Exam 2 Flashcards
What is masking?
The ability of one acoustic signal to obscure the presence of another acoustic signal so it cannot be detected
Keeping one ear busy so that we can get accurate results for the ear being tested
What does masking do?
Raises the threshold of audibility for one sound by the presence of another (masking)
What is the test ear?
Ear that the signal is directed to
What is the non test ear?
Ear receiving masking noise
Why is masking needed?
- Human ears are not acoustically isolated so sound crosses over to both ears
- Tones presented via air conduction to one ear can be loud enough to stimulate the opposite ear via bone conduction (crossover or cross hearing)
What is crossover?
- When a tone is presented to one ear at a given level and is heard at a lower level in the opposite ear
- Determined by the level of tone in the test ear and loss in signal strength as it passes to the opposite non test ear
What is inter-aural attenuation?
- Difference in level of the acoustic signal at the two ears
- Difference in level from test ear to non test ear
- Decrease in the level of an acoustic signal (in dB) as it passes from one ear to the cochlea of the opposite ear
True or false: type of transducer used affects interaural attenuation
True
What is the lowest acceptable interaural attenuation for supra-aural headphones? Insert earphones?
40 dB supra aural
70 dB insert earphones
Anytime the _ conduction threshold in one ear differs from the _ or _ conduction threshold in the other ear by _ or _ dB, crossover may have occurred and the _ ear will need to be isolated acoustically
air
air, bone
40, 70
better
What is the interaural attenuation for bone conduction?
0 dB
Placing bone vibrator on the mastoid, assume that the tone may be heard in both ears
With bone oscillator testing, we can assume that the patient hears the tone in the ear with the better __
Cochlea
We will always mask bone conduction testing if there is an air bone gap of ____ dB HL or more
15
Why do we use masking?
- To determine the hearing sensitivity of one ear while making sure that the test signals are not heard in the opposite ear
- Allows us to acoustically isolate the test ear
How is masking performed for pure tones?
- Noise presented in the non test ear as narrow band noise centered around the frequency that is being tested
- Follows the critical band theory, meaning we play noise right around the frequency that we are interested in and effectively mask without needing any extra frequencies
How is masking performed for speech audiometry?
- use a speech shaped noise that mimics everyday human speech
- shaped to have the spectral energy similar to that of speech
What is the first step when determining if masking is needed?
Confirm if crossover occured
Procedure for confirming cross over
- present narrow band of noise continuously to the non test ear at a level 10 dB above the threshold in that ear
- measure the threshold of the test ear again
- If the threshold increases by 5 to 10 dB, the original threshold was the result of crossover
After crossover has been confirmed, what procedure is followed to find the true threshold of the test ear?
- Increase the noise in the non test ear incrementally until the threshold in the test ear no longer increases
- Looking for a plateu, where multiple increases in noise in non test ear does not cause a change in the test ear threshold
What is the plateu?
Levels between undermasking and overmasking at which true threshold of the test ear is established
What is undermasking?
- Occurs when a masking noise presented to the non-test ear is of insufficient intensity to prevent the test signal from being heard in the non-test ear
- Turning up volume and threshold still changing so not enough for acoustic isolation
What is overmasking?
- Occurs when a masking noise presented to the non-test ear is intense enough to shift the threshold in the test ear
- Too much noise in the test ear to the point where noise is crossing over to the test ear rather than staying in the non test ear and keeping it busy
- Test ear has been compromised
On the audiogram, symbols are ___ to indicate that masking was used
- changed
- level of masking is also sometimes indicated
What is the minimum masking level?
- Lowest level of noise necessary to mask the non test ear
- usually 10 dB above air conduction threshold in non test ear
What is the maximum effective masking level?
- Highest level of noise in the non test ear that would have crossed back over to the test ear if the level had been any higher (ceiling for accurate results)
- Equivalent to the bone conduction threshold in the test ear + the interaural attenuation
- Bone conduction threshold in the test ear + interaural attenuation
Bone conduction testing stimulates ____ cochlea
Both
Intra-aural attenuation for bone conduction is _ dB. We mask for BC when there is ___
0 dB
ABG (airbone gap)
A bone-conduction threshold indicates the sensitivity of the ____ cochlea.
Better
Bone-conduction can never be _____ than air-conduction.
Poorer
With air-conduction testing, crossover occurs when the signal is heard by _____
cochlea of the opposite ear
Intra-aural attenuationfor supra-aural earphones is, for insert earphones is
supra aural: 40 dB
inserts: 70 dB
To determine the true threshold of the poorer ear, masking is presented to the ____ while tones are presented to the ____
non test ear
test ear
When we mask, noise is presented via _____
air conduction
On an audiogram, _____ are changed to indicate that masking was used.
audiometric symbols
IA – TE – NTE – RE – LE – AC – BC –
IA – Interaural Attenuation TE – Test Ear NTE – Non-test Ear RE – Right Ear LE – Left Ear AC – Air Conduction BC – Bone Conduction
How do you calculate if masking is necessary for air conduction threshold using supraaural headphones? For bone conduction thresholds?
TE AC - NTE BC > or equal to 40 dB
TE AC - TE BC > 10 dB
How do you calculate minimum and maximum masking level?
Minimum: NTE AC + 10 dB
Maximum: TE BC + 40 dB
What is admittance?
Ease with which sound flows through a system
Measured with mmhos (ohm spelled backwards)
What is impedance?
Opposition to flow of acoustic energy
High impedance leads to low admittance
What equipments is used to measure acoustic immittance?
Tympanometer
Acoustic admittance measures: Probe assembly creates airtight seal at ___
opening of the ear canal
Acoustic admittance measures: loudspeaker presents a ___ tone
226 Hz
Acoustic admittance measures: pump reduces the air in the canal below ___ pressure then increases it above ___ pressure
A microphone measures the __ __ __ in the ear canal as the ___ ___ is changed
atmospheric pressure x2
sound pressure level, air pressure
Acoustic admittance is measured (in ___ units) as air pressure in the ear canal is changed from ___ to ___
Results are plotted on a graph called _____
mmhos, negative, positive
tympanogram
Tympanometry: what is peak Ya?
- Total acoustic admittance at the peak
- How much sound was admitted through the system
Tympanometry: what is peak Ytm?
- Just the admittance of the TM
- Go from positive tail to the peak
Tympanometry: what is TPP?
Tympanometic peak pressure
Pressure at which ya or Ytm is at its max
Look at peak and draw the line straight down
Tympanometry: what is tympanometric width? (TW)
Width of the tympanogram at 1/2 the height of Ytm (peak to tail)
Tympanometry: what is ear canal volume?
Acoustic estimate of the volume between the probe tip and TM
What is the cut off for TPP value?
-150 to 25 is normal
Normal ear tymps is a ….
Type A tymp
Tymps: negative middle ear pressure is a
Type C tymp
Tymps: middle ear problems is a
Type B tymp Foreign body (abnormally small volume) Otitis media (normal volume)
Type B tymps with high volume indicate
PE tubes or perforation in TM
Type As tymp details
Shallow type A
reduced compliance meaning system is more stiff and not moving as much as it should be
Type Ad tymps details
Deep type A
Hypermobile TM can be due to loose skin or breakage in the ossicular chain
Preak Ytm is over 2.0
What is the acoustic reflex?
Time-locked contraction of the stapedius muscle in response to an acoustic signal of sufficient intensity level and duration
Stiffening of the ossicular chain allows us to hear better in ___
Background noise
How are acoustic reflex thresholds tested? (procedure)
- middle ear system pressurized to point of max compliance
- present pure tone stimulus and measure changes in stiffness
- lowest intensity where a change in compliance can be measured is the acoustic reflex threshold
What stimuli are used for ART?
-Clicks, tones, complex noise stimuli
Ipsilateral ART stimuli tones, contralateral ART stimuli tones
Ipsilateral: 500, 1000, 2000 Hz
Contralateral: 500, 1000, 2000, 4000 Hz
ART Stimuli start at loudness of ___ and then take __ dB steps to find the threshold
Disordered ear will have threshold at ___, ____ or ___
85 dB HL, 5 dB
105, 110, or no response
ART measurement procedures: ipsilateral
Tone (activator) is presented in the ear while acoustic admittance is being measured (probe assembly) in the same ear
ART measurement procedures: contralateral
Tone (activator) is presented to one ear while acoustic admittance is being measured (probe assembly) in the other ear
The ear receiving the tone (activator) is the test ear
Clinical acoustic reflex measures ….
test for the presence or absence of the acoustic reflex
What is the acoustic reflex threshold?
Level of the activator tone producing the smallest measurable change in acoustic admittance
What is acoustic reflex decay?
Amount by which the reflex amplitude has changed after 5 seconds for signals at 500 or 1000 Hz
Drop of 50% in amplitude
A disorder at any stage of the acoustic reflex arc can result in _____
Abnormal reflex measures
Acoustic reflex measures for middle ear disorder will …
Be absent for all measures involving that ear
Acoustic reflex measures for cochlear disorders will …
Be absent ipsilaterally and contralaterally if bilateral and > 50 dB HL in both ears
Be absent ipsilaterally and contralateral if unilateral and > 50 dB in the affected ear only
What are auditory evoked potentials testing?
Neural integrity
What is the definition of auditory evoked potentials?
Waveforms that arise from synchronous activity of neurons in various parts of the auditory system
Measuring electrical activity
What causes the electrical potentials generated by the auditory evoked potentials?
Acoustic signals
The activation of the electrical potentials follows a specific ___ and ____
Auditory evoked potentials are measures of the amount of ____ _____ (amplitude) as a function of ____.
pathway, timeline
electrical activity, time
What is the set up and procedure to measure auditory evoked potentials?
Set up: Electrodes are placed on the patient’s skull and a receiver is seated in the ear canal
Procedure: series of brief tones or clicks are presented, amplitude of electrical activity that occurs after each stimulus is recorded at each electrode, hundreds of stimuli are averaged to find the response common to every stimulus
ABR looks at the ____ ______ and ___ ____
Auditory nerve, brain stem
ECoG or ECochG is an electrophysiologic measure that records ….
Electrical activity generated by the cochlea and auditory nerve
In an ECochG ____ ____ (__ ___) is generated by the cochlea and ____ ____ (___ ___) is generated by the auditory nerve
Summating potential (SP), action potential (AP)
Abnormal response in the ECochG indicates
inner ear fluid or Mienieres disease
Middle latency response reflects ….
Electrical energy that radiates from the cortex following an auditory stimulus
When looking at middle latency response we are focused on
Early evoked potentials that occur 15 to 60 ms post stimulus
CAEP or auditory late response is generated by ___ and occurs ___
Auditory thalamic and cortical sources
60 msec post stimulus
What is the diagnostic significance of MLR and CAEP?
Evaluate and monitor cortical function in individuals
Monitor maturation of the central auditory system
Identify auditory problems at the level of the brain
ABR is the most common ….. and originates in the
Most common evoked potential used clinically
Originates in the VIIIth cranial auditory nerve and extends to the inferior colliculus
ABR: wave I, wave II, wave III, wave IV, and wave V are generated by
I: Auditory nerve II: Cochlear nucleus III: Superior olivary complex IV: Lateral lemniscus V: Inferior colliculus
What is the diagnostic significance of ABR?
Determine hearing loss for patients who cannot subjectively give information (young children, dementia etc)
Interpret health of the auditory nerve/hearing beyond the cochlea
ABR procedure
Presentation level is reduced incrementally until the waves are no longer visible
Waveform is evaluated in terms of amplitude and latency of individual peaks (waves)
Describe the change in amplitude based on stimulus level during ABR
Directly related to level of stimulus so amplitude increases as level increases and vice versa
ABR: what is latency?
Absolute and relative timing of each wave in msec
ABR: Absolute vs relative latencies
Absolute: wave I, wave III, wave V, where actual peaks occur
Relative: Wave I-III, wave III-IV, wave I-V, peak to peak differences
ABR: what is latency’s relationship to stimulus level?
Inversely related
As stimulus level increases, latency decreases
ABR: values are plotted on a graph of ____ as a function of ____ ____, resulting function is called _____-_____ ____
Latency, stimulus intensity, latency-intensity function
ABR: The latency-intensity functions of adults with ____ ____ are used to evaluate the results of patients with ____ ____ ____
normal hearing, suspected hearing loss
ABR: what are the normal wave latencies at high presentation levels?
Wave I: 2
Wave II: 4
Wave III: 6
All in msecs
ABR: what are the normal interpeak latencies?
I-III: ~2.51 msec
III-V: ~2.31 msec
I-V: ~4.54 msec
ABR: relation to hearing sensitivity
- Because the latency and amplitude of the ABR response is related to the intensity of the stimulus, a threshold response can be determined
- Use ABR to get best guess of what their thresholds would be on the audiogram when the patient cannot give you subjective information
Abnormal ABRs: conductive hearing loss
Latency is late for all the waves, latency shifted for every single peak
Why? Takes longer to get past the roadblock
Abnormal ABRs: SNHL
Amplitude is reduced overall
Cochlea is impaired so do not pick up the sound with the same intensity as someone with typical hearing
Abnormal ABRs: Neuropathology
Higher latency for some of the peaks
Peak I is fine since it is the first stop after the cochlea, peaks after that will hiit the road block and create extended inner peak latency
Like acoustic immittance, OAES ….
Objective
Not a test of hearing senstivity
Definition of OAEs
Low-level acoustic signals of cochlear origin that may be recorded within the ear canal
Estimate of cochlear function
Where do OAEs come from?
-Cochlear amplifier (the outer hair cells that add energy to the system)
OAEs are a by-product of the active process in a ____ ____
Any signal presented to the ear has two components: ____ and _____
normal cochlea
forward transmission, backward transmission
OAEs: With forward transmission, the signal proceeds through the auditory system in an ____ _____
efficient manner
OAEs: Backward transmission
- When the signal reaches the cochlea, the active process generated by the outer hair cells causes a ____ that moves ____ along the ____ ____
- That ___ is transmitted back through the ___ ___ in the ___ ____ and then converted to an ___ ___ by the ___
Ripple, backward, traveling wave
Ripple, ossicular chain, middle ear, acoustic signal, TM
OAEs: acoustic signal is very ____ (ranging from _ to _ dB SPL) and is ___ related to the level of the stimulus
Emissions only occur in ____ cochlea and ____ need to be functioning normally to produce emissions
small, 0, 20, directly
healthy, OHCs
OAEs: testing setup
Probe assembly seated in the ear canal
Probe contains a loudspeaker (tone generator) and a microphone
Stimuli presented through the tone generator in the ear canal
What are the two categories of OAEs?
Spontaneous: OAEs occur in absence of external stimulation
Evoked: OAEs occur after a stimulus is presented to the cochlea
What are the three types of Evoked OAEs?
Transient Evoked (TEOAE): elicited by transient pulse, very quick
Distortion product (DPOAEs): elicited by simultaneous presentation of 2 pure tones, present 2 pure tones and get 3rd back out
Stimulus Frequency (SFOAEs): elicited by continuous tone
Transient evoked OAES:
OAEs are elicited using a ___ ___
Clicks stimulate a ___ range of frequencies along the ___ ___
Produce OAEs across a ____ range of frequencies
Occur about __ msec after the onset of the stimulus and last about ___ msec
Click stimulus
Wide, Basilar membrane
Wide
4, 10
TEOAEs:
Usually present at frequencies between ___ and ___ in normal ears
Absent at frequencies with hearing thresholds > ___ dB HL
Not super sensitive to ___ hearing losses at 30 dB
Normal response indicated by __ dB SNR or more
1000 and 5000
30
mild
6 dB HL
DPOAEs:
Evoked by presenting ___ tones ____
__ tones interact on the basilar membrane to produce
Two, simultaneously
Two
DPOAEs:
Third tone can be calculated based on the frequency relationship between the __ tones
Equation: _____
Two
2F1 -F2 = DPOAE, F2 being the higher of the two freqeuncies
DPOAEs:
Emissions are present for frequencies between ___ and ____ Hz in ears with normal hearing and absent in ears with hearing thresholds >____ dB HL.
DPOAEs are absent with hearing loss greater than ___ dB HL
SNR still needs to be __ dB or more
1000, 8000
40 dB HL
40 dB HL
6 dB
DPOAEs:
Anything below 2000 Hz can be contaminated by ____ _____
Background noise
OAEs relation to hearing sensitivity:
Results can be used to tell if there is or is not a cochlear insult at ___ ___
Does not indicate ____ of ____
Only know that thresholds are better than ___ dB HL for TEOAEs or better than __ dB HL for DPOAEs for specific frequency regions
Specific frequencies
Degree of loss
30, 40
OAEs are ___ or ___ in cases of significant middle ear disorders (negative pressure, middle ear fluid, etc.)
reduced, absent
OAEs are used to identify individuals with potential hearing loss for ….
Newborn hearing screening
Difficult to test patients
Functional hearing loss
OAEs are used to monitor changes in cochlear function during ….
Ototoxicty (chemotherapy)
Progressive hearing loss
Noise exposure
OAEs are also used to differentiate diagnosis between ___ and ____
OAEs are useful for ___ the site of ___ to area peripheral, or central, to the OHCs
Cochlear vs neural lesions
Narrowing the site of lesion
Would OAEs be affected with lesion at … o Outer ear canal o Pathology at TM o Pathology in the ossicles, middle ear space o Pathology at OHCs o Pathology at IHCs o Pathology at the nerve
Outer ear canal YES CHL means no OAEs Pathology at TM YES CHL means no OAEs Pathology in the ossicles, middle ear space Yes CHL means no OAEs Pathology at OHCs YES OHCs generate OAEs Pathology at IHCs NO Beyond the scope of the test so no Pathology at the nerve NO, beyond the scope of the test
Purpose of audiometric testing of children is to determine …. (3)
The child’s hearing sensitivity and auditory function
The etiology of hearing loss (Cause)
Appropriate intervention
Most of the diagnostic tests and tools used with adults are ____ for use with children
Adapted
Picking test based on what is appropriate for the age group
__ hearing loss can be identified, the ___ intervention can be applied, the ___ the outcomes for the child because there is a ___ ____ for language development
earlier, sooner, better, critical period
Cut off for normal hearing is __ dB HL for pediatrics
20 dB HL
Intake procedure for pediatric audiology
Observe the child
Interview parents/guardians
Obtain a medical history
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss?
- Concerns from parents or other caregivers of speech, language, hearing, or developmental delay
- Recurrent otitis media
- Family history of permanent hearing loss*
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (NICU)
Extracorporeal Membrane Oxygenation (ECMO)
Ototoxic medications or Loop diuretics
Hyperbilirubinemia requiring exchange transfusion
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (In utero infections)
Cytomegalovirus (CMV)* Herpes Rubella (German Measels) Syphilis Toxoplasmosis
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (craniofacial anomalies)
The pinna Ear canal Ear tag Ear pits Temporal bone abnormalities
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (syndromes)
Syndromes associated with hearing loss or progressive or late-onset hearing loss such as:
- Neurofibromatosis (causes tumors and growth)
- Osteopetrosis
- Usher’s syndrome
- Waardenburg
- Alport
- Pendred
- Jervell and Lange-Neilson
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (neurodegenerative disorders and sensorimotor neuropathies)
Neurodegenerative disorders* -Hunter syndrome Sensorimotor neuropathies -Friedreich’s Ataxia -Charcot-Marie-Tooth syndrome
What are some indicators of risk for permanent, congenital, delayed-onset, or progressive childhood hearing loss? (postnatal)
Culture-positive postnatal infections associated with sensorineural hearing loss*
- Confirmed bacterial and viral (especially herpes viruses and varicella) meningitis
- head trauma
- chemotherapy
Objective tests that can be used in pediatrics because they are for all ages
Acoustic immittance (tymps and acoustic reflexes), OAEs, ABR
Subjective tests that can be used for pediatrics (ages) …
Visual reinforcement Audiometry (9 months to 2 years)
Conditioned play audiometry (2-4 years)
Objective tests:
Tympanometry is used for children __ months of age and older
Use a ___ probe tone
To overcome resonance differences in infant ears, a higher frequency probe tone is used ( ____ or ____ Hz)
7 months of age or older
226 Hz probe tone
660 to 1000 Hz
Objective tests:
Acoustic reflex thresholds can be measured in infants less than ___ months of age
Require ____ Hz probe tone and ___ activating stimulus
Reflex thresholds are about ___ dB ( __ dB SPL) lower than adults
7 months of age
Require 1000 Hz probe tone, broad
14 dB (70 dB SPL)
Objective tests:
OAEs useful for identifying patients with hearing loss but __ of hearing loss cannot be determined due to OAEs being __ in normal hearing ears and ___ in ears with hearing loss
Degree
Present
Absent
Objective tests:
OAE amplitude in newborns is ___ than in adults, continue to __ in amplitude for the first 2 months of life then ___ throughout life
Larger
Increase
Decrease
Objective tests:
ABR are appropriate for children ___ months of age and older
Need to make ___ for younger children
Latency of wave V matures to adult values around __ months of age
In infants, wave __ is the prominent response rather than wave V (in adults) because wave I is mature at birth for infants
Need to use __ ___ norms to interpret ABR results
12 months of age or older Adjustments 12 months of age I Age specific
Thresholds obtained with ABRs are only ____ of actual hearing thresholds. Thresholds should be obtained with ____ measures as soon as possible (when the child is old enough).
Estimates
Subjective
Subjective tests for auditory sensitivity are based on … and include which four criteria?
- Operant conditioning techniques
- Four conditions:
- Work for the majority of the population for which they were intended
- Yield results that are precise and relevant for case management
- Quick
- Cost effective
Subjective tests: primary goal when testing children is to …
Obtain individual ear, frequency specific, hearing thresholds.
Subjective tests include …
Sound field testing, frequency specific stimuli
Subjective tests:
Behavioral observation audiometry involves and is used for
Involves:
Observing changes in activity state of an infant in response to sound (eye widening, eye blink, smiling, stopping activity, startle reflex, etc.)
Used for:
Newborns to about 4 months
Subjective tests:
Visual reinforcement audiometry basis
The child is conditioned to look toward the source of a sound.
Localization on the horizontal plane develops at about 6 months.
Localization for auditory stimuli is easily reinforced in 8-15 month olds
Subjective tests:
Visual Reinforcement Audiometry Procedure
- One examiner is outside the sound treated room operating the audiometer.
- Another examiner is inside the room directing the child’s attention towards a midline position.
- A tone is played through a loudspeaker or earphones to one ear.
- The child indicates that he/she heard the sound by turning toward the sound.
- Toys light up while everyone goes crazy with cheers and clapping.
Subjective tests:
Visual Reinforcement Audiometry considerations
Speech awareness threshold can be obtained using __ ___ __
Testing ___ to ___ Hz
Considerations:
The room must be free of distracters.
The reinforcement must be appropriate.
monitored live voice
500 to 4000 Hz (as much as you can get while keeping child engaged)
Subjective tests:
Conditioned play audiometry basis ….
The child is conditioned to respond to a stimulus by playing a game
Subjective tests:
Conditioned play audiometry procedure
- One examiner is outside the sound treated room operating the audiometer.
- Another examiner is inside the room playing with the child.
- A tone is presented through a loudspeaker or earphone.
- The child indicates that he/she heard the sound by throwing a ball into a bucket (or something equivalent).
- Joy and merriment ensue.
Subjective tests:
Conditioned play audiometry considerations
Speech awareness threshold can be obtained using ___ ___ ___
May be able to get speech reception threshold by ___
Testing ___ to ___ Hz
Considerations:
Must also include control trials (periods with no stimulus).
The more variety of games available the longer the child will play.
Monitored live voice
Pointing
500 to 4000 Hz (as much as you can get with cooperative child)
Conventional audiometric procedures can be used ~ ___ and older
May need to skip ___ to keep interest
Instruct child to raise ___, push ___, or make a ___
Watch for _____
5 years and older
Interoctaves (3000, 6000 Hz)
Hand, button, game
Malingering
Speech audiometry involves using ___ words, __ toys, ___ picture board
Have child ___ to whatever is said
Spondee
Point
Speech understanding tests involve ___ ___ by picture identification
Uses closed set test with _ pictures to choose from
Northwestern University Children’s Perception of Speech (NU-CHIPS)
-Closed set test with _ pictures to choose from
Word intelligibility
6
4
Speech understanding tests can also include ……
Phonetically Balanced Kindergarten words (PbK)
- Present similar to WRS for adults
- May need to do MLV to get child involvement
