Language Disorders Flashcards

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1
Q

language basics

A
  • Comes from word for tongue
  • Combination of sound for communication (although ASL is included here too)
  • Uniquely human (animals have similar abilities, but not language per say)
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2
Q

7 components of language structure

A
  • Phonemes: fundamental language sounds that form a word
  • Morphemes: smallest meaningful units of words
  • Lexicon: collection of all words in a given language
  • Syntax: rules of grammar; thing that no other species appear to be able to do
  • Semantics: meaning of words and sentences that correspond to all lexical items
  • Prosody: vocal intonations (“tone of voice”)
  • Discourse: stringing sentences together to form a meaningful narrative
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3
Q

language in non-human animals

A
  • Some success with ASL and “Yerkish” in chimpanzees
    • Nim Chimpsky experiment – raised like a human in terms of language development, but never learned syntax
    • Mothers who learned “Yerkish” passed it down to their babies
  • Alex the Parrot showed impressive cognition and comprehension, including generativity
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4
Q

key brain regions in language production

A
  • Broca’s area

- Wernicke’s area

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5
Q

Broca’s area (2 parts, damage)

A
  • damage to it results in ability to understand speech, but cannot produce it (ex. “Tan” - man who could only say Tan after a stroke)
  • 2 parts:
    • Anterior region involved in semantical processing (meaning of words)
    • Posterior region involved in phonetic production
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6
Q

Wernicke’s area (damage)

A

damage to it results in ability to produce speech, but it’s non-sensical and may reflect lack of comprehension (“word salad”)

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7
Q

anatomical areas associated with language

A
  • Fissures and gyri
  • Brodmann’s area
  • Insula and medial superior temporal gyrus
  • Arcuate fasciculus: white matter bundle travelling from Broca’s area to Wernicke’s area
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8
Q

speech zone mapping with brain imaging techniques

A
  • Through fMRI, Binder et al. Found that speech zones are widespread throughout the brain
  • Different areas activated depending on tasks:
    • Ex. Thinking about nouns activates 3 different areas
    • Hearing overlaps more with Wernicke’s area, speaking overlaps more with Broca’s areas
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9
Q

Wilder Penfield

A

identified and mapped neocortical language/speech zones during surgery

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10
Q

Effects of cortical stimulation in speech zones

A
  • Total arrest of speech
  • Hesitation and slurring of speech
  • Speech distortion and repetition of speech
  • Number confusion while counting
  • Naming difficulties
  • Misnaming and perseveration
  • These apply to modern stimulation (e.g. TMS)
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11
Q

Wernicke-Geschwind Model

A
  • the old theory
  • word sounds sent to Primary Auditory cortex -> meaning represented in Wernicke’s area -> sent to Broca’s area -> Broca’s sends speech articulation to motor cortex
  • when reading, visual cortex sends info to angular gyrus and to Wernicke’s or Broca’s area
  • Damage to Broca’s area causes issues with production, damage to Wernicke’s area causes issues to comprehension
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12
Q

Shortcomings to the Wernicke-Geschwind Model

A
  • Doesn’t take into account many other brain regions involved
  • Overly simplistic when it comes to “regions” of Broca’s area, Wernicke’s area, and directionality of flow
  • Relied mostly on diffuse loss-of-function studies
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13
Q

Dual-Language Pathway theory

A
  • contemporary theory
  • language moving in multiple directions: bottom-up/dorsal language pathway and top-down/ventral language pathway
  • area 6 (motor cortex) and 47 (semantics) often targets of flow of info
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14
Q

Dual-Language Pathway theory: bottom-up/dorsal pathway

A
  • language production
  • phonetics
  • used when repeating nonsense words
  • short-term/working memory
  • damage causes problems with speech production
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15
Q

Dual-Language Pathway theory: top-down/ventral processes

A
  • semantics/meaning of language
  • separating homonyms
  • long-term memory (vocabulary)
  • damage causes problems understanding the meaning of words
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16
Q

language disorders

A
  • Aphasia (fluent vs. Non-fluent)
  • Alexia (inability to read)
  • Dyslexia (difficulty reading)
  • Agraphia (inability to write)
17
Q

fluent aphasia

A
  • impairment in input or reception of language, but not production
  • 3 sub-components:
    • Wernicke’s/Sensory aphasia
    • Conduction aphasia
    • Anomic/Amnesic aphasia
18
Q

Wernicke’s/Sensory Aphasia

A
  • Deficits in classifying sounds or comprehending words
  • “Word salad”: intelligible words strung together randomly (patient confuses phonetic characteristics)
  • Cannot write because cannot discern phonemic characteristics
19
Q

conduction aphasia

A
  • Can speak, name objects, and understand speech but cannot repeat words
  • Problem is a disconnection between the “perceptual word image” and the motor systems producing the words
20
Q

Anomic/amnesic aphasia

A
  • Can comprehend speech, produce meaningful speech, and can repeat speech
  • Great difficulty naming objects
  • Ex. Seeing a picture of an anchor, being able to describe it (ie. “you use it to anchor a ship”), but can’t access it as a noun
21
Q

non-fluent aphasia (2 types)

A
  • Broca’s/expressive aphasia

- Global aphasia (laboured speech, poor comprehension)

22
Q

Broca’s/expressive aphasia

A
  • Can understand speech
  • Labours hard to produce speech
  • Can be mild or severe
23
Q

fluent and non-fluent aphasia

A
  • Transcortical aphasia, or isolation syndrome
    • Can repeat words (echolalia)
    • Cannot speak spontaneously
    • Often poor comprehension
24
Q

why is studying neural basis of language (and localizing lesions) complex?

A
  • Most of the brain takes part in language in one way or another
  • Most patients who add information to studies of language have had strokes, usually of the middle cerebral artery
  • Immediately following stroke, symptoms are generally severe but improve considerably as time passes
  • Aphasia syndromes described as nonfluent (Broca’s) or fluent (Wernicke’s) have many varied symptoms, each of which may have different neural basis
25
Q

cortical language components: non-fluent

A

usually to Broca’s area, presumably dorsal pathways

26
Q

cortical language components: fluent

A

Usually to Wernicke’s area, presumably ventral pathway

27
Q

Right-hemisphere contributions to language

A
  • Good auditory comprehension of language
28
Q

Left-hemisphere contributions to language

A
  • syntactical language
    • sequencing
    • relations
    • grammar
29
Q

symptoms of non-fluent aphasia

A
    • Apraxia of speech: damage to the insula
    • Deficits in sentence comprehension: damange to superior temporal gyrus
    • Repetition of speech: damage to arcuate fasciculus
    • Working memory and articulation impairment: Broca’s area damage
30
Q

symptoms of fluent aphasia

A
    • Lack of speech comprehension and other core difficulties with language
    • Damage to the medial temporal lobe and underlying white matter
    • Damage to temporal cortex contributes to deficits in holding sentences in memory until can be repeated
31
Q

what is aphasia?

A
  • Neurologic disorder that impairs an individual’s ability to use and/ or understand language
  • Commonly occurs after stroke to left cerebral hemisphere or other injury to the brain’s language network
  • Impairments depend on size of lesion and individual patient differences
32
Q

Diagnosing & treating aphasia

A
  • Diagnosed using object naming, comprehension, repetition, reading, writing, etc. tasks
  • treated using speech-language therapy, medication, or brain stimulation
33
Q

aphasia treatment: speech-language therapy (SLT)

A
  • Capitalize on preserved abilities, provide compensatory strategies to improve communication (ie. communication boards, online device)
  • 3 recovery stages: acute, subacture, chronic
34
Q

SLT: acute recovery stage

A
  • Up to 3 weeks

- Spontaneous recovery of function due to physiological restitution of damaged brain

35
Q

SLT: subacture recovery stage

A
  • 3 weeks-12 months
  • Spontaneous recovery due to physiological reorganization of the brain
  • SLT is effective beginning in this phase
36
Q

SLT: chronic recovery stage

A
  • More than 12 months
  • SLT is still effective in this phase (effective across life course)
  • Most positive effects with higher intensity of treatment
37
Q

aphasia treatment: medication

A

drugs that enhance neurotransmitter pathways may mitigate the damage done to those pathways due to strokes

38
Q

aphasia treatment: brain stimulation

A
  • non-invasive electrical stimulation or magnetic pulses
  • Effects can last for hours after session and enhance learning during motor or language training
  • Either enhance left hemisphere activity, reduce right hemisphere activity, or both
39
Q

hemispheres and language -> responsibility & removal

A
  • left hemisphere usually more responsible (but in some people, both are)
  • If left hemisphere removed early, the right can acquire language (if removed in adulthood, severe deficits in speech but still good auditory comprehension)
  • Removal of the right hemisphere produces subtle changes in language comprehension