Transcript speech disorders

DISORDERS OF SPEECH
AND LANGUAGE
Aphasia or dysphasia

Loss or impairment of the production or
comprehension of spoken or written
language because of an acquired lesion of
the brain.
Dysarthria and anarthria

A defect in articulation with intact mental
functions and comprehension of spoken
and written language and normal syntax
(grammatical construction of sentences).

pure motor disorder of the muscles of
articulation and may be a result of flaccid
or spastic paralysis, rigidity, repetitive
spasms (stuttering), or ataxia.
Aphonia or dysphonia
An alteration or loss of voice because of a
disorder of the larynx or its innervation
 Articulation and language are unaffected

APHASIA
Alexia
loss of the ability to read
 common accompaniment of aphasia
caused by temporal or parietal lobe
lesions.
 In most cases, accompanied by agraphia,
the inability to write.

Pure alexia
without agraphia and with normal
comprehension of spoken words
From
 single lesion lateral to the occipital horn
of the left lateral ventricle or
 combination of two lesions, one in the left
occipital lobe and the other in the
splenium of the corpus callosum.


Such lesions sever connections between
both visual cortices and the unilaterally
located language areas
Dyslexia
incomplete alexia
 characterized by an inability to read more
than a few lines with understanding.
 Developmental dyslexia is a common
condition in children of normal
intelligence who have difficulty learning to
read.


MRI examination reveals that some such
children lack the usual anatomical
asymmetry in the size of the planum
temporale on the left and right sides.
Expressive aphasia (Broca's aphasia),
lesion in Broca's area of the frontal lobe,
 hesitant and distorted speech with
relatively good comprehension.
 patient with Broca's aphasia can hear that
he or she is talking nonsense
 patient with receptive aphasia talks fluently
without being aware of the failure to
produce meaningful words.

Broca's Original Patient
In April 1861 Broca encountered a patient
named Leborgne who had a 20-year
history of inability to produce meaningful
words.
 He had been nicknamed "Tan" because
"he could no longer produce but a single
syllable, which he usually repeated twice
in succession;

Regardless of the question asked him, he
always responded: tan, tan, combined with
varied expressive gestures.
 This is why, throughout the hospital, he is
known only by the name Tan."


Leborgne died a week later and at
autopsy was found to have long-standing
damage to his left inferior frontal gyrus

Although attention was focused on the
cortical area that came to bear Broca's
name, the damage was clearly more
extensive, affecting additional cortical
areas (including the insula) and parts of
the basal ganglia
Over the next 2 years, Broca investigated
seven more cases of loss of spoken
language.
 As in the case of Leborgne, all seven had
left hemisphere damage.
 In an 1865 paper, Broca was one of the
first to describe the idea of hemispheric
dominance for language.


This traditional model is appealingly
simple and often successful in explaining a
variety of aphasic disorders, but it is
certainly an oversimplification.
Functional imaging studies have shown
increased blood flow in extensive
networks of multiple cortical areas during
most language tasks.
 In addition, not all aphasic patients have
damage in the expected location.


For example, damage restricted to Broca's
area causes only a mild, temporary deficit
in fluency; patients with severe, persistent
Broca's aphasia always have more
extensive damage that involves the insula
and possibly the head of the caudate
nucleus

Similarly, patients with persistent
Wernicke's aphasia typically have
extensive lesions that include not just the
superior temporal gyrus but also parts of
the middle temporal gyrus and inferior
parietal lobule.

Finally, damage that includes the
supramarginal gyrus is now thought to be
the basis for conduction aphasia; a lesion
of the arcuate fasciculus alone is
insufficient
Despite these complications, however, it is
consistently found that within the cortical
areas important for language,
 More anterior lesions result in greater
deficits in the production of language, and
more posterior lesions result in greater
deficits in comprehension

Receptive aphasia (Wernicke's
aphasia),
lesion in the receptive language area,
notably in Wernicke's area.
 auditory and visual comprehension of
language, naming of objects, and repetition
of a sentence spoken by the examiner are
all defective

ISOLATION OF THE LANGUAGE AREAS
(TRANSCORTICAL APHASIAS)

The identifying feature of these language
disturbances is a preservation of the
ability to repeat.

Destruction of the vascular border zones
between anterior, middle, and posterior
cerebral arteries may effectively isolate
the intact motor and sensory language
areas, all or in part, from the rest of the
cortex of the same hemisphere.
Transcortical aphasia of the
receptive (or sensory) type
Some patients cannot understand words
and sentences or produce intelligible
speech, but they can correctly repeat
what the examiner says.
 associated with destruction of cortex in
the middle temporal gyrus, inferior and
posterior to Wernicke's receptive
language area.


Presumably, in transcortical sensory
aphasia, as in Wernicke's aphasia,
information cannot be transferred to the
Wernicke area for conversion into verbal
form.
Transcortical aphasia of the
expressive (or motor) type
Cortical lesion anterior to Broca's
expressive speech area.
 The impairment of spontaneous speech is
similar to Broca's aphasia, but the patient
can accurately repeat words or phrases
spoken by someone else.

Comprehension is relatively preserved
 occurs in two clinical contexts:
 (1) in a mild or partially recovered Broca's
aphasia in which repetition remains
superior to conversational speech
(repeating and reading aloud are generally
easier than self-generated speech)
 (2) with frontal lobe damage.

Conduction aphasia
Interruption of the arcuate fasciculus
connecting Wernicke's and Broca's areas
 patient has poor repetition of a sentence
spoken by the examiner but relatively
good comprehension and spontaneous
speech

In other respects, the features of
conduction aphasia resemble those of a
mild Wernicke's aphasia.
 They share fluency and paraphasias in selfinitiated speech, in repeating what is
heard, and in reading aloud;


comprehension is by no means perfect,
but compared with one who has
Wernicke's aphasia, the patient with
conduction aphasia has relatively little
difficulty in understanding words that are
heard or seen and is aware of his deficit.
Global aphasia
virtually complete loss of the ability to
communicate after destruction of the
cortex on both sides of the lateral sulcus.
 one of the consequences of occlusion of
the left middle cerebral artery

Main Aphasic Syndromes
Type
Broca's
Speech
Comprehension
Repetition
Localization
Nonfluent, effortful, Relatively
preserved
agrammatical,
paucity of output
but transmits ideas
Fluent, voluble, Greatly
well articulated impaired
but lacking
meaning
Impaired
Frontal
None
Temporal,
infrasylvian
including angular
and
supramarginal
gyri
Conduction
Fluent
Relatively
preserved
None
Supramarginal
gyrus or insula
Global
Scant,
nonfluent
Very impaired
None
Large perisylvian
or separate
frontal and
temporal
Wernicke's
Nonfluent and Fluent Aphasia

The difference between nonfluent and
fluent language production can be
illustrated by transcriptions of the speech
of two patients as they tried to describe a
drawing of a picnic scene
Patient MN was a right-handed, 62-yearold man who had a stroke in the anterior
distribution of the left middle cerebral
artery
 When tested at 2 years post stroke, his
language profile was consistent with
moderately severe Broca's aphasia.

His spoken language was characterized by
single-word utterances that contained
articulation errors but was largely
intelligible.
 His utterances were lacking grammatical
structure, consisting primarily of nouns
and a few verbs.


When asked to describe the picnic scene,
he said: "picnic … flying kite … swimming
… house… tree … pouring water …
boat … trees … okay … car."
Patient JS was a right-handed, 65-year-old
man who had a stroke in the posterior
distribution of the left middle cerebral
artery
 His initial diagnosis was conduction
aphasia.


At 3½ years post stroke, his speech was
fluent, with a relatively normal sentence
structure, but word-finding difficulties
were evident.

When describing the picnic scene, he said:
"In the pier, somebody is fishing.
Somebody is playing into the water. The
man with the kite has the jeans with the
pocket deal."
His word-finding difficulties were more
noticeable when he was asked to perform
a naming task.
 For example, when trying to name a
paper clip he said, "safety pin, no, the little
clip."

Anomic aphasia (isolation
syndrome),



Infarcts that isolate the sensory language
area from surrounding parietal and temporal
cortex
characterized by fluent but circumlocutory
speech caused by word-finding difficulties.
Some authorities doubt the existence of
anomic aphasia as a distinct clinical entity
because most patients with lesions in the left
parietal lobe have difficulty with naming
Main Aphasic Syndromes
Type of
aphasia
Transcortical
motor
Speech
Comprehensio Repetition
n
Good
Largely
preserved
Localization
Transcortical
sensory
Fluent
Impaired as
Wernicke's
Largely
preserved
Surrounding
Wernicke area
Pure word
blindness
(and alexia
without
agraphia)
Anomic
aphasia
Normal but
unable to
read aloud
Normal
Normal
Calcarine and
white matter
or callosum (or
angular gyrus)
Normal
Deep temporal
lobe
Nonfluent
Isolated
Normal
word- finding various sites
difficulty
Anterior or
superior to
Broca area