Transcript
Neurogenic communication disorders
Aphasia: A syndrome known for centuries, but poor understood for a long time.
Increasingly greater involvement of speech-language pathologists in treating aphasia.
Demographic changes: An increase in the aged population, with a concomitant increase in the communicative disorders
associated with aging, including aphasia .
Scientific Importance:
Aphasia is a window on the relationship between brain and language.
It provides insight into the relation between brain and behavior.
Aphasia helps us understand the relationship between brain and language functions.
Historical Introduction Paul Broca (1824-1880), French neurosurgeon and physical anthropologist.
He was the first to the relate the frontal lobe and left brain to language production .He said we speak with the left hemisphere. His term to describe language disorders associated with brain lesions was aphemia.
He described the following symptoms:
*Reduced fluency.
*Nongrammatic, telegraphic speech .
*Many language production errors .
*Only limited impairment of comprehension of spoken language.
Broca conducted an autopsy of a man whose speech was destroyed by stroke and reported a damage lower, posterior portion of the left frontal lobe (Broadman area 44). This portion of the brain soon came to be known as Broca’s area.
Broca removed the brain from the skull, but did not dissect it to see the extent of damage. The intact brain is displayed in Paris museum.More recent research has shown that :
Damage to broca’s area is not necessary to create the symptom of Broca’s aphasia.
Lesions elsewhere in the brain can cause those very symptoms.
Carl Wernicke (1848-1905)
A German neuropsychiatrist, Wernicke was the first to describe another major type of aphasia. He thus strengthened the localist
viewpoint of the brain and language .
At age 26, Wernicke described a case of aphasia with:
*Fluent but meaningless speech.
*Grammatically correct speech .
*Severe problems in understanding spoken language .
*Difficulties in comprehending material read silently or orally.
He called it sensory aphasia. Now Wernicke’s aphasia.
This lesion was noted in the posterior portion of the left superior temporal gyrus, but portions of the left parietal lobe, especially the angular gyrus, also may be
involved .
These portions of the brain are now known as Wernicke’s area.
Localization And Association
The early localization- Broca and Wernicke – were also associationists who suggest
that :Aphasia is a disorder of disassociation between verbal labels and events, objects, and ideas to which those labels are attached. Aphasia is purely a linguistic disorder with no intellectual deterioration. Associationism and
localization go together.
The Emergence of Cognitivism
The cognitive school emerged when clinicians began to show that aphasic patients do have intellectual problems. Accordingly: Aphasia involves cognitive impairments.
The French clinician Trousseau (1801-1867) argued against a purely linguistic-associationist view of aphasia. He claimed that intelligence is always impaired in
aphasia .
The founder of the cognitive school is thought to be John Hughlings Jackson (1835-1911), an English neurologist who
held that :
Speech has an automatic or emotional component and a propositional component. The propositional component
of speech is disturbed in aphasia .
Jackson said that : *Aphasia is the loss of ability to
propositionize . *Word may be used emotionally,
automatically.*Because speech is a part of thought,
aphasic patients with disturbed speech (language) are also disturbed processes .
The cognitivists considered localization as “diagram makers ”
Two other neurologists contributed heavily to the cognitive school of thought were :
The Frenchman Pierre Marie (1853-1940) and the Englishman Henry Head (1861-1940).
In 1906, Marie challenged the notion that the lift frontal convolution (Broca;s area) is the center for expressive speech. He presented cases with lesions in Broca’s area without speech problems and cases of Broca’s aphasia with intact Broca’s
area .
Recent research has posed similar challenges to the concept of Broca’s aphasia.
Marie said that : aphasia is single disorder.
It is not a collection of multiple disorders distinguished on the basis
of the site of lesion.
Henry Head Add :
Aphasia is a disturbance in symbolic formulation.
It is a disturbance in verbal and nonverbal symbolic behavior.
Kurt Goldstien also insisted that: Abstract thinking ability is impaired in aphasia.
The Modern Period
Weisenburg and McBride studying 60 aphasic patients performance on verbal
and nonverbal tasks, they claimed that : *A majority of pts had impaired nonverbal
performance , but also great variability. *Aphasia does not necessarily involve
intellectual problem( some severely aphasic persons could perform adequately
on nonverbal tests of intelligence) .
Neurophysiological Considerations
Neurophysiological Aspects of Aphasia.
Much of neuophysiollogical research and writing related to aphasia is concerned with specific regions of the brain that may control particular language functions.
Neurophysiological aspects of aphasia.
For instance, we know:
# That the left hemisphere in most individuals is dominant for language.
# About Broca’s area in the frontal lobe.
# About Wernicke’s aera in the temporal and parietal lobes.
Cerebral Blood Supply
Brain is the big eater
Though it is only 2% of the body weight, it is requires 20% of body’s blood .
It consumes 25% of the body’s oxygen .
The brain is totally dependent and vulnerable:
-It depends on the blood supply to provide nourishment .
-Consciousness is lost within 10 seconds of blood interruption .
-The brain will be permanently damage within 3 minutes of blood interruption.
So…. What Is Aphasia?
It is a communication disorder caused by brain damage and characterized by complete or partial impairment of language comprehension, formulation, and use; excludes disorders associated with primary sensory deficits, general mental
deterioration, or psychiatric disorders .
But there are many definition, much controversy, and some agreement about
what aphasia is .
Some definition are typological ( suggest types of aphasia), others are nontypological (suggest only one kind of
aphasia) .
Nontypological Definitions
Schuell and her colleagues define aphasia in a notypological manner as :
A language deficit that crosses all modalities and may be complicated by other sequelae of brain damage.
Darley defines aphasia as:
An impairment as a result of brain damage of the capacity for interpretation and formulation of language symbols.
So aphasia for Darley is:
*A multimodality problem ( reading, writing, speaking, and comprehension).
*Deficiency in speaking and understanding language especially morphemes and large
syntactic units .
*A language impairment that exceeds impairment of other intellectual functions .
*Not due to dementia, confusion, sensory loss, or motor dysfunction .
*Reduced access to vocabulary.
*Impairment in using syntactic rules .
*Impaired auditory retention span. * disturbed input and output channel
selection .
The Central Nervous system (CNS)
The CNS is important in understanding aphasia and other neurologically based
language disorders .
The CNC includes the brain and the spinal cord. Specifically, the system includes the
following :
1. The cerebrum.
2 .Cerebellum.
3 .Brain stem .
4 .Spinal cord.
Thalamic structures and basal ganglia often are included. The thalamus has been implicated in some forms of aphasia.
Basal ganglia are important in understanding motor speech disorders.
The Brain Stem The brain stem includes medulla, pons, and
midbrain .However, some neurologists do not include midbrain and others include the basal
ganglia .Medulla is the lowest (caudal) part of the brain stem, midbrain is the highest; pons is
in the middle .
Medulla: Contains all the fibers that originate the brain and cerebellum and move down to form
the spinal cord .
Pons: A bridge to the hemispheres of the cerebellum ( not cerebrum).
It concerned with hearing and balance; some cranial nerve originated here .
Midbrain: Also called mesencephalon. Controls eye movement and postural reflexes.
Cerebellum: This is the “little brain .”
It is located at the base of the brain .Has two hemispheres (cerebellar hemispheres not to be confused with cerebral
hemispheres) .Coordinates and modulate movement .
It is responsible for smooth, and rhythmic motor movements, including those involved in speech
“Dose not initiate movement ”
Cerebellar lesions may produce various form of ataxia (a disorder of movement )
and ataxic dysarthria .
Subcortical Brain Structures
Diencephalons and basal ganglia are among the relevant structures of subcortical gray matter.
Above the midbrain (mesencephalon) is the Diencephalons which consists of thalamus and hypothalamus.
The thalamus integrates sensory experiences and relays to cortical areas.
Thalamus is supposed to play some role in speech and language (Penfield). The possibility of thalamic aphasia has been discussed but more research is needed.
Hypothalamus is a part of third ventricle; it is concerned mostly with emotional behavior, controlling body temperature, and food and
water intake .The basal ganglia, part of the extrapyramidal system, is involved in movement control.
The pyramidal system of motor cortex controls voluntary movements, but the extrapyramidal system regulates and modifies those movements.
Damage to the basal ganglia could result in unusual postures, uncontrolled (involuntary) movement (dyskinesias) and variety of dysarthria.
Connecting Fibers .
Several bundles of nerve fibers connect the cerebral structures to each other .
Some connecting fibers are short and others are long. Shorter fibers connect adjacent areas and longer fibers connect distant areas.
The association and commissural fibers are important .
Association fibers connect areas within a hemisphere.
The most important of the association fibers are the superior longitudinal or arcuate fasciculus. This bundle of fibers arches backwards from the lower part of the frontal lobe to the posterior superior part of the
temporal lobe.
Arcuate fasciculus connect the motor speech areas with the sensory speech areas ( Broca’s
and Wernicke’s).
Commissural Fibers connect the corresponding areas of the two hemispheres, which are divided by the median longitudinal fissure. At the base of the hemispheres, a broad and thick band of fibers known as corpus collosum connect the two hemispheres.
Damage to corpus collosum can disconnect the two hemispheres. This results in various form of movement, reading, naming, and other problems that are described as disconnection
syndrome .
Cerebrum: The brain contains about 10 billion neurons .
An average human brain weights about 1400 grams .
The outermost surface, called the cortex, is gray .The term cortex means the bark of a tree .
The surface is a folded mass of rolling hills and valleys .
The frontal lobe:
The frontal lobes is in frontal of central fissure and above the lateral fissure .
The frontal lobe is all of the cortex in front of the central fissure; it makes up about one
third of the surface area of the cortex .
The frontal lobe is extremely important for speech and language.
The precentral gyrus is the major portion of the Primary Motor Cortex (strip) controlling voluntary movements of skeletal muscles on the opposite side of
the body .
The motor strip controls movements through a neural pathway called the Pyramidal
system.
The motor impulses are modified by the extrapyramidial system with its complex
and indirect relay stations .A portion of the frontal lobe directly in front of the primary motor cortex is called the Supplementary Motor Cortex.
The frontal lobe contains the famous Broca’s area in the left ,lower, and posterior portion of the frontal lobe.
The Parietal Lobe
Lies just behind the central fissure and just above the lateral fissure, with an imaginary posterior boundary that separates from the occipital lobe.
This lobe concerned with perception and somesthetic sensation ( touch, pressure, position in space, and bodily awareness.
There are two parts in parietal lobe are significant for language :
*Supramarginal gyrus: this lies above the lateral fissure in the inferior portion of the parietal lobe and its posterior portion curve around the lateral fissure.
Damage to this gyrus may cause agraphia or conduction aphasia.
Supramaginal gyrus
*Angular gyrus : this lies posterior to the supramarginal gyrus. Damage to the angular gyrus can cause naming, reading, and writing difficulties.
Angular gyrus
The temporal lobe
Is the lowest one third of the brain. It starts at the lateral fissure and ends at the imaginary boundary of the anterior portion of the occipital lobe.
The temporal lobe is under the frontal and parietal lodes and in front of the occipital lobe.
Temporal lobe
The three important structural and functional landmarks of the temporal lobe are :
1 .The superior (upper) temporal gyrus .
2 .The middle temporal gyrus .
3 .The inferior (lower) temporal gyrus.
Temporal lobe
The primary auditory cortex (area) is at the border of the superior temporal gyrus and the lateral fissure. This area is concerned
with hearing .Wernicke’s area is located posterior to the primary auditory area. It is located portion of the superior temporal gyrus, and close to the intersection of the temporal, parietal, and occipital lobes.
Wernicke’s area
Primary auditory area
This is important in comprehension of written and spoken language.
Remember this area is connected to the frontal (motor speech) area through the
arcuate fasciculus .
The occipital lobe
The smallest of the lobes, the occipital is behind the parietal lobe .
Neurodiagnostic Methods of Aphasia
The methods of diagnosing neural pathology and its effects are called neurodiagnostic methods. Most of these methods are apart of general neurological procedures.
Some methods are post hoc, some are invasive, and others are inferential.
Postmortem: the post hoc method.The oldest method of relating certain areas of the brain to specific language function.
In this method, the patient’s language problems are noted, and upon his death, a postmortem to see changes in the brain tissue. they observed changes that are related to the previously noted language
problems .
The problem with this method is that its post hoc and the postmortem may only be partial. Not all structures may be examined. It is not a clinical diagnostic that benefits the patient. it might be helpful to
others and to science .
Surgical Method:
Surgical method is both experimental and in vivo. Many classic studies of the relation between brain and language were made
with this method .
Electroencephlogram (EEG)
Is standard clinical diagnostic method of the neurologist .
Is a method to pick up, amplify, and record on paper the electrical impulses the brain
generates .
Shows different patterns of brain waves for different types of activities such as listening, talking, thinking.
Shows abnormal electrical activity suggesting underlying cortical lesions .
A problem with the traditional EEG is the artifacts due to :
-Movement.-Unknown variables .
Cerebral Angiography.This is a radiographic procedure combined with the injection of radio-opaque contrast material into selected arteries, typically the carotid artery.
In this method :
-A rapid series of X-ray is taken to evaluate the health of the vascular system .
-The X-rayed radio-opaque material shows variation in blood circulation that might
suggest vascular occlusions.
Computerized Axial Tomography. (CT)
)axial: rotation around a line; Tomo= section ;
Tomography= pictures of bodily section.(
A matching that rotates around structures takes the pictures.
In this method :
-An x-ray generator rotates around the head of a patient and scans the tissue for its density .
-The computer analyzed the images generated by the scanning machine and produce picture of the
scanned parts .
CT scans show internal, lesions, tumors, hemorrhages, and other neuropathologies .
However, small lesions may go undetected.
CT scans have been used to study the location and extent of lesions in various
types of aphasia .
Single-Photon Emission Computed Tomography (Regional Cerebral Blood Flow)
….(SPECT) or (RCBF). It measures the amount of blood flowing through a structure. It is a method of estimating cerebral
metabolism. Different types of cerebral activities require different amounts of blood. Therefore differences in blood flow can suggest normal or abnormal activities of cerebral structures.
In this procedure:
-The patient inhales xenon 133,a radioactive-gas which is immediately distributed throughout the hemispheres; the gas enters the bloodstream.
-A scanner detects radiation uptake in the cerebral blood .
-A computer calculates the amount of blood flow in given regions and displays variations in blood flow in different colors.
One problem with SPECT :It misses areas that are damaged but whose blood
flow is near normal. Positron Emission Tomography (PET)
PET is a newer method of studying brain activity through differences in metabolic rates of
different areas of the brain . -The patient takes glucose mixed with positron-
emitting isotope which is metabolized in the cerebral cells.
) iso=equal; topos=place. Any two or more forms of an element having the same or closely related properties and the same
atomic number but different atomic
weights .(
Area of greater metabolism suggest greater neural activity and blood flow.
The isotopes emit positrons the machine detects and amplifies them; a computer analyzes ……
the data to show areas of high or low metabolic activity.
Lower glucose metabolism suggests cerebral structure and functional problems.
Problems with PET:
*Expensive.
*Currently, research- oriented.
* Physicists and chemists are needed to conduct the procedure ( to prepare the
isotope) . *Poor resolution of pictures (unclear
boundaries of lesions) .Like SPECT also provides information on cerebral blood flow, but PET can show areas of damage that are near normal in
blood flow, something SPECT cannot do.
PET also can show areas that are not working although no structure damage is seen on CT
scans .Magnetic Resonance Imaging (MRI) Its another method of studying brain functions :
*Does not introduce radio active material to patient’s body .
*Was formerly known as nuclear magnetic resonance imaging.
*Generates pictures similar to CT scanning.
In the MRI procedure:
*The patient’s head is placed in a strong magnetic field .
*The spinning atoms of the brain produce magnetic properties which are exploited in constructing a picture of the brain structures.
*Much like iron filings lining up and pointing in the direction of a magnet, the nuclei of the body tissue align themselves with the
magnetic field. *When the nuclei of the brain tissue are
aligned with the external magnetic field, an electromagnetic pulse is introduced .
*The patient hears a noise similar to that produced by washing machine .
This pulse of energy disturbs the alignment of the brain nuclei for a brief moment and
then they swing back to alignment .
*While swinging back to alignment with the magnetic field, the nuclei produce small electromagnetic signals that are detected, analyzed, and used to construct an image of the tissues.
Both CT scans and MRI provide images of the body. But MRI provides clearer images. It can detect lesions missed by CT scans. However, CT can better detect cerebral hemorrhage than the MRI. Only a few studies have shown some promise of MRI in diagnosis lesions in patients with
aphasia .
B-Mode Carotid Imaging-This technique is :
*Used to assess the health of the superficial arteries, especially those in the neck.
* Noninvasive *Also known as echo arteriogram.
In this procedures : *A highly- frequency sound generator is
placed over the neck .
-A computer analyzes sounds deflected by the arterial tissue .
Carotid Phonoangiography This technique :
-Also is a procedure to assess the health of the carotid arteries .
-Does not generate sound, but picks up the sound of the blood gushing through the
arteries.
*Analyzes the characteristics of sound of blood movement .
Arterial stenosis (narrowing) creates turbulence as the blood moves and this could be detected through carotid
phonoangiography.
General Neuropathology of Aphasia
Aphasia has many causes and most are chains of causes with remote and immediate elements of the chain. Some form of brain damage is most immediate or even simultaneous cause of
aphasia .The elements of a causal chain
Brain damage and aphasia An interrupted blood supply
Arterioscleriosis
High blood cholesterol
Poor eating habits
Genetic disposition
Many other chains of events cause damage to the language structures that result in
aphasia .
These causes are acute events and insidious processes.
Acute events
*Immediate effects .
*Generalized disruption of behavior.
*Impaired physical condition .
*Gradual clearing of some of the generalized problems .
*Specific disturbance that persist for varied time periods .
Cerebrovascular Accidents (CVA). - it is popularly known as stroke .
- it is the third leading cause of death in the United States. (Coronary heart disease
is #1, cancer is # 2) . -About half a million new strokes are
reported each year in US . -There are about 2 million people who have
survived a stroke .
-More than a million of those will have aphasia .
-Strokes cause 40% of people who have a stroke die within a month .
-Stroke is the most common cause of aphasia. Cause of CVA Strokes may be ischemic or hemorrhagic.
Ischemic strokes are caused by blocked arteries that interrupt blood supply to
region of brain resulting in an infraction.
Hemorrhagic strokes are caused by a ruptured blood vessel resulting in internal
bleeding .
Blood supply may be interrupted by either cerebral thrombosis or cerebral embolism.
Cerebral Thrombosis is:
-More likely in larger arteries that in the smaller ones. - Associated with arteriosclerosis
(thickening of the arteries) .
-Thickening associated with an accumulation of lipids and fibrous material, the results in atherosclerotic plaque.
The thickened artery slows down the flow of blood and encourages the formation of clots. The clot occludes the artery. The tissue down the stream may die for lack of oxygen.
Cerebral Embolism
An embolus (emboli, plural)
-Is a traveling mass.
-Occludes an artery. - may have been formed elsewhere. Contrast that with thrombosis ( a clot at its
place of origin) .
Causes of embolism:
-A traveling blood clot formed elsewhere. - A clump of tissue from a tumor or a
diseased artery.
-Moving atherosclerotic plaque .
-A mass of bacteria .
-An air bubble .
-Heart disease .
Thrombosis or an embolism in the middle cerebral artery is a common cause of stroke and aphasia. It is a branch of the internal carotid artery.
With its many cerebral branches, it is supplies blood to most of the
hemispheres .Cerebral Hemorrhage:
Ruptured cerebral blood vessels cause cerebral bleeding .Common causes of rupture:
-Weakened arterial walls. -High and fluctuating blood pressure .
-Trauma to the blood vessel. Hemorrhaged blood forms clot and
destroys brain cells .
Strokes tend to have a sudden onset .
Headache, vomiting, memory loss, and speech- language problems are the frequent symptoms.
Brain trauma:
Closed and penetrating head injuries are a frequent cause of aphasia and other
disorders of communication .
Insidious Processes:
-Slow and gradual disease processes.
-Time of onset unclear .
-Mild, often ignored initial symptoms.
Intracranial Tumors:Tumors may be primary or metastatic,
benign or cancerous .Primary: originally grown in the brain (intracranially).
-Common in the age group 25-50. -Unknown causes.
-Heredity and former sites of injury are involved .
Growing tumors may: -Destroy healthy tissue .
-Cause other tissue to swell . -Result in focal or generalized symptoms.
-Cause sensory problems . * blurred vision.
* loss of other sensation. * vertigo.
-Cause behavior changes: * memory problems .
* lethargy. * personality change .
-Cause herniation of brain stem .Obstructive hydrocephalus
Swollen tissue may obstruct the flow of cerebrospinal fluid.
Intracranial pressure increases.Affect brain functions.
Toxic Damage
Drug overdose.
Drug interactions .
Metal toxicity: lead and mercury .
Infections:
Bacterial: a frequent cause is bacterial:
1 .Meningitis :
-The meninges and the cerebrospinal fluid is infected .
-fever, lethargy, and other symptoms follow .
-treatment can be effective, but some behavioral symptoms may persist .
2 .Brain abscess: bacterial, fungus, or parasites may migrate into the brain from sinuses, middle ear, or mastoid cells.
Viral infections: Rabies, HIV, and so forth.
Metabolic disorders: hypoglycema, thyroid disorders, and so forth.
Classification of Aphasia
Issues and types:
Aphasia has had many names and many types, resulting in many arguments, these arguments revolve around a few observations.
The arguments are based on observations related to neuroanatomy, symptoms of
aphasia, and assessment and treatment .
The main arguments classifying aphasia into types :
1 .Different brain areas control different language functions .
2 .Different type of aphasia have different cerebral sites of lesion .
3 .Therefore, different lesion sites produce distinctively different syndromes (types of aphasia).
4 .Some aphasic patients are more fluent than others.
5 .Fluent aphasia is associated with lesions in the posterior region of the sylvian fissure; nonfluent aphasia is related to lesions in the anterior region of the
sylvian fissure .6 .Comprehension of spoken language is
better in some Aph than in others .
7 .Many of aphasic symptoms are dominant in certain patients; therefore, types may be established based on dominant
symptoms .
8 .Clinical experience supports types of aphasia .
9 .Different types of aphasia require different forms of treatment .
General symptoms of aphasia:1 .paraphasia: is unintended word or sound
substitutions. Many consider it a central sign of aphasia .
- verbal paraphasia: the entire word is substituted, there are two types:
* semantic paraphasia: the substitute word is similar in meaning to the one intended ( son for daughter)
* random paraphasia: substitute and intended words are not semantically
similar .2 .Neologistic paraphasia: the use of a
meaningless invented word .3 .Phonetic (literal) paraphasia: substitution
of one sound for another (loman for woman) and adding of a sound (wolman
for woman)
Paraphasia are generally absent in automatic speech, such as exclamation,
cursing, number series, etc .
Because paraphasia is present in almost all causes of aphasia, it is not a critical factor
in syndrome identification .
Disorder of fluency:
Aphasiologists define fluency as speech that
approximates the normal rate, length of sentences, and the melodic contour. Patients who produce five or more
connected words may be judged fluent .
Based on fluency, aphasia is classified into the following types-:
Nonfluent aphasiaFluent aphasia
Broca’sWernicke’s
GlobalTranscortical sensory
IsolationConduction
Transcortical motorAnomia
Fluency and articulation are independent to each other .
*Most fluent patients have good articulation, but some may have problems .
*Most nonfluent patients also have good articulation, but again some may not .
3 .Auditory comprehension
most aphasic patients have problems of auditory comprehension of spoken language.
the degree of impairment varies across patients; some have a mild problem,
others have a profound problem .
-Among the nonfluent patients those with global and isolation aphasia have moderate to severe problems in
comprehension .
-Among the fluent patients, those with Wernicke’s and transcortical sensory aphasia also have moderate to severe problems in comprehension.
-Among the nonfluent, patients with Broca’s and transcortical motor aphasia show mild to moderate impairment in
comprehension .
-Among the fluent patients, those with conduction and anomic aphasia have mild to moderate impairment in comprehension.
Summary of auditory comprehension
Degree of impairment
NonfluentFluent
MILD TO MODERATE
Broca’s
Transcortical
motor
Conduction
Anomic
MODERATE TO SEVERE
Global
Isolation
Wernicke’s
Transcortical
sensory
As you can see from the previous slide auditory comprehension problems do not distinguish the fluent from nonfluent.
Those problems are present in all types only the degree varies.
Even the degree of impairment does not distinguish the fluent from the nonfluent
patients .
Repetition (imitation) of modeled single words, phrases, and sentences is impaired in
most cases of aphasia .
Impaired repetition is the dominant symptom of conduction aphasia .
Degree of impairmentTypes of Aphasia
No impairment to
Some impairment
Transcortical motor
Transcortical sensory
Isolation
Anomic
Moderate to severe impairment
Broca’s
Global
Wernicke’s
Conduction
The Broca’s and Wenicke’s aphasia are similar in this respect (repetition); both have moderate to severe impairment in
repetition skills .
Repetition errors are more frequent or more severe in cases of impaired auditory
comprehension (Wernicke’s) .
However, some patients may not repeat because of impaired production, not
comprehension (Broca’s) .
Hence, two different groups may show the same problem for different reasons.
Naming and Word Finding Problems (Anomia) :
Anomia could be either be a symptom of aphasia or a type of aphasia .
Almost all aphasic patients experience word finding and naming problems. Even those who recover well tend to retain some
naming problems .Response to “what is this?” is less difficult..
) confrontational naming (than response to name as many Jordan cities as you can
(free recall) .
When anomia is the name for a special type of aphasia, persistent and severe word finding and naming difficulty is the
dominant if not the only problem .
Reading and writing problems :
Reading and writing problems do not distinguish different types of aphasia. Most aphasic patients have those problems, however, rare cases of pure alexia with only reading difficulty have been reported ( impaired visual cortex).
In reading the severely affected patients:
*May not recognize the printed word at all .
*May struggle to read .
*May read sentences word-by-word .
*Read with many errors .
*May not understand what they read.
In writing, the severely affected patients:
*Write with poor letter and word formation.
*Reverse, confuse, or substitute letters .
*Experience more difficulty with less frequently used word .
*Make unsuccessful attempts as self correction during writing .
*May write nonsensical words .
Gestures:
Understanding or using gestures are pantomime in communication often are
disturbed in most aphasic patients .
Bilingual Impairment:
Most bilingual patients show roughly equal kinds of impairment in born the languages .
The degree of impairment, however……
may be different.Better performance or recovery is
associated with : *The native language .
*The language used most often . *The language of the surroundings.
In some rare cases, the little- used long forgotten native language may be better
retrained to the dismay of younger family ...
members who have not heard the language .Residual language performance :
Even the most profoundly involved global aphasic persons retain some communication performance.Such persons may distinguish :
*There native language from a foreign language .
*Meaningful utterances from the nonsensical .
*Nouns from verbs when stress is the clue. * Grammatical sentences from the
nongrammatical .
The patient may :
- Guess the first letter or the size (big, small) of the word they cannot say.
-Repeat more of grammatical sentences than of ungrammatical sentences .
-Produce more frequently used words of their language .
-Learn alternative model of communication .
A general description of how aphasic patients talkBecause the various symptoms described so far, most aphasic patients: * Speak either little with some struggle or abundantly with ease but without much
meaning or grammar . *When they began to speak, most cannot find the
words at all or the right words, resulting in a slow rate.
*May substitute sounds or words and create new words that do not mean anything to the listener. * May omit sounds within words or whole words. However, serious articulation disorders are usually due to coexisting dysarthria or apraxia of
speech .
*May use certain copying strategies: use a word similar in sound or meaning; delay response so
they can think of the word; try to get the word…
by semantic or phonemic association; explain or describe what they are trying to
say; and so forth . *Have limited range and variety of
vocabulary. * may have limited range and types of
grammatical sentences . *May misuse morphological elements or not
use them at all .
*Use wrong word order .
*May repeat the same utterance for any type of question .
*May not correctly repeat what they hear, especially the long utterances .
*May beat around the bush.
*Some of them can produce only disjointed, brief, telegraphic utterances .
Other patients: *Produce long, redundant, meaningless
utterances with neologisms. Such pts may be unaware that the listener do not understand them. Some of them deny they
have a communication problem .Most aphasic patients :
*Cannot fully or partially comprehend spoken language .
*Cannot point to a picture or object named . *May give the impression that they are deaf
to words ( word deafness) . *May misunderstand words that are similar
in meaning or sound . *May say that they do not know the
meaning of ordinary words . *Who understand single words may not
understand sentences.
*May have greater difficulty with longer sentences or message units .
*May omit all details when resulting a story. *Have difficulty with order or sequence of
events .However most aphasic persons :
* are welling to talk . * Are alert and know what is going on
around them .
Only in the first few hours of a stroke are the patients:
*Unable to make attempts at speech .
Some patients with chronic difficulties may show:
*Poor recovery
*Complicating diseases .
*Deteriorating physical conditions.
* depression .
* unwillingness to talk .
Etiology And Symptomatology Of Nonfluent Aphasia
Fluency is a good criterion to distinguish one aphasic patient from the other .
The following four types of aphasias have disturbed fluency as their main
characteristic :1 .Broca’s aphasia .
2 .Transcortical motor aphasia .3 .Isolation aphasia.
4 .Global aphasia.
Of course we have to distinguished from each other on other bases.
Generally, the more anterior the lesion, the greater is the degree of disturbance in fluency.
Broca’s Aphasia
First described in 1861, other names: expressive, motor, verbal aphasia.
The posterior- inferior (third) frontal gyrus of the lf hemisphere is known as Broca’s area (Broadman’s area 44). Damage to this area may be involved in Broca’s aphasia.
Generally, it is the area supplied by the upper division of the middle cerebral arteryOther areas are involved in Broca’s aphasia:
CT scan studies, positron emission studies ..
and critical review of literature have shown that :
*The lower portion of the motor strip may be involved .
*The areas anterior and inferior to area 44 may be affected .
*Deep cortical damage is necessary to produce Broca’s aphasia.
*Damage limited to Broca’s is more likely to produce transient mutism and
subsequent mild apraxia than aphasia . *Broca’s patients have more extensive
cortical damage than originally thought . *Portion of frontal, temporal, and parietal
regions may be involved. *Even Wenicke’s area may be involved in
Broca’s aphasia.
*Patient with Broca’s aphasia without damage to Broca’s area may be observed.
*Some patients with injured Broca’s area may have transcortical motor aphasia .
*Damage to Broca’s area is neither necessary nor sufficient to produce Broca’s aphasia .
*Almost all aphasic patients show cerebral hypometabolism in widespread areas
discrediting a strict localization view. *Lesions may localized, but not necessarily
functions.
General characteristics of Broca’s aphasia
*Neurologically they are more easily recognized than Wernick’s patients .
*Typically Broca’s patients present a right- sided hemiparesis (muscular weakness in one half side of the body. Contrasted with paralysis) and initial confinement to
wheelchair .
*later, they may use a walker or a cane .
*Such motor problems improve over time ( such motor problems are absent in
Wernicke’s ) .
*Often depressed, they may react emotionally when they fail on assessment tasks (catastrophic reactions of weeping and refusal).
Major language characteristics of BA :
*Nonfluent and effortful speech .
*Too many pauses .
*Slow rate with uneven flow .
*Limited word output .
*Short sentences .
*Misarticulated or distorted sounds .
*Presence of dysarthria and apraxia of speech.
*Agrammatism to varying degree .
*Telegraphic speech, often limited to content words (nouns and verbs) .
*Omission of grammatical (function) words .
*Impaired confrontation naming ( naming objects, pictures, persons upon request) .
*Better auditory comprehension of spoken language than production ( but rarely completed normal).
*Varied comprehension of material read (depending upon the degree of impaired
auditory comprehension) .
*Generally poor oral reading .
*Writing problem ( full or spelling errors and letter omissions, possibly because of the use of the nonpreferred left hand to write)
* lack of intonation .
Individual differences in Pt with Broca’s aphasia:
*There are notable individual differences in the number and the severity of symptoms
*Some say just a few words, others can carry on limited conversation .
*Even fluency may be good to poor .
*Agrammatsim may be marked or negligible
*By and large, expressive skills may be more impaired than receptive skills .
Transcortical Motor Aphasia (TMA)
Another nonfluent aphasia, another name: dynamic aphasia.
Neuroanatomical bases of TMA:
*The lesions causing TMA are usually outside Broca’s area. The lesions are often found in deep portions of the left frontal lobe
or below or above Broca’s area .
*Supplemental motor areas may be involved .
*It is thought that lesions may separate the…
supplemental motor cortex from Broca’s area .
*The areas affected are supplied by the anterior cerebral artery and the anterior
branch of the middle cerebral artery . *The wastershed region between the MCA
and anterior artery is often involved . *Head trauma with frontal lobe damage may
also cause TMA .
General characteristics of TMA
In most respects, TMA is similar to Broca’s aphasia .
*Transient urinary incontinence .
*Rigidity of upper extremity .
*Hemiparesis ( legs more involved than the arms) .
*Paucity and slowness of movements .
Major language characteristics of TMA
*Speech is nonfluent, paraphasic, agrammatic, telegraphic .
*Distinguishing feature is intact repetition (repetition is impaired in Broca’s) .
*Patients may have echolalia .
*Comprehension is generally good for simple conversation .
* comprehension may be impaired for complex speech .
* in essence, a discrepancy between language production problems (impaired) and repetition skills (spared)
distinguishes broca’s from TMA .
Individual differences in patients with TMA
*Apraxia of speech may be present in some individuals .
*Across individuals, the similarity between TMA and Broca’s aphasia may be more
or less.
Positive features of TMA
*The distinguishing features is its most important positive feature: intact verbal
repetition skills .
*When echolalia is dominant, repetition skills may be nonfunctional.
Isolation aphasia A rare syndrome .
A nonfluent aphasia .Similar to global aphasia, except that in isolation aphasia the repetition skill is
better preserved .Goldstein and others have described it, but it is not a part of the Boston classification of Goodglass and Kaplan.
Neuroanatomical Bases of Isolation Aphasia
Carbon monoxide poisoning damage areas surrounding the perisylvian speech area. The speech area itself is not damage. Hence, the speech area is said to be
isolated from other areas .
Major Language Characteristics Of Isolation :
*Severely impaired fluency .
*No functional auditory comprehension for even simple conversation .
*Marked naming difficulty .
*Only moderate to mild problems in repetition .
Positive Features of Isolation Aphasia
*Can repeat sentences .
*Can sing along.
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