Re: How many standard deviations?

March 27, 2010

The measurement they gave you meadures the Cephalic Ratio which is

Cranial Breadth/Cranial Length

ideal ratio - 78%

normal - 73-83%

moderate - 83.1% to 87.9%

severe - 88% and higher

Most doctors recommend banding when it is over 90%.

Molly

Novato, CA

Nicolas, STARband graduate

On Mar 26, 2010, at 7:08 PM, " alb5118 " <alb5118@...> wrote:

> We had the dsi done yesterday at CT. I asked how bad Devin's case

> was. She told me it was 4.7 standard deviations or about 97%. It

> just made me wonder where everyone else started. I was also told

> that his is a severe case... really?

>

> ------------------------------------

>

> For more plagio info

March 27, 2010

I'm not sure I understand the rationale behind these labels. 83% is " normal, "

but 83.1% is " moderate? " I have read that medical dictionaries and

anthropologic sources define brachycephaly as a cephalic index greater than 81%.

Of course that was before the back to sleep protocol. But saying that 83% is

" normal, " and that 83.1% is " moderate " doesn't make sense to me.

>

> > We had the dsi done yesterday at CT. I asked how bad Devin's case

> > was. She told me it was 4.7 standard deviations or about 97%. It

> > just made me wonder where everyone else started. I was also told

> > that his is a severe case... really?

> >

> > ------------------------------------

> >

> > For more plagio info

March 27, 2010

It doesn't make sense to me either. If the experts are recommending banding at 90 percent and banding is generally for moderate to severe cases (as I've heard for plagio), then I would guess that today's experts are judging 90 percent to be moderate. Now days, I would even guess that 83.1 percent would be considered normal (not moderate) by most people and even the experts. So, what would be considered mild? Probably somewhere in the high 80's. Mabe 86, 87, or 88? My daughter's head ended at 92.2 and I'm guessing that she is somewhere between that and 90, but in no way would I consider her case to be severe, even though I do believe that she was severe when she started at 95 percent. In fact, our ortho told us that she was on the border between moderate and severe when we went for our consult. That just tells me that there are no universal standards for what the numbers for brachy mean. This is probably because most experts realize just how out of date those statistics are. Re: How many standard deviations?

I'm not sure I understand the rationale behind these labels. 83% is "normal," but 83.1% is "moderate?" I have read that medical dictionaries and anthropologic sources define brachycephaly as a cephalic index greater than 81%. Of course that was before the back to sleep protocol. But saying that 83% is "normal," and that 83.1% is "moderate" doesn't make sense to me.> > > We had the dsi done yesterday at CT. I asked how bad Devin's case > > was. She told me it was 4.7 standard deviations or about 97%. It > > just made me wonder where everyone else started. I was also told > > that his is a severe case... really?> >> >> >> > ------------------------------------> >> > For more plagio info

March 28, 2010

This is from Wikipedia (so may not be correct, but likey is)....

In statistics, the 68-95-99.7 rule, or three-sigma rule, or empirical rule,

states that for a normal distribution, nearly all values lie within 3 standard

deviations of the mean.

About 68% of the values lie within 1 standard deviation of the mean (or between

the mean minus 1 times the standard deviation, and the mean plus 1 times the

standard deviation). In statistical notation, this is represented as: & #956; ±

& #963;.

About 95% of the values lie within 2 standard deviations of the mean (or between

the mean minus 2 times the standard deviation, and the mean plus 2 times the

standard deviation). The statistical notation for this is: & #956; ± 2 & #963;.

Nearly all (99.7%) of the values lie within 3 standard deviations of the mean

(or between the mean minus 3 times the standard deviation and the mean plus 3

times the standard deviation). Statisticians use the following notation to

represent this: & #956; ± 3 & #963;.

So 4.7 as a standard deviation is definitely severe. This means that this head

is flatter/wider than nearly all heads (statistically speaking).

Here it a link to an Aetna page on Cephalic Index.

http://www.aetna.com/cpb/medical/data/300_399/0379.html

It shows that the CI differs by age and gender but if you look at the table they

show 2 SD from the norm for a baby 6-12 mo is about 91 for boys and 88 for

girls. So 95% of all babies would be at or below this number.

As for the number " moderate " number molly posted, it seems to be approximately

the +1 Standard deviation number, so 68% would be at this number or less.

As for the original poster, my daughter started at 96% and graduated at 85%.

-christine

sydney, 4 yrs, starband grad

> >

> > > We had the dsi done yesterday at CT. I asked how bad Devin's case

> > > was. She told me it was 4.7 standard deviations or about 97%. It

> > > just made me wonder where everyone else started. I was also told

> > > that his is a severe case... really?

> > >

> > > ------------------------------------

> > >

> > > For more plagio info

March 28, 2010

,

You are slightly off in your explanation because you forgot to divide by two. Half of the babies outside of the standard deviation are below the average.

Everyone needs to remember that the insurance company is basing the statistics on old norms, probably because there is nothing more recent available. If I remember correctly, the study was also done on only a small number of babies. That's not very good stats because it may also mean that it wasn't representative of babies even at the time that it was done. I know a little about this. Although I'm not a researcher or statitician, I took my share of courses when I got my Ph.D.

Plus, in the field of statistics, the usual standard for things to be considered statistically significant is when it reaches two standard deviations. This is definately true for psychometrics, which is how I use stats daily in my job. I would never diagnosed a child with mental retardation with an IQ of 85 (or one standard deviation). That would mean that 16 percent of the population had MR (or now ID). The standard is two standard deviaitons (IQ of 70 or below). The same is true for all sorts of behavioral tests. Two standard deviaiton is considered significant. One standard deviation is usually considered to be borderline or "at risk" for something significant. Because everything changes over time, all of the test publishers know that they need to redo the norms every few years, certainly no longer than 10 years. The field of plagio and brachy has been negligent in this respect. I would lose my job if I made a diagnosis based upon norms over 30 years old. We would end up with nearly half of our school population in special education for one disorder or another. 16 percent would have mental disabilities, 16 percent would have emotinal disturbance, etc. You get the idea.

If you read the link that you give, it recommends a helmet for two standard deviations, which is consistent with the standard that I mention.

So, yes, one standard deviation means it is a problem, but it should never be considered a moderate problem - maybe mild at the most. If it were considered moderate, then that would mean that 16 percent of the population has moderate to severe brachy. That just doesn't make sense. It does make sense to me for the two standard deviation standard - 2.5 percent of the population having moderate to severe brachy makes sense. The question that has not been answered is what is the average for a baby born in the last 10 years and what would the standard deviation be? I'd even settle for a number from after we started putting babies to sleep on their backs, but I haven't seen any numbers posted. Therefore, I don't think that it is accurate for CT to give out standard deviations, without an explanation that the statistics are old and probably no longer accurate for today's babies. Those numbers compare today's babies with those of us who slept on our tummies.

So, yes, 4 standard deviations is very significant, but who knows what 4 standard deviations really is at this time.

I actually think that it is more helpful for parents to recognize that they ought to get the numbers out of the 90s or 100's and into the 80's. This is because I'm pretty sure that the average is somewhere in the low 80's and two standard deviations is probably somewhere in the low 90's. And the goal should be to get as close to one standard deviation as possible. I'm pretty sure that my daughter's 92.2 would be around 2 standard deviations or possibly slightly more, but I can say that I think I've seen some heads that are wider than hers.

But, back to the original poster's question - yes, 97 percent is considered pretty high (although maybe not really 4.7 standard deviations) and most people would go forward with a band at that number. I would recommend trying to get at out of the 90's if at all possible. In my opinion, it will be about more than just the number. You will know when the rounding is there and the flat spot is no longer staring at you. You will know when that head no longer stands out as wider than the other heads. It might be at 90 percent, 85 percent, or somewhere in between. In the end, it's what it looks like that matters and not the number.

Okay - I can't believe I actually said that since I'm the one that has been obsessed with getting my daughter down to 90 percent. However, I do believe that it is true. In her daily life, I am never asked what her brachy number is.

, mom to , 2.5 years

STARband grad, May 2009

Chiro and CST

land Re: How many standard deviations?This is from Wikipedia (so may not be correct, but likey is)....In statistics, the 68-95-99.7 rule, or three-sigma rule, or empirical rule, states that for a normal distribution, nearly all values lie within 3 standard deviations of the mean.About 68% of the values lie within 1 standard deviation of the mean (or between the mean minus 1 times the standard deviation, and the mean plus 1 times the standard deviation). In statistical notation, this is represented as: & #956; Â± & #963;.About 95% of the values lie within 2 standard deviations of the mean (or between the mean minus 2 times the standard deviation, and the mean plus 2 times the standard deviation). The statistical notation for this is: & #956; Â± 2 & #963;.Nearly all (99.7%) of the values lie within 3 standard deviations of the mean (or between the mean minus 3 times the standard deviation and the mean plus 3 times the standard deviation). Statisticians use the following notation to represent this: & #956; Â± 3 & #963;.So 4.7 as a standard deviation is definitely severe. This means that this head is flatter/wider than nearly all heads (statistically speaking). Here it a link to an Aetna page on Cephalic Index. http://www.aetna.com/cpb/medical/data/300_399/0379.htmlIt shows that the CI differs by age and gender but if you look at the table they show 2 SD from the norm for a baby 6-12 mo is about 91 for boys and 88 for girls. So 95% of all babies would be at or below this number. As for the number "moderate" number molly posted, it seems to be approximately the +1 Standard deviation number, so 68% would be at this number or less.As for the original poster, my daughter started at 96% and graduated at 85%.-christinesydney, 4 yrs, starband grad > > > > > We had the dsi done yesterday at CT. I asked how bad Devin's case > > > was. She told me it was 4.7 standard deviations or about 97%. It > > > just made me wonder where everyone else started. I was also told > > > that his is a severe case... really? > > > > > > > > > > > > ------------------------------------ > > > > > > For more plagio info

March 28, 2010

Thank you all so much for your responses. It all makes a bit more sense now.

My goal for D's head is to be in the low 90's. A number in the 80's would make

me beyond thrilled. We get his band on 4/5 so we will finally get this rounding

started!

> > >

> > > > We had the dsi done yesterday at CT. I asked how bad Devin's case

> > > > was. She told me it was 4.7 standard deviations or about 97%. It

> > > > just made me wonder where everyone else started. I was also told

> > > > that his is a severe case... really?

> > > >

> > > > ------------------------------------

> > > >

> > > > For more plagio info

March 28, 2010

Hi,

Yes, I also think that average is most likely in the low 80's.Â My

guess is around 81% to 82%.Â We think at 83% 's head looks barely

worse than average in terms of brachy.Â This is fine, since we believe

's head is naturally wider than average.

Our problem is asymmetry, even though 's measurements aren't that

bad any more.Â I'm thinking even if 's measurements end up within

normal range, there will still be remaining plagio damage.Â Hopefully,

if we keep up with alternative treatments, we can mitigate this.Â

-Kathy, mom to 22 months, treating plagio for 10 months

wrote:

Â

,

Â

You are slightly off in your explanation because you forgot to

divide by two. Half of the babies outside of the standard deviation are

below the average.

Â

EveryoneÂ needs to remember that the insurance companyÂ is

basingÂ the statistics on old norms, probably because there is nothing

more recent available. If I remember correctly, the study was also done

on only a small number of babies. That's not very good stats because it

may also mean that it wasn't representative of babies even at the time

that it was done. I know a little about this. Although I'm not a

researcher or statitician, I took my share of courses when I got my

Ph.D.

Â

Plus, in the field of statistics,Â the usual standard for things to

beÂ considered statistically significantÂ is whenÂ it reaches two standard

deviations. This is definately true for psychometrics, which is how I

use stats daily in my job. I would never diagnosed a child with mental

retardation with an IQ of 85 (or one standard deviation). That would

mean that 16 percent of the population had MR (or now ID).Â The standard

is two standard deviaitons (IQ of 70 or below). The same is true for

all sorts of behavioral tests. Two standard deviaiton is considered

significant. One standard deviation is usually considered to be

borderline or "at risk" for something significant. Because everything

changes over time, all of the test publishers know that they need to

redo the norms every few years, certainly no longer than 10 years. The

field of plagio and brachy has been negligent in this respect. I would

lose my job if I made a diagnosis based upon norms over 30 years old.

We would end up with nearly half of our school population in special

education for one disorder or another. 16 percent would have mental

disabilities, 16 percent would have emotinal disturbance, etc. You get

the idea.

Â

If you read the link that you give, it recommends a helmet for two

standard deviations, which is consistent with the standard that I

mention.

Â

So, yes, one standard deviation means it is a problem, but it

should never be considered a moderate problem - maybe mild at the most.

If it were considered moderate, then that would mean that 16 percent of

the population has moderate to severe brachy. That just doesn't make

sense. It does make sense to me for the two standard deviation standard

- 2.5 percent of the population having moderate to severe brachy makes

sense. The question that has not been answered is what is the average

for a baby born in the last 10 years and what would the standard

deviation be? I'd even settle for a number from after we started

putting babies to sleep on their backs, but I haven't seen any numbers

posted. Therefore, I don't think that it is accurate for CT to give out

standard deviations, without an explanation that the statistics are old

and probably no longer accurate for today's babies. Those numbers

compare today's babies with those of us who slept on our tummies.

Â

So, yes, 4 standard deviations is very significant, but who knows

what 4 standard deviations really is at this time.

Â

I actually think that it is more helpful for parents to recognize

that they ought to get the numbers out of the 90s or 100's and into the

80's. This isÂ Â because I'm pretty sure that the average is somewhere in

the low 80's and two standard deviations is probablyÂ somewhere in the

low 90's.Â And the goal should be to get as close to one standard

deviation as possible. I'm pretty sure that my daughter's 92.2 would be

around 2 standard deviations or possibly slightly more, but I can say

that I think I've seenÂ some heads that are wider than hers.

Â

But, back to the original poster's question - yes, 97 percent is

considered pretty high (although maybe not really 4.7 standard

deviations)Â and most people would go forward with a band at that

number. I would recommend trying to get at out of the 90's if at all

possible. In my opinion, it will be about more than just the number.

You will know when the rounding is there and the flat spot is no longer

staring at you. You will know when that head no longer stands out as

wider than the other heads. It might be at 90 percent, 85 percent, or

somewhere in between. In the end, it's what it looks like that matters

and not the number.

Â

Okay - I can't believe I actually said that since I'm the one that

has been obsessed with getting my daughter down to 90 percent. However,

I do believe that it is true. In her daily life, I am never asked what

her brachy number is.

Â