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18 Interpreting Audiologic Test Results and Using the Test Information to Plan Management
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
and conceptual knowledge, auditory attention, and auditory
memory and to teach children to love literature.
Sing to and with the child every day. (Adult-directed singing
•
is an important aspect of auditory brain development and the
paralinguistic aspects of language development.)
Educational Recommendations
See Appendix 18.1 for an extensive list of possible recommendations that include the topics of RM use, classroom noise
accommodations, strategic seating, teaching accommodations,
test accommodations, and other services.
Special Considerations
Recommendations should not be made based on degree of
hearing loss; they should be made based on formal and informal
assessments.
Profound Hearing Loss
A child with a profound hearing loss who receives an implant
at 9 months of age is in a completely dierent situation than a
child with a profound hearing loss who receives an implant at 18
months of age or at 4 or 5 years.9 Although both children should
have good auditory brain access through the technology, the
child who was implanted later will have had a longer period of
auditory deprivation. As a result, it will take him much longer
to obtain the necessary auditory exposure and practice for
auditory/linguistic development. Work by Sharma10 and others
indicates that he will not achieve the same level of performance
as the child implanted at 9 months. A child with a profound hearing loss who is not implanted until age 10 or 12 years and who
did not have access to auditory information prior to receiving an
implant is dealing with an extremely dicult situation because
of cross-modal reorganization of the auditory cortex, a process
that will make auditory skill development very dicult.
Mild and Unilateral Hearing Loss
A mild hearing loss in a child does not pose a simple, “mild”
problem. A mild hearing loss can have substantial social, emotional, developmental, and academic implications. Most studies
suggest that children with a mild hearing loss are more likely
to have to repeat a grade then their typically hearing peers and
to have academic and/or cognitive deficits. They score more
poorly on standardized tests, including tests of reading vocabulary, language mechanics, phonological short-term memory
and discrimination, and word analysis. Teachers have observed
higher levels of dysfunction in classroom settings for children
with mild hearing loss compared with their typically hearing
peers. Several authors
with mild hearing loss rated themselves as having less energy
11,12
have reported that younger children
than their typically hearing peers, which may be the result of
increased listening eort. Because of diculty listening in any
thing other than an ideal acoustic environment, children with a
ild hearing loss may not hear or may mishear their peers in a
m
social situation, resulting in inappropriate behaviors.
Minimal and mild hearing loss is often missed during newborn
hearing screening and school screenings. ABR may not identify
mild hearing loss, and school screenings often utilize a passing
criterion at 25 dB HL. As a result, children with mild hearing loss
often do not get identified until they start demonstrating lan-
guage learning issues or academic problems in school. Population
studies have indicated that by the time children reach school age,
as many as 0.88%13 of school-aged children have a minimal or
mild hearing loss and as many as 14%12 may have a low- or high-
frequency unilateral hearing loss.
Noise presents a significant problem for any child with a
hearing loss, even a mild hearing loss. The eect of hearing loss
in a classroom may result in problems with word recognition
and spelling, distinguishing morphological markers, and hearing
indicators of plurality, possession, and tense.
Evaluation should include assessment of speech perception in
soundfield at normal and soft conversational levels in quiet and
in competing noise to accurately assess a child’s ability to hear
in daily living situations and to make appropriate management
recommendations.
14
18.5 Conclusion
The audiologist has a responsibility to evaluate fully all aspects
of a child’s performance before finalizing audiologic recommendations. That is, the audiologist should be studying the
whole child: the child’s language, educational performance, and
social-emotional functioning. By considering all aspects of a
child’s performance, the audiologist has a key role in ensuring
the child’s developmental progress.
Discussion Questions
1. What is validity as applied to audiologic tests?
2. What is reliability as applied to audiologic tests?
3. What is the distinction between verication and validation of
hearing aid ttings?
4. How are speech perception data used in making educational
recommendations for a child with hearing loss?
References
[1] Leigh J, Dettman S, Dowell R, Sarant J. Evidence-based approach for making
cochlear implant recommendations for infants with residual hearing. Ear Hear
2011;32(3):313–322
[2] Dillon H. Hearing Aids. 2nd ed. New York, NY: Thieme; 2012
[3] Demorest ME, Walden BE. Psychometric principles in the selection, interpreta-
tion, and evaluation of communication self-assessment inventories. J Speech Hear
Disord 1984;49(3):226–240
[4] Haskins H. A Phonetically Balanced Test of Speech Discrimination for Children
[master’s thesis]. Evanston, IL: Northwestern University; 1949
[5] Humes LE. Verification and validation: The chasm between protocol and
practice. Hear J 2012;65(3):8–12. http://journals.lww.com/thehearingjournal/
-
201
II Diagnosing Hearing Disorders in Infants and Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Fulltext/2012/03000/Cover_story__Verification_and_Validation__The.1.aspx.
Accessed December 27, 2017
[6] Elliot L, Katz D. Development of a New Children’s Test of Speech Discrimination.
St Louis, MO: Auditec; 1980
[7] Glista D, Scollie S. Development and evaluation of an English language measure
of detection of word-final plurality markers: the University of Western Ontario
Plurals Test. Am J Audiol 2012;21(1):76–81
[8] Cole E, Flexer C. Children with Hearing Loss: Developing Listening and Talking,
Birth to Six. 3rd ed. San Diego: Plural; 2016
[9] Boons T, Brokx JP, Dhooge I, et al. Predictors of spoken language development
following pediatric cochlear implantation. Ear Hear 2012;33(5):617–639
[10] Sharma A, Martin K, Roland P, et al. P1 latency as a biomarker for central
auditory development in children with hearing impairment. J Am Acad Audiol
2005;16(8):564–573
[11] Bess FH, Dodd-Murphy J, Parker RA. Children with minimal sensorineural hear-
ing loss: prevalence, educational performance, and functional status. Ear Hear
1998;
19(5):339–354
[12] Tharpe AM. The impact of minimal and mild hearing loss on children. Paper
presented at the 4th Widex Congress of Paediatric Audiology, Ottawa, Canada,
May 19–21, 2006
[13] Tharpe AM. Unilateral and mild bilateral hearing loss in children: past and
current perspectives. Trends Amplif 2008;12(1):7–15
[14] Anderson K, Arnoldi KA. Building Skills for Success in the Fast-Paced Classroom:
Optimizing Achievement for Students with Hearing Loss. Hillsboro, OR: Butte;
2011
[15] Madell JR. Acoustic accessibility: the role of the clinical audiologist. In: Smaldino
JJ, Flexer C, eds. Handbook of Acoustic Accessibility: Best Practices for Listening,
Learning, and Literacy in the Classroom. New York, NY: Thieme; 2012:128–142
Appendix 18.1
The following was adapted from Madell.
Educational Environment
Recommendations
Personal Remote Microphone Systems
1. RM for use during all academic subjects
2. Teacher training in appropriate use of the RM system
3. Troubleshooting information for RM system
4. Develop a system for the teacher to verify that the RM is working
daily
5. Assign responsibility for charging the system daily
6. Loaner RM system available should the child’s system break
Assign responsibility for having RM system checked and
returned to the factory for servicing over the summer when
needed.
Classroom Noise Accommodations
1. No open classrooms
2. Select a classroom away from lunchroom, toilets, elevator shafts,
hallways, and playground to reduce noise
3. Carpeting in noisy places such as the block corner
4. Acoustic tiles on walls and ceilings as possible
5. Tennis balls or Hushh-ups (Sound Listening Environments, Inc.,
Mississauga, ONT, Canada) on chair and table legs to reduce noise
6. Monitor noise from heating and ventilation system and repair
as needed
16
Strategic Seating
1. Seating in the front third of the classroom near the side to allow
the student to see the teacher and also other students, keeping
in mind that, realistically, teachers move around the classroom,
which further supports the need for RM technology
2. Permission to move around the room as needed to hear and see
Teaching Accommodations
These accommodations can make a significant dierence in a
child’s success.
1. Work to keep the classroom quiet to facilitate listening and
learning for all children.
2. Teacher’s rate, pitch, articulation make speech easy to
understand.
3. Teacher faces student when speaking to facilitate receiving
information.
4. The classroom should encourage verbal communication, with
the opportunity for children to speak with each other.
5. Repeat comments of other students into the RM to be sure the
student with hearing loss hears them.
a. Use pass mic for RM to allow each student in the classroom
to speak for herself.
b. Identify by name students who are speaking so that the child
with hearing loss knows where to look for the student who
is speaking
6. When students are working in small groups, allow another student in the group to wear the RM.
7. Call the student with hearing loss by name to be sure she knows
you are talking to her.
8. Confirm that the child with hearing loss hears and understands by asking questions (not “Did you hear that?” or “Do you
understand?”).
9. Reword, rather than repeat, if the message is not understood.
10. Encourage the student to ask for clarification when information
is not clear.
11. Write assignments and school announcements on the board or
in a handout to be certain that the child receives the information
accurately.
12. Consider assigning a buddy who can help the student with hearing loss get assignments, obtain written notes, know what page
to turn to, and so forth.
13. Observe what the student does and does not hear, and report
this information to the audiologist, Teacher of Deaf or Hard of
Hearing (TOD/HH), and speech-language pathologist to modify
management.
14. Activities requiring critical listening should be interspersed with
activities that do not require listening, to reduce fatigue.
15. Provide listening breaks during the day to reduce the stress of
listening.
Test Accommodations
1. Testing should take place in a quiet room away from noise and
interference.
2. Directions should be provided clearly, and the tester should verify that the student understands.
202
18 Interpreting Audiologic Test Results and Using the Test Information to Plan Management
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
3. Spelling tests should include a sentence so that words that sound
similar will not be confused.
Other Services to Be Considered
1. Regular audiological evaluations to monitor unaided and aided
hearing
2. Auditory-based speech-language therapy with a therapist experienced in working with children with hearing loss
3. TOD/HH students to assess academic skills and preview and
review academic material
4. Other tutoring as needed
5. Resource room as needed
6. Therapy or tutoring services conducted in a quiet place to facil-
itate learning
7. System for connecting to computers or other media in “smart
classrooms”
8. Team meetings for all sta working with the child with hearing
loss to discuss concerns and plan remediation
203
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
III
Hearing Access Technologies for Infants and Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
19 The Acoustic Speech Signal
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Arthur Boothroyd
19 The Acoustic Speech Signal
Summary
The sound patterns of speech have an average overall level of
around 60 dB sound pressure level when measured at a conversational distance. These patterns contain components that
are distributed across a wide frequency range, from below 125
Hz to higher than 8,000 Hz. Most of the energy is in frequency
regions below 1,000 Hz, but the maximum concentration of
useful information is between around 1,000 and 3,000 Hz. This
is the range covered by the second vocal-tract formant, which
conveys considerable information about place of articulation. At
any frequency, the short-term amplitude varies rapidly between
15 dB above and below the average. Expressing speech levels in
relation to normal hearing threshold and transferring them to
an audiogram form results in the “speech banana.” Examination
of this area in relation to a child’s audiogram can provide
insights into the acoustic cues, phonetic cues, and phonemes
that are likely to be accessible to the child with and without the
benefits of assistance from hearing aids or cochlear implants. It
is important to realize that assisted hearing, regardless of the
form that assistance takes, is not perfect and that diculties
of discrimination and noise susceptibility are likely to remain.
Nevertheless, providing comfortable access to the information
contained in the acoustic patterns of speech is an essential first
step in auditory-oral intervention.
Keywords
acoustics, amplitude, distance, spectrum, formant, audiogram,
speech banana, audibility, intelligibility index, intelligibility,
spoken language, hearing aid, cochlear implant
form. Its relationship to aided and unaided thresholds can
provide a sense of the child’s access to the acoustic speech
signal.
19.1 Speech Amplitude
As is clear from this text, management of children with hearing
loss has many interrelated components. Key among them is
provision of comfortable audibility of the information-bearing
components of the acoustic speech signal. Accomplishment of
this goal sets the stage for optimal development of the ability to
interpret, produce, and use language in its spoken form. It follows
that a thorough understanding of the acoustic speech signal and
its information-bearing properties is an important component
of the knowledge base of clinicians, educators, and therapists
involved in the management of children with hearing loss.
A basic property of the acoustic speech signal is its amplitude,
or decibel level. Unfortunately, specifying a single decibel level for
speech is not simple. The level varies with distance from the talker,
it varies with frequency, and it changes over time. To complicate
matters, it diers from talker to talker and it varies with talker
eort and orientation. If, however, we select an average talker,
speaking with average eort, at a conversational distance of 4 feet,
sum across frequency, and average over time, we arrive at a single
value of around 60 dB sound pressure level (SPL), as shown for the
child closest to the talker in Fig. 19.1.
Pearl
The sound energy in conversational speech, summed across
Key Points
The proportion of the useful information in the acoustic
•
speech signal that is accessible to a listener is known as the
speech intelligibility index.
The goal of sensory management is to provide the child with
•
as high a speech intelligibility index as possible as a rst step
in promoting spoken language prociency.
A good speech intelligibility index may lead to good speech
•
intelligibility, but the two are not the same thing.
The acoustic speech signal covers a wide frequency range
•
from below 125 Hz to above 8,000 Hz, but most of the useful
information is concentrated between 1,000 and 3,000 Hz.
The acoustic speech signal also covers a wide amplitude
•
range from 15 dB below the average to 15 dB above, and
useful information is assumed to be spread uniformly across
this range.
The speech banana shows the frequency and amplitude range
•
of the acoustic speech signal as an area on the audiogram
frequency and averaged over time, has a level of around 60 dB at
the listener’s location.
19.2 Amplitude and Distance
Fig. 19.1 also illustrates the eect of distance. Speech amplitude
falls with increasing distance from the talker, following the
inverse square law. When amplitude is expressed in decibels,
the inverse square law translates into the 6-dB rule. The speech
level falls by 6 dB for every doubling of distance from the talker.
Assuming the adult in Fig . 19.1 is addressing the nearest child,
who is 4 feet away, that child hears her at 60 dB; the next child,
at 8 feet, hears her at 54 dB; the child at 16 feet hears her at 48
dB; and the child at 32 feet hears her at only 42 dB. Of course,
if the talker were actually addressing the child at 32 feet, she
would most likely raise her voice. We are aware of the eects
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III Hearing Access Technologies for Infants and Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
of distance and usually try to compensate by increasing speech
level—sometimes unnecessarily so when using a telephone or a
wireless microphone system (see Chapter 24).
Strictly speaking, the 6-dB rule applies only outdoors or in
special anechoic rooms with walls, oor, and ceilings that do not
reect sound; hence the choice of context for Fig. 19.1. In typ-
ical rooms, however, the rule breaks down beyond the distance
(known as the critical distance) at which sound reections begin
to dominate the received signal. These reections can actually add
to the amplitude for listeners who are beyond the critical distance,
but they detract from intelligibility if they arrive too late.
Note that the 6-dB rule works in reverse. That is, the level
increases by 6 dB when the talker-listener distance is cut in half.
Because the talker’s ear is only about 6 inches from the talker’s
mouth, the decibel level at one’s own ear can be as much as 18 dB
higher than at the ear of a listener who is 4 feet away. The loud-
ness of the wearer’s own speech needs to be taken into account
when fitting or adjusting hearing aids and cochlear implants. The
benefit of reduced distance is particularly relevant when holding
a baby. The distance from the talker’s mouth to the baby’s ear is
only about 1 foot, so the speech level is some 12 dB higher than it
is at 4 feet.
To deal with the eects of distance, and other factors aecting
the received speech level, hearing aids and cochlear implants
usually incorporate compression amplification. When this is
activated, a wide range of decibel levels at the input to the microphone produces a smaller range of output levels to the listener
(see Chapters 23 and 24).
2
1
Fi g . 19.1 The long-term average level of speech, in dB sound pressure
level (SPL), at various distances from an average talker. The talker is
assumed to be speaking with conversational eort to the rst child,
who is 4 feet away.
Pearl
The level of speech signal coming directly from the mouth of the
talker falls by 6 dB for every doubling of distance and rises by 6 dB
for every halving of distance.
19.3 The Speech Spectrum
Sound energy is not distributed uniformly across frequencies.
To determine the relationship between level and frequency, we
filter the speech signal into narrow frequency bands, typically
one-third of an octave wide. By measuring the average level in
each band, we obtain the long-term average speech spectrum
(LTASS), as shown in Fig. 19.2. Several researchers have provided
empirical data on this topic, and their results have been quite
consistent,
19.2 are taken from Cox and Moore4 and represent the average of
30 men and 30 women. The published levels have been adjusted
in Fig. 19.2 to correspond with an overall level of 60 dB SPL. Also
shown is the normal threshold of hearing for young adults.
Note that the normal soundfield hearing threshold tends to parallel the long-term average spectrum. In other words, the loss of
speech energy in the higher frequencies is partially compensated
by an increase of hearing sensitivity at those frequencies. As we
will see later, access to the information contained in those fre-
quencies has a major eect on the ability of speech and hearing to
play their full role in the development and use of spoken language
for communication.
3,4
even across languages.5 The specific data in Fig.
6,7
Fig. 19.2 The long-term average speech spectrum (LTASS) in one-
third-octave band levels.
Pearl
The acoustic speech signal contains frequency components
between around 100 and 8,000 Hz (or even higher). When
analyzed by frequency, most of the energy is found in the lower
frequencies. The level at the listener’s location falls by around 6
dB for every doubling of frequency (i.e., 6 dB per octave) above
500 Hz.
19.4 Short-Term Amplitude
Variation
So far, the discussion has been about the level and spectrum of
speech averaged over time. But one characteristic of speech is its
208
19 The Acoustic Speech Signal
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
rapid variability. Words follow each other at the rate of around
four per second. Some words contain louder vowels, and some
receive more stress than others. Within the words, individual
speech sounds follow each other at the rate of around 13 per
second, and some are inherently louder than others. Add to this
the facts that talker eort can change over time and that talkers
dier from each other. When these factors are taken into account,
it is found that the short-term speech level can vary by as much as
15 dB above and below the average, as illustrated in Fig. 19.3. This
figure seems to indicate an upper limit of 8,000 Hz for the sound
energy in speech. In fact, the spectrum does extend to higher
frequencies, especially for the “s” sound.8 But the ability to hear
these higher frequencies, though it may be important for such
things as sound localization, makes little contribution to speech
intelligibility. This is one of the reasons that pure-tone audiome-
try does not normally include frequencies higher than 8,000 Hz.
Pearl
In any frequency band, the level of useful information in the
acoustic sp eech signal changes rapidly from m oment to moment,
from around 15 dB above the average to around 15 dB below it.
19.5 Speech and the Audiogram
Form
So far, we have examined the spectral distribution of speech in
dB SPL, with 0 dB representing a standard reference and increasing amplitude shown in an upward direction on the graphs. In
order to show this distribution in relation to a child’s audiogram,
however, we need to turn our data upside down and express it
in dB HL, where 0 dB represents the normal threshold of hearing
and increasing (i.e., poorer) threshold is shown in the downward
direction. The result is shown in Fig. 19.4.
Because of its shape, the spectral distribution of speech on the
audiogram is usually referred to as the “speech banana.” Gunnar
Fant9 was one of the first to examine the spectral distribution of
speech energy in relation to the audiogram form. He apparently
referred to it as the “speech sausage” (Plant G, personal communication, 2016), but subsequent researchers started using “banana,”
and the name has stuck.
Note that the falling amplitude of speech in the 500 to 3,000
Hz range is no longer apparent in Fig. 19.4. As indicated earlier,
the normal increase of sensitivity to higher-frequency sounds
helps compensate for the loss of high-frequency energy in the
acoustic speech signal. Unfortunately, however, sensorineural
hearing loss most often aects the higher frequencies more than
the lower ones. To make matters worse, the presence of a hearing
aid removes some of the benefits of the ear canal resonance that
contributes to our increased sensitivity to the higher frequencies.
This last eect can, however, be canceled by replicating the resonance eect in the hearing aid response.
Pearl
Transferring the amplitude range and spectrum of conversational speech to an audiogram form results in a banana-shaped
area. The loss of energy in the higher frequencies is no longer
apparent because the undamaged ear is more sensitive to these
frequencies.
Fig. 19.3 The range of moment-to-moment variation in the acoustic
speech signal for an overall level of 60 dB SPL.
Fig. 19.4 The spectral distribution of conversational speech (at 60 dB
SPL) as it appears on an audiogram form.
209
III Hearing Access Technologies for Infants and Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
19.6 The Speech Intelligibility Index
The distribution of useful information across frequencies is not
uniform. Moreover, this distribution is dierent from that of the
sound energy. While most of the energy is concentrated in the
lower frequencies, most of the information is concentrated in the
higher frequencies.
To investigate this issue, researchers have measured the ability
of listeners with normal hearing to recognize individual speech
sounds in syllables from which varying amounts of low- and
high-frequency energy have been removed.
of each frequency band can then be computed and the results
combined to produce the Speech Intelligibility Index (SII).12
This index, known in an earlier form as the Articulation Index,10
provides an estimate of the proportion of the useful information
in the acoustic speech signal that is available to the listener. It is
assumed to be 1 (or 100%) when the listener has access to the
full 30-dB range in all frequency bands. Each band, however, con-
tributes a dierent amount, as shown in Fig. 19.5. In this figure
the contribution of each one-third-octave band is shown both by
the numbers and by the dots. Each dot contributes 1 percentage
point to the total, and the distribution across the 30-dB range, at
each frequency, is assumed to be uniform. This “count the dots”
approach to representing the spectral contribution to the SII was
introduced by Mueller and Killion.
The concentration of information in the higher frequencies is
immediately apparent from Fig. 19.5. A little computation shows
that the frequency bands from 500 to 4,000 Hz, for example,
account for 80% of the total, with the highest concentration being
around 2,000 Hz.
By counting the dots below the threshold line for an individual
child, we can estimate his or her SII. The process is illustrated
in Fig. 19.6. In the left panel we see that only 26% of the useful
13
10,11
The contribution
Fig. 19.5 The contribution of frequency to Speech Intelligibility Index
(SII), represented by dots within the speech banana.
information in the typical conversational speech signal is audible
to this child. In the right panel a plot of the aided soundfield
threshold shows the SII raised to 83%.
Note that Fig. 19.6 shows the spectral distribution of con-
versational speech at around 4 feet. Both values of SII would be
wer for more distant speech and higher for speech that is closer,
lo
a b
Fig. 19.6 Counting the dots that fall below the threshold curves provides an estimation of (a) unaided and (b) aided Speech Intelligibility Index (SII)
for an individual listening to speech of average eort at a conversational distance.
210
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