Language 2 Flashcards
Aphasia is
defined as a loss of language processing ability after brian damage
Nb: people with aphasia
PWA not aphasics
aphasia is not
- An impairment of intellectual functioning
- A psychiatric disturbance
- A primary motor or sensory deficit
- A developmental disorder
classic views of aphasia
three principles underlying classic aphasia syndrome :
1: localization of language processors
2: Damage to single processor can produce multiple deficits
3:Language processors localized because of relationship to primary sensory/motor functions
Brocas aphasia
difficulty forming complete sentences. omitting certain words, such as “the,” “an,” “and,” and “is” (a person with Broca’s aphasia may say something like “Cup, me” instead of “I want the cup”)
wernickes aphasia
Major disturbance of auditory comprehension
* Fluent speech, normal rate, rhythm, intonation
* Disturbances of sounds, structures of words
* Semantic substitutions or paraphasias
* Poor repetition, naming
Someone with Wernicke’s aphasia may have difficulty processing the meaning of spoken words. Regarding speech and comprehension, people with Wernicke’s aphasia may: deliver words in a normal melodic line, even though the content may not make any sense
Conduction aphasia
- failure to repeat words
say words which sound like they should be producing but the word is still wrong (paraphasias - phonemic)
Disconnection syndrome: disruption of arcuate fasciculus (dorsal white matter tract
between Broca’s and Wernicke’s areas)
lichtheiems house model
able to predict existence of new aphasic syndroms from developing his framework
brocas aphasia model = lesion to motor area
wernickes aphasia =lesion to auditory area
Transcortical sensory aphasia
cannot comprehend what others say but can speak fluently
- understand whats she wants to say and cant get words out
symptoms:
- disturbance of auditory comprehension
- semantic paraphasias
- fluent grammatical speech
- good repetition
Transcortical motor aphasia
dissconnection syndrome: disconection from concept centre from motor and auditory language centres
symptoms:
- good repetition
- severe disturbance in intiating a response
classic aphasia syndromes have limitations:
- poor classification of patients
- lesions overlap/variability
- little assistance for treatment planning
psycholinguistics and aphasia
- psycholinguistics does not view language in terms of production and comprehension
emphasis language processing operations:
phonology, semantics and syntax
phonology is
sounds that conpose language and the rules that govern their combination
semantics are
words and their meanings
syntax is
methods for combinding indivudal words to convey propositional meaning
Phonology - two ways to represent sound in speech
1: Phonemes: smallest unit of sounf that can distinguish one word from another e.g. b in bat and p in pat
allophones are different representations of the swame phoneme e.g. p in pill vs spill
2: phoentic: how phonemes are produced in different contexts i.e. select correct allophone
- international phonetic alphabet
e.g. the difference between english and frnech prononciation of cave
psycholinguistic: phonology : people with brocas aphasia have difficulty producing allophone of a phoneme
misspronunciation of a phoneme
poor phonetic ability and phonemic selection/ discrioination
psycholinguistic: phonolgy
peo0ple with wernickes aphasia select the wrong phoeneme
substitute phonemes (e.g p for b)
poor phonemic selection/ discrimination BUT presernved phonetic ability
psycholinguistics: syntax and brocas aphasia have difficulty with syntax production
Few function words (e.g., verbs) are produced
* Content words preserved (telegraphic speech)
* Evident in spontaneous speech, repetition and writing.
* We now know that these anterior lesions are also associated with comprehension deficits…
Psycholinguistics: syntax - agrammatic aphasia
grammatic aphasia (a graded impairment)
* Production and comprehension are impaired, although deficits are
dissociable
* “agrammatism” first coined by Adolf Kussmaul (1877)
* Sentence: “The girl the boy is chasing is tall”
Question: “Who is being chased?”
- Broca’s patients have trouble answering
* Wernicke’s aphasia patients usually do not have difficulties with syntax
psycholinguistics:
Word meaning considered separate to lexical (surface) form
* Nb. Simplistic distinction
Lesions resulting in “double dissociation” of lexical and semantic
representations of words:
* Intact semantic knowledge, impaired naming = ‘Tip of-the-
tongue’ & anomic deficits
* Intact naming, impaired semantics = knowledge loss; semantic
dementia/primary progressive aphasia.
psycholinguists: semantics:
Semantic processing is relatively spared in anterior lesioned (Broca’s) patients.
* Problems arise for anterior lesion patients when syntax is important in sentence
comprehension (e.g., “Place the blue circle on top of the big red square
* Posterior lesions (Wernickes) are more often characterized by semantic impairments
* Lesions to the anterior temporal lobes (semantic dementia) are also characterized by
semantic impairments, but affect spontaneous (fluent) speech and sentence comprehension
less (Ogar et al., 2011)
psycholinguistic vs classical
Classical characterisation of aphasia deficits:
* Broca’s = poor speech production
* Wernicke’s = poor speech comprehension
* Dissociation: comprehension vs. production
Psycholinguistic characterisation:
* Anterior = syntactic processing
* Posterior = semantic processing
* Dissociation: syntax vs. semantics
dysarthria and apraxia of speech are
both articulatory motor disorders
- they are not disturbances of language i.e. not aphasias
dysarthria
is the disturbance of speech musculature in terms of speed, strength, streadiness, coordination, precision, tone and range of motion
- corticospinal tract is commonly affect
think cerebral paulsey, motor neuron disease
apraxia of speech
Articulatory-motor disorder (rare)
* Characterised by
articulatory errors
increasing with increasing
word and phrase length.
* Impairment in the ability to
programme speech
movements
* Debate about the critical
lesion (but most strongly
associated with motor
cortex lesions)
Alexia and agraphia
Alexia is the impairment in the ability to read, subtypes:
- surface
- phonological
- deep
agrpahia: impairment in the ability to write
dissociable is
alexia without agraphia
Jospeh Jules Dejerine
Two patients with left parietal lesions
* One with poor reading and writing
* Alexia with agraphia
* Disturbance to the ‘optical images for
words’
* Second patient with poor reading and
preserved writing
* Alexia without agraphia (i.e. pure alexia)
alexia and dual routes to reading
1: phonologicsl route to reading - convert letter strings to sound -> understand the meaning (grapheme to phoneme)
2: direct route -printed words are directly linked to meaning in a visual form system
- when reading irregular words, such as “yacht” or “colonel” or
“pint”
alexia subtypes:
surface alexia
surface alexia:
- read by sound, using grapeme to phoneme conversion
- no difficulty with regular words and non words
- difficulty with irregular words e.g. yacht
alexia subtypes:
phonological alexia
Alexia subtypes
Phonological Alexia
*Able to read previously learned words (regular or irregular) via the direct route
* Extract the meaning directly from the visual form of the word
* Difficulty reading new words and nonwords (pseudowords)
both regular or irregular
* Associated with lesions to superior temporal lobe, parietal lobe
(supramarginal gyrus, angular gyrus
deep alexia
Deep Alexia
* Semantic substitutions (related to target word, e.g., “hot” for
“cold”)
* Influence of “imageability” of word: more difficulty with abstract
words
* Better with nouns than verbs (imageability?)
* Visual errors (e.g. skate for scale)
* Damage to both direct and phonological routes
brain regions involved in reading are
The “Visual word form area” (VWFA)
* Left fusiform gyrus (lesions produce alexia)
* EEG shows N170 (100-200ms) response to letter vs
symbol strings
* Writing is only ~5000 years old, so how did our brain
evolve a specialised region for orthographic
processing so quickly?
* Reading requires coordinated activation in
areas responsible for visual word form
recognition, phonological and semantic
processing
Agraphia is
inability to write or spell whilst writting
subtypes
- central dysgraphia refers to problems accessing orthographic info from lexical stores or from applying sound to spelling rules (dual rule)
- peripheral dysgraphia reflects distorians in written letter formatio spelling or typing (motor programs
key features of dysgraphia
in pariatal lobes:
problem with spelling words - as words get longer spelling becomes more difficult
