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Normal Values and EMG Habits Survey
Joe F Jabre, MD Boston University Department of Neurology
Patient Cohort Normal Cohort
Anonymous Web Survey Conducted Between 8/14-9/14, 2014 n = 47 Respondents
15%
62%
23%
20-39 years
40-59 years
> 60 years
-10 10 30 50 70 90
110 130 150 170 190 210 230 250
Mean Median Min Max
Participants Age Group
Participants Reported Number of EMGs/Month
Dem
ogra
phic
s
Participants
© Jabre 2014
The Normal Values I use are Usually a Mixture of Mine & Someone Else’s
n=47 Survey Respondents
6%
41% 53%
100% my own
100% someone else's
A mixture
© Jabre 2014
The Normal Values I use are Generally Broken Down by Age & Sex
n=47 Survey Respondents
38%
62%
Generally not broken down by age or sex
Generally broken down by age and/or sex
47%
23%
30%
Broken down by age
Broken down by sex
Broken down by age and sex
© Jabre 2014
My Feeling about collecting Normal Values is that it would take too much time But Would Not Significantly Change the Way I Do Things
n=47 Survey Respondents
36%
64% It Would signifcantly change the way I do things
It Would Not significantly change the way I do things
© Jabre 2014
When interpreting a study, I do so mostly From Memory and Looking at a Table of Normal Values
n=47 Survey Respondents
66%
21%
13%
Memory and a Table
Memory Alone
Table Alone
© Jabre 2014
EMG training – I feel There is a Mixture of Training Levels Among EMGers
n=47 Survey Respondents
39%
28%
33%
% of EMGer are well trained
% of EMGers OK trained
% of EMGers could use more training
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
100%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Well Trained
0%
10%
20%
30%
40%
50%
60%
70%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
OK Trained
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
100%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Train More
© Jabre 2014
Patient Cohort
Normal versus Abnormal How Much Overlap?
• In a Normal Cohort, there are Abnormal Studies • In a Patient Cohort, there are Normal Studies • There is an Overlap between “Normal” and “Abnormal”
Normal Cohort Overlap
© Jabre 2014
My Laboratory’s Percentage of “Normal” Studies Of the last 100 nerve conduction studies you performed,
Can you estimate the percentage of studies that you reported as “Normal”?
“Normal” being that when you compared the study results to the normal or reference values you use, they all fell within your accepted normal limits n=25 Survey Respondents
47% 53%
Percent NCS Read as "Normal"
Percent NCS Read as "Abnormal"
0%
10%
20%
30%
40%
50%
60%
70%
80%
Min Mean Max
0%
10%
20%
30%
40%
50%
60%
70%
80%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
% Read As Normal
© Jabre 2014
Would I Trust an Algorithm? If I have access to a good algorithm to analyze my results, I would
n=47 Survey Respondents
23%
68%
9%
Trust it completely
Trust is somewhat
Not Trust at all
© Jabre 2014
My Norms on the web http://mynorms.com/
© Jabre 2014