Language Disorders

Question 1

language basics

Answer 1

• 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)

Question 2

7 components of language structure

Answer 2

• 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

Question 3

language in non-human animals

Answer 3

• 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

Question 4

key brain regions in language production

Answer 4

• Broca’s area

- Wernicke’s area

Question 5

Broca’s area (2 parts, damage)

Answer 5

• 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

Question 6

Wernicke’s area (damage)

Answer 6

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

Question 7

anatomical areas associated with language

Answer 7

• 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

Question 8

speech zone mapping with brain imaging techniques

Answer 8

• 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

Question 9

Wilder Penfield

Answer 9

identified and mapped neocortical language/speech zones during surgery

Question 10

Effects of cortical stimulation in speech zones

Answer 10

• 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)

Question 11

Wernicke-Geschwind Model

Answer 11

• 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

Question 12

Shortcomings to the Wernicke-Geschwind Model

Answer 12

• 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

Question 13

Dual-Language Pathway theory

Answer 13

• 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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

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

Question 16

language disorders

Answer 16

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

Question 17

fluent aphasia

Answer 17

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

Question 18

Wernicke’s/Sensory Aphasia

Answer 18

• 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

Question 19

conduction aphasia

Answer 19

• 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

Question 20

Anomic/amnesic aphasia

Answer 20

• 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

Question 21

non-fluent aphasia (2 types)

Answer 21

• Broca’s/expressive aphasia

- Global aphasia (laboured speech, poor comprehension)

Question 22

Broca’s/expressive aphasia

Answer 22

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

Question 23

fluent and non-fluent aphasia

Answer 23

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

Question 24

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

Answer 24

• 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

Question 25

cortical language components: non-fluent

Answer 25

usually to Broca's area, presumably dorsal pathways

Question 26

cortical language components: fluent

Answer 26

Usually to Wernicke's area, presumably ventral pathway

Question 27

Right-hemisphere contributions to language

Answer 27

- Good auditory comprehension of language

Question 28

Left-hemisphere contributions to language

Answer 28

- syntactical language - - sequencing - - relations - - grammar

Question 29

symptoms of non-fluent aphasia

Answer 29

- - 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

Question 30

symptoms of fluent aphasia

Answer 30

- - 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

Question 31

what is aphasia?

Answer 31

- 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

Question 32

Diagnosing & treating aphasia

Answer 32

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

Question 33

aphasia treatment: speech-language therapy (SLT)

Answer 33

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

Question 34

SLT: acute recovery stage

Answer 34

- Up to 3 weeks | - Spontaneous recovery of function due to physiological restitution of damaged brain

Question 35

SLT: subacture recovery stage

Answer 35

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

Question 36

SLT: chronic recovery stage

Answer 36

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

Question 37

aphasia treatment: medication

Answer 37

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

Question 38

aphasia treatment: brain stimulation

Answer 38

- 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

Question 39

hemispheres and language -> responsibility & removal

Answer 39

- 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