CAPD Quiz 1 Flashcards
sylvian fissure
appears to be the marker for linguistic capacity
-runs between broca’s and wernicke’s area
angular gyrus
involved in processing of auditory/visual input and language comprehension
-between the parietal, occipital and temporal lobe
angular gyrus integrates, processes and connects functional areas including …..
auditory, visual and language
aphasia
impairment of language that affects the production or comprehension of speech and the ability to read or write
-due to a brain injury (such as a stroke) but can also occur from disorders such as tumors, trauma, infections and MS
wernicke’s aphasia
comprehension of speech is impacted, motor language skills intact
-what they speak is not true speech, it is often nonsense due to lacking feedback comprehension
wernicke’s aphasia has damage to …
wenicke’s area, in the left temporal lobe
-adjacent to the primary auditory area
broca’s aphasia
most language skills are impacted, comprehension is intact
-non-fluent speech, poor repetition, few words and many pauses but aural comprehension is generally intact
global aphasia
occurs when a stroke or other condition impacts extensive parts of the front and back regions of the left hemisphere
-significant damage occurs
broca’s aphasia has damage to …..
broca’s area, in the inferior frontal gyrus of the frontal lobe
-cerebellum may be involved due to it being the internal clock
anomia
specific type of aphasia in which there is difficulty remembering the proper words to describe an attribute, action or object
-results from cortical or subcortical strokes or cerebral insults
executive function
higher level cognitive skills used to control other cognitive abilities and behaviors
-both organizational and regulation abilities
examples of regulation abilities
initiation of action, self control, emotional regulation and decision making
where do executive functions occur
frontal lobe in particular the prefrontal cortex
examples of organizational abilities
attention, planning, sequencing, problem solving, working memory and cognitive flexibility
what are the 3 divisions of the auditory cortex
primary auditory cortex/core (A1), belt (A2) and the parabelt (A3)
how is spatial processing mediated
it is mediated by two perceptual channels, each with hemifield azimuth tuning with medial borders
-processing near midline depends on the output from both
-spatial processing of sources deep in one or other auditory hemifield is dominated by one or the other channel
how does location of the speech and noise impact how the person perceives the signal
if they are in the same spatial channel it is harder, if they are in different spatial channels it is easier
how do efferent pathways play a role in audition
efferent pathways run from the cortex to the cochlea mediating auditory mechanisms
-in particular the olivocochlear bundle
-carries information from the CANS to the cochlear
-making contact with OHCs affecting their activity
olivocochlear bundle (OCB) in relation to audition
extends from SOC to fibers to cochlear hair cells
-medial OCB is believed to cause OAE suppression
sensitivity
correctly identifying those who have the disorder
- (hit / hit + miss) x 100
specificity
correctly identifying those who do not have the disease
- (correct rejection / correct rejection + false alarms) x 100
stimulus presented, heard it ….
hit
no stimulus, heard it ….
false alarm
stimulus presented, did not hear it …
miss
predictive value
the likelihood that a positive result indicates disease or that a negative result excludes disease
-positive PV (PPV) the proportion of positive tests that are true positives
-negative PV (NPV) are the proportion that are negative tests and correct rejections
no stimulus, did not hear it ….
correct rejection
PPV will be stronger when ……
the disease is more common
within an ROC, there is a diagonal line. what is the function of this
the line is the random guess or chance (50%) performance line
-below the line indicates a not very good test
-above the line indicates a better, more sensitive test
ROC curves
a measure of accuracy and meaningful interpretations of test results
-importance in finding the optimal cut off values for normal vs. abnormal test results
on an ROC, what is plotted on each axis
sensitivity is on the y axis and specificity is on the x axis
what are two pitch perception concepts
frequency discrimination and frequency selectivity
theories of pitch perception
place theory and temporal/volley theory
place theory
based around the place of maximum stimulation and tonotopic organization along the basilar membrane
-this corresponds to the maximum displacement in the traveling wave response (frequency place mapping)
frequency discrimination
ability to detect changes in frequency
frequency selectivity
ability to resolve a complex sound to its component frequencies
what frequencies does the place theory play a larger role with
high frequencies
-believed that phase locking might be necessary for the sensation of pitch
temporal or volley theory (role of auditory neurons)
based on how neurons phase lock to vibrations of the BM and therefore the pitch is assigned to a signal that is determined by the timing pattern of neural impulses evoked by a stimulus
-dependent on the timing
how does the temporal or volley theory work
with neural desynchrony, they fire in a poor pattern leading to not understanding what is being said
-when low frequencies are heard, neurons tend to fire at a particular phase of the waveforms so that the neural spikes are at or close to multiples of the period of pure tones
when there are broader auditory filters or a reduced frequency selectivity, what occurs
speech perception and music appreciation is difficult
what is the pitch of missing fundamental
even if the fundamental frequency was removed from the signal, pitch perception did not change which is due to the brain interpreting repetition patterns
how does the pitch of the missing fundamental occur
the first tone that is heard has all the frequencies and the second tone heard has the fundamental removed but maintains all the higher harmonics
-although the character of each note changes, the pitch remains the same
why is there variability among people with cochlear HL despite them having similar thresholds
all relating to individual differences in auditory filter size and neural synchrony
-well preserved synchrony is good pitch discrimination
how is pitch perception impacted by a cochlear HL
a cochlear HL is associated with reduced frequency selectivity, meaning a broader auditory filters
-individuals are getting the correct cues
-rely more on temporal information
how is pitch perception impacted with CI patients
they will often complain about not liking music as they cannot perceive pitch anymore
-due to the filters in the cochlea
-with a HL, there is a wider filter and the discrete ability to detect differences is impacted and therefore music is impacted
with regards to temporal resolution, what are the two different gap detection thresholds
within channel (within their own filter/channel, detecting within the channel) and across channels (outside of the filter/channel, using additional filters)
gap detection threshold
the smallest amount of silence detected between two signals
-generally is around 2 to 3 ms
-needs to be tested above threshold
-done at frequencies between 200 and 4000 Hz
two aspects that are important when discussing amplitude modulation
modulation rate : how close or how far they are depending on the rate
modulation depth : how far above does it move from baseline
temporal integration or summation
ability of the auditory system to add information over time
-appears to integrate a pure tone signal over a 200 to 300 ms period
-thresholds will therefore not improve if the signal duration is greater than 300 ms (it could worsen due to adaptation)
amplitude modulation detection threshold
determine the smallest amount of variation needed to detect that a sound if fluctuating
-the degree of change determines modulation depth of a signal
ability to detect modulation worsens at …..
low SL’s and high frequencies
forward masking
signal is presented after the masker
-signal duration needs to be short and the masker duration is long
-within the 100 to 200 ms time frame, anything over this will not occur
temporal masking
when the masker and test signal do not overlap in time, there is a separation between the signal and masker
-forward and backward masking
duplex theory
based around the idea of containing two sound cues used for localization
-involves interaural temporal or level differences
backward masking
signal is presented before the masker
-signal duration is short and masker is long
-within the 25 to 50 ms time frame
interaural temporal or phase differences (ITD or IPD)
provides localization information for low frequency stimuli
-comparing phase differences arriving to each ear
-the wavelength of sound waves is smaller than the diameter of the head
interaural level difference (ILD)
provides localization information for high frequency stimuli
-comparing intensity difference between the signals between each ear
-higher frequencies have shorter wavelengths which are around the side of the head, which produces a sound shadow
minimum audible angle (MAA)
detection of small shifts in position of sound source between reference and comparison signals
-basically, how different a signal has to be positional wise to detect a difference
MAA with ITD cues
smallest for sounds coming from the front
-around 3 degrees for frequencies up to 900 Hz
MAA with ILD cues
smallest for sounds coming from the front
-changes can be detected when degrees are greater than zero
two binaural hearing processes
fusion (sensation of hearing a fused signal at midline) and beats (when two signals produce a beat)
in order to hear beats, the signals has to have ….
two frequencies that are very close to each other
what are the beats
waxing and waning of a signal
-the difference between the two frequencies are the amount of beats that will be heard!!
-so subtract the two from each other
beats will not be heard if …
signals are the same frequency and if the different is greater than 50 to 100 Hz
perceptual coherence
if signals have similar acoustic properties those signals can then be equaled out
-common properties can include fundamental frequency and voice onset time
precedence effect (law of the first waveform)
describes and illusion produced when two similar sounds are delivered in quick succession from sound sources at different locations but only a single sound is perceived
-whichever wave hits the ears first is what is heard
-the binaural auditory system tends to suppress the later arriving sounds and emphasizes the first wave
modulation detection interference (MDI)
amount of masking or interference caused by the modulating masker
-a modulated signal can cross filters whereas a unmodulated signal can’t cross filters which is why the modulated signal is therefore able to mask
when testing speech, what does MDI have to do with it
shows why we need to use a modulated signal as a masker!
when the masker and signal frequency are different, the threshold for modulation detection for the signal ……
decreases (gets better)
comodulation masking
the detection of a tone centered in a modulated band of noise is improved with the addition of another band of modulated noise
-threshold gets better when the two noises (maskers) are similar and the signal is the only thing that is different
when the masker and signal frequency are similar, threshold for detection for the amplitude modulated signal …….
increases (gets worse)
what are some factors that may aid listening in regards to the cocktail party effect
spatial separation, different pitches of different speakers, different fundamental frequencies of speakers, different accents and different speeds of sound reaching the ears
cocktail part effect (spatial separation)
ability to focus the listening attention on a single talker among various voices and background noise
-the brain is able to detect the important signal vs. the not important signal/background noise
what are normal auditory processing functions
sensation, localization, auditory resolution/discrimination, auditory attention, auditory figure ground, auditory closure, auditory analysis, auditory synthesis, auditory association, auditory memory, temporal effects, temporal masking and binaural hearing
localization
ability to determine the location of the acoustic signal relative to the listeners position in space
sensation
ability to identify the presence of a sound
auditory attention
ability to attend to relevant acoustic signals, such as speech and sustain that attention for an age appropriate amount of time
-if impacted, they cannot attend to the important things
auditory resolution or discrimination
ability to discriminate between sounds that differ in frequency, duration and intensity
-problems with this can result in academic difficulty, reading, spelling and writing skills
auditory figure ground
ability to identify the primary linguistic or non-linguistic sound source from background noise
auditory synthesis
ability to synthesize phonemes into words
-critical to the reading process
auditory analysis
important for distinguishing verb tenses and other morphological markers that may be acoustically distorted or masked by background noise
auditory closure
ability to understand the whole word or message when a part is missing
auditory memory
recall of an acoustic signal after it has been labeled and stores
-sequential memory : ability to recall the order of acoustic stimuli
-short term memory : ability to retain and recall auditory information as it was presented
auditory association
ability to attach meaning to the sound
-important for developing auditory memory
temporal effects
talking about aspects that occur within the nerve
-temporal integration and temporal resolution
temporal resolution
detection of small timing differences when processing speech
-common method is gap detection threshold
temporal integration
ability to integrate inputs over time, enhancing the detection and discrimination of a sound
-pure tone duration of 200 to 300 ms
-increase in duration results in 10 dB improvement in threshold
temporal masking
occurs when the masker and test signal do not overlap in time
central auditory processing disorder (C)APD
a complex, heterogenous, bottom up perceptual disorder affecting the auditory system
-a sensory processing deficit that impacts listening, spoken language, comprehension and learning
binaural hearing
two ears are better than one
two hypotheses behind (C)APD
general auditory hypothesis (auditory modality deficit) or language specific hypothesis (language modality deficit)
academic profile of (C)APD
typically almost all children referred for these evaluation are struggling academically
-child not working up to potential
-weakness in spelling, reading and/or writing
-strong math skills
-difficulty following instructions/multi step instructions
-failed or failing a grade
-significant scatter in ability
-better performance on non-auditory tasks
-verbal IQ score lower than performance IQ
non academic profile of (C)APD
all can be exaggerated in noise or with degraded acoustic stimuli
-may appear hearing impaired but hearing sensitivity is normal
-history of chronic or recurrent OME
-repeatedly saying huh or what and asking people to repeat
-poor sound localization
-may have poor music skills and difficulty learning rhymes/songs
-may have problems with fine
-gross motor skill or may inhibit behavioral problems
what are the diagnostic criteria for (C)APD
age, cognitive abilities, speech and language abilities, auditory function and exclusionary diagnosis
(C)APD diagnostic criteria : age
children should be at least 7 years old
-we cannot test diagnostically under the age of 7
why is there an age requirement for diagnostic testing
the tests require a certain level of cognition and language skills to complete
(C)APD diagnostic criteria : cognitive abilities
a child with reduced intellectual skills would demonstrate reduced auditory ability therefore, intelligence should not be a factor when assessing a child
(C)APD diagnostic criteria : speech and language
minimum language age should be 6 years or older or within a year of the chronological age of language development
-English should be primary language
-children should have intelligible speech so it can be interpreted
(C)APD diagnostic criteria : auditory function
hearing should be WNL and there should be no ME dysfunction
(C)APD diagnostic criteria : exclusionary diagnosis
the following need to be ruled out prior :
-ADHD
-language and phonological processing problems
-learning delay/disability
-cognitive impairment
-autism and autism spectrum disorder
what are the subtypes of (C)APD
lexical decoding deficits, tolerance fading memory (TFM), organizational deficits or output organization deficit, integration deficits
lexical decoding deficits
characterized by difficulties in processing the words of a language, both verbal and written
-most common type
-mistakenly diagnosed as ADHD
-cortical area is the let posterior temporal lobe
tolerance fading memory (TFM)
characterized by difficulty listening in noise and recalling information presented earlier
-includes weak expressive language and poor handwriting
-cortical area is the frontal and anterior temporal lobe
organizational deficits or output organizational deficit
diagnosed when significant corrupted auditory sequencing or planning is noted
-difficulty with sequential information
-cortical area is the pre and post central gyri
integration deficits
decreased ability to integrate acoustic and linguistic information across different processing modalities
-long delays in response to auditory stimuli, writing and use of language
-cortical area is the corpus callosum
common comorbidities with (C)APD
ADHD, phonological processing and language deficits, reading/spelling problems and learning delays
lax criterion
if they fail only one test, they have it
-yields a better sensitivity but poor specificity
-as the size of the battery increases, greater probability that a patient will fail any single test
strict criterion
all tests need to be failed to have the diagnosis
-yields a better specificity but poor sensitivity
-as size of battery increases, less probability that a patient will fail all of the tests
intermediate criterion
abnormal on at least 2 tests or abnormal on at least 1 test
-based on standard deviations of tests
-the most reliable
