Aphasia
A disorder caused by damage to the parts of
the brain that control language. It can make
it hard to read, or write and to comprehend
or produce language.
Developmental Aphasia
• Approximately 1 in 20 children has symptoms of a
language disorder. When the cause is unknown, it
is called a developmental language disorder.
• Language disorders may occur in children with
other developmental problems such as autistic
spectrum disorders, hearing loss, and learning
disabilities.
• A language disorder may also be caused by
damage to the central nervous system, which is
called aphasia.
• Language disorders are rarely caused by a lack
of intelligence.
Acquired Aphasia
• Result of accident or disease
 Stroke
 Tumor
 Trauma
 Disease (e.g., Pick’s Disease,
AKA frontotemporal dementia)
• aphasia may occur suddenly or develop over
time, depending on the type and location of brain
tissue damage.
Paul Broca
In 1861, Broca heard of a
patient who had a 21-year
progressive loss of speech
and paralysis but not a loss
of comprehension nor
mental function.
He was nicknamed "Tan"
due to his inability to
clearly speak any words
other than "tan"
Paul Broca - 1860’s
When Tan died Broca performed an autopsy. He
determined that Tan had a lesion in the frontal
lobe of the left cerebral hemisphere.
Broca went on to find autopsy evidence from 12
more cases in support of the localization of
articulated language.
Broca’s (Expressive) aphasia
Type of aphasia, which involves impairments in
speech output.
• Halting, non-fluent speech.
• Content words are correct but function words
(i.e., articles and adjectives) were impaired.
• Grammatical errors
• the person knows what he or she wants to say,
yet has difficulty communicating it to others.
Broca’s Aphasia cont.
• Motor speech problems (apraxia)
• Broca’s area seems to play a major role in the
planning and control of speech behavior
Telegraphic Speech
• consisting of simple three or more word
sentences usually comprising at least one
noun and verb that adhere to the grammatical
standards .
• Similar to developing speech in children.
Ted Talk of Gabby Gifford
Congresswoman Gabrielle
("Gabby") Giffords captured
the attention—and deep
sympathy—of a nation
when she was shot by Jared
Lee Loughner in a Safeway
parking lot on January 8,
2011, in Tucson.
Giffords' injury to her
brain's left hemisphere
resulted in aphasia.
Carl Wernicke
Wernicke noticed that not all
language deficits were the
result of damage to Broca's
area. He found that damage to
the left superior temporal gyrus
resulted in deficits in language
comprehension. This region is
now referred to as Wernicke's
area, and the associated
syndrome is known
as receptive aphasia.
Carl Wernike 1880’s
Example of Wernicke's Aphasia
• Comprehension is impaired
• Speech is fluent but has little informational
value. They speak easily or even abundantly,
yet may produce unintended syllables of
words. They will experience the same
difficulties when writing as when speaking.
Wernicke’s Aphasia cont
• Fluent function words, but impaired content
words.
• Might have
– Random words (Word salad)
– Neologisms
• rarely correct errors, seem unaware of errors
(anosognosia)
Wernicke's Model
Broca’s Area: Speech – Phonemic Movement
Programs.
Wernicke's Area – Phonological input Lexicon
Wernicke predicted the existence of Conduction
Aphasia in which people can understand speech
but make errors in repetition. Due to lesion of the
connection between Wernicke's and Broca’s areas.
Arcuate fasciculus
Conduction Aphasia
Comprehension and production are relatively intact.
• capable of understanding what they are hearing but
they will have difficulty repeating
• display frequent errors during spontaneous speech,
such as substituting or transposing sounds.
• Are aware of their errors, and will show significant
difficulty correcting them.
Speech- Phonetic
Movement Programs
Motor Systems
Phonological Analysis
Auditory Analysis
Speech Input
Lichtheim (1885)
Found cases of patients with conduction aphasia
partially confirming Wernicke's Model
But
New forms of Aphasia were identified that
required that the model be extended.
Models of Aphasia
Wernicke-Lichtheim Model of Aphasia
Semantic
Conceptual Area F
G
E
Speech- Phonetic
Movement
Programs D
Phonological
Analysis B
C
Motor Systems
A
Auditory Analysis
Speech Input
Boston Aphasia Classifications
Broca’s Aphasia - Speech is laborious and
grammar can be incorrect. D
Wernicke's Aphasia: Comprehension is
impaired B.
Conduction Aphasia Comprehend and produce
speech accurately – difficulty repeating. C
Global Aphasia
Both Comprehension and production impaired.
•
•
•
•
most severe type of aphasia.
often seen right after someone has a stroke.
person is unable to read or write.
Generally involves widespread left
hemisphere damage
Global Aphasia – neither comprehend nor produce
speech. Damage to both Broca’s and Wernicke's areas.
B and D
Transcortical Motor Aphasia (TMA)– Similar to Broca’s
but can’t repeat . G
Transcortical Sensory Aphasia (TSA) – Similar to
Wernicke's but repetition is preserved. E
- exhibit echolalia, or even compulsive repetition of
words.
Isolation Aphasia (Mixed Transcortical Aphasia)
– cannot understand or produce speech but can
repeat words. E and G
Anomic Aphasia – Problems in naming objects
across modalities. G or E
Anomic Aphasia
Problems recalling words, names, and numbers.
• often use circumlocutions (speaking in a
roundabout way) in order to avoid a name
they cannot recall or to express a certain word
they cannot remember.
• can recall the name when given clues.
• are able to speak with correct grammar
Transient Anomia
Might result from:
• Aneurism (e.g. Ashcroft)
• Epileptic seizure
E.g., A 37-year-old man had episodes of transient
anomia for people's names over a period of 6
months. The first episode lasted about 10 min and
was restricted to an inability to remember his 2year-old son's first name. The second, was limited
to an inability to recall his daughter's first name for
5 min. (Ghika-Schmid & Nater, 2003)
Ashcroft
"The most powerful realization I had during the episode ...
was a dissociation between the thought and the word or
phrase that expresses the thought. The subjective
experience consisted of knowing with complete certainty
the idea or concept that I was trying to express and being
completely unable to find and utter the word that expressed
the idea or concept. ... The experience was not one of
being unable to articulate a word currently held in
consciousness. Instead, it was one of being fully aware of
the target idea yet totally unable to accomplish what
normally feels like a single act of finding-and-saying the
word."
Optic anomia
• Patient JF was impaired when naming visually
presented objects but could define them from
their spoken names or by touch (Beauvois et al.,
1973; 1982; 1985).
• He could mime the use of the objects so this
was not agnosia (i.e. knew what object was).
• C.f. Tactile anomia e.g., RG could not name
objects by touch but could name visually
presented objects and pantomime their use
(suggesting that he knew what the object was).
Pure Word Deafness
• No comprehension of speech, No ability to
repeat or to write to dictation
• feel as though they can't hear when someone
else is speaking, even if the person speaking is
doing so in a loud voice.
• they have no trouble hearing other sounds,
such as a telephone ringing or a door bell.
• maintain the ability to write spontaneously
Phonagnosia
• Disturbance in the recognition of familiar
voices
• the impairment of voice discrimination
• does not suffer from comprehension deficits.
Speech Apraxia
Speech Production Disorder
• People who have it find it difficult or impossible to make
certain motor movements, even though their muscles are
normal.
• Due to damage to primary motor cortex.
Milder forms of apraxia are known as dyspraxia.
• affect the articulation of consonants, causing the slurring of
speech.
• in very severe cases, vowels may also be distorted
Prosody Production and Perception
Problems producing or interpreting inflections
Due to Right frontal lobe damage
Take-home Message
Language is very complex
Relies on:
• motor ability
• phonemics
• Syntax
• Semantics