Without further delay, we will pass through our next
presenter, Professor Mehran.
He's ahead then.
Professor and chairman at the Department of Audiology
and for Fanatics at the Charity University
UNIVERSITATSMEDIZIN in Berlin, Germany.
He's a specialist in fanatics and pediatric audiology
as well as a specialist in EMT medicine.
His medical work covers the entire spectrum of community
disorders, with a focus on the surgical
and conservative treatment of patients with voice disorders,
especially professional singers and actors.
Parallel to his medical studies at universities over at Rostock,
Dublin and Dresden, he completed his singing studies at the Princeton
University of Music with an artistic diploma in 1996
as a scholarship holder of the German National Academy Foundation.
In a research, he is particularly concerned
with the morphological and functional properties of professional voices
and the electrophysiological of the objective
of hearing and language acquisition within scientific work
comprising over 100 specialist articles and book contributions.
He's a member of National and
international scientific committees in this field.
Welcome, Professor Dittmar, And my dear friend,
I hope you enjoy as much as we will of having you here today.
Dear Phillip, our dear colleagues and friends.
It's a great pleasure to contribute to this conference.
And first of all, congratulations
to the lab in metrics and do the marvelous work
which contributes to the world of voice
in this special manner and the gender studies and the aspects
of changing of the voice during the professional work.
This is a highly interesting topic, which is focused by Philip
My employees and her colleagues.
So when we talk about the voice,
then most of the time we talk about acoustics.
We talk about morphology.
What is the reason that you can
distinguish between an artistic singing voice and
just a normal singing voice?
But within the last two years,
we were forced to focus at a totally different aspect.
And this is the voice
and the generator of ourselves.
And droplets and why
this came into our focus,
because the respiratory system works as a dual system.
It's not only the main tune for ventilation,
it is also the source of
voice and spoken language production.
So within the last two years,
the issue of particle generation within the respiratory system
has initiated an immense research activity.
And because of the SARS-CoV-2 pandemic
and the life threatening COVID 19 disease,
that's why today I will not speak about the professional voice
and the special acoustics, the call, but
about the Arizona
acceleration during singing and speaking
And the reason is that aerosols and droplets
are the main carrier, for example, in voices or the SARS-CoV-2 voice.
And SARS-CoV-2 virus within the last two years,
aerosols are not only generated in the lab,
I believe this has been known for a long time
because of the transmission of infectious diseases.
If a means of breathing aerosols are generated as well by
means of the by breaking vocal solids and the articulatory instruments.
And even at the beginning of the pandemic,
we have scientific evidence with regard to increased
infection rates during quieter singing in closed rooms.
So at the beginning of the pandemic, the focus was on droplets
because this was
easy to imagine.
Everybody has seen droplets on the theater stage,
but in the aerosols, the small particles
smaller than the one microliter in diameter, which they have
for a long time in the air, They came later
in our research focus.
But they are one of the main threats
with the transmission routes for the SARS-CoV-2 virus.
That's why we have carried out a couple of studies
about the aerosol particles machine and the clean room condition.
And this has been carried out
in cooperation with the test and certainly doesn't get better.
And here you see all the collaborators
why we need to clean room conditions.
Particles are everywhere.
If we touch our skin, if we touch the tissue, we create particles.
So to find out about the amount of the aerosols
generated by vibrating mobile phones, you need to exclude
all the other sources
as strong as possible.
And that's why clean room conditions are a suitable
experimental set up to investigate the aerosols
which are generated during singing and speaking.
And once more.
This lecture does not focus on
biological or medical issues.
It focuses on the amount of virus
possible virus carrying a suitcase,
which makes it tell you something
about the possible risk of infection
within this.
That is the serious of studies.
We investigated different age groups
to run adolescents and adults,
and we looked at the dependance on loudness.
The dependance on loudness
was described before the ongoing pandemic
And that means if what we're speaking
now is the area of research
with us telling us that loud speaking voice creates
higher emission rates of aerosols,
then lower level speaking voice.
And that's why the risk of
transmission of infectious
viruses is higher producing, not less
The cell phone was that we
included professional singers and nonprofessional singers
to accept the light on the issue on the professional merits of device.
With regard to the Arizona product.
Here you have a photograph
of the experimental condition since we're in the clean room.
You see a singer of the Abbey has come a cappella
and she is singing in a class, too.
And at the middle portion of the glass tube,
there is a laser taking control
and within the glass cylinder or the glass to the wall.
The design is meant there would the particles that transported
and the laser had to get curved.
That allowed us to distinguish the measurement of six size glasses.
Starting from proponents we micrometer
up to 25 microns in
and out
of the measurements and within the
of the air movement
in the cylinder, we could calculate the particle,
the source strains or the particular emission rings.
And because we knew about the relationship between
emission rates and vocal loudness,
we measure that's where the sound rests on that,
which was not easy because usually you measure sound pressure.
So the centimeters away from that.
But that was embedded in the measurements too.
So we had to find the compromise and that was the maximum pressure
level of the experimental air task
which they're produced by the different singers.
First, I would like to tell you
the results of the air are professional singers,
and this has been recently published in scientific reports.
And we had the nice opportunity to include
eight singles of one of the most famous
and professional chamber choirs in Germany.
The results come up with a very And the participants were between
22 and 62 years of age.
And all of our professionals and two of them,
The Sopranos, took over as those two bare tenors.
And we included a sweater to baritone voices
when we asked them to do
two different experiments.
First experiment had four condition, the breathing condition.
So to see the reference condition for singing and speaking,
then the reading condition, they were asked to read the text down,
not or dissolve.
And this is the typical reference text used in a format for
in Germany to assess the quality of voice.
And then we asked them to sing the chorus line of the choir piece
actually provided by Felix Mendoza and our team.
And they did it in their own chorus line for the brand new forward
with the idea for ten children for the parents group pass
This was Experiment one.
In Experiment two, we asked them to do SS team formation
task to find out about
the vocal loudness influence.
And we asked to do the sustained formation
for the piano condition such grouping loudness
medium and our mezzo falter
and the sort of condition with a strong voice.
And first
of all, we assessed the size of the particles.
Here you see the measure size from
1.3 micrometer up to ten micrometer
And you see that nearly 99%
of all metallic particles rest more than six micrometer
So here we really talk about aerosols,
small particles with the
possibility to state for hours
in the air within the room.
And the size of the particles did not differ significantly
between the different conditions breathing,
speaking, singing.
And they didn't differ
significantly for this patient formation task.
Piano mezzo filter cancels
the next figure.
So through the comparison of the eight professional singers
here we have the baritones, tenors, actors, and soprano and the left.
Y axis shows you the Partita and mission rate
in particles per second in the logarithmic scales
and the right access shows to the maximum sound level
showing one or two represented by books.
So first of all, you see that
the singers created here some crucial errors during the scene
task in comparison with the speaking task.
Always guess unprecedented for singing in comparison to speaking
and with regards to the particle emission rates,
the amount of area was possible in virus carriers per second.
You see strong, statistically significant differences
between breathing, speaking and singing.
And that wasn't true for all the choir members.
And for this group, we found a ratio between singing
and speaking about 70
Now, if we combine
all of the measurements we have done, we would
assess the ratio between
singing and speaking about ten.
So ten times more errors there was in singing in comparison to speaking
more cases with the same vocal.
Let's have a look
at the experiment to the different levels, loudness
levels, and we now see the experimental conditions.
Piano mezzo thought that consulted
First of all, obviously the professional ones were highly
educated and they easily could produce
piano mezzo for two and a full day.
And this is reflected by the initial sound
pressure levels for piano mezzo filter and frontal
and over the particular emission rate again in particles
per second in an elaborate mix
and you see a statistically significant difference between
the 40 conditions in comparison to the mezzo condition and the slower
statistically significant difference between the mezzo for the condition
and the piano condition.
And if you plot that in this way, showing the same pressure
never on the axis and the particle emission rate on the by X is
so you see the strong dependency
of the practical emission rate on both the lines
we didn't find
in this investigation going back to this figure that
sopranos, tenors and terrorists
and baritones differed significantly from each other
and this was the result for the comparison of Springsteen's
speaking and singing, as well as the
loudness conditioning experiment, too.
Let's turn to the next experiments.
And we are keen on investigating children and adolescents
because in the pandemic has had or still
has a strong an influence
on our curricular settings in school and in spare time
conditions singing in school and choir activities.
So it seems to be necessary to distinguish
between the Araceli emission rates for adults and children.
To facilitate, if possible,
the conditions for children in the school.
And in this experiment, we included eight children,
adolescents, a with an age of 13 years.
One child was 15 years.
And although we are members of a semiprofessional choir
and we had four girls and boys and all
had the experience of choir singing of the couple.
Yes. And
the record is where the reference text
they are not saying it would be desire
and for singing we ask them to produce a song
very similar to the choir members and this was a Swedish folk song
and because to reflect reality in their children's lives,
we asked them to create conditions like shouting, cheering
to cats in the high vocal loudness this.
And this was all done
with sustained formation
and this figure is similar
to the ones we have professional ones and you can again you see
there are significant differences between speaking in green
and singing in lyrics.
And again you see differences in the sound professional levels
from speaking singing to shouting
are impressive enough.
The shouting condition really ended up with much higher up
aerosol emission rates in comparison
to the singing condition.
And again, if you look at the dependency
of the Arizona emission rate on the vocal loudness
in this not showing
the correlation between the two measures
and from this investigation,
we draw the first conclusion well, that the condition of when children
might sing a song in mezzo photo or the piano,
this might be less associated with increased
infection risk in comparison with the typical condition in the classroom.
A teacher friend running around
cheering, laughing with
higher levels of problems
So finally, we got the permission to investigate
whether children bring with the age of eight to ten.
We saw small children
in class three or four.
And so we had 15 children that participated in this study.
They all we delighted by the experimental set up
bearing this especially closes as you can imagine.
And here we included nonprofessional or semiprofessional singers
as a reference group, a 15 singers of the Philharmonia
School, Philharmonic Choir, violin
and the small children.
But we are not able to read the reference text
development and design now instead of that to be included in
text available for reading for the Turner
C, Faulkner Review and for the singing task,
we decided for a Beatles song.
I just mean apart from their core required piece
from the Ninth Symphony.
And again, we had this out to completion.
And this is David Furnish epic for Americans Condition.
And here
this figure summarizes the comparison for adults in rats
and children and newborns for the four conditions breathing,
speaking, singing and shouting.
And again, you see both
for the adults and for the children
and for speaking, you see higher
emission rates in comparison to breathing and for seeking.
You have higher interest rates in comparison to breathe
the air into speaking and challenging again.
And with the highest emission rates, especially for the children.
And it's different with regard to the singing condition.
I started to get the difference
between ad ads and children within then
plausible a comparison you can see that
the amount of emitted aerosols was in a similar range
when adults even
children are seen in comparison.
And that's breathing.
And when children we are seeing the emitted
a similar amount of aerosols
as when adults we are speaking.
So the age dependency of the aerosol emission
was clearly supported by the results of this study.
And again, we found a development dependency
you see here of the adults and children for the general medicine
for the condition.
And again you see the lower you know assume emission rates
for a piano condition and aspirate for the air
and that introduces children to comparison.
So this figure summarizes
all these results of the different age
groups and tells you that we have a strong dependency
for the age groups, children, adolescents,
adults, children, adolescents, adults.
And you see the difference amount of all the different reaching
of Arizona particle emission rates for the breathing, the singing
and the speaking, the singing and the shouting conviction
and coming back to the very beginning,
the measurement of the size of the Arizona size.
Here, we didn't found any significant differences between children,
adolescents and adults.
So how could
we use now a these results
for the practical works functionally for the children?
But all of the adults in the cultural contexts
And that's why I would
shortly focus a little bit on the measurement,
inquire and establish a singing
and from the point of the Arizona emission rates.
Of course, first of all, entrance control,
this is independent of Arizona.
So that focuses on
its time
to do if you have any signs of infection
and now this includes the vaccination status and the testing status.
But still, even if we now have the powerful tools
of testing and vaccination,
the mechanical aspects
should be used as well to minimize risk and just to facilitate
as much as possible in the educational and
cultural context in our daily life.
And when we talked about the
the possibility then
to not pass up the toxic possible
instruments to reduce
the amount of possibility of virus carrying
aerosols, we have different
strategies to reduce the risk
of transmission to infection.
And this is, of course, the limitation of the number of participants
This is a limitation of the duration of rehearsal.
It is, of course, the room size
and the different ventilation concepts
It is the distance rules, not only in rodents or droplets,
but all of also for the New York
of the aerosol emissions It is in the mouth, nose protection,
which is a powerful tool, especially in normal daylight.
But it's difficult sometimes in singing.
That's why it's not in the first line here.
And nowadays, of course, the testing and the vaccination tools,
which contributes
strongly to a proper risk management.
And they talk about the ventilation concepts.
Of course, we know about the enormous potential of the mechanical
ventilation systems and the possible
of the use of adequate students.
And here I would like to show you another investigation
which we have carried out in cooperation with the Texas
State Government, the same research group
and here you see singing for a 30 minutes,
an interruption or pulse, a break for 60 minutes, and again,
singing and you see the air assuming it's
erasing absolute concentration
in different room sizes.
And here you see the huge concert halls.
They have a very low increase.
They are also in concentration, concentration.
And this is different for the rehearsal room
and floor of the office and the office.
You see the differences between ventilated piping and ventilated by
mechanical ventilation.
And this
shows you, for instance, a brick metal comparison.
So the increase of Arizona, the constant creation
within the mechanical and ventilated office,
which wasn't a normal sized office or small offices through walls
and the same grounds lie in the rehearsal room of the school
where the transference choir is carried out in the rehearsals.
So you need to improve the tenor,
the aspects of ventilation.
Many engineers and mechanical ventilation.
And nowadays you have the nice opportunity
to use calculation models and there are a couple of calculation
models for the risk assessments available.
And these calculation models allow you to assess the specific
risk for your specific room and your specific conditions.
And here you see the mask of such an insect risk
and a calculator as you can
find it on the website of our department.
You include the age dependent in recent grades.
You include room parameters.
You you include various parameters.
And then you can get an easy
entrance to
as the assessment of the infection risks to be quite reckless.
So to summarize these
this lecture, we have not a lot that our beloved activities
of speaking and singing that has had hard times
during the SARS-CoV-2 pandemic because of the possibility
of carrying the SARS-CoV-2 virus by aerosols in France,
we have learned a lot
about Aristo attenuation and separation.
On the one hand, we have specific information
on aerosol and machine for age, dependency, fallout and dependency,
but on the other hand we have developed risk management
tools and those tools allow us
this time and in future
to further minimize the risk of transmission
of the SARS-CoV-2 by air to virus or other airborne viruses.
And hopefully this is a powerful instrument to get back to in the area.
Normal
sort of
conditions, especially for children
singing in school or in extracurricular settings and for
our beloved cultural environments and theaters and opera houses.
Thank you very much.
For your attention.
Thank you for being so punctual
and that we had such an important, interesting talk.
Just a quick question, if I may.
How do you think that the all the research
knowledge that we have nowadays about aerosol
transmissions will change, for example, practices
even when COVID is already
being settled and controlled, hopefully sooner than later.
Sooner than later.
Would that this research about aerosol transmission in singing,
do you think, will impact on the way that teachers at school
kindergarten and primary schools will teach singing and do
singing activities with children?
Because besides COVID, there is a lot of other respiratory
diseases that are aerosol transmitted.
So what is your opinion about that?
My hope
is that this knowledge will be used, all of that in future
to enable as much as possible what we've been seeing,
and especially the aspect of efficient ventilation
concepts that will be helpful in the future better.
And if you plan and b the room acoustics, it's not just room
acoustics, it should be included smell the ventilation tower you have.
So I think in creating
the optimal conditions for children, we we will include this
in further developments in Paris room constructions.
And and it's not just SARS-CoV-2
all the other airborne
virus transmissions it might be restricted
due to this knowledge if you apply it to practice.