TB4 Lecture 4; Disorders of Communication

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  • Created on: 04-05-15 14:02

Communication disorders; General Overview

What is a communication disorder?

  • A communication disorder is an impairment in the ability to send, receive, process and comprehend concepts or, verbal, non-verbal and graphic symbol systems.
  • The disorder may become evident in the processes of language, hearing or speech.
  • They can range on severity between individuals, from mild to profound.
  • They can be developmental or acquired.
  • Individuals can develop a single or combination of these disorders.
  • It can be a primary, or secondary disorder.

Are there different kinds?

  • There are three known types of communication disorder. These are
    • Language disorders (SLI)
    • Auditory processing disorders
    • Motor speech disorders
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1) Specific Language Impaiment (SLI)

  • Features of SLI include:
    • Selective problem with language devlopment
    • Often identified in children when language development is below expected for their age group.
    • Modularity; when self-help skills, socialisation, nonverbal abilities and motor skills all develop normally.
  • There are several diagnostic 'flags' that lead to a disagnosis of SLI, including;
    • Child not talking much
    • Language is immature for age
    • Child struggles to 'find words'
    • Child doesn't understand what is being said
    • Older children may fail to understand written language.
  • Further considerations that can influence a diagnosis of SLI include the incidence rate, 3-10%/approx one child in ever classroom will have the disorder and problems can interfere with everyday life and school achievements. Etiologically, SLI is not thought to be part of a general developmental delay, or due to hearing loss, learning disability, physical abnormality, lack of language experience or acquired brain damage.
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SLI and ASD; Is there a divide??

  • Clinicians often find it difficult to distinguish SLI from Autistic Spectrum Disorder (SLI).
  • In autism, difficulties are pervasive, often affecting three areas known as the 'autism triad'. These are;
    • Communication
    • Social Interaction
    • Behaviours/interests, they are repetitive and restrained.
  • Research has shown evidence for the development of autistic features in some children with receptive language impairments.
  • ^ Bartak et al (1975) tested 47 boys, aged 5-10yrs that had normal hearing, no neurological disease and a non-verbal IQ od 70+. They were seperated into 3 conditions, these were;
    • 1) 19 with Autistic Disorder
    • 2) 23 with Receptive Language Disorder (SLI)
    • 3) 5 into a Mixed Group
  • Findings showed that in terms of language milestones, SLI and autistic children scored similarly on many of the tests. Two of the most prominent are no phrase speech by 30 months and no single words by 24 months.
  • Non-linguistic behaviour and on the other hand showed a clear difference between ASD and SLI pps.
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SLI, ASD and diagnosis, what does this mean?

  • Research also showed that SLI children, at follow up were beginning to show ASD like behaviours (non-language related) at a similar level to ASD pps.
    • This means that the clinical picture changes with age.
  • There is difficulty in evaluating ASD-like symptoms in children with SLI.
  • The categorical diagnosis of such symptoms is not well suited to capturing clinical variation!
  • 'Textbook' SLI and ASD is clear cut, but for many children this is not the case.
  • In conclusion, as of yet there is no dividing line between SLI and ASD.
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2) Auditory Processing disorder (APD)

  • Features of APD include;
    • Children reporting hearing problems but passing hearing tests on an audiogramme.
    • A common feature is difficulty hearing speech in noisy situations.
    • Trouble paying attention to/remembering oral infomation
    • Trouble with executing multi-step directions
    • Poor listening skills
    • More processing time is needed
    • Often low academic performance and difficulties in reading, comprehension, spelling and vocabulary.
    • Behavioual problems
    • Language difficulty, e.g confusing syllable sequences, problems understanding language and developing vocabulary.
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APD and misunderstanding

  • APD is often misunderstood as its symptomatic behaviours are often co-morbid with other disabilities, such as learning disabilities, ADHD and even depression!
    • Even though symptoms can be common in both e.g APD and ADHD it is possible to have both or any of these three co-occuring.
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APD; The possible aetiology of the disorder

  • There are two potential causes of APD.
    • 1) Auditory problems are caused by higher-level brain abnormalites
    • 2) The problem is not auditory at all, auditory difficulties may arise due to limitations of attention, memory or language.

1) Brain abnormalities; Beyond the auditory nerve, auditory information is processed through a complex series of pathways. During this, info about pitch, loudness, spatial location, duation etc is extracted. In adults, damage to these higher auditory pathays can produce problems in recognising sounds.

2) Problem lies elsewhere; Many children with poor language/literacy do poorly on APD tests, these problems are therefore possibly caused by auditory difficulties. BUT, it could also mean that the tests are misleading, with children failing as they have trouble recognising/remembering words in hard listening conditions. There is concern of misdiagnosis, APD may be wrongly diagnosed instead of dyslexia or SLI. Clearly the cause of APD has important implications for treatment and locus of intervention.

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3) Motor Speech Disorders (MSD)

  • In speech, there are four subsystems of production;
    • Respiratory
    • Phonatory
    • Resonatory
    • Articulatory
  • A MSD is a speech production defect that results from an impairment of the neuromuscular system (peripheral) and/or motor control system (central).
  • It is NOT a language impairment but it may co-occur with them.
  • Other oral movements such as chewing or smiling may be collatarally impaired alongside those related to speech.
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Etiology of MPD

  • There are two potential root causes of MPD. These are;
    • Acquired; Damage to a previously intact nervous system
      • E.g caused by cerebrovascular accidents (strokes), degenerative diseases, brain tumours or traumatic brain injury.
    • Developmental; Abnormal development resulting in damage to the nervous system.
      • Can be caused by congenital diseases or damage to a developing (different from already intact!) nervous system.
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Types of MSD

  • 1) Impairments of planning/programming;
    • The coordination of relevent muscles and muscle groups is disrupted, but muscle physiology and movement are intact.
      • E.g apraxia of speech - acquired and developmental
  • 2) Impairments of execution;
    • disruptions in muscle physiology, affected by involuntary movements and reductions in movement abilities (whether speech is programmed normally or not).
      • e.g disarthia - acquired and developmental
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Apraxia of Speech (AoS) (MSD)

What is it?

  • An inability to transform an intact linguistic representation into co-ordinated movements of the articulators (it is NOT a muscle issue).
  • Thought to be caused by neurological damage to Brocas area, due to stroke, brain injury, illness or infection


  • Slow speech
  • Sound distortions
  • Prolonged duration of sounds
  • Reduced prosody
  • Consistent utterance errors
  • Difficulties initiating speech and groping articulators.
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Dystharthia (MPD)

What is it?

  • Disruptions in the execution of speech movements resulting from neuromuscular disturbances to muscle tone, reflexes or kinematic aspects of movement.
  • Typically occurs due to a progressive disease or trauma (CNS/PNS).


  • Speech sounds are slurred, slow, harsh or quiet, possibly even uneven depending on the type.

There are 3 main concepts of dystharthia;

  • Spasticity - Excessive muscle tension
  • DyskinesiaInvoluntary muscle movements
  • AtaxiaLack of muscle control
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