Speech Flashcards
1
Q
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Distinguish between aphasia and dysphasia
A
- American textbooks often use these as synonyms.
- In Australia and the UK, aphasia means complete loss of a particular language skill, while dysphasia means a partial loss.
- ANUMS students are expected to use the Australian/UK terminology.
2
Q
Breakdown dysphasia types
A
- Receptive Dysphasia: Problem with understanding language input
- Expressive Dysphasia: Problem with producing language output
- Mixed or Global Dysphasia: Problem with both input and output
3
Q
Describe the modular nature of language processing
A
- Different elements of language processing and speech production are performed by different anatomical components of the nervous system.
- The important ones are Broca’s, Wernicke’s, and the arcuate fasciculus.
4
Q
Describe language input/output
A
- For most of our evolutionary history (before the invention of writing), all language input was auditory.
- Not surprisingly, the language input center (Wernicke’s Area) is located right next to the primary auditory cortex, but…
- One hemisphere plays the major role in language processing, while the other plays a minor supporting role (Wernicke’s Area is unilateral).
- In >95% of right-handed subjects and 60-70% of left-handed subjects, the dominant hemisphere for language is the left hemisphere.
Language Components - Output
- For most of our evolutionary history, all language output was spoken.
- Not surprisingly, the language output center (Broca’s Area) is located right next to the mouth and tongue part of the primary motor cortex, but…
- As with language input, one hemisphere plays the major role in language processing, so Broca’s Area is unilateral.
- The dominant language output area is on the same side as the dominant input area. (Left in >95% of right-handed subjects and 60-70% of left-handed subjects).
5
Q
Describe the connection between input and output
A
- The major input and output areas for language are separated by the Sylvian fissure.
- The shortest available route between the two centers is thus a curved (arcuate) path running around the posterior end of the Sylvian fissure.
- The major direct connection between Wernicke’s and Broca’s Areas uses this obvious route, and is known as the Arcuate Fasciculus.
6
Q
Briefly describe how compression expression and repetition may be tested
A
Three Main Language Skills
- Comprehension
- Expression
- Repetition
Testing the Three Basic Components
- Comprehension
- Can the patient follow one-step, two-step or three-step commands?
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Expression
- tell me how you make a cup of coffee
- Note the patient’s spontaneous use of speech. Is it hesitant?
- If necessary, ask them to explain or describe something.
- Listen for grammatical usage, “telegraphic speech” (loss of short grammatical words, with meaning largely conveyed by the main verbs and nouns), semantic paraphasias (use of a word with a neighboring meaning – “arm” for “leg”) and literal paraphasia (use of a similar sounding word – “short” for “stroke”).
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Repetition
- eg no ifs ands or buts
- The simplest language task, repeating a spoken phrase, requires all three basic components (Wernicke’s Area, the Arcuate Fasciculus, and Broca’s Area) but no other language components or connections.
- Note that the repetition task also requires:
- Working ears and intact auditory pathways
- Working mouth and intact motor pathways
- Working vocal cords
- … but these modules are not part of language processing.
- Also note that this task only just qualifies as language; an infant, a home computer, or even a parrot may pass the repetition test, and we could pass the test in language we didn’t know.
- In two relatively rare dysphasias, the repetition task may be the only part of the language system that fails (Conduction Aphasia) or the only part that still works (Transcortical Aphasia).
- More commonly, the brunt of the injury falls on the input center (Wernicke’s Aphasia), the output center (Broca’s Aphasia), or both (Global Aphasia), causing a failure of repetition along with other deficits.
7
Q
Describe other languge areas
A
- The main difference between mere “parroting” and human language use is that our language has meaning.
- Although the nature of that meaning is not completely sorted out, it is clear that anatomical connections and functional translations are required between the two major language regions (Wernicke’s and Broca’s Areas) and the rest of the cognitive machinery.
- Anatomically, these connections appear to be distributed diffusely around the border of the language centers (in the neighboring cortex and in the white matter deep to the language centers).
8
Q
Describe language and grammar
A
- Vocabulary and Grammar, the two divisions of language that are most obvious when learning a second language, are needed for both comprehension and expression: Wernicke’s Area needs to “know” both grammar and vocabulary, and so does Broca’s Area.
- Wernicke’s and Broca’s have each specialized in one of these skills.
- The “lexicon”, or mapping between word-sounds and word-meanings, is closely associated with Wernicke’s Area. (Vocabulary)
- The “syntactical engine”, responsible for correct application of grammar rules to sentences, is closely associated with Broca’s Area. (Grammar)
- This specialization makes some sense. When learning a foreign language, for instance, vocabulary is more likely to be stretched during comprehension tasks, while grammar is rarely critical for correct interpretation (“man car drive”); conversely, our grammar is more likely to be stretched when we try to express ourselves.
9
Q
Describe consequences of insults to language apparatus
A
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Wernicke’s aphasia
- Loss of comprehension plus word-meanings
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Broca’s aphasia
- Loss of expression plus grammar
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Conductive aphasia (Arcuate fasciculus)
- Loss of repetition
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Transcortical sensory aphasia
- Loss of comprehension but preserved repetition
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Transcortical motor aphasia
- Loss of expression but preserved repetition
10
Q
Descrieb Broca’s apahsia
A
- A common dysphasia, predominantly affecting expression.
- The hallmark is a delay or complete failure at the expression phase of language processing, which affects both expression of the patient’s own ideas as well as repetition.
- Impairment of the syntactical engine leads to preferential loss of syntactical words (“if”, “then”, “but”) and relative preservation of content words (“stroke”, “ambulance”, “cigarettes”). This is evident in spontaneous speech and in repetition tasks (“No ifs ands or buts”).
- Speech is slow, hesitant (non-fluent) and syntactically simple (“telegraphic”, as if written in an old-fashioned telegram where each word cost money). For instance: “Blood pressure… doctor give tablet”.
- The patient is usually frustrated.
- For these reasons, it is often called “Expressive Dysphasia”.
Broca’s Aphasia
- In a classic case of Broca’s Aphasia, comprehension is largely intact, but it is never completely intact.
- There are two main reasons why comprehension may be mildly impaired in what otherwise looks like a predominantly expressive Broca’s Aphasia:
- There may be some mild damage to Wernicke’s Area.
- The “syntactical engine” is likely to be damaged, so sentences requiring complex or non-standard parsing maybe misinterpreted. (“The lion was killed by the tiger. Which animal died?” Patients with Broca’s aphasia may simply perceive “Lion…killed…tiger”).
11
Q
DeSCRIBE w’S
A
- A reasonably common aphasia, but rarely a pure syndrome. (More often a mixed aphasia with dominant involvement of Wernicke’s Area.)
- The hallmark is impaired comprehension. Questions are not answered appropriately and complex commands are not carried out. In milder versions, with only partial damage to Wernicke’s, this may be the only obvious feature.
- Repetition is impossible in a complete case.
- For both of these reasons, Wernicke’s Aphasia is often called “Receptive Aphasia”.
- Because of the complex interdependence of Wernicke’s and Broca’s Areas, there are actually major impairments in expression, as well.
Wernicke’s Aphasia
- In true Wernicke’s Aphasia, there is lexical impairment, and a poor mapping of sounds to meanings, causing word-substitutions (paraphasias).
- There can be near-misses at the sound end of the mapping (literal or phonemic paraphasia - “pish” instead of “fish”) or at the meaning end of the mapping (verbal or semantic paraphasia - “clock” instead of “watch”).
- Broca’s area is working well, but its output is based on poor lexical information (garbage in, garbage out) and the patient cannot self-monitor speech, or comprehend the first half of a sentence while trying to express the second half.
- Patients often have anosognosia (unawareness of the deficit).
- Speech is thus fluent and grammatically normal, but is often empty, meaningless or littered with phonemic and semantic paraphasias. (“The dird went in the doctor, my tablet was in the page with the words, and he gop a headache”).
12
Q
Describe global or mixed
A
- In complete global aphasia, comprehension and speech are both absent.
- In cases that are almost complete, the patient is reduced to single words (“yes” and “no”, or common nouns) and may only understand simple questions or single-word prompts (“drink?” “yes”).
- More commonly, there is a dysphasia with incomplete impairment in comprehension and expression. Speech is non-fluent and littered with errors. The problems with comprehension are only noted when specifically tested with complex commands.
13
Q
Describe transcortical and conduction
A
- Lesion is not intrinsic to language areas
- Does affect their connections with the rest of the cortex
- Hallmark is intact repetition either with a comprehension issue, expression issue or both
- Both or mixed: one’s own language is foreign. Can repeat words verbatim but with impaired understanding
Conduction Dysphasia
- This is a rare but interesting dysphasia. It provides good evidence that the “language of thought” is not our native language (English, etc), even though our thoughts are often presented to us in a linguistic form and some forms of higher thinking may be impossible without language.
- The hallmark is impaired repetition, in the presence of normal comprehension. Ideas can be understood, and then re-expressed, but the original words are lost, as though repeating a story a day later.
- For instance, when asked to repeat: “The fuel truck crashed and spilled petrol on the road,” a patient might say “A truck carrying petrol crashed, and there was petrol all over the road.”
- Because Broca’s Area is separated from the lexicon, however, paraphasic errors are common in spontaneous speech, so it may resemble mild Wernicke’s Dysphasia.
14
Q
Describe anomia
A
Anomia
- Anomia = the inability to name objects
- Common in all dysphasias (Wernicke’s/lexicon needed to retrieve the word, Broca’s to prepare the word for motor output).
- Has poor localizing value.
- Many dysphasias recover to leave a mild dysnomia as the only residual sign.
- Ease of recall depends on frequency of use, so mild dysnomias will only affect low-frequency words (“telescope”), leaving high-frequency words intact (“pen”).
15
Q
Discuss delirium and psychosis
A
- Both dysphasia and confusion may be described by laypeople as “speaking gibberish”.
- Delirium should be considered whenever there is an apparent language disorder. Non-verbal behavior should be assessed, to determine whether the problem extends beyond language.
- An episode of dysphasia (especially Wernicke’s) may be misdiagnosed as an episode of confusion.
- Severe schizophrenia may produce such disordered thought processes that the language output may consist of unrelated words (“word salad”). This may superficially resemble Wernicke’s Aphasia.
- Note that a patient may fail at repetition tasks because they don’t understand what is required (confusion) or have no interest in cooperating (drowsiness, apathy, severe schizophrenia).
