Lecture 19: Neurological Disorders Flashcards
recovery for patients with Wernicke’s aphasia
occurs first in reading, then in word comprehension. They are often unable to recover the ability to spell or repeat words.
inner monologue
when we talk to ourselves in our head
subvocal articulations
very slight movements of the muscles involved in speech that do not actually cause obvious movement
are there subvocal articulations during our inner monologues?
yes
functional imaging when a patient is asked to say if the names of items rhyme
shows increased activation in Broca’s area because the person says the two words subvocally
dysgraphia
trouble with writing
two types of writing
Phonetically sounding out the word
Visually imaging the word
phonological dysgraphia
a condition where people cannot spell words by sounding them out. They can only write words by imagining how they look. Thus, they have to be very familiar with how the word looks or they cannot write it. They cannot write non-words that sound fine
damage to what region is associated with phonological dysgraphia?
damage to the frontal regions & common in Broca’s aphasia
Orthographic dysgraphia
a condition where people cannot spell words by visualizing them. They can only sound words out, which means they cannot correctly spell any words that have an irregular spelling
damage to what region is associated with orthographic dysgraphia
damage to VWFA – visual word form area in visual association cortex
likelihood of having a stroke
related to age–probability doubles each decade after 45 years of age & reaches 1-2% by age 75
Atherosclerosis
Process in which linings of arteries develop a layer of plaque, deposits of cholesterol, fats, calcium, and cellular waste products.
risk factors for atherosclerosis
include high blood pressure, cigarette smoking, diabetes, and high blood levels of cholesterol
atherosclerosis is a precursor for what conditions
heart attacks, myocardial infraction and strokes
Internal carotid artery
supplies most of the blood flow to the cerebral hemispheres. Goes from the heart to the brain
where do atherosclerotic plaques form?
in the internal carotid artery
result of atherosclerotic plaques
severe narrowing of the interior of an artery, greatly increasing the risk of a massive stroke
how can the narrowing of an artery be seen?
in an angiogram, produced by injecting a radiopaque dye into the blood and examining the artery with a computerized x-ray machine
Hemorrhagic stroke
rupture of a cerebral blood vessel
Ischemic stroke
occlusion of a blood vessel
what is the most common type of stroke
ischemic; it makes up 87% of strokes
how is the type of stroke determined?
ct scan
thrombus
a blood clot that forms within a blood vessel, which may block it and reduce blood flow to the affected area
what type of stroke are thrombi associated with?
ischemic strokes
embolus
a piece of matter (such as a blood clot, fat, or bacterial debris) that dislodges from its site of origin and occludes an artery. In the brain, an embolus can lead to a stroke.
how do researchers reduce the amount of brain damage caused by strokes?
administering drugs that dissolve blood clots to reestablish circulation. This has been met with some success; the administration of a clot-dissolving drug called tPA (tissue plasminogen activator) after the onset of a stroke has clear benefits, but only if it is given within 3-4 hours
dissolving blood clots only works for what type of stroke?
ischemic
reducing the risk of strokes
devices, including coils, aspiration devices, and stints can be deployed through the vascular system to the site of occlusion to secure/remove them
treatments after strokes
Drugs that reduce swelling and inflammation
Physical, speech and/or occupational therapy
Exercise and sensory stimulation (constraint-induced movement therapy)
tumour
mass of cells whose growth is uncontrolled and that serves no useful function
non-malignant (bening) tumour
non-cancerous tumour. Has distinct borders and cannot metastasize
malignant tumour
cancerous (literally “harm-producing” tumour). Lacks distinct borders and may metastasize
do non-malignant tumours regrow?
no. If there is a border, the surgeon can cut it out and it won’t regrow
do malignant tumours regrow?
yes, When surgeons remove malignant tumours, some cancer cells are often missed, and these cells will produce new tumours
how does cancer occur
where there is cell division as a result of a mutation & replication is uncontrollable
can nerve cells be cancerous
no
what types of brain tumours are dangerous?
all of them. Any tumour growing in the brain, malignant or benign, can produce neurological symptoms and threaten the patient’s life
two methods by which tumours can damage brain tissue
compression and infiltration
compression
the tumour takes up space and pushes against the brain
gliomas
a type of malignant brain tumour originating in the neural stem cells that make glia. They rapidly proliferate and are more resistant to chemotherapy and radiation than most tumour cells
survival rate of gliomas
very low
meningioma
a type of non-malignant brain tumour composed of cells that constitute the meninges (the dura mater or arachnoid membrane) often right between the two cerebral hemispheres
astrocytomas
type of brain tumour that originates in the astrocytes
ependymoma
type of brain tumour that originates in the ependymal cells that line the ventricles
medulloblastoma
type of brain tumour that originates in the cells in the roof of the fourth ventricle
oligodendrocytoma
type of brain tumour that originates in the oligodendrocytes
pituitary adenoma
type of brain tumour that originates in the hormone-secreting cells of the pituitary gland
neurinoma
type of brain tumour that originates in the Schwann cells or cells of connective tissues covering the cranial nerves
metastatic carcinoma
type of brain tumour that originates in various place depending on the nature of the primary tumour
angioma
type of brain tumour that originates in the cells of blood vessels
pinealoma
type of brain tumour that originates in the cells of the pineal gland
encephalitis
inflammation of the brain caused by infection (bacterial or viral), toxic chemicals, or allergic reactions
first symptoms of encephalitis
headache, fever, nausea
Meningitis
inflammation of the meninges caused by viruses or bacteria
first symptoms of meningitis
headache and stiff neck
Polio (acute anterior poliomyelitis)
a viral disease that destroys motor neurons of the brain and spinal cord
rabies
a fatal viral disease that causes brain damage; usually transmitted through the bite of an infected animal
herpes simplex virus
a virus that normally causes cold sores near the lips or genitals. In rare cases, it instead enters the brain causing encephalitis and brain damage
closed-head injury
caused by a blow to the head with a blunt object
coup
the brain comes into violent contact with the inside of the skull
contrecoup
the brain then recoils in the opposite direction and smashes against the skull again
open head injuries
penetrating brain injuries obviously cause damage to the portion of the brain that is damaged by the object or the bone
what happens when there is damage to blood vessels in the brain
can deprive parts of the brain of their normal blood supply. Accumulations of blood within the brain can cause further damage by exerting pressure on the brain
traumatic brain injury deaths
Almost a third of deaths caused by injury involve TBI
what happens to survivors of traumatic brain injury
scarring often forms within the brain around the sites of injury which increases the risk of developing seizures & brain problems like Alzheimer’s
causes of seizures
many diffent causes. the most common is scarring related to an injury. other causes include high fevers in young children and withdrawal from GABA agonists like alcohol
are seizures genetic?
they can be but most seizure disorders are caused by nongentic factors
seizure disorder
the preferred term for epilepsy
convulsions
violent sequence of uncontrollable muscular movements caused by seizures
what causes convulsions?
if the neurons that make up the motor system are involved in the seizure
do most seizures have confulsions
no
partial (focal) seizure
a seizure that begins at a focus and remains localized, not generalizing to the rest of the brain
simple partial seizure
a seizure that does not produce loss of consciousness
complex partial seizure
a seizure that produces a loss of consciousness
generalized seizure
seizures that involve most of the brain (non-localized seizure)
examples of generalized seizures
tonic-clonic seizures, atonic seizures, and absence seizures
grand mal seizure
Involve the whole brain & are characterized by convulsions
aura
the sensation that precedes a seizure. Its exact nature depends on the location of the seizure focus
tonic-clonic seizure
a generalized, grand mal seizure that typically starts with an aura. Followed by a tonic phase and a clonic phase. This type of seizure involves convulsions
tonic phase
the first phase of a tonic-clonic seizure, in which all of the patient’s skeletal muscles are contracted
clonic phase
second phase of a tonic-clonic seizure, in which the patient shows rhythmic jerking movements
seizure disorders in children
children are especially susceptible.
absence seizures
people stop what they are doing and stare off into the distance for a few seconds, often blinking their eyes repeatedly
how are seizures treated?
with anticonvulsants like benzodiazepines
how do anticonvulsants work?
Increasing the effectiveness of inhibitory synapses
atonic seizure
loss of muscle tone; temporary paralysis
is brain surgery necessary to treat seizures?
only when it doesn’t respond to medication, which is rare
what is the most dangerous drug during pregnancy
alcohol
what happens to babies born to alcoholic women?
they are typically smaller and develop more slowly
fetal alcohol syndrome
a serious condition associated with alcohol consumption during the 3rd & 4th week of pregnancy. Has been associated with certain facial abnormalities and severe intellectual disabilities
what happens to babies born to heroin/cocaine addicts?
they recover fine after withdrawal
inherited metabolic disorders
several inherited errors of metabolism that can cause brain damage or impair brain development
errors of metabolism
genetic abnormalities in which a recipe for a particular protein is in error.
what causes errors of metabolism?
Typically caused by an enzyme that is not synthesized on account of mutations in both copies of the gene. If the enzyme is a critical one, the results can be very serious
Phenylketonuria (PKU)
a hereditary disorder caused by the absence of an enzyme that converts the amino acid phenylalanine to tyrosine. Accumulation of phenylalanine causes brain damage unless a specific diet is implemented soon after birth
toy sachs disease
Heritable, fatal, metabolic storage disorder. Lack of enzymes in lysosomes causes accumulation of waste produces and swelling of cells in the brain
infiltration
the malignant tumours invade the surrounding region and destroy cells in the path
