions imposed by the nature of the disorder.
Students with ED may exhibit difficulty interacting appropriately with teachers and other students, avoiding eye contact, or not responding to social initiations. Also, irrational fears or fantasies may distract the student and inhibit learning. Fears can include fear of failure, fear of group interaction, or fear of adults. Depression or persistent negative affect may inhibit motivation or desire to succeed, encourage school phobia, and psychosomatic physical problems, such as stomach aches, headaches, or fainting spells.
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The most common distinction in characterizing hearing impairments is between deaf and hard of hearing. Generally speaking, deaf refers to a hearing disability which is sufficiently severe to preclude processing of language, when presented auditorily, with or without a hearing aid. Hard of hearing generally refers to hearing impairments which allow at least some processing of spoken language, often with the use of a hearing aid.
Hearing ability is often assessed with a pure-tone audiometer. Tones of different pitch and volume are presented through headphones to students who indicate (e.g., by raising their hands) which sounds they have heard. Pitch is referred to as frequency, and is measured in Hertz (Hz) units. Most speech sounds occur in the 500 (low) - 2,000 (high) Hz range. Volume is measured in decibels (dB), whereby zero decibels indicates the quietest sound a person with normal hearing can detect. Levels of hearing impairment based on audiometric evidence are presented in the accompanying table. Hearing loss above 90 decibels is often characterized as deafness, and below 90 decibels as hard of hearing. In general, students with the least severe hearing impairments are the most likely to receive instruction in mainstream classes.
About .12%, or a little more than one student in a thousand, are identified as hearing impaired.
1. Mild (26-54 dB); may have difficulty with faint speech and some normal speech.
2. Moderate (55-69 dB); may often have difficulty understanding normal speech.
3. Severe (70-89 dB); may understand only amplified speech.
4. Profound (90 and above); may not understand amplified speech.
Because of the vital role hearing plays in language acquisition, professionals often discriminate between adventitiously deaf (acquired) and congenitally deaf (from birth) individuals. Also, prelingual and postlingual deafness refers to occurrence before or after language development. Individuals who were born deaf or who acquired deafness before language developed usually have much more difficulty acquiring spoken language.
The causes of hearing impairments include heredity, prematurity, prenatal infections, oxygen deprivation, ear infections, head trauma, and excessive noise. In many cases, the specific cause is unknown.
Although most nonhandicapped people feel they would rather be deaf than blind, deafness is in many ways a more severe handicap for school age populations, because the ability to communicate with others can be severely impaired.
In general, students with hearing impairments exhibit severe deficits in the area of language development. Many have learned very little about language by the beginning of the school years, and so are at a great disadvantage with respect to their peers. Although some students may become fluent in sign language, a great majority have difficulty producing and understanding spoken language. Although many profoundly deaf students do not speak intelligibly, the majority of students with lesser hearing losses can be understood.
Most hearing impaired students are taught either by oral techniques, in which students are taught "speechreading" (i.e., lipreading) and taught to use the hearing they do possess; or they are taught by total communication, in which use of sign language is paired with oral techniques. Today, about two thirds of hearing impaired students are taught by total communication, and about one third are taught by oral techniques.
If the hearing impairment is not associated with another handicapping condition, such as mental retardation, there is little reason to believe that students with hearing impairments differ from the general hearing population in overall native intelligence.
Most students with hearing impairments exhibit delayed performance in academic achievement. Even math achievement, the overall strongest area for most students with hearing impairments, typically is several years' below grade level. Written work may appear disorganized or lack proper construction, particularly in use of prepositions, possessives, articles, and verb tense. Reading deficits are also usually very pronounced, although these can be improved by systematic and intensive instruction. Hearing impaired students who have benefited from excellent instruction, particularly if their parents were heavily involved, may exhibit good language and academic skills.
Although some students with hearing impairments exhibit social and personality characteristics that are different from their hearing peers (e.g., excessively shy, or easily frustrated), they are generally not severe, and often predictable given the important role of language and communication in our society. Social maladjustment is relatively more common in students with multiple handicapping conditions (e.g., visual impairment), in addition to hearing impairment. As with other disability areas, positive social adjustment has much to do with how well the disability is accepted by others. If parents, other adults and peers, are cheerful, positive, and accepting of the disability area, and students are given a chance to succeed, there is little reason to expect social or emotional problems. Nevertheless, given the severe communication problems of students with hearing impairments, they typically have more difficulty establishing friendships with other students, and as a group, are more likely to seek out friendships among others with the same disability.
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When asked to choose, most adults say they would rather be deaf than blind. However, prelingually deaf students often have more difficulty in school (because of communication problems), than do visually impaired students. One thing that is generally not known is that the majority of "blind" people can see! Up to 85% of students with visual impairments can benefit to some extent from their remaining sense of sight.
Visual impairment is one of the least common disabling conditions, affecting only about I in 2,000 students. However, the incidence of visual impairment is about ten times higher in the adult population ( 1 in 200). Some general information about visual impairment is provided next.
The legally blind student has, with correction, vision no better than 20/200. This means the student sees at 20 feet what a normally sighted person can see at 200 feet. The vision of partially sighted individuals lies generally between 20/70 and 20/200.
There is no necessary link between visual impairment and intelligence, social adjustment or language development.
Visually impaired students may function below average in academic achievement. Students with visual impairments do not automatically develop a "sixth sense," or greater acuity in other senses, to compensate for their sensory disadvantage. However, they can learn to use their senses more efficiently.
As with any other handicapping condition, students with visual impairments present a wide variety of abilities and personalities, and generally prefer others to consider their similarities with, rather than their differences from, other students. Nevertheless, the following characteristics are relatively more common in visually impaired students:
Visually impaired students may use factual sense to replace visual observations. If objects are small enough to fit into the student's hands, most physical attributes can be observed simultaneously (synthetic touch); but if the objects are much bigger, analytic touch is necessary. This means the student must touch different parts sequentially, and then attempt to combine these observations mentally. In this way, students with visual impairments may have more difficulty developing integrated concepts.
There is a great deal of variability in the relative mobility of students with visual impairments, although generally those who lost their sight at a later age are more mobile than those who lost their sight early, or were never sighted. Mobility often depends on spatial ability, and visually impaired students may use cognitive mapping to create a mental sense of a physical environment.
Some students with visual impairments develop stereotypies or stereotypic behaviors (sometimes referred to as blindisms), such as rocking or rubbing the eyes. It is generally the repetitiveness of the behavior, rather than the behavior itself, which is unusual.
The most common travel aid for individuals with visual impairments is the long cane, but extensive training is necessary for it to be used properly. Other travel aids include human guides, guide dogs (not commonly used with children), and electronic devices, such as laser canes.
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Physical disabilities may be, overall, the broadest category of disability. Physical disabilities and health impairments can assume many forms, and each may carry some specific but unique implications for instruction. There is enormous variation in these handicapping conditions, from relatively mild and short-lived, to progressive, incapacitating, and life-threatening. Because of this, it is possible to discuss physical disabilities and other health impairments only in a very general way in this manual; interested readers can consult other texts, particularly Bleck and Nagel (1982), and Hallahan and Kauffman (1991, chapter 9) for further information.
About .5% (I in 200) of the school-age population have physical disabilities. About half of these students have cerebral palsy or other crippling conditions; another half may suffer from severe chronic illness. Some general information about the most common physical disabilities are given in the table on the next page.
Students with physical disabilities or other health impairments often benefit from the use of prosthetics, orthotics, and adaptive devices. Prosthetics replace a missing body part (e.g., arm or leg), while orthotics enhance the function of a body part (e.g., leg braces). Adaptive devices can be used to more easily cope with ordinary tasks (e.g., specialized grips).
Some students with physical disabilities are positioned on wedges, which free their arms and hands for movement. Wedges require large amounts of floor space.
ˇ Cerebral palsy is a disabling condition in which paralysis or other motor dysfunction is caused by damage to the child's developing brain, by such factors as infection, diseases, trauma, lack of oxygen, or problems during the birth process. The neurological damage is permanent, but not progressive. Involved individuals may also have seizures, psychological problems, impaired intellectual ability, communication problems, or visual and hearing problems; however, many individuals with cerebral palsy do not have these additional problems.
ˇ Epilepsy (or seizure disorder) results from an abnormal discharge of electrical energy in certain brain cells. When enough cells are effected, the individual may lose consciousness, move involuntarily, or experience abnormal sensory phenomena. Individuals are characterized as epileptic only if they have repeated seizures.
ˇ Spina bifida is a condition which results when the spinal column does not close completely during fetal development, resulting in paralysis. The protruding nerve fibers are referred to as a myelomeningocele, or meningomyelocele. Spina bifida may be associated with hydrocephalus (excessive pressure of cerebrospinal fluid) which could lead to attention or learning problems, or mental retardation. Sometimes hydrocephalus can be treated surgically, so the fluid drains away from the head.
ˇ Traumatic head injury is frequently the result of vehicular accidents or near drownings. Students with such injuries may have difficulty sustaining attention, learning new things, remembering, and organizing their thoughts and their work. They may also have difficulty with social behavior.
ˇ Muscular Dystrophy refers to a progressive and hereditary weakening and wasting away of muscle tissue. At present, the specific cause is unknown, and there is no cure. Some forms are generally fatal, but other forms may allow for a relatively normal life span with few obvious symptoms. Intelligence does not seem to be affected.
ˇ Rheumatoid arthritis involves mild to severe inflammation, swelling, and/or stiffness in the joints or connective tissues. In most cases of the juvenile form, individuals improve completely over time. Osteoarthritis can occur among students with other physical disabilities, such as cerebral palsy, or when joints have been dislocated.
ˇ Other conditions include scoliosis (curvature of the spine), Osteomyelitis (bacterial bone infection), Osteogenesis imperfecta (improper and brittle bone formation), and Arthrogryposis (missing or weakened limb muscles).
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This material was developed by the National Center to Improve Practice (NCIP), located at Education Development Center, Inc. in Newton, Massachusetts. NCIP was funded by the U.S. Department of Education, Office of Special Education Programs from October 1, 1992 - September 30, 1998, Grant #H180N20013. Permission is granted to copy and disseminate this information. If you do so, please cite NCIP. Contents do not necessarily reflect the views or policies of the Department of Education, nor does mention of trade names, commercial products, or organizations imply endorsement by NCIP, EDC, or the U.S. Government. This site was last updated in September 1998.
ŠEducation Development Center, Inc.