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