Deficit : Reduced mental or physical functioning.
Delay : performance below expected norms according to chronological (actual) age or grade level.
Decibel (dB) – The unit used to measure the intensity or loudness of sound.
Dizziness – Physical unsteadiness, imbalance, and lightheadedness associated with balance disorders. Learn more about balance disorders and dizziness. Dizziness refers to an impairment in spatial perception and stability The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness.
One can induce dizziness by engaging in disorientating activities such as spinning.
- Vertigo is a specific medical term used to describe the sensation of spinning or having one’s surroundings spin about them. Many people find vertigo very disturbing and often report associated nausea and vomiting. It represents about 25% of cases of occurrences of dizziness.
- Disequilibrium is the sensation of being off balance, and is most often characterized by frequent falls in a specific direction. This condition is not often associated with nausea or vomiting.
- Presyncope is lightheadedness, muscular weakness and feeling faint as opposed to a which is actually fainting.
- Non-specific dizziness is often psychiatric in origin. It is a diagnosis of exclusion and can sometimes be brought about by hyperventilation.
A stroke is the cause of isolated dizziness in 0.7% of people who present to the emergency room
Dysequilibrium – Any disturbance of balance.
Developmental Disability: Developmental Disabilities in infants and toddlers are displayed as significant differences between expected level of development for age and current level of functioning. Developmental disability is a term used in the United States and Canada to describe lifelong disabilities attributable to mental or physical impairments, manifested prior to age 22. It is not synonymous with “developmental delay” which is often a consequence of a temporary illness or trauma during childhood. There are many social, environmental and physical causes of developmental disabilities, although for some a definitive cause may never be determined. Common factors causing developmental disabilities include:
- Brain injury or infection before, during or after birth;
- Growth or nutrition problems (prenatally, perinatally, or postnatally);
- Abnormalities of chromosomes and genes;
- Birth long before the expected birth date – also called extreme prematurity;
- Poor maternal diet and absent or minimal health care;
- Drug abuse during pregnancy, including alcohol intake and smoking;
- Drug-related prenatal developmental insult, such as thalidomide;
- Severe physical maltreatment (child abuse), which may have caused brain injury and which can adversely affect a child’s learning abilities and socio-emotional development;
- An autism spectrum
Developmental disabilities affect between 1 and 2% of the population in most western countries, although many government sources acknowledge that statistics are flawed in this area. The worldwide proportion of people with developmental disabilities is believed to be approximately 1.4%. It is twice as common in males as in females, and some researchers have found that the prevalence of mild developmental disabilities is likely to be higher in areas of poverty and deprivation, and among people of certain ethnicities.
Physical health issues
There are many physical health factors associated with developmental disabilities. For some specific syndromes and diagnoses, these are inherent (such as poor heart function in people with Down syndrome); however lack of access to health services and lack of understanding by medical professionals is also a major contributing factor. People with severe communication difficulties find it difficult to articulate their health needs, and without adequate support and education might not recognize ill health. Epilepsy, sensory problems (such as poor vision and hearing), obesity and poor dental health are over-represented in this population Life expectancy among people with developmental disabilities as a group is estimated at 20 years below average, although this is improving with advancements in adaptive and medical technologies, and as people are leading healthier, more fulfilling lives, and some conditions (such as Freeman-Sheldon syndrome) do not impact life expectancy.
Mental health issues (dual diagnoses)
Mental health issues, and psychiatric illnesses, are more likely to occur in people with developmental disabilities than in the general population. A number of factors are attributed to the high incidence rate of dual diagnoses:
- The high likelihood of encountering traumatic events throughout their lifetime (such as abandonment by loved ones, abuse, bullying and harassment)
- The social and developmental restrictions placed upon people with developmental disabilities (such as lack of education, poverty, limited employment opportunities, limited opportunities for fulfilling relationships, boredom)
- Biological factors (such as brain injury, epilepsy, illicit and prescribed drug and alcohol misuse)
- Developmental factors (such as lack of understanding of social norms and appropriate behavior, inability of those around to allow/understand expressions of grief and other human emotions)
- External monitoring factor: all people with developmental disabilities that are in a federal- or state-funded residence require the residence to have some form of behavioral monitoring for each person with developmental disability at the residence. With this information psychological diagnoses are more easily given than with the general population that has less consistent monitoring.
- Access to health care providers: in the United States, all people with developmental disabilities that are in a federal- or state-funded residence require the residence to have annual visits to various health care providers. With consistent visits to health care providers more people with developmental disabilities are likely to receive appropriate treatment than the general population that is not required to visit various health care providers.
These problems are exacerbated by difficulties in diagnosis of mental health issues, and in appropriate treatment and medication, as for physical health issues.
Abuse and vulnerability
Abuse is a significant issue for people with developmental disabilities, and as a group they are regarded as vulnerable people in most jurisdictions. Common types of abuse include:
- Physical abuse (withholding food, hitting, punching, pushing, etc.)
- Neglect (withholding help when required, e.g., assistance with personal hygiene)
- Sexual abuse
- Psychological or emotional abuse (verbal abuse, shaming and belittling)
- Constraint and restrictive practices (turning off an electric wheelchair so a person cannot move)
- Financial abuse (charging unnecessary fees, holding onto pensions, wages, etc.)
- Legal or civil abuse (restricted access to services)
- Systemic abuse (denied access to an appropriate service due to perceived support needs)
- Passive neglect (a caregiver’s failure to provide adequate food, shelter)
Lack of education, lack of self-esteem and self-advocacy skills, lack of understanding of social norms and appropriate behavior and communication difficulties are strong contributing factors to the high incidence of abuse among this population.
In addition to abuse from people in positions of power, peer abuse is recognized as a significant, if misunderstood, problem. Rates of criminal offense among people with developmental disabilities are also disproportionately high, and it is widely acknowledged that criminal justice systems throughout the world are ill-equipped for the needs of people with developmental disabilities—as both perpetrators and victims of crime.
Some people with developmental disabilities exhibit challenging behavior, defined as “culturally abnormal behaviour(s) of such intensity, frequency or duration that the physical safety of the person or others is placed in serious jeopardy, or behaviour which is likely to seriously limit or deny access to the use of ordinary community facilities”. Common types of challenging behavior include self-injurious behavior (such as hitting, headbutting, biting), aggressive behavior (such as hitting others, screaming, spitting, kicking, swearing, hairpulling), inappropriate sexualized behavior (such as public masturbation or groping), behavior directed at property (such as throwing objects and stealing) and stereotyped behaviors (such as repetitive rocking, echolalia or elective incontinence).
Challenging behavior in people with developmental disabilities may be caused by a number of factors, including biological (pain, medication, the need for sensory stimulation), social (boredom, seeking social interaction, the need for an element of control, lack of knowledge of community norms, insensitivity of staff and services to the person’s wishes and needs), environmental (physical aspects such as noise and lighting, or gaining access to preferred objects or activities), psychological (feeling excluded, lonely, devalued, labelled, disempowered, living up to people’s negative expectations) or simply a means of communication. A lot of the time, challenging behavior is learned and brings rewards and it is very often possible to teach people new behaviors to achieve the same aims. Challenging behavior in people with developmental disabilities can often associated with specific mental health problems.
Experience and research suggests that what professionals call “challenging behavior” is often a reaction to the challenging environments that those providing services create around people with developmental disabilities. “Challenging behavior” in this context is a method of communicating dissatisfaction with the failure of those providing services to focus on what kind of life makes most sense to the person, and is often the only recourse a developmentally disabled person has against unsatisfactory services or treatment and the lack of opportunities made available to the person. This is especially the case where the services deliver lifestyles and ways of working that are centered on what suits the service provider and its staff, rather than what best suits the person.
In general, behavioral interventions or what has been termed applied behavior analysis has been found to be effective in reducing specific challenging behavior Recently, efforts have been placed on developing a developmental pathway model in the behavior analysis literature to prevent challenging behavior from occurring.
Societal attitudes towards developmental disabilities
Throughout history, people with developmental disabilities have been viewed as incapable and incompetent in their capacity for decision-making and development. Until the Enlightenment in Europe, care and asylum was provided by families and the church (in monasteries and other religious communities), focusing on the provision of basic physical needs such as food, shelter and clothing. Stereotypes such as the dimwitted yokel, and potentially harmful characterizations (such as demonic possession for people with epilepsy) were prominent in social attitudes of the time.
Early in the twentieth century the eugenics movement became popular throughout the world. This led to the forced sterilization and prohibition of marriage in most of the developed world and was later used by Hitler as rationale for the mass murder of mentally challenged individuals during the Holocaust. The eugenics movement was later proven to be seriously flawed and in violation of human rights and the practice of forced sterilization and prohibition from marriage was discontinued by most of the developed world by the mid 20th century.
The movement towards individualism in the 18th and 19th centuries, and the opportunities afforded by the Industrial Revolution, led to housing and care using the asylum model. People were placed by, or removed from, their families (usually in infancy) and housed in large institutions (of up to 3,000 people, although some institutions were home to many more, such as the Philadelphia State Hospital in Pennsylvania which housed 7,000 people through the 1960s), many of which were self-sufficient through the labor of the residents. Some of these institutions provided a very basic level of education (such as differentiation between colors and basic word recognition and numeracy), but most continued to focus solely on the provision of basic needs. Conditions in such institutions varied widely, but the support provided was generally non-individualized, with aberrant behavior and low levels of economic productivity regarded as a burden to society. Heavy tranquilization and assembly line methods of support (such as “birdfeeding” and cattle herding) were the norm, and the medical model of disability prevailed. Services were provided based on the relative ease to the provider, not based on the human needs of the individual.
Ignoring the prevailing attitude, Civitans adopted service to the developmentally disabled as a major organizational emphasis in 1952. Their earliest efforts included workshops for special education teachers and daycamps for disabled children, all at a time when such training and programs were almost nonexistent. The segregation of people with developmental disabilities wasn’t widely questioned by academics or policy-makers until the 1969 publication of Wolf Wolfensberger’s seminal work “The Origin and Nature of Our Institutional Models”, drawing on some of the ideas proposed by SG Howe 100 years earlier. This book posited that society characterizes people with disabilities as deviant, sub-human and burdens of charity, resulting in the adoption of that “deviant” role. Wolfensberger argued that this dehumanization, and the segregated institutions that result from it, ignored the potential productive contributions that all people can make to society. He pushed for a shift in policy and practice that recognized the human needs of “retardates” and provided the same basic human rights as for the rest of the population.
The publication of this book may be regarded as the first move towards the widespread adoption of the social model of disability in regard to these types of disabilities, and was the impetus for the development of government strategies for desegregation. Successful lawsuits against governments and an increasing awareness of human rights and self-advocacy also contributed to this process, resulting in the passing in the U.S. of the Civil Rights of Institutionalized Persons Act in 1980.
From the 1960s to the present, most states have moved towards the elimination of segregated institutions. Along with the work of Wolfensberger and others including Gunnar and Rosemary Dybwad, a number of scandalous revelations around the horrific conditions within state institutions created public outrage that led to change to a more community-based method of providing services. By the mid-1970s, most governments had committed to de-institutionalization, and had started preparing for the wholesale movement of people into the general community, in line with the principles of normalization. In most countries, this was essentially complete by the late 1990s, although the debate over whether or not to close institutions persists in some states, including Massachusetts.
Individuals with developmental disabilities are not fully integrated into society. Person Centered Planning and Person Centered Approaches are seen as methods of addressing the continued labeling and exclusion of socially devalued people, such as people with a developmental disability label, encouraging a focus on the person as someone with capacities and gifts, as well as support needs.
Services and support
Today, support services are provided by government agencies (such as MRDD), non-governmental organizations and by private sector providers. Support services address most aspects of life for people with developmental disabilities, and are usually theoretically based in community inclusion, using concepts such as social role valorization and increased self-determination (using models such as Person Centred Planning). Support services are funded through government block funding (paid directly to service providers by the government), through individualized funding packages (paid directly to the individual by the government, specifically for the purchase of services) or privately by the individual (although they may receive certain subsidies or discounts, paid by the government). There also are a number of non-profit agencies dedicated to enriching the lives of people living with developmental disabilities and erasing the barriers they have to being included in their community.
Education and training
Main article: Special education
Education and training opportunities for people with developmental disabilities have expanded greatly in recent times, with many governments mandating universal access to educational facilities, and more students moving out of special schools and into mainstream classrooms with support.
Post-secondary education and vocational training is also increasing for people with these types of disabilities, although many programs offer only segregated “access” courses in areas such as literacy, numeracy and other basic skills. Legislation (such as the UK’s Disability Discrimination Act 1995) requires educational institutions and training providers to make “reasonable adjustments” to curriculum and teaching methods in order to accommodate the learning needs of students with disabilities, wherever possible. There are also some vocational training centers that cater specifically to people with disabilities, providing the skills necessary to work in integrated settings, one of the largest being Dale Rogers Training Center in Oklahoma City. (See also Intensive interaction)
At-home and community support
Many people with developmental disabilities live in the general community, either with family members, in supervised-group homes or in their own homes (that they rent or own, living alone or with flatmates). At-home and community supports range from one-to-one assistance from a support worker with identified aspects of daily living (such as budgeting, shopping or paying bills) to full 24-hour support (including assistance with household tasks, such as cooking and cleaning, and personal care such as showering, dressing and the administration of medication). The need for full 24-hour support is usually associated with difficulties recognizing safety issues (such as responding to a fire or using a telephone) or for people with potentially dangerous medical conditions (such as asthma or diabetes) who are unable to manage their conditions without assistance.
In the United States a support worker is known as a Direct Support Professional (DSP). The DSP works in assisting the individual with their ADLs and also acts as an advocate for the individual with a developmental disability, in communicating their needs, self expression and goals.
Supports of this type also include assistance to identify and undertake new hobbies or to access community services (such as education), learning appropriate behavior or recognition of community norms, or with relationships and expanding circles of friends. Most programs offering at-home and community support are designed with the goal of increasing the individual’s independence, although it is recognized that people with more severe disabilities may never be able to achieve full independence in some areas of daily life.
Austin State Supported Living Center (previously Austin State School) in Austin, Texas
Some people with developmental disabilities live in residential accommodation (also known as group homes) with other people with similar assessed needs. These homes are usually staffed around the clock, and usually house between 3 and 15 residents. The prevalence of this type of support is gradually decreasing, however, as residential accommodation is replaced by at-home and community support, which can offer increased choice and self-determination for individuals. Some U.S. states still provide institutional care, such as the Texas State Schools.
Employment support usually consists of two types of support:
- Support to access or participate in integrated employment, in a workplace in the general community. This may include specific programs to increase the skills needed for successful employment (work preparation), one-to-one or small group support for on-the-job training, or one-to-one or small group support after a transition period (such as advocacy when dealing with an employer or a bullying colleague, or assistance to complete an application for a promotion).
- The provision of specific employment opportunities within segregated business services. Although these are designed as “transitional” services (teaching work skills needed to move into integrated employment), many people remain in such services for the duration of their working life. The types of work performed in business services include mailing and packaging services, cleaning, gardening and landscaping, timberwork, metal fabrication, farming and sewing.
Workers with developmental disabilities have historically been paid less for their labor than those in the general workforce, although this is gradually changing with government initiatives, the enforcement of anti-discrimination legislation and changes in perceptions of capability in the general community.
In the United States, a variety of initiatives have been launched in the past decade to reduce unemployment among workers with disabilities—estimated by researchers at over 60%. Most of these initiatives are directed at employment in mainstream businesses. They include heightened placement efforts by the community agencies serving people with developmental disabilities, as well as by government agencies.
Additionally, state-level initiatives are being put launched to increase employment among workers with disabilities. In California, the state senate in 2009 created the Senate Select Committee on Autism and Related Disorders. The Committee has been examining additions to existing community employment services, and also new employment approaches. Committee member Dr. Lou Vismara, chairman of the MIND Institute at University of California, Davis, is pursuing the development of a planned community for persons with autism and related disorders in the Sacramento region. Another committee member, Michael Bernick, the former director of the state labor department, has established a program at the California state university system, starting at California State University East Bay, to support students with autism on the college level. Other Committee efforts include mutual support employment efforts, such as disability job networks, job boards, and identifying business lines that build on the strengths of persons with disabilities.
Non-vocational day services are usually known as day centers, and are traditionally segregated services offering training in life skills (such as meal preparation and basic literacy), center-based activities (such as crafts, games and music classes) and external activities (such as day trips). Some more progressive day centers also support people to access vocational training opportunities (such as college courses), and offer individualized outreach services (planning and undertaking activities with the individual, with support offered one-to-one or in small groups).
Traditional day centers were based on the principles of occupational therapy, and were created as respite for family members caring for their loved ones with disabilities. This is slowly changing, however, as programs offered become more skills-based and focused on increasing independence.
Advocacy is a burgeoning support field for people with developmental disabilities. Advocacy groups now exist in most jurisdictions, working collaboratively with people with disabilities for systemic change (such as changes in policy and legislation) and for changes for individuals (such as claiming welfare benefits or when responding to abuse). Most advocacy groups also work to support people, throughout the world, to increase their capacity for self-advocacy, teaching the skills necessary for people to advocate for their own needs.
Other types of support
Other types of support for people with developmental disabilities may include:
- therapeutic services, such as speech therapy, occupational therapy, physical therapy, massage, aromatherapy, art, dance/movement or music therapy
- supported holidays
- short-stay respite services (for people who live with family members or other unpaid carers)
- transport services, such as dial-a-ride or free bus passes
- specialist behavior support services, such as high-security services for people with high-level, high-risk challenging behaviors
- specialist relationships and sex education
Developmental Language Disorder: Children who do not develop language skills appropriately or according to language norms are language delayed or disordered. Expressive language disorder is a communication disorder in which there are difficulties with verbal and written expression. It is a specific language impairment characterized by an ability to use expressive spoken language that is markedly below the appropriate level for the mental age, but with a language comprehension that is within normal limits. There can be problems with vocabulary, producing complex sentences, and remembering words, and there may or may not be abnormalities in articulation.
Expressive language disorder is now classified as a specific language impairment or SLI, where a child has failed to acquire normal expressive language even though they have been adequately exposed to language and there is an absence of notable medical or genetic causes.
As well as present speech production, very often, someone will have difficulty remembering things. This memory problem is only disturbing for speech; non-verbal or non-linguistically based memory will be unimpaired. An example of a child with expressive language disorder can be seen here.
Expressive language disorder affects work and schooling in many ways. It is usually treated by specific speech therapy, and usually cannot be expected to go away on its own.
Expressive language disorder can be further classified into two groups: developmental expressive language disorder and acquired expressive language disorder. Developmental expressive language disorder currently has no known cause, is first observed when a child is learning to talk, is more common in boys than girls, and is much more common than the acquired form of the disorder. Acquired expressive language disorder is caused by specific damage to the brain by a stroke, traumatic brain injury, or seizures.
Care must be taken to distinguish expressive language disorder from other communication disorders, sensory-motor disturbances, intellectual disability and/or environmental deprivation (see DSM-IV-TR criterion D). These factors affect a person’s speech and writing to certain predictable extents, and with certain differences.
Careful diagnosis is also important due to the fact that “atypical language development can be a secondary characteristic of other physical and developmental problems that may first manifest as language problems”.
Developmental Speech Disorder : Children who do not develop speech production skills appropriately or according to normative data are speech delayed or disordered. Speech disorders or speech impediments are a type of communication disorders where ‘normal’ speech is disrupted. This can mean stuttering, lisps, etc. Someone who is unable to speak due to a speech disorder is considered mute. Classifying speech into normal and disordered is more problematic than it first seems. By a strict classification, only 5% to 10% of the population has a completely normal manner of speaking (with respect to all parameters) and healthy voice; all others suffer from one disorder or another.
- Stuttering affects approximately 1% of the adult population.
- Cluttering, a speech disorder that has similarities to stuttering.
- Dysprosody is the rarest neurological speech disorder. It is characterized by alterations in intensity, in the timing of utterance segments, and in rhythm, cadence, and intonation of words. The changes to the duration, the fundamental frequency, and the intensity of tonic and atonic syllables of the sentences spoken, deprive an individual’s particular speech of its characteristics. The cause of dysprosody is usually associated with neurological pathologies such as brain vascular accidents, cranioencephalic traumatisms, and brain tumors
- Muteness is complete inability to speak
- Speech sound disorders involve difficulty in producing specific speech sounds (most often certain consonants, such as /s/ or /r/), and are subdivided into articulation disorders (also called phonetic disorders) and phonemic disorders. Articulation disorders are characterized by difficulty learning to produce sounds physically. Phonemic disorders are characterized by difficulty in learning the sound distinctions of a language, so that one sound may be used in place of many. However, it is not uncommon for a single person to have a mixed speech sound disorder with both phonemic and phonetic components.
- Voice disorders are impairments, often physical, that involve the function of the larynx or vocal resonance.
- Dysarthria is a weakness or paralysis of speech muscles caused by damage to the nerves and/or brain. Dysarthria is often caused by strokes, parkinsons disease, ALS, head or neck injuries, surgical accident, or cerebral palsy.
- Apraxia of speech may result from stroke or be developmental, and involves inconsistent production of speech sounds and rearranging of sounds in a word (“potato” may become “topato” and next “totapo”). Production of words becomes more difficult with effort, but common phrases may sometimes be spoken spontaneously without effort. It is now considered unlikely that childhood apraxia of speech and acquired apraxia of speech are the same thing though they share many characteristics.
There are three different levels of classification when determining the magnitude and type of a speech disorder and the proper treatment or therapy:
- Sounds the patient can produce
- Phonemic- can be produced easily; used meaningfully and contrastively
- Phonetic- produced only upon request; not used consistently, meaningfully, or contrastively; not used in connected speech
- Stimulable sounds
- Easily stimulable
- Stimulable after demonstration and probing (i.e. with a tongue depressor)
- Cannot produce the sound
- Cannot be produced voluntarily
- No production ever observed
Digital/ Programmable hearing aid: Hearing aids with an external computer temporarily connected to the device and can adjust all processing characteristics on an individual basis. It allows implementation of many additional features not possible with analog circuitry, can be used in all styles of hearing aids and is the most flexible; for example, digital hearing aids can be programmed to amplify certain frequencies more than others, and can provide better sound quality than analog hearing aids.
Disorder: Conditions affecting the function of mind or body.
Direct audio input (DAI): Allows the hearing aid to be directly connected to an external audio source like a CD player or an assistive listening device (ALD)
Down syndrome: A congenital disorder due to genetic abnormality (21st chromosome trisomy). Down syndrome (DS) or Down’s syndrome, also known as trisomy 21, is a chromosomal condition caused by the presence of all or part of a third copy of chromosome 21. It is named after John Langdon Down, the British physician who described the syndrome in 1866. The condition was clinically described earlier in the 19th century by Jean Etienne Dominique Esquirol in 1838 and Edouard Seguin in 1844. Down syndrome was identified as a chromosome 21 trisomy by Dr. Jérôme Lejeune in 1959. Down syndrome can be identified in a baby at birth, or even before birth by prenatal screening.
The CDC estimates that about one of every 691 babies born in the United States each year is born with Down syndrome. Down syndrome occurs in all human populations, and analogous conditions have been found in other species such as chimpanzees.
Often Down syndrome is associated with a delay in cognitive ability and physical growth, and a particular set of facial characteristics. The average IQ of young adults with Down syndrome is around 50, compared to children without the condition with an IQ of 100. A large proportion of individuals with Down syndrome have a severe degree of intellectual disability.
Many children with Down syndrome who have received family support, enrichment therapies and tutoring manage to graduate from high school and are able to do paid work, and some participate in post-secondary education as well. Early childhood intervention, screening for common problems, medical treatment where indicated, a conducive family environment, and vocational training can improve the overall development of children with Down syndrome. Education and proper care will improve quality of life significantly, despite genetic limitations. The signs and symptoms of Down syndrome are characterized by the neotenization of the brain and body to the fetal state. Down syndrome is characterized by decelerated maturation (neoteny), incomplete morphogenesis (vestigia) and atavisms Individuals with Down syndrome may have some or all of the following physical characteristics: microgenia (abnormally small chin), oblique eye fissures with epicanthic skin folds on the inner corner of the eyes (formerly known as a mongoloid fold), muscle hypotonia (poor muscle tone), a flat nasal bridge, a single palmar fold, a protruding tongue (due to small oral cavity, and an enlarged tongue near the tonsils) or macroglossia”face is flat and broad”, a short neck, white spots on the iris known as Brushfield spots, excessive joint laxity including atlanto-axial instability, excessive space between large toe and second toe, a single flexion furrow of the fifth finger, a higher number of ulnar loop dermatoglyphs and short fingers
Growth parameters such as height, weight, and head circumference are smaller in children with DS than with typical individuals of the same age. Adults with DS tend to have short stature and bowed legs—the average height for men is 5 feet 1 inch (154 cm) and for women is 4 feet 9 inches (144 cm). Individuals with DS are also at increased risk for obesity as they age
Dysarthria : Its a motor speech disorder that is due to a paralysis, weakness, altered muscle tone or incoordination of the speech muscles. Speech is slow, weak, effortful, imprecise or uncoordinated. Voice and breathing for speech may also be affected.Dysarthria (‘dys’ meaning ‘having a problem with’; ‘arthr’ meaning ‘articulating’) is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech system and is characterized by poor articulation of phonemes (cf. aphasia: a disorder of the content of language). In other words, it is a condition in which problems occur with the muscles that help you talk; this makes it very difficult to pronounce words. It is unrelated to any problem with understanding cognitive language. Any of the speech subsystems (respiration, phonation, resonance, prosody, and articulation) can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication.
Neurological injury due to damage in the central or peripheral nervous system may result in weakness, paralysis, or a lack of coordination of the motor-speech system, producing dysarthria. These effects in turn hinder control over the tongue, throat, lips or lungs for example; swallowing problems (dysphagia) are also often present.
The term dysarthria does not include speech disorders from structural abnormalities, such as cleft palate, and must not be confused with apraxia, which refers to problems in the planning and programming aspect of the motor-speech system.
Cranial nerves that control these muscles include the trigeminal nerve’s motor branch (V), the facial nerve (VII), the glossopharyngeal nerve (IX), the vagus nerve (X), and the hypoglossal nerve (XII). Dysarthrias are classified in multiple ways based on the presentation of symptoms. Specific dysarthrias include spastic (resulting from bilateral damage to the upper motor neuron), flaccid (resulting from bilateral or unilateral damage to the lower motor neuron), ataxic (resulting from damage to cerebellum), unilateral upper motor neuron (presenting milder symptoms than bilateral UMN damage), hyperkinetic and hypokinetic (resulting from damage to parts of the basal ganglia, such as in Huntington’s disease or Parkinsonism), and the mixed dysarthrias (where symptoms of more than one type of dysarthria are present). The majority of dysarthric patients are diagnosed as having ‘mixed’ dysarthria, as neural damage resulting in dysarthria is rarely contained to one part of the nervous system — for example, multiple strokes, traumatic brain injury, and some kinds of degenerative illnesses (such as amyotrophic lateral sclerosis) usually damage many different sectors of the nervous system.
Ataxic dysarthria is an acquired neurological and sensorimotor speech deficit. It is a common diagnosis among the clinical spectrum of ataxic disorders. Since regulation of skilled movements is a primary function of the cerebellum, damage to the superior cerebellum and the superior cerebellar peduncle is believed to produce this form of dysarthria in ataxic patients. Growing evidence supports the likelihood of cerebellar involvement specifically affecting speech motor programming and execution pathways, producing the characteristic features associated with ataxic dysarthria. This link to speech motor control can explain the abnormalities in articulation and prosody, which are hallmarks of this disorder. Some of the most consistent abnormalities observed in patients with ataxia dysarthria are alterations of the normal timing pattern, with prolongation of certain segments and a tendency to equalize the duration of syllables when speaking. As the severity of the dysarthria increases, the patient may also lengthen more segments as well as increase the degree of lengthening of each individual segment.
Common clinical features of ataxic dysarthria include abnormalities in speech modulation, rate of speech, explosive or scanning speech, slurred speech, irregular stress patterns, and vocalic and consonantal misarticulations.
Dysarthria may affect a single system; however, it is more commonly reflected in multiple motor-speech systems. The etiology, degree of neuropathy, existence of co-morbidities, and the individual’s response all play a role in the effect the disorder has on the individual’s quality of life. Severity ranges from occasional articulation difficulties to verbal speech that is completely unintelligible.
Individuals with dysarthria may experience challenges in the following:
- Vocal quality
- Breath control
Examples of specific observations include a continuous breathy voice, irregular breakdown of articulation, monopitch, distorted vowels, word flow without pauses, and hypernasality.
The causes of dysarthria can be many, including toxic, metabolic, degenerative diseases (such as Parkinsonism, ALS, Huntington’s Disease, Niemann Pick disease, Ataxia etc.), traumatic brain injury, or thrombotic or embolic stroke. These result in lesions to key areas of the brain involved in planning, executing, or regulating motor operations in skeletal muscles (i.e. muscles of the limbs), including muscles of the head and neck (dysfunction of which characterises dysarthria). These can result in dysfunction, or failure of: the motor or somatosensory cortex of the brain, corticobulbar pathways, the cerebellum, basal nuclei (consisting of the putamen, globus pallidus, caudate nucleus, substantia nigra etc.), brainstem (from which the cranial nerves originate), or the neuro-muscular junction (in diseases such as Myasthenia Gravis) which block the nervous system’s ability to activate motor units and effect correct range and strength of movements.
- Brain tumor
- Cerebral palsy
- Guillain-Barre syndrome
- Head injury
- Lyme disease
- Multiple sclerosis
- Parkinson’s disease
- Wilson’s disease
- Intercranial Hypertension (formerly known as Pseudotumor Cerebri)
- Tay-Sachs, and Late Onset Tay-Sachs (LOTS), disease
Articulation problems resulting from dysarthria are treated by speech language pathologists, using a variety of techniques. Techniques used depend on the effect the dysarthria has on control of the articulators. Traditional treatments target the correction of deficits in rate (of articulation), prosody (appropriate emphasis and inflection, affected e.g. by apraxia of speech, right hemisphere brain damage, etc.), intensity (loudness of the voice, affected e.g. in hypokinetic dysarthrias such as in Parkinson’s), resonance (ability to alter the vocal tract and resonating spaces for correct speech sounds) and phonation (control of the vocal folds for appropriate voice quality and valving of the airway). These treatments have usually involved exercises to increase strength and control over articulator muscles (which may be flaccid and weak, or overly tight and difficult to move), and using alternate speaking techniques to increase speaker intelligibility (how well someone’s speech is understood by peers). With the speech language pathologist, there are several skills that are important to learn; safe chewing and swallowing techniques, avoiding conversations when feeling tired, repeat words and syllables over and over in order to learn the proper mouth movements, and techniques to deal with the frustration while speaking. Depending on the severity of the dysarthria, another possibility includes learning how to use a computer or flip cards in order to communicate more effectively.
More recent techniques based on the principles of motor learning (PML), such as LSVT (Lee Silverman Voice Treatment) speech therapy and specifically LSVT may improve voice and speech function in PD. For Parkinson’s, aim to retrain speech skills through building new generalized motor programs, and attach great importance to regular practice, through peer/partner support and self-management. Regularity of practice, and when to practice, are the main issues in PML treatments, as they may determine the likelihood of generalization of new motor skills, and therefore how effective a treatment is.
Augmentative and Alternative Communication (AAC) devices that make coping with a dysarthria easier include speech synthesis and text-based telephones. These allow people who are unintelligible, or may be in the later stages of a progressive illness, to continue to be able to communicate without the need for fully intelligible speech.
Dysphagia : A disorder/condition that affects an individual’s ability to swallow. Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under “symptoms and signs” in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia.
It is derived from the Greek dys meaning bad or disordered, and phago meaning “eat”. It may be a sensation that suggests difficulty in the passage of solids or liquids from the mouth to the stomach, a lack of pharyngeal sensation, or various other inadequacies of the swallowing mechanism. Dysphagia is distinguished from other symptoms including odynophagia, which is defined as painful swallowing, and globus, which is the sensation of a lump in the throat. A psychogenic dysphagia is known as phagophobia.
It is also worthwhile to refer to the physiology of swallowing in understanding dysphagia.
Dysphasia: Difficulty in speech production and understanding often associated with stroke or brain injury. Aphasia ( /əˈfeɪʒə/ or /əˈfeɪziə/, from ancient Greek ἀφασία (ἄφατος, ἀ- + φημί), “speechlessness”) is an impairment of language ability. This class of language disorder ranges from having difficulty remembering words to being completely unable to speak, read, or write. Acute aphasia disorders usually develop quickly as a result of head injury or stroke, and progressive forms of aphasia develop slowly from a brain tumor, infection, or dementia. The area and extent of brain damage or atrophy will determine the type of aphasia and its symptoms. Aphasia types include expressive aphasia, receptive aphasia, conduction aphasia, anomic aphasia, global aphasia, primary progressive aphasias and many others (see Category:Aphasias). Medical evaluations for the disorder range from clinical screenings by a neurologist to extensive tests by a Speech-Language Pathologist.Most acute aphasia patients can recover some or most skills by working with a Speech-Language Pathologist. This rehabilitation can take two or more years and is most effective when begun quickly. Only a small minority will recover without therapy, such as those suffering a mini-stroke. Improvement varies widely, depending on the aphasia’s cause, type, and severity. Recovery also depends on the patient’s age, health, motivation, handedness, and educational leave
Directional Microphone: Amplify sounds from certain directions more than sounds from other directions. An omnidirectional (or nondirectional) microphone’s response is generally considered to be a perfect sphere in three dimensions. In the real world, this is not the case. As with directional microphones, the polar pattern for an “omnidirectional” microphone is a function of frequency. The body of the microphone is not infinitely small and, as a consequence, it tends to get in its own way with respect to sounds arriving from the rear, causing a slight flattening of the polar response. This flattening increases as the diameter of the microphone (assuming it’s cylindrical) reaches the wavelength of the frequency in question. Therefore, the smallest diameter microphone gives the best omnidirectional characteristics at high frequencies.
The wavelength of sound at 10 kHz is little over an inch (3.4 cm) so the smallest measuring microphones are often 1/4″ (6 mm) in diameter, which practically eliminates directionality even up to the highest frequencies. Omnidirectional microphones, unlike cardioids, do not employ resonant cavities as delays, and so can be considered the “purest” microphones in terms of low coloration; they add very little to the original sound. Being pressure-sensitive they can also have a very flat low-frequency response down to 20 Hz or below. Pressure-sensitive microphones also respond much less to wind noise and plosives than directional (velocity sensitive) microphones.
An example of a nondirectional microphone is the round black eight ball
dB – decibel, a unit for measuring and describing sound intensity or loudness; named after Alexander Graham Bell.
Digital hearing aid – an instrument that converts the electric signal from the microphone to digital values for processing, then converts them back to electric signals for the ear.
Direct audio input – the hearing aid has a jack to receive sound directly from another device such as a TV or a personal entertainment system. Direct audio input (DAI) allows the hearing aid to be directly connected to an external audio source like a CD player or an assistive listening device (ALD). By its very nature, DAI is susceptible to far less electromagnetic interference, and yields a better quality audio signal as opposed to using a T-coil with standard headphones.
Directional microphone – a microphone that is more sensitive to sound approaching from one direction
Dynamic range – The difference in dB between the threshold of hearing and discomfort level.
Dysarthria – Group of speech disorders caused by disturbances in the strength or coordination of the muscles of the speech mechanism as a result of damage to the brain, nerves, or muscles. Dysarthria (‘dys’ meaning ‘having a problem with’; ‘arthr’ meaning ‘articulating’) is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech systemand is characterized by poor articulation of phonemes (cf. aphasia: a disorder of the content of language). In other words, it is a condition in which problems occur with the muscles that help you talk; this makes it very difficult to pronounce words. It is unrelated to any problem with understanding cognitive language. Any of the speech subsystems (respiration, phonation, resonance, prosody, and articulation) can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication.
Neurological injury due to damage in the central or peripheral nervous system may result in weakness, paralysis, or a lack of coordination of the motor-speech system, producing dysarthria. These effects in turn hinder control over the tongue, throat, lips or lungs for example; swallowing problems (dysphagia) are also often present.
The term dysarthria does not include speech disorders from structural abnormalities, such as cleft palate, and must not be confused with apraxia, which refers to problems in the planning and programming aspect of the motor-speech system.
Cranial nerves that control these muscles include the trigeminal nerve’s motor branch (V), the facial nerve (VII), the glossopharyngeal nerve (IX), the vagus nerve (X), and the hypoglossal nerve (XII
Dysfluency – Disruption in the smooth flow or expression of speech
Dyslexia – Learning disability characterized by reading difficulties. Some individuals may also have difficulty writing, spelling, or working with numbers. Dyslexia is a very broad term defining a learning disability that impairs a person’s fluency or comprehension accuracy in being able to read, and which can manifest itself as a difficulty with phonological awareness, phonological decoding, orthographic coding, auditory short-term memory, or rapid naming.
Dyslexia is distinct from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction. It is believed that dyslexia can affect between 5 and 10 percent of a given population although there have been no studies to indicate an accurate percentage.
There are three proposed cognitive subtypes of dyslexia: auditory, visual and attentional. Reading disabilities, or dyslexia, is the most common learning disability, although in research literature it is considered to be a receptive language-based learning disability. Researchers at MIT found that people with dyslexia exhibited impaired voice-recognition abilities.
Adult dyslexics can read with good comprehension, but they tend to read more slowly than non-dyslexics and perform more poorly at spelling and nonsense word reading, a measure of phonological awareness. Dyslexia and IQ are not interrelated as a result of cognition developing independently
Dysphonia – Any impairment of the voice or speaking ability. Dysphonia is the medical term for disorders of the voice: an impairment in the ability to produce voice sounds using the vocal organs (it is distinct from dysarthria which means disorders of speech, that is, an impairment in the ability to produce spoken words). Thus, dysphonia is a phonation disorder. The dysphonic voice can be hoarse or excessively breathy, harsh, or rough, but some kind of phonation is still possible (contrasted with the more severe aphonia where phonation is impossible).
Dysphonia has either organic or functional causes due to impairment of any one of the vocal organs. However, typically it is caused by some kind of interruption of the ability of the vocal folds to vibrate normally during exhalation. Thus, it is most often observed in the production of vowel sounds. For example, during typical normal phonation, the vocal folds come together to vibrate in a simple open/closed cycle modulating the airflow from the lungs. Weakness (paresis) of one side of the larynx can prevent simple cyclic vibration and lead to irregular movement in one or both sides of the glottis. This irregular motion is heard as roughness. This is quite common in vocal fold paresis
Dyspraxia of Speech – Partial loss of the ability to consistently pronounce words in individuals with normal muscle tone and coordination of the speech muscles. Developmental dyspraxia is a chronic neurological disorder beginning in childhood that can affect planning of movements and co-ordination as a result of brain messages not being accurately transmitted to the body. Up to 50% of dyspraxics have ADHD. It may be diagnosed in the absence of other motor or sensory impairments like cerebral palsy, muscular dystrophy, multiple sclerosis or Parkinson’s disease. Epidemiology
Developmental dyspraxia (referred to as developmental coordination disorder (DCD) in the US and Europe) is a lifelong neurological condition that is more common in males than in females, with a ratio of approximately four males to every female. The exact proportion of people with the disorder is unknown since the disorder can be difficult to detect due to a lack of specific laboratory tests, thus making diagnosis of the condition one of elimination of all other possible causes/diseases. Current estimates range from 5% to 20% with 5–6% being the most frequently quoted percentage in the literature. Some estimates show that up to 1 in 30 children may have dyspraxia.
Assessment and diagnosis
Assessments for dyspraxia typically require a developmental history, detailing ages at which significant developmental milestones, such as crawling and walking, occurred. Motor skills screening includes activities designed to indicate dyspraxia, including balancing, physical sequencing, touch sensitivity, and variations on walking activities. A baseline motor assessment establishes the starting point for developmental intervention programs. Comparing children to normal rates of development may help to establish areas of significant difficulty.
However, research in the British Journal of Special Education has shown that knowledge is severely limited in many who should be trained to recognise and respond to various difficulties, including developmental coordination disorder, dyslexia and Deficits in attention, motor control and perception (DAMP). The earlier that difficulties are noted and timely assessments occur, the quicker intervention can begin. A teacher or GP could miss a diagnosis if they are only applying a cursory knowledge.
“Teachers will not be able to recognise or accommodate the child with learning difficulties in class if their knowledge is limited. Similarly GPs will find it difficult to detect and appropriately refer children with learning difficulties.”
Various areas of development can be affected by developmental dyspraxia and these will persist into adulthood, as dyspraxia has no cure. Often various coping strategies are developed, and these can be enhanced through occupational therapy, physiotherapy, speech therapy, or psychological training.
Speech and language
Developmental verbal dyspraxia (DVD) is a type of ideational dyspraxia, causing linguistic or phonological impairment. This is the favoured term in the UK; however it is also sometimes referred to as articulatory dyspraxia and in the United States the usual term is childhood apraxia of speech (CAS).
Key problems include:
- Difficulties controlling the speech organs.
- Difficulties making speech sounds
- Difficulty sequencing sounds
- Within a word
- Forming words into sentences
- Difficulty controlling breathing and phonation.
- Slow language development.
- Difficulty with feeding.
Fine motor control
Difficulties with fine motor co-ordination lead to problems with handwriting, which may be due to either ideational or ideo-motor difficulties. Problems associated with this area may include:
- Learning basic movement patterns.
- Developing a desired writing speed.
- The acquisition of graphemes – e.g. the letters of the Latin alphabet, as well as numbers.
- Establishing the correct pencil grip
- Hand aching while writing.
Fine-motor problems can also cause difficulty with a wide variety of other tasks such as using a knife and fork, fastening buttons and shoelaces, cooking, brushing one’s teeth, applying cosmetics, styling one’s hair, opening jars and packets, locking and unlocking doors, shaving and doing housework.
Whole body movement, coordination, and body image
Issues with gross motor coordination mean that major developmental targets including walking, running, climbing and jumping can be affected. The difficulties vary from child to child and can include the following:
- Poor timing.
- Poor balance (sometimes even falling over in mid-step). Tripping over one’s own feet is also common.
- Difficulty combining movements into a controlled sequence.
- Difficulty remembering the next movement in a sequence.
- Problems with spatial awareness, or proprioception.
- Some people with dyspraxia have trouble picking up and holding onto simple objects such as picking pencils and things up, owing to poor muscle tone and or proprioception.
- This disorder can cause an individual to be clumsy to the point of knocking things over and bumping into people accidentally.
- Some people with dyspraxia have difficulty in determining left from right.
- Cross-laterality, ambidexterity, and a shift in the preferred hand are also common in people with dyspraxia.
- Problems with chewing foods
- People with dyspraxia may also have trouble determining the distance between them and other objects.
In addition to the physical impairments, dyspraxia is associated with problems with memory, especially short-term memory. This typically results in difficulty remembering instructions, difficulty organizing one’s time and remembering deadlines, increased propensity to lose things or problems carrying out tasks which require remembering several steps in sequence (such as cooking). Whilst most of the general population experience these problems to some extent, they have a much more significant impact on the lives of dyspraxic people. However, many dyspraxics have excellent long-term memories, despite poor short-term memory. Many dyspraxics benefit from working in a structured environment, as repeating the same routine minimises difficulty with time-management and allows them to commit procedures to long-term memory.
People with dyspraxia may have sensory processing disorder, including abnormal oversensitivity or undersensitivity to physical stimuli, such as touch, light, sound, and smell. This may manifest itself as an inability to tolerate certain textures such as sandpaper or certain fabrics and including oral toleration of excessively textured food (commonly known as picky eating), or even being touched by another individual (in the case of touch oversensitivity) or may require the consistent use of sunglasses outdoors since sunlight may be intense enough to cause discomfort to a dyspraxic (in the case of light oversensitivity). An aversion to loud music and naturally loud environments (such as clubs and bars) is typical behavior of a dyspraxic individual who suffers from auditory oversensitivity, while only being comfortable in unusually warm or cold environments is typical of a dyspraxic with temperature oversensitivity. Undersensitivity to stimuli may also cause problems. Dyspraxics who are undersensitive to pain may injure themselves without realising. Some dyspraxics may be oversensitive to some stimuli and undersensitive to others. These are commonly associated with autism spectrum conditions.
People with dyspraxia sometimes have difficulty moderating the amount of sensory information that their body is constantly sending them, so as a result these people are prone to panic attacks. Having other autistic traits (which is common with dyspraxia and related conditions) may also contribute to sensory-induced panic attacks.
Dyspraxia can cause problems with perception of distance, and with the speed of moving objects and people This can cause problems moving in crowded places and crossing roads and can make learning to drive a car extremely difficult or impossible.
Many dyspraxics struggle to distinguish left from right, even as adults, and have extremely poor sense of direction generally. Moderate to extreme difficulty doing physical tasks is experienced by some dyspraxics, and fatigue is common because so much extra energy is expended while trying to execute physical movements correctly. Some (but not all) dyspraxics suffer from hypotonia, which in this case is chronically low muscle tone caused by dyspraxia. People with this condition can have very low muscle strength and endurance (even in comparison with other dyspraxics) and even the simplest physical activities may quickly cause soreness and fatigue, depending on the severity of the hypotonia. Hypotonia may worsen a dyspraxic’s already poor balance.
Overlap with other conditions
Dyspraxics may have other difficulties that are not due to dyspraxia itself but often co-exist with it. This is sometimes referred to as comorbidity. Dyspraxics may have characteristics of dyslexia (difficulty with reading and spelling), dyscalculia (difficulty with mathematics), dysgraphia (an inability to write neatly and/or draw) expressive language disorder (difficulty with verbal expression), ADHD (poor attention span and impulsive behaviour), or Asperger syndrome (consisting variously of poor social cognition, a literal understanding of language [making it hard to understand idioms or sarcasm] and rigid, intense interests). However, they are unlikely to have problems in all of these areas. The pattern of difficulty varies widely from person to person, and it is important to understand that a major weakness for one dyspraxic can be a strength or gift for another. For example, while some dyspraxics have difficulty with reading and spelling due to an overlap with dyslexia, or numeracy due to an overlap with dyscalculia, others may have brilliant reading and spelling or mathematical abilities. Some estimates show that up to 50% of dyspraxics have ADHD. Students with dyspraxia struggle most in visual-spatial memory. When compared to their peers who don’t have motor difficulties, students with dyspraxia are seven times more likely than typically developing students to achieve very poor scores in visual-spatial memory. As a result of this working memory impairment, students with dyspraxia have learning deficits as well. Some students with dyspraxia can also have comorbid Specific Language Impairment (SLI). Research has found that students with dyspraxia and normal language skills still experience learning difficulties despite relative strengths in language. This means that for students with dyspraxia their working memory abilities determine their learning difficulties. Any strength in language that they have is not able to sufficiently support their learning.
Collier first described developmental dyspraxia as ‘congenital maladroitness’. A. Jean Ayres referred to it as a disorder of sensory integration in 1972 while in 1975 Dr Sasson Gubbay called it the ‘clumsy child syndrome’. It has also been called minimal brain dysfunction although the two latter names are no longer in use. Other names include:
- Clumsy Child Syndrome
- Developmental Apraxia
- Disorder of Attention and Motor Perception (DAMP)
- Developmental Co-ordination Disorder (DCD) – a subtly different condition by definition, in practice, very similar.
- Motor Learning Difficulties
- Perceptuo-motor dysfunction
- Sensorimotor dysfunction The World Health Organisation currently lists Developmental Dyspraxia as Specific Developmental Disorder of Motor Function. Notable dyspraxics
Living people who have publicly stated they have been diagnosed with dyspraxia include actor Daniel Radcliffe, photographer David Bailey, Florence Welch from Florence and the Machine and actress Hannah McDonnell. Writers suspected to have had the condition include Emily Bronte, Charlotte Bronte, poet Samuel Taylor Coleridge, G.K. Chesterton, Ernest Hemingway, Jack Kerouac and George Orwell.
Helen Burns, a character from Charlotte Bronte’s Jane Eyre, is alleged to have been based on the author’s dyspraxic elder sister Maria Bront.