Speech and Language disability

As per Census 2011, there were 2.0 million persons with disability in speech in India. However it is difficult to collect the accurate prevalence of speech and language disability in a country like India.

Definitions

The Rights of Persons with Disabilities Act, 2016 defines Speech and Language Disability as a permanent disability arising out of conditions such as laryngectomy or aphasia which affect one or more components of speech and language due to organic or neurological causes.
Speech and language impairment are basic categories that might be drawn in issues of communication involving hearing, speech, language, and fluency.

A speech impairment is characterized by difficulty in articulation of words. Examples include stuttering or problems producing particular sounds. Articulation refers to the sounds, syllables, and phonology produced by the individual. Voice, however, may refer to the characteristics of the sounds produced—specifically, the pitch, quality, and intensity of the sound. Often, fluency will also be considered a category under speech, encompassing the characteristics of rhythm, rate, and emphasis of the sound produced.

A language impairment is a specific impairment in understanding and sharing thoughts and ideas, i.e. a disorder that involves the processing of linguistic information. Problems that may be experienced can involve the form of language, including grammar, morphology, syntax; and the functional aspects of language, including semantics and pragmatics.
An individual can have one or both types of impairment. These impairments/disorders are
identified by a speech and language pathologist.

A animated image of someone trying to teach a kid | © Pixaway

Variations

Speech Disorders
The following are brief definitions of several of the more prominent speech disorders:

  • Apraxia of speech: Apraxia of speech, or verbal apraxia, refers specifically to the impairment of motor skills that affect an individual's ability to form the sounds of speech correctly, even when they know which words they want to say.
  • Developmental verbal dyspraxia: Developmental verbal dyspraxia refers specifically to a motor speech disorder. This is a neurological disorder. Individuals suffering from developmental verbal apraxia encounter difficulty saying sounds, syllables, and words. The difficulties are not due to weakness of muscles, but rather of coordination between the brain and the specific parts of the body. Apraxia of speech is the acquired form of this disorder caused by brain injury, stroke or dementia.
     
  • Dysarthria: Dysarthria is a motor speech disorder that results from a neurological injury. Some stem from central damage, while other stem from peripheral nerve damage. Difficulties may be encountered in respiratory problems, vocal fold function, or velopharyngeal closure, for example.
  • Orofacial myofunctional disorders: Orofacial myofunctional disorders refers to problems encountered when the tongue thrusts forward inappropriately during speech. While this is typical in infants, most children outgrow this. Children that continue to exaggerate the tongue movement may incorrectly produce speech sounds, such as /s/, /z/, /ʃ /, /tʃ /, and /dʒ/. For example, the word, "some," might be pronounced as "thumb".
     
  • Speech sound disorder: Speech sound disorders may be of two varieties: articulation (the production of sounds) or phonological processes (sound patterns). An articulation disorder may take the form of substitution, omission, addition, or distortion of normal speech sounds. Phonological process disorders may involve more systematic difficulties with the production of particular types of sounds, such as those made in the back of the mouth, like "k" and "g".
  • Stuttering: Stuttering is a disruption in the fluency of an individual's speech, which begins in childhood and may persist over a lifetime. Stuttering is a form of disfluency; disfluency becomes a problem insofar as it impedes successful communication between two parties. Disfluencies may be due to unwanted repetitions of sounds, or extension of speech sounds, syllables, or words. Disfluencies also incorporate unintentional pauses in speech, in which the individual is unable to produce speech sounds.
  • Voice disorders: Voice disorders range from aphonia (loss of phonation) to dysphonia, which may be phonatory and/or resonance disorders. Phonatory characteristics could include breathiness, hoarseness, harshness, intermittency, pitch, etc. Resonance characteristics refer to overuse or underuse of the resonance chambers resulting in hypernasality or hyponasality.

    Several examples of voice problems are vocal cord nodules or polyps, vocal cord paralysis,
    paradoxical vocal fold movement, and spasmodic dysphonia. Vocal cord nodules and polyps are different phenomena, but both may be caused by vocal abuse, and both may take the form of growths, bumps, or swelling on the vocal cords. Vocal fold paralysis is the inability to move one or both of the vocal cords, which results in difficulties with voice and perhaps swallowing. Paradoxical vocal fold movement occurs when the vocal cords close when they should actually be open. Spasmodic dysphonia is caused by strained vocal cord movement, which results in awkward voice problems, such as jerkiness or quavering.

Language Disorders

  • Specific language impairment: Now often referred to as Developmental Language Disorder (DLD) is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development, physical abnormality of the speech apparatus, autism spectrum disorder, apraxia, acquired brain damage or hearing loss.
  • Selective mutism: Selective mutism is a disorder that manifests as a child that does not speak in at least one social setting, despite being able to speak in other situations. Selective mutism is normally discovered when the child first starts school.
  • Aphasia: Aphasia refers to a family of language disorders that usually stem from injury, lesion, or atrophy to the left side of the brain that result in reception, perception, and recall of language; in addition, language formation and expressive capacities may be inhibited.
  • Language-based learning disabilities: Language-based learning disabilities, which refer to difficulties with reading, spelling, and/or writing that are evidenced in a significant lag behind the individual's same-age peers. Most children with these disabilities are at least of average intelligence, ruling out intellectual impairments as the causal factor.

Causes

In most cases, the causal factors that create these speech and language difficulties are
unknown. There are a wide variety of biological and environmental causal factors that
can create them:

  • Developmental disorders: Developmental disorders tend to have a genetic origin, such as mutations of FOXP2, which has been linked to developmental verbal dyspraxia and specific language impairment. Some of these impairments are caused by genetics. Case histories often reveal a positive family history of communication disorders. Between 28% and 60% of children with a speech and language deficit have a sibling and/or parent who is also affected. Down syndrome is another example of a genetic causal factor that may result in speech and/or language impairments. Stuttering is a disorder that is hypothesized to have
    a strong genetic component as well.

    Some speech and language impairments have environmental causes. A specific language impairment, for example, may be caused by insufficient language stimulation in the environment. If a child does not have access to an adequate role model, or is not spoken to with much frequency, the child may not develop strong language skills. Furthermore, if a child has little stimulating experiences, or is not encouraged to develop speech, that child may have little incentive to speak at all and may not develop speech and language skills at an average pace.

    Developmental disabilities such as autism and neurological disorders such as cerebral palsy may also result in impaired communicative abilities. Similarly, malformation or malfunctioning of the respiratory system or speech mechanisms may result in speech impairments. For example, a cleft palate will allow too much air to pass through the nasal cavity and a cleft lip will not allow the individual to correctly form sounds that require the upper lip. The development of vocal fold nodules represents another issue of biological causation.
     
  • Acquired disorders: Acquired disorders result from brain injury, stroke or atrophy, many of these issues are included under the Aphasia umbrella. Brain damage, for example, may result in various forms of aphasia if critical areas of the brain such as Broca's or Wernicke's area are damaged by lesions or atrophy as part of a dementia.

Treatments

There are a wide spectrum of treatments including speech and language therapy, physical exercise, augmentative and alternative communication (AAC) method or device/assistive technology, medication and surgery.

Statistics in India

As per Census 2011, there were 2.0 million persons with disability in speech in India. However it is difficult to collect the accurate prevalence rate of speech and language disability in a country like India.

References for More Reading and Understanding/Sources

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