 |
| A |
|
|
- acalcula:
- difficulties with arithmetic;
may be the result of damage to the angular gyrus in
the hemisphere dominant for speech and language
-
- acceleration-deceleration trauma:
- According to Love and
Webb (1992) the most predominant injury type is acceleration-deceleration
trauma. Acceleration-deceleration trauma causes discrete
lesions which affect only certain areas of the brain,
occurs when the head is accelerated and then stopped
suddenly, as in a car accident, and causes discrete,
focal lesions to two areas of the brain, The prefrontal
areas and the anterior portion of the temporal lobes.
The brain will suffer contusions at the point of direct
impact and at the site directly opposite the point
of impact due to the oscillation of the brain within
the skull.
It should be noted that brain injuries may occur as
a result of acceleration-deceleration trauma unaccompanied
by impact.
-
- acetylcholine:
- a neurotransmitter
for motor neurons that is involved in the inhibitory
function (as is dopamine) of the basal ganglia
-
- afferent fibers:
- nerve fibers that take
messages from the periphery to the brain; afferent
fibers are almost always sensory fibers
-
- alexia:
- acquired disturbance
of reading due to brain injury (Love and Webb, 1996,
p. 314)
-
- agnosia:
- lack of sensory recognition
as the result of a lesion in the sensory association
areas or association pathways of the brain. An example
is looking at a common object but not recognizing
it, or associating meaning with the image.
-
- agraphia:
- acquired disturbance
of writing due to brain injury (Love and Webb, 1996,
p. 314)
-
- alexia with agraphia:
- difficulties with reading
and writing; may be the result of damage to the angular
gyrus in the hemisphere dominant for speech and language
-
- alpha
cells:
- the principle lower
motor neurons of the spinal cord (they are located
on the ventral aspect of the cord); they form the
main part of the final common pathway and conduct
rapid motor impulses; each alpha cell innervates approximately
200 muscle fibers
-
- alternating hemiplegia:
- paralysis of different
structures on each side of the body; this condition
may be the result of a lesion in the brain stem that
damages both the nucleus of a cranial nerve and one
side of the upper motor neurons of the pyramidal tract
-
- amygdala:
- a structure which is
attached to the tail of the caudate nucleus; it is
considered to be a part of the limbic system and is
involved in emotion
-
- anastomosis:
- communication or connection
between the separate components of a branching system;
as in the Circle of Willis,
anastomosis allows blood carried by different arterial
branches to come together and be redistributed
-
- angular gyrus:
- the gyrus that lies
near the superior edge of the temporal lobe, and immediately
posterior to the supramarginal gyrus; it is involved
in the recognition of visual symbols (Geschwind referred
to it as the "association cortex for association cortices"
and "the most important cortical areas of speech and
language"). Lesions in this area can result in alexia and agraphia.
-
- anomia:
- difficulty with word-finding
or naming; anomia may be the result of damage to the
angular gyrus in the hemisphere dominant for speech
and language. According to Goodglass and Kaplan (1983),
anomia can be localized with the least reliability
of any of the aphasic syndromes. Also, according to
Keenan (1975) all patients with Aphasia experience
some problems with word finding.
-
- anosmia:
- a loss of the sense
of smell; may be a result of a lesion on the olfactory
pathway
-
- anterior:
- toward the front (opposed
to posterior)
anterior
cerebral artery:
- a branch of the internal
carotid artery; the anterior cerebral artery supplies
blood to the medial cortex, some areas of the frontal
lobe, and the corpus striatum
-
- anterior commissure:
- one of the three major
groups of commissural fibers; part of the Circle of
Willis, the anterior commissure connects the temporal
lobes, as well as connecting the temporal lobe to
the amygdala and to the opposite occipital lobe; it
is also connected to the corpus callosum
-
- anterior communicating artery:
- an artery which arises
from the internal carotids; it joins together the
anterior cerebral arteries of each hemisphere
-
- aorta:
- the main artery supplying
blood to the body (with the exception of the lungs);
it ascends from the heart then forms an arch, from
which two subclavian arteries arise
-
- aphasia:
- a disturbance of the
skills, associations, and habits of language due to
injury to certain brain areas that are specialized
for these functions. Disturbances of language usage
that are due to paralysis or incoordination of the
musculature of speech or writing or poor vision or
hearing are not, of themselves, aphasic." Thus, aphasia
can affect auditory comprehension, oral expression,
reading and writing. (Goodglass and Kaplan, 1983)
-
- apraxia:
- comes from the Greek
word "praxis," which means action. According to Halperin
(1986 in Chapey, 1986, p.422), "apraxia of speech
is an articulation disorder that results from impairment
due to brain damage, of the capacity to order the
positioning of speech musculature and the sequencing
of muscle movements for volitional production of phonemes
and sequences of phonemes; but it is not accompanied
by significant weakness, slowness, or incoordination
of these same muscles in reflex and automatic acts."
-
- Apraxia of speech is
a disruption of the capacity to program the skilled
oral movements necessary for speech. The problem is
with the programming associated with incorrect neural
commands at higher, more central levels. In the past,
apraxia was often classified as a type of articulation
disorder and was in fact called central dysarthria
by some. Now, it is considered a motor planning/programming
deficit. According to Wertz (1984), apraxia of speech
"is a neurogenic phonological disorder, resulting
from the sensorimotor impairment of the capacity to
select, program and execute coordinated movements
of the speech musculature for the production of voluntary
speech." In other words, the part of the brain that
generates the motor programs for speech/phonology
is damaged. Kearns and Simmons (1989, in Northern,
1989) reported that research using spectographic analysis
of voice onset time (VOT) supports the programming
position. Includes limb apraxia, oral apraxia, apraxia
of gait, and apraxia of the swallow.
-
- apraxia of gait:
- difficulty with programming
the motor movements involved in walking
-
- apraxia of the swallow :
- inability to swallow
volitionally.
-
- apical dendrites:
- a type of dendrite
which has a stalk that is filled with cytoplasm, these
appear to be part of the soma of the neuron to which
they are attached; the majority of apical dendrites
are found in the cerebral cortex
-
- Aqueduct of Sylvius
(cerebral aqueduct):
- a channel which connects
the third and fourth ventricles
-
- arachnoid mater:
- the middle layer of
the meninges; in some areas it has projections (arachnoid
granulations or villi) into the sinuses formed by
the dura mater
-
- arachnoid villi
(arachnoid granulations):
- projections of the
arachnoid mater into the sinuses formed by the dura
mater that transfer cerebrospinal fluid back into
the bloodstream
-
- arcuate fasciculus:
- the groups of fibers
that connect Broca's area with Wernicke's area (these
fibers connect to the angular gyrus) and are located
below the supramarginal gyrus. According to Geschwind,
damage to this area results in Conduction Aphasia.
-
- arteriosclerosis:
- formation of "plaque"
consisting of muscle cells and fats on arterial walls
making the flow of blood through arteries more
difficult. Informally, "hardening of the arteries"
-
- arteries of
stroke:
- striata arteries, which
are branches of the middle cerebral arteries
-
- ascending reticular
formation (reticular activating system):
- the component of the
reticular formation that is responsible for the sleep-wake
cycle; it mediates various levels of alertness
-
- aspiration:
- occurs whenever food
enters the airway below the true vocal folds. Aspiration
can occur before, during, or after the swallow.
-
- association fibers:
- nerve fibers that connect
areas within the same lobe or between lobes, within
the same hemisphere; the most prevalent type of neuroal
tracts found in the cortex
-
- ataxia:
- an incoordination of
motor movement; ataxia results from cerebellar lesions;
the term may also be used to describe the unsteady
walk and unusual postures seen in patients who have
suffered injury to the cerebellum
-
- ataxic dysarthria
(cerebellar dysarthria):
- a disorder that results
in jerky, uncoordinated movements of the speech musculature;
it is caused by lesions in the cerebellum
-
- athetosis:
- disorder that causes
slow writhing movements of the entire body but especially
of the arms, face and tongue.
- auditory association areas:
- Brodmann's areas 21
and 22
-
- auditory comprehension:
- the ability to understand
spoken language
-
- autonomic
nervous system:
- one of the three main
divisions of the nervous system; it innervates the
involuntary structures of the body (e.g., heart, smooth
muscles, glands) and is involved in control of automatic
and glandular functions; it is divided into two parts,
the sympathetic and parasypathetic
-
- axon:
- the part of the neuron
that allows it to send messages to other nerve cells;
although each neuron can have only one axon, the axon
itself can have many branches which connects it to
many others
-
|
| B
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- Barium:
- contrast material,
not radioactive, used during barium and modified barium
studies
-
- basal
ganglia:
- the largest subcortical
structure of the brain; it is made up of the caudate nucleus
and the lenticular nucleus;
it is located at the level of the thalamus
-
- basilar artery (vertebral basilar
artery):
- the artery that is
formed when the two vertebral arteries join together
at the lower border of the pons; the basilar artery
again divides at the superior border of the pons to
form the posterior cerebral arteries (other arteries
that arise from the basilar prior to this division
include the anterior cerebellar arteries, inferior
cerebellar arteries, posterior cerebellar arteries,
and the pontine branches)
-
- basilar dendrites:
- a type of dendrite
that does not have a stalk; these are more numerous
than apical dendrites
-
- BDAE:
Boston Diagnostic Aphasia Examination
- developed by Goodglass
and Kaplan in 1972, is currently being revised. (I
was asked by the publishing company to critique/review
the upcoming edition. It promises to be quite good.)
At the moment it consists of twenty-seven subtests
divided into the following sections: conversational
and expository speech, auditory comprehension, oral
expression, understanding written language, and writing.
The severity of a patient's aphasia can be rated on
a scale from one to seven based on speech and language
characteristics as well as auditory comprehension.
The Boston Naming Test, a test for anomia which was developed to be used along with
the BDAE, is the supplementary instrument most often
used in the evaluation of aphasia (Chapey, 1994).
-
- bilateral innervation:
- both left and right
nuclei of a pair of cranial nerves receive innervation
from both the left and the right motor pyramidal tracts,
provides both ipsilateral and contralateral innervation
-
- biological intelligence:
- the complex cognitive
processes (such as reasoning and judgment) that are
mediated by the most anterior part of the frontal
lobe
-
- BDAE: Boston
Diagnostic Aphasia Examination
-
- bradycardia:
- slowed heart rate
-
- Bradykinesia:
- the "reduced speed
of movement of a muscle through its range" (Love &
Webb, 1992, p. 146).
-
- brain
stem:
- the midbrain, pons,
and medulla oblongata
-
- bradycardia:
- slow heart rate
-
- broad-based gait:
- a term used to describe
the way in which some patients compensate for problems
related to cerebellar injury by walking with their
feet far apart
-
- Broca's aphasia:
- affects the third frontal convolution (both the gyrus and the sulcus) of the left frontal
lobe. ( Broca's area, Brodmann's
area #44)
-
- Characteristics are
telegraphic speech, affected
syntax, as well as labored and slow speech, Melodic
Contour is
flat and Articulatory
Agility is
impaired. Potential problems include: simplification
of consonant clusters (e.g. t/st, p/spl) and distortion
of phonemes, substitutions are infrequent. A few paraphasias may occur.
They will usually be literal. Repetition is typically impaired, as is Word
finding. Auditory Comprehension is superior to expressive language. The patient's ability
to understand grammatical morphemes will be affected.
So, while it can be said that auditory comprehension
is good in comparison to that of Wernicke's aphasics,
it is not normal.
The Token Test
(DeRenzi & Vignolo, 1966), which assesses subtle
receptive language dysfunction, can be used to evaluate
the auditory comprehension of Broca's aphasics and
to help distinguish between Broca's aphasia and verbal
apraxia. Also, limb apraxia may not allow the
patient to carry out the instructions, even though
he/she understands them.
Hemiplegia/Hemiparesis of the right side is common in left hemisphere lesions causing
Broca's aphasia (remember, the language center is
in the left hemisphere for more than 90% of the population)
The face and arm are most likely to be affected due
to the organization of the motor strip.Apraxia frequently accompanies
this type of aphasia as it is also caused by lesions
to area 44. Broca's aphasics typically have low frustration
tolerance. They are aware of their errors and may
respond to them with a catastrophic reaction which might include crying, screaming and yelling, etc.
-
- Broca's area:
- the area of the brain
involved in the programming of motor movements for
the production of speech sounds; it is also involved
in syntax; Broca's area is located on the inferior
third frontal gyrus in the hemisphere dominant for
language; injuries here may result in apraxia or Broca's
aphasia
-
- Brodmann's Classification
System:
- a map of the cortex
developed by neurologist Korbinian Brodmann that classifies
the different areas of the brain by number
-
- buccinator
muscle (oral cavity):
- holds food in contact
with the teeth. with the obicularis oris and zygomaticus
all three are innervated by the facial nerve
(CN. VII).
-
- bulbar lesions:
- injuries to the nuclei
of the cranial nerves located in the brain stem; they
are considered to be lesions of the final common pathway:
usually bilateral, they produce bulbar palsy
-
- bulbar palsy:
- paralysis produced
by bulbar lesions
|
| C |
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|
- catastrophic reaction:
- crying, screaming and
yelling, etc. by a person with Broca's aphasia
as an expression of low frustration tolerance/awareness
of their errors
-
- cauda
equina:
- The continuation of
nerve fibers in the part of the vertebral column that
lies below the spinal cord; cauda equina is Latin
for "horse's tail"
-
- caudal:
- "toward the tail,"
may mean the same as inferior; an antonym is rostral
-
- caudate nucleus:
- one of the two structures
that make up the basal ganglia; it is divided into
a head, body, and tail and is bounded on one side
by the lateral ventricle
-
- central canal:
- the space in the middle
of the grey matter of the spinal cord; it contains
cerebrospinal fluid
-
- central sulcus (fissure of Rolando):
- the deep sulcus that
separates the frontal and parietal lobes
-
- cephalic:
- a synonym of superior;
refers to the upper parts of the nervous system
-
- cerebellar peduncles:
- three pairs of fiber
bundles (the superior cerebellar peduncle, the middle
cerebellar peduncle, and the inferior cerebellar peduncle)
which connect the cerebellum to the brain stem; information
passes on these tracts in both directions, every message
that is sent or received by the cerebellum travels
on the cerebellar peduncles
-
- cerebellar dysarthria
(ataxic dysarthria):
- a disorder that results
in jerky, uncoordinated movements of the speech musculature;
it is caused by lesions in the cerebellum
-
- cerebellum:
- It is involved in the
coordination and production of speech, the organization
of muscle movement, coordination of fine motor movement,
and balance; it is the center of a feedback loop involving
motor and sensory information; "cerebellum" means
"little brain" in Latin
-
- cerebral dementia:
- may result from anterior
cerebral artery blockages.
Confused
language,
or a language indicative of cognitive impairment,
may also occur.
-
- cerebral peduncles:
- fiber bundles that
are located in the brain stem; the cerebral peduncles
connect the pons to the cerebrum
-
cerebral vascular accident:
- is a temporary or permanent
loss of functioning of brain tissue caused by an interruption
in the cerebral blood supply
-
- cerebrospinal fluid:
- a clear liquid produced
and found in the ventricles. It flows through the
subarachnoid space (surrounding the brain and spinal
cord), and inside the central canal of the spinal
cord; it functions as a protective cushion for, brings
nutrients to, and removes waste from, the neuraxis
-
- cerebrovascular
resistance:
- makes it more difficult
for blood to flow from one area to another. It can
be caused by arterial spasm, a high level of tri-glycerides
in the blood which increases its viscosity, or by
elevated levels of cerebral spinal fluid.
-
- cholesterol:
- HDLs or high density
lipoproteins are the "good" cholesterol. LDLs or low
density lipoproteins are the "bad" cholesterol. It
is all right to have high levels of HDLs, but a high
concentration of LDLs is a health risk. Overall cholesterol
levels should be under 200.
-
- choroid
plexes:
- structures that produce
cerebrospinal fluid by allowing certain components
of blood to enter the ventricles; formed by a fusing
of the pia mater and the ependyma
-
- cingulate gyrus:
- a cortical area (a
gyrus) considered to be a part of the limbic system;
it is located immediately superior to the corpus callosum
-
- Circle
of Willis (Circulus Arteriosus):
- the main arterial anastomatic
trunk of the brain; the Circle of Willis is a point
where the blood carried by the two internal carotids
and the basilar system comes together and is subsequently
redistributed by the anterior, middle, and posterior
cerebral arteries
-
- circumlocutions:
- wordy and circuitous
description of unrecalled terms. For example the patient
may say "have one of them up there" when trying to
explain he's had brain surgery.
-
- claustrum:
- a structure considered
by some anatomists to be a part of the basal ganglia
-
- Closed Head Injury (CHI):
- brain injury resulting
from coup-contra coup, acceleration or deceleration
injury. Classified as severe, moderate, or mild based on the degree to which consciousness is impaired
immediately after injury. According to Clifton (1989),
severe head injury has been defined as coma for longer
than six hours. Concussion defines mild head injury.
- Secondary damage in
CHI includes widespread or localized edema as well
as slowly developing hemorrhages (Ylvisaker and Szekeres,
1994, in Chapey, 1994).
-
- cocktail hour speech:
- often seen in a person
with Wernicke's
Aphasia
-
- cognitive approach:
- introduced by Schuell
with the use of auditory stimuli, evolved through
Duffy to use a multi-modality approach and by Chapey
(1994) to use divergent thinking
-
- collateral circulation:
- a safety mechanism
of the arterial system of the brain; collateral circulation
involves the redirecting of blood through a route
that is different than normal; it can be crucial when
blockages occur
-
- commissural fibers:
- nerve fibers that connect
the hemispheres of the brain; the corpus callosum,
anterior commissure, and the posterior commissure
are composed of commissural fibers
-
- commissurectomy:
- an operation that severs
the corpus callosum; commissurectomies have been used
as a treatment for severe epileptic seizures
-
- completed stroke:
- type most commonly
seen, the infarction of brain tissue has ceased to
occur
-
- conduction aphasia:
- a type of aphasia that
may be the result of a lesion to the arcuate fasciculus
- may result from anterior
cerebral artery blockages
-
- conduit d'approche:
- (Goodglass and Kaplan,
1983) patient is aware of his/her paraphrasitic errors
and will produce repeated approximations of the intended
word, as if he is trying to untangle it
-
- confrontation naming:
- one way of testing
one's word finding ability
-
- confused language:
- a language indicative
of cognitive impairment that may occur as a result
of anterior cerebral artery blockages and may accompanied
by cerebral
dementia, seems
to be the result of cognitive problems with right
hemisphere lesions.
-
- contralateral
hyposthesia:
- lack of sensation on
side of body opposite to site of lesion
-
- contralateral innervation:
- when a cranial nerve,
or a portion of it, receives information only from
fibers on the opposite side of the brain
-
- conus medularis:
- the point at which
the spinal cord ends, just above the small of the
back
-
- convolution:
- the corrogated appearance
of the cortex, includes both gyri and sulci
-
- coronal cut:
- a cut that separates
the brain into front and back portions; a cut that
runs from ear to ear
-
- corpora quadrigemina:
- consists of the tectum
and the four colliculi which are bumps on the tectum
(two superior colliculi and two inferior colliculi);
the corpora quadrigemina is located on the posterior
surface of the midbrain
-
- corpus callosum:
- Latin for "large body,"
the corpus callosum is the major group of commissural
fibers; it is located some distance down inside the
longitudinal cerebral fissure; it connects the hemispheres
and mainly connects mirror image sites
-
- corpus striatum:
- the group of structures
that includes the basal ganglia and internal capsule;
it is called the "striped body" because the internal
capsule runs between the caudate nucleus and lenticular
nucleus of the basal ganglia, creating a striped appearance
-
- cortex:
- the layer of cells
that cover the two hemispheres of the brain; its surface
is composed of gyri and sulci
-
- cortical blindness:
- caused by damage to
occipital lobes, often when blood is cut off in the
posterior cerebral arteries.
-
- corticobulbar tract:
- the fibers of the pyramidal
tract that synapse with the cranial nerves located
in the brain stem
-
- corticopontine tract:
- fibers from the motor
strip of the cortex
-
- corticopontocerebellar
tract:
- a fiber tract that
brings a copy of the motor information (including
information about the nature, destination, strength,
and speed of the motor impulse being sent by the precentral
gyrus) to the cerebellum from the frontal lobe; the
information travels on this tract from the precentral
gyrus, descending in the internal capsule, then synapsing
with cells in the pons; pontine nuclei then
send second order neurons to the cerebellum on the
middle cerebellar peduncle
-
- corticospinal tract:
- the fibers of the pyramidal
tract that synapse with spinal nerves; these fibers
carry information about voluntary movement to the
skeletal muscles; as they descend they form part of
the posterior limb of the internal capsule
-
- coup contre-coup:
- usually due to a fall
or a blow to the head. The coup is the damage to the
braim just beneath the site of impact. Contra-coup
is the damage to the opposite side of the brain as
the brain bounces against the skull.
-
- cranial:
- a synonym of superior;
cranial refers to the upper parts of the nervous system
-
- cricopharyngus m.
or pharyngeal-esophageal (P.E) segment:
- separates the pharynx
from the esophagus. At the end of the pharyngeal stage
of the swallow, it must relax to allow the bolus to
enter the esophagus. (It is normally closed to prevent
the reflux of food and to keep air out of the digestive
system.)
|
| D |
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|
- deep
nuclei of the cerebellum:
- four different nuclei
(the dentate nucleus, the emboliform nucleus, the
globose nucleus, and the fastigial nucleus) located
deep within each cerebellar hemisphere that have axons
to the brain stem and thus send messages out to be
conveyed to other parts of the central nervous system;
these nuclei are regulated by Purkinje cells which
perform an inhibitory function.
-
- Dementia:
- Between 30 and 40 percent
of Parkinson's patients suffer from dementia; loss
of mental acuity
-
- dendrite:
- the part of the neuron
that receives messages from the axons of other nerve
cells; the two types of dendrites are apical dendrites
and basilar dendrites
-
- descending reticular
formation:
- the component of the
reticular formation that is involved in autonomic
nervous system activity; it receives information from
the thalamus; the descending reticular formation also
plays a role in motor movement
-
- diabetes insipidus:
- the most serious type
of diabetes; diabetes insipidus is caused by lesions
in the hypothalamus or between the pituitary gland
and the hypothalamus
-
- diachisis:
- is a kind of post-lesional
cerebral shock resulting in sudden inhibition of function
diminishment and possibly a complete loss of functioning
in brain areas distal to the site of lesion, may be
far away from the point of original damage,
usually connected to the infarcted area by nerve pathways
(Steadman, 1997). Cause of diachisis in unknown; it
may be the result of edema, reduced cerebral blood
flow, the release of neurochemicals or other factors
which have not yet been identified. Diachisis can
occur after CHI as well as after stroke.
-
- diencephalon:
- the thalamus and hypothalamus
-
- Diffuse Brain Injury:
- wide spread injury,
it can impair attention and perception causing problems
like neglect and prosopagnosia. An inability to analyze and synthesize information and a reduction
in the rate of information processing may also result
from wide-spread brain damage. In addition, long term memory and problem solving
may be impaired. Reasoning, both inductive and deductive,
may be involved. Convergent and divergent thinking
are the two main parameters of reasoning. Convergent
thinking often produces single conclusions while divergent
thinking is open ended e.g. how many things can you
do with a toothbrush? Pragmatic problems like impaired social judgment, reduced inhibition, and poor comprehension
of abstraction may occur as well.
-
- direct pyramidal
tract (ventral pyramidal tract, anterior corticospinal
tract):
- the uncrossed (direct)
fibers of the corticospinal tract that synapse with
the spinal nerves on the ipsilateral side of the body;
these fibers travel down the ventral aspect of the
cord
-
- diskinesias:
- disorders of involuntary
movement; may be the result of extrapyramidal tract
lesions
-
- divergent thinking:
- a patient with aphasia
is required to produce several creative responses
to every stimulus. For example, the patient might
be asked to think of several unusual ways to make
use of an everyday object.
-
- dopamine:
- a neurotransmitter
involved in the inhibitory function of the basal ganglia;
it is produced by the substantia nigra. Lack of dopamine
can result in Parkinson's disease.
-
dorsospinocerebellar tract:
- one of the two main
tracts that bring sensory information from the periphery
to the cerebellum; proprioceptive information from
the upper body travels on this fiber tract; it carries
messages received by the reticular nuclei in various
parts of the brain stem from the cortex, spinal cord,
vestibular system and red nucleus; information from
this tract enters the cerebellum on the inferior cerebellar
peduncle
-
- dura
mater:
- Latin for "hard mother,"
the dura mater is the most superior of the layers
of the meninges; this tough, inflexible tissue forms
several structures that serve to separate the cranial
cavity into compartments and protect the brain from
displacement, as well as forming several vein-like
sinuses that carry blood back to the heart
-
- dysarthria:
- According to Darley,
Aronson and Brown (1975), a speech disorder resulting
from a weakness, paralysis, or incoordination of the
speech musculature that is of neurological etiology.
All types of dysarthria result from damage to
the central or peripheral nervous system that impairs
the transmission of neural messages to the muscles
involved in speech. In contrast to apraxia which affects
the brain's capacity to produce the "programs" necessary
for coordinated motor movements, dysarthria results
from an inability to send the proper messages to the
musculature. While apraxia affects articulation and,
to some extent, prosody, dysarthria can impair all processes involved in speech production including respiration,
phonation, articulation, resonance and prosody. Based
on etiology, Darley, Aronson and Brown (1969), identified
six different types of dysarthria. These include four
forms of the disorder which are caused by damage to
upper motor neurons. They include spastic, hyperkinetic, hypokinetic,
and ataxic
dysarthria.
-
- dysphagia:
- difficulty
swallowing, types can include the
most common type, delayed/absent initiation of the pharyngeal stage of the swallow,
disorders of
the pharyngeal stage of the swallow
which are the most prevalent type of dysphagia among
the CVA population, and types associated with site
of lesion including brain stem stroke, subcortical
stroke, unilateral left hemisphere stroke, Unilateral
Right Hemisphere Stroke, and multiple strokes. Therapy
strategies may include Icing, Thermal Stimulation, Sensory Stimulation, Suck-Swallow
technique, Chewing, Oral-motor exercises. Posture
to facilitate swallow is
also utilized for therapy, as is selection of food
consistencies and techniques for protecting the airway
-
- Dystonia:
- causes slow jerky movements
which are most likely to occur in the trunk, neck
and proximal parts of the limbs.
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- Edema:
- swelling, begins two
or three days after a cerebral insult. Only in the
area that has been injured, however, as localized
swelling can greatly increase pressure throughout
the whole cranium, the functioning of the entire brain
may be affected. Edema of the brain should begin to
decrease by the beginning of the first week post-injury.
As intracranial pressure returns to normal levels,
any behavioral changes that were caused by the swelling
rather than by the brain injury will disappear.
-
- efferent fibers:
- nerve fibers that take
messages from the brain to the peripheral nervous
system; motor fibers are efferent
-
- Effortful Swallow:
- increases the tongue
driving force by causing exaggerated retraction of
the tongue. This helps to get food past the valleculae.
The patient is directed to squeeze hard with hi/her
throat and neck muscles during the swallow.
*** The above techniques are most often used with
patients who have had brain stem lesions and so have
severe dysphagia, but still have good cognitive ability.
-
- endolymph:
- the fluid that fills
the semicircular canals of the inner ear
-
- ependyma:
- the membranous lining
of the ventricles
-
- Epidural Bleeding:
- According to Stedman
(1997) epidural hemorrhaging, also called extra dural,
is an accumulation of blood between the skull and
the dura mater. It is usually the result of acceleration-deceleration
trauma. This type of bleeding results from lesions
of the arteries, most commonly the middle
meningeal artery.
The patient is usually unconscious immediately, then
lucid briefly, then loses conscious again from a large
clot in the epidural space. The clot may compress
cranial nerves resulting in pupillary dilation, as
well as ipsalateral weakness or paralysis (Pires,1984,
in Urosovich, 1984).
-
- Surgical aspiration
of hematomas resulting from epidural bleeding may
be used as a life-saving technique.
-
- epidural space:
- a potential space between
the dura mater and the skull
-
- esophageal stage of the swallow:
- involuntary stage where
the larynx returns to its normal position, and the
cricopharyngus muscle contracts to prevent reflux
and respiration resumes.
-
- executive function:
- according to Dunkla,
1996, the executive function regulates and directs
cognitive processes. It organizes behavior, sets goals,
and facilitates goal achievement while inhibiting
behavior detrimental to goal completion.
-
- expressive
Aphasia:
- most commonly called
Broca's Aphasia,
also
called
Motor Aphasia
-
- external carotid
artery:
- a division of the common
carotid; the external carotid supplies blood to the
face
-
- external granular
layer:
- the second most superior
layer of the cortex; it is very dense and contains
small granular cells and small pyramidal cells
-
- external circular
layer (of
the pharynx):
- made up of the superior, middle, and inferior
pharyngeal constrictor muscles
-
- external pyramidal
layer (medial pyramidal layer):
- the third most superior
layer of the cortex; it contains pyramidal cells in
row formation and the cell bodies of some association
fibers
-
- extraneural
factors:
- factors that may include
abnormal blood pressure, cerebrovascular resistance,
and arteriosclerosis may impede collateral circulation
-
- extrapyramidal tract:
- involved in automatic
motor movements, gross motor movements, posture and
muscle tone (in combination with the autonomic nervous
system) and facial expression; it is an indirect,
multisynaptic tract; the components of the extrapyramidal
system include the basal ganglia, the red nucleus,
substancia nigra, the reticular formation, and the
cerebellum, consists of neurons that regulate involuntary/automatic
movements. Lesions in the extrapyramidal tract cause
various types of diskinesias or disorders
of involuntary movement. The problems mostly commonly
affecting the extrapyramidal tract include degenerative diseases, encephalitis, and tumors.
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- Facial Nerve
(Cranial Nerve VII):
- innervates the lip muscles
including the obicularis oris and the zygomaticus.
The muscles must contract during the oral preparatory
and oral transport stages of the swallow to prevent
food from dribbling out of the mouth. The facial also
innervates the buccinator muscles of the cheeks.
These must remain tense during the oral component
of the swallowing process to prevent the pocketing
of food between the teeth and the cheeks.
Sensory Component carries information about taste
from the anterior 2/3 of the tongue. -
- falx cerebelli:
- separates the lobes
of the cerebellum; the falx cerebelli is formed by
the dura mater
-
- falx cerebri:
- separates the lobes
of the cerebrum; the falx cerebri is formed by the
dura mater
-
- festinating
movements:
- movements which become
increasingly rapid and uncontrolled
-
- final common
pathway:
- lower motor neurons
traveling to the muscles of the body on the only route
by which information from any of the upper motor tracts
can reach the periphery. Thus, when lower motor neurons
are damaged, the parts of the body that they innervate
are deprived of input from the pyramidal and extrapyramidal
tract as well as cerebellar pathways. Thus, voluntary,
automatic and reflexive movements are all affected.
-
- finger agnosia:
- an inability to recognize
objects through the sense of touch; may be the result
of damage to the angular gyrus in the hemisphere dominant
for speech and language
-
- fissure:
- a particularly deep
sulcus
-
- fissure
of Rolando (central sulcus):
- the sulcus that separates
the frontal and parietal lobes
-
- fissure of Sylvius
(lateral fissure):
- the fissure that separates
the frontal and temporal lobes
-
- flaccid
(lower motor neuron) dysarthria:
- the only form of dysarthria
that results from damage to lower motor neurons.
-
- Fluent
Aphasias:
- Fluent aphasias are
the result of lesions affecting the post Rolandic
area. Problems with meaning are associated
with posterior lesions.
- Phoneme selection and
sequencing as well as syntax are preserved. Speech
is characterized by a facility of articulation and
many long runs of words combined using a variety of
grammatical constructions. However, fluent speech
is not equivalent to meaningful speech. Often the
speech of fluent aphasics sounds like "jabberwocky."
Typically, there are word-finding problems that affect
nouns and picturable action words. Comprehension is
typically poor with fluent/posterior lesion aphasias.
(Conduction aphasia would be the exception to this).
The amount and type of paraphasias, the presence of
auditory receptive impairments and of impaired repetition
are variable in fluent aphasias, depending upon the
exact site of lesion.
-
- flocculi:
- the most ancient part
of the cerebellum; the flocculi are part of flocculonodular
lobe
-
- flocculonodular lobe:
- the lobe of the cerebellum
that consists of the flocculi and the nodulus; the
flocculonodular lobe is involved in the maintenance
of equilibrium
-
- focal
lesions:
- generally small and
just in one area, focal lesions can affect the language
and swallowing centers of the brain, they can cause
symptoms similar to those seen as a result of a left
cerebral vascular accident including apraxia,
dysarthria, aphasia, dysphagia,
agnosia, anomia, and dysphonia.
Focal lesions can also cause more general impairments
that affect language, similar to those resulting from
right hemisphere damage. These include attentional,
perceptual and pragmatic deficits.
-
- foramina of Luschka:
- two lateral openings
(along with the medial foramen of Magendie) which
serve to connect the fourth ventricle to the subarachnoid
space
-
- foramen of Magendie:
- a medial opening (along
with the lateral foramina of Luschka) which serves
to connect the fourth ventricle to the subarachnoid
space
-
- foramina of Munro
(interventricular foramina):
- two openings which connect
the lateral ventricles to the third ventricle
-
- fornix:
- a subcortical component
of the limbic system; the fornix is a group of fibers
that arise from the hippocampus and connect the rhinencephalon
to the thalamus and hypothalamus; the fornix is connected
to the septal nuclei and the mamillary bodies
-
- fourth ventricle:
- one of the four ventricles
of the brain; it is filled with cerebrospinal fluid;
the fourth ventricle is located between the cerebellum
and the pons
-
- frontal
lobe:
- the most anterior lobe
of the brain; it is bounded posteriorly by the central
sulcus and inferiorly by the lateral fissure; this
lobe is associated with higher cognitive functions
and is involved in the control of voluntary muscle
movement
-
- fusiform layer (multiform
layer):
- the sixth and most inferior
layer of the cortex
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- GABA:
- Gamma Amino Butric Acid;
a neurotransmitter that is involved in the inhibitory
function of the basal ganglia; it is a glutamate
-
- gag reflex:
- a good example of a
true reflex. It is "triggered" whenever
a noxious substance touches the back of the tongue,
back of the pharynx, or soft palate. The swallow response,
on the other hand, cannot be initiated by touching
any particular area in the oral cavity. The gag reflex
and the swallow response also differ in terms of neurological
control. The gag reflex is completely controlled by
the brain stem. The swallow, on the other hand, is
only partially controlled by the brain stem. It also
receives cortical input, and input from muscle spindles,
including feedback from tongue movements.
(It is important to note that the gag reflex and the
swallow response are not related. In the past,
many physicians would determine feeding status based
on the presence or absence of a patient's gag. Actually,
the presence or absence of a gag reflex does not predict
the status of the swallow response.)-
- gamma neurons:
- neurons of the final
common pathway (located on the ventral aspect of the
spinal cord); these cells conduct slow motor impulses
and their main function is to stretch muscle spindles;
gamma cells are only half as numerous as alpha cells
-
- ganglionic cells:
- neurons of the autonomic
system that originate within the ganglia of the autonomic
nervous system and project to post-ganglionic neurons
-
- ganglionic layer:
- the fifth layer of the
cortex; it contains small granular cells, large pyramidal
cells, and the cell bodies of some association fibers
(the association fibers that originate here form the
Bands of Baillerger and Kaes Bechterew, which are
two large fiber tracts)
-
- Glasgow Coma Scale:
- developed by Jennett
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