Quiz 1 Review (Lecture 1, 2 & 3 & part of 4&5 Flashcards
what is ABR a test of
neural synchrony
test of timing
what are the 3 timing signals the brain gets to understand
amplitude(intensity) timing and frequency
When there are problems with the nerve, this is why we see issues understanding speech - timing is off
true
how do we understand how the brain workds
from those who had strokes or some kind of trauma
what is the cerebral cortex
Extensive thin outer layer of unmyelinated gray matter of the brain covering the surface of each cerebral hemisphere
Forms gyri (convulsions) & sulci (crevices)
Has several layers of nerve cells and nerve pathways that connect them
Nerve cells here die in Alzheimer’s and other diseases that affect the brain
cerebral cortex
what is the responsibility of the cerebral cortex
Responsible for processes of thought, perception, reasoning & memory; also for advanced motor function, social abilities, language & problem-solving
Organized by histology & numbers
cerebral cortex
how does information flow in the brain
back to front
what comines with what in the cortex
Vision combines with somatosensory - gives a sense of where one’s body is in space
processed sensory information makes its way to the ____
decisions are made here about what to do with various stimuli
frontal lobe
memory function
allows for recognition of visual perceptions
temporal lobe
what is executive function? where is it located? what are its divisions?
Higher-level cognitive skills used to control/coordinate other cognitive abilities and behaviors
Located in the frontal lobe - the prefrontal cortex
divided into organization and regulation abilities
organization abilities in the executive function division
Attention, planning, sequencing, problem-solving, working memory, cognitive flexibility, abstract thinking, selecting relevant sensory info
regulation abilities in the executive function division
Initiation of action, self-control, emotional regulation, monitoring internal and external stimuli, initiating and inhibiting context-specific behavior, moral reasoning, decision-making
what does the temporal lobe house
primary auditory cortex (Heschel’s gyrus; Broadmann’s 41) and the association areas (Broadmann’s 21 & 22)
whhere is primary auditory cortex located
Heschel’s gyrus is located in the Sylvian fissure and posterior 1/3 of the superior temporal gyrus
what is the function of the priamary auditory cortex
cortical neurons in this area can precisely represent timing (temporal encoding) of phonetically important components of speech, it code rapid acoustic events needed for fine grain discrimination, and it develop concepts of auditory space for localization
where is the secondsry auditory area
Posterior superior temporal lobe
where is the tertiary auditory area
Posterior-inferior part of the temporal lobe
auditory association area
Includes Wernicke’s area - superior temporal gyrus
Language comprehension
receptive
wernicke’s
where is wernicke’s area
Located on the superior temporal gyrus in the superior portion of Broadmann’s area 22
Lies between the primary auditory cortex (Heshl’s & Broadmann’s 41), the auditory association area (area 42), and the inferior parietal lobule
what are the 2 regions of the inferior parietal lobule
Caudally - angular gyrus (area 39) and dorsally the supramarginal gyrus (area 40)
Supramarginal gyrus
involved in phonological and articulatory processing of words
supramarginal gyrus
involved in memory of sound, recognition of words & spoken language, contributes to language formation, reading and writing and processing involves multi-modal and multi-function integration
auditory association area? or Wernickes?
Spoken speech; Motor
Expressive
broca’s area
where is brocas area
Located in the inferior frontal gyrus of the frontal lobe close to the motor strip
Deep cleft seen in both hemispheres but more pronounced in the left
Mostly horizontal
sylvian/lateral fissure
what is the sylvian/lateral fissure
Separates temporal lobe from parietal and frontal lobes
Runs between Broca’s & Wernicke’s areas
Marker for linguistic capacity
Sylvian/Lateral Fissure
once the brain figures out the sounds of language (phonetics), it sends this information to other areas like the angular gyrus to help us understand the meaning behind those sounds
true
Region of the inferior parietal lobe of the brain involved in processing auditory and visual input and language comprehension
angular gyrus
what is teh angular gyrus? where is it?
Involved in auditory, vision, and speech
The location lies between the parietal, occipital, and temporal lobes
angular gyurs is Connected to both Broca’s & Wernicke’s and in turn are connected to each other by
arcuate fasciculus (bundle of nerve fibers)
bundle of nerve fibers
arcuate fasciculus
part of the brain on the left side where information from hearing, seeing, and touch comes together
inferior parietal lobule (which includes the angular gyrus and supramarginal gyrus)
what makes up the inferior parietal lobule
angular gyrus & supramarginal gyrus
brain cells in this area can handle sounds, images, and touch signals all at the same time. Because of this, the area might help us organize and label different types of information, which is important for understanding ideas and thinking abstractly
inferior parietal lobule (which includes the angular gyrus and supramarginal gyrus)
what is the planum temporale
forms the heart of Wernicke’s area and is one of the most important functional areas for language and music
Triangular area situated on the superior temporal gyrus just posterior to the auditory cortex (Heschl’s gyrus) within the Sylvian fissure
planum temporale
what is meant by leftward assymetry? what happens when this is reduced
planum temporale Shows significant leftward asymmetry in normal individuals
Larger in the left hemisphere because it is involved in language and music
leftward asymmetry is reduced in individuals with language issues such as dyslexia and schizophrenia
what is the corpus callosum
The largest band of white matter in the brain that is made up of myelinated axons
axons connecting one hemisphere of the brain to the other
the largest collection of white matter within the brain
contains a high myelin content, which facilitates quicker transmission of information
corpus callosum
what are the auditory functions in the CC
Dichotic listening (listening to different acoustic events presented to each ear simultaneously)
Binaural listening and localization
Auditory figure-ground (speech in noise)
Perception of midline fusion (when sound comes from the center vs the sides)
language functions in the CC
Phonologic processing (sarcasm or not?)
Linking of prosodic and linguistic input for judging communicative intent
Development of interhemispheric specialization
Syntactic, semantic, and pragmatic functions
what happens if there is damage to the CC
damage/dysfunction along transcallosal pathway: impact on interhemispheric exchange of cognitive, sensory and motor information
knee of cc
genu
Transversely oriented white matter tract that connects the two temporal lobes in the midline.
Anterior Commissure
An axon tract running transversely through the gray matter that forms the roof of the cerebral aqueduct in the midbrain.
posterior commissure
This tract contains commissural axons interconnecting the right and left pretectal areas
posterior commissure
grey matter
used for computation, thinking, memory, storage, etc.
used for computation, thinking, memory, storage, etc.
grey matter
allows different parts of the brain to communicate with each other
Thalamus
white matter
wite matter
allows different parts of the brain to communicate with each other
Thalamus
A large mass of grey matter in the posterior forebrain that is the main relay center for the nervous system, including hearing
thalamus
thalamus
A large mass of grey matter in the posterior forebrain that is the main relay center for the nervous system, including hearing
Lies below the thalamus and is vital for temperature regulation, emotional states, & control over the autonomic nervous system
hypothalamus
hypothalamus
Lies below the thalamus and is vital for temperature regulation, emotional states, & control over the autonomic nervous system
what is the function of the cerebellum
to coordinate movements related to the exact timing
Internal clock
internal clocks
cerebellum
whata happens with damage to the cerebellum
can lead to issues with slurred or unclear speech; ataxia (most characteristic feature of damage here)
most characteristic feature of damage in teh cerebellum
ataxia
they do not have connectivity, support cells
glial cells
in the immune system
neutrophil
have the connectivity
neurons
dominant for language function in the majority of people
left hemisphere
involved in the perception of nonlinguistic stimuli
right hemisphere
describe the differences between left and right hemispheres
Left is dominant for language function in the majority of people
Primarily involved in (understanding & creating sentences, figuring out word meanings, breaking down sounds in speech, telling the difference between sounds, & remembering & finding the right words to use)
right: involved in the perception of nonlinguistic stimuli
Rhythm - like in music or speech
Stress - emphasis on certain words
Nonlinguistic acoustic parameters - nonverbal sounds like music or noises
Perception of acoustic contours - understanding changes in sound patterns
Discrimination and ordering of tonal stimuli - recognizing and organizing different tones or pitches
Prosodic elements of speech - rhythm, intonation, and stress in how we speak
both hemispheres are used to understand music
true
previously left was thought to be for langauge and right for music but now it might be connected to onse side more but not the whole function being separated
The brain structures around the Sylvian fissure help with auditory and language repetition
true
Auditory signals get processed in
Heschl’s gyrus
describe the connection between audition and language
Hearing new words repeatedly strengthens your brain’s ability to remember them.
When you hear words often, even if you don’t know their meaning at first, your brain forms memory traces.
With hearing loss (HL), you miss out on this repetition, making it harder to understand language because you’re not getting the repeated exposure needed for memory.
Brain processes sound of speech (phonemic analysis) in Wernicke’s area to help us understand what we heard. Then Broca’s area takes the understood speech and helps us produce our own speech by directing parts of the brain controlling muscles needed for speech
Wernicke’s helps us understand speech and Broca’s helps us talk
wernickes helps us ______ speech and brocas helps us _______
understand
talk
Damage to any of the regions near the Sylvian fissure impairs language repetition and is the hallmark of
perisylvian aphasias
describe how speech is processed in wernickes
receptive (gets speech, understands what is said, and based on memory and understanding goes to Broca’s to respond)
describe how speech is processed in brocas
expressive (gets what is understood from wernickes and produces a response)
what is aphasia
Language disorder is caused by damage to specific areas of the brain, often after a stroke or brain injury (brain tumor, head trauma, infections like encephalitis, dementia, MS, etc.), and affects a person’s ability to speak, understand, read or write depending on where the damage is
what are the types of aphasia
brocas
wernickes
global
what is broca’s aphasia
non-fluent; difficulty speaking but their understanding is mostly intact with broken or slow speech
what is wernickes aphasia
fluent; speech is smooth but doesn’t make sense with trouble understanding language
what is global aphasia
severe form; both understanding and speech are heavily impacted
what is the perisylvian zone
speech area of the brain
other names for brocas aphasia
nonfluent/motor or expressive aphasia
controls speech production
brocas area
Damage to the cerebellum leads to
ataxia (slurred or unclear speech)
what is ataxia
a condition that affects a person’s coordination, balance, and ability to control their movements
may appear unsteady when walking, have trouble with fine motor tasks (like writing), or experience slurred speech
primary cortex & cerebellum is involved with this aphasia
broca’s
what is global aphasia
When strokes or other conditions affects extensive portions of front and back regions in the left hemisphere
Characterized by: difficulty understanding words and sentences, difficulty in forming words and sentences, understanding some words but not others, they are able to utter a few words at a time, having severe s/l difficulties that prevent them from communicating effectively
what is anomia
Aphasia resulting from cortical or subcortical strokes or cerebral insults
characterized by: issues remembering the right word to describe something (more noticeable with words not used every day or often), circumlocutions are common (more words than necessary are used to identify something - like “fuzzy things you wear on your feet in the winter” instead of “fuzzy socks”
loss of memory after trauma
amnesia
occurs when both Heschl’s are damaged or if the subcortical areas are damaged that leads to the cortical areas
central deafness
CAPD Hx
Aphasia was already known but there was a subset of people who could hear but not identify things
Over time this concept, first studied in brain-injured adults, was applied to non-brain injured children with normal hearing who had
Difficulty separating auditory foreground (the speaker or signal you want to attend to) from auditory background (noise, etc.)
Difficulties hearing in noise - characteristic of CAPD
Poor language and academic skills
present until around 12 yrs old
right ear advantage REA
what are the two assessment approaches to CAPD
audiological or psychoeducational
what is the audiological approach to capd
Initially studied patients with brain injuries and then applied the findings to kids
We can diagnose CAPD
Current CAPD tests: SCAN-3C test, Staggered spondaic Words (SSW) test, Pediatric speech intelligibility (PSI) test
what is the psychoeducational approach to capd
Based on the concept of discrete auditory perceptual disabilities; adopted by many audiologists
waht is the differences between the psychoeductional and audiological appraches
audiological focuses on auditory processing abilities through objective testing and psychoeducational broadly looks at how auditory processing impacts learning and behavior and involves various assessments by educational professionals
he who stretches, thief
procrustes
what is bottom-up sensory perception
all sensory perceptions, they then go to the brain and it analyzes what is going on
Hearing is this
Without hearing, spoken language is not possible
Without strong language development, efficient learning cannot occur
what is the one disorder we can diagnose
capd
Since 40’s and 50’s debate has continued with some stating we lack a clear framework for conceptualizing
CAPD
None of these paths have yet solved the diagnostic problems of (C)APD
true
To date for capd as a profession
No standardized definition for CAPD is accepted by all
No gold standard or universally agreed upon diagnostic test or criteria for assessment/diagnosis of CAPD
No evidence-based or standardized management techniques for CAPD
the point at which nerve fibers interact
synapses
postsynaptic membrane potentials decrease allowing the cell to fire
excitatory synapses
postsynaptic membrane potentials increase making it less likely for the cell to fire
inhibitory synapses
put the signal into code at the cochlea level; happens at the cochlear level
Timing, frequency, & intensity - how the brain makes sense of what it heard
The tonotopic organization is a part of this code
encoding
cortical primary and association areas break down the auditory signal into its constituent parts; code is broken at the cortical level (also association areas)
Gives an idea of what exactly that sound was
decoding
CANS neural transmisssion
Different regions receive the same acoustic information source but respond differently to it
Some have complex temporal properties, some are binaurally sensitive, some are sensitive to ILD (HFs), and some are sensitive to ITDs (LFs)
primarily composed of areas that receive input from the medial geniculate nucleus in the thalamus.
auditory association cortex
what areas of sound processing is the auditory association cortex involved in
Perceiving sound pitch
Localization
Identifying a sound source
Recognizing speech-related characteristics
3 main areas of auditory association cortex
core
belt
parabelt
Located in Heschl’s gyrus in the superior temporal lobe, including the primary auditory cortex
core (a1)
Surrounds the core area
belt (a2)
what is the core (A1)
Has a precise tonotopic organization, meaning neurons are arranged according to their response to specific sound frequencies (characteristic frequency - CF)
Responsible for conscious awareness of sound, like waking up to noise
Receives direct input from the ventral division of the medial geniculate complex
Surrounds the core area
belt (a2)
what is the belt (a2)
Receives input from the core and other parts of the medial geniculate nucleus but is less organized tonotopically
Shows frequency tuning and responds to tones and narrow-band noises
Located next to the belt (adjacent to the lateral side of the belt)
parabelt (a3)
what is the parabelt (a3)
Gets input from the belt and connects to auditory association areas of the brain involved in memory and decision-making
More responsive to complex sounds, like speech, rather than simple tones like pure tones
Proximity to Wernicke’s area suggests it plays a role in processing language
where are neurons found in the cortex
Inferior frontal lobe (where Wernicke’s area connects to Broca’s area for speech production)
Inferior parietal lobe
Anterior occipital lobe
other areas of the brain that processes auditory info but doens’t primarly receive input from the medial geniculate complex
temporal lobe, superior temporal sulcus, intraparietal sulcus, and prefrontal cortex
auditory related areas of the context
temporal lobe, superior temporal sulcus, intraparietal sulcus, and prefrontal cortex
There isn’t just one area in the brain responsible for auditory processing. why is this a good thing
This is beneficial because if one area is damaged, other areas can help with sound processing, ensuring that we maintain our auditory abilities.
an auditory association area
Wernicke’s Area (Broadman’s 22)
what is the auditory association cortex involved in
Memory of sound, therefore, recognition of words and spoken language
Contributes to language formation
Reading and writing
Processing involves multi-modality and multi-function integration
primary auditory cortex receives input from the auditory nuclei in the ________ of the thalamus after extensive processing
medial geniculate complex
primary auditory cortex receives input from the auditory nuclei in the medial geniculate complex of the thalamus after extensive processing by
Brainstem nuclei including the cochlear nuclei
Superior olivary complex
Lateral lemniscus
Inferior colliculus
In the cerebral cortex, the primary auditory area is flanked by ________ and _______ regions that cover much of the superior temporal gyrus and are connected to other areas of the brain
belt and parabelt
In the cerebral cortex, the primary auditory area is flanked by belt and parabelt regions that cover much of the superior temporal gyrus and are connected to other areas of the brain
These areas are sites of multiple auditory integration where ____, ______. &______ cortices overlap
These inputs contribute to the interactive effects of______, ______, & ______
auditory, visual, and somatosensory
audition, vision, and somatosensation
This area of the brain responds to both verbal cues (like words) and nonverbal cues (like gestures, eye movements, and facial expressions). It’s sensitive to many different types of information, not just one.
superior temporal gyrus
As we move away from the primary auditory cortex (A1), the brain becomes better at processing speech.
true
The early auditory cortex (which includes parts of the auditory cortex but isn’t the primary area) can be influenced by
attention
what is the role of A1 in speech
Historically, it’s been hard to see how A1 is involved in speech perception because:
A1 is very adaptable and depends on context.
It identifies constant sound properties but needs information from both incoming sounds and previous knowledge.
A1 relies on an ascending auditory path and top-down modulation information
Cells extracting constant properties of sound show a heterogeneous response
Neurons in A1 show varied responses to sounds.
If A1 is damaged, people can hear pure tones but have difficulty processing speech, showing it does play a role in understanding speech.f
part of the brain that processes sound
auditory cortex
what is the involvement of areas outside of the temporal lobe
Language processing areas in the angular and inferior frontal gyrus.
Semantic processing areas in the medial frontal cortex.
Nonlinguistic executive function and attention areas in the frontal lobe and right parietal lobe.
Language processing areas in
angular gyrus & inferior frontal gyrus
Semantic processing areas are in
medial frontal cortex
Nonlinguistic executive function and attention areas are
in
frontal lobe and right parietal lobe.
what is meant by top down processing
Our prior knowledge influences how we process speech
how can top down knowledge happen
automatically or deliberately
when we predict what will be said.
automatic
when we focus on understanding speech in noisy environments
deliberate
what is suppressive binaural interaction
Some neurons work by suppressing (reducing) the sound from one ear while responding to sounds from the other ear.
For example, a neuron might get a strong signal from the right ear (contralateral ear) and a weak or inhibited signal from the left ear (ipsilateral ear).
This process helps focus on sounds from one side while ignoring sounds from the other.
what is binaural input
Most neurons in the auditory cortex (the part of the brain that processes sound) are affected by hearing from both ears. This helps us recognize where sounds are coming from in space (spatial recognition)
This process helps focus on sounds from one side while ignoring sounds from the other.
suppressive binaural interaction
This helps us recognize where sounds are coming from in space
binaural input specifically spatial recognition
where do suppressive interactions happen in the brain
likely happen in specific areas of the brain that are located within the same hemisphere (half) of the brain
Intra-hemispheric
contralateral
Inter-hemispheric
ispi
what does inter hemispheric mean
connections between two hemispheres
what does intra hemispheric mean
connections that occur in a wingle hemisphere
what hemisphere dominates with spatial information
intra-hemispheric
contralateral
connections in one hemisphere are mainly influenced by sounds coming from the opposite hemisphere
how many channels do we use to process spatial information
two
Each channel tunes in to sounds coming from either the left or right side, with some overlap in the center (midline)
For sounds that are located close to the center (midline), both channels work together.
true
For sounds that are farther to the left or right, processing is mainly managed by one channel or the other.
true
stronger indicators of where sound is coming from
contralateral pathways
if sounds come from the same side then the ipsi pathways might be stronger
If they are coming from the opposite sides the contras might be stronger
true
in front of the nose, 0 deg, need input from both sides and it has to be somewhat equal; midline neurons are the most dominant here
midline
All neurons do not respond the same way → depends on the location, nature, etc of sound
true
why do we have two ears?
helps us to localize and this is needed for understanding speech in noise
The perceptual benefit of a 90 deg separation between speech and noise is ~ ____ dB if speech and noise are in the same acoustic hemifield
1.3
slightly easier to hear speech over noise
The perceptual benefit of a 900 separation between speech and noise is ~ ____ dB if speech and noise are located on opposite sides of the midline
8.6
significantly easier to hear speech over noise
When speech and noise are in the same areas, the brain can focus better on the speech, leading to improved hearing.
false
separate areas
function of the efferent pathways
help control various auditory functions, allowing for both excitatory (increasing) and inhibitory (decreasing) activities in the auditory system
may play a role in helping us identify signals, especially when there’s background noise.
efferent pathways
what is the olivocochlear bundle
a group of fibers that extend from the superior olivary complex (SOC) to the hair cells in the cochlea, mainly affecting outer hair cells (OHCs).
may help with focusing attention on certain sounds
OCB
what is OAE suppression
medial part of the OCB is thought to help suppress otoacoustic emissions (OAE), which are sounds produced by the inner ear. This suppression is important for hearing well in noisy environments.
will you see suppression in normal auditory systems
yes
when might you not see suppression in the auditory system
ANSD
how do we measure OAE suppresion
To test this suppression, noise is played in one ear (the opposite ear) while measuring the otoacoustic emissions in the other ear. If the emissions decrease in amplitude, it shows that suppression is happening.
what is psychoacoustics
study of how humans perceive sound
Branch of psychophysics
relationship between stimulus and perception of it by the listener
what happens when we hear a sound
Our perception changes → We hear and interpret the sound (e.g., recognizing a loud noise or a soft one)
Our personal biases affect our response → We might react differently based on our expectations or experiences (e.g., expecting a sound to be louder, so we “hear” it that way)
you hear a sound (stim) and how we perceive stimulus is different for everybody meaning that Heschl’s s not the only place in the brain that is perceiving sound
they heard it and there was a stimulus
hit
true positive
there was a stimulus and they didn’t hear it
miss
false negative
when there is no stimulus but they say they heard it; happens close to threshold most and is normal
false alarm
false positive
no stimulus and they will not respond
true negative
correct rejection
sensitivity and formula
The ability of the test to correctly identify those with the disease
Hit ÷ (Hit + miss) x 100 = sensitivity
Or TP ÷ (TP + FN) x 100
what does high sensitivity mean and an ex
few false negatives
need a cancer screening test and it says its ok but you do have cancer… dangerous and not a good test… not picking up a disease that has the disease
what question does sensitivity answer
If PT has the disease how likely will they have a positive test?
specificity and formula
The ability of the test to correctly identify those without the disease
Correct rejection ÷ (false alarm + correct rejection) x 100
Or TN ÷ (TN + FP) x 100
what does high specificity mean and an ex
few false positives
Ex → go in for a mammogram and it says you have lumps bu
what question does specificity answer
If PT doesn’t have the disease how likely will they have a negative test?
are sensitivity and specificity equal
NO
one is higher than the other
if a test is close to 50%, is it a good test
not so good
What causes changes in specificity and sensitivity?
Strict criteria → high specificity and low sensitivity
Lax criteria → high sensitivity and low specificity
Which one we want depends on the disease we are testing
what is validity
accuracy of a test → what it is the test is supposed to measure → is the test measuring what it is supposed to be measuring → is this test the right test for what I need to know
example of validit
tymp - what is the site it is measuring? ME status
if you think they have Meniere’s would you use a tymp? no so it is not a valid measure for IE problems
what is the underlying component of validity
sensitivity and specificity
If a test is not sensitive then it is not valid either
true
what is predictive value
likelihood that a positive test result indicates disease or that a negative test result excludes disease
Does a positive result mean that the patient actually has it
PV of a positive test decreases with increasing sensitivity and specificity
falsae
increases
what is positive predictive value
tells you how likely it is that someone actually has a condition if they tested positive for it; it’s the probability that a positive test result is correct.
PPV of a test increases with increasing _______ in a population
disease prevalence
what is prevalence
total number of cases of a particular condition or disease in a population at a specific point in → time tells you how widespread the condition is within that population.
what is stronger for more common diseases
PPV
what happens as prevalence rises
PPV rises
NVP fals
what is an example of predictive value use
Comparing a new test to the Gold Standard (best single test or combination of tests considered the current preferred method of diagnosing a particular disease
New tests have to have high PPV (as close to 100 as possible) to be as good as the gold standard
Questions clinicians are more likely to ask
If PT has a +ve test, how likely will they have the disease?
For example, +ve test for the BRCA1 and BRCA2, breast cancer genes
If PT has a -ve test, how likely will they not to have the disease?
For example, -ve test for the BRCA1 and BRCA2, breast cancer genes
NPV is high with common diseases
false
with rare
PPV is high with rare diseases
false
common
what does ROC stand for
Receiver Operating Characteristic curve
The conventional approach of the evaluation of tests uses sensitivity and specificity as measures of accuracy in comparison to the gold standard status
true
what varies across different thresholds of test results
specificity and sensitivity
what is ROC
when sensitivity versus specificity is plotted
what is AUC
area under the curve
what is ROC considered
Effective measure of accuracy and meaningful interpretation of test results
Plays a role in evaluating the diagnostic ability of tests to discriminate true state of subjects (diseased vs not-diseased)
Finds cut off values for normal vs abnormal results
Compares two alternative diagnostic tasks when each task is performed on the same subject
ROC is created from
2x2 matrix
what is on the y axis of the roc
hit rate/sensitivity
what is on the x axis of the roc
false alarm rate (false positive)/specificity
Upper left quadrant =
best tests
