Interpreting Pie Charts

Saturday, April 7, 2007 | 0

By Dr. Christopher Brigham

Thank you all for your positive feedback regarding our Weekly Tips. Our goal is to provide insight on the proper use of the AMA Guides when assessing impairment in challenging areas.

We would also like to share with you our most recent results regarding impairment ratings in our presentation that can be viewed on our website at www.impairment.com/ratings (http://rs6.net/tn.jsp?t=5xald5bab.0.v7opd5bab.84wzdpbab.10354&ts=S0234&p=http%3A%2F%2Fwww.impairment.com%2Fratings) and click on the "Presentation" link. These presentations present our data, examine the root causes of erroneous ratings and provide you with practical strategies to achieve reliable impairment assessments.

Interpreting and Interpolating Chapter 16 Pie Charts

Although the pie charts in Chapter 16, The Upper Extremities, are designed for simple interpretation, at Brigham and Associates, Inc., we see frequent and repeated errors when they are referenced during an impairment assessment. Here are a few reminders when using these charts:

* Remember to reference the correct motion arc in the pie chart to match the joint motion you are measuring. This is a simple error that usually will result in a substantial miscalculation of impairment.

* For a fused joint, only reference the motion arc for Ankylosis. The remaining motion arcs are no longer applicable and should not be included in your analysis.

* For motion values that fall between those listed in the pie charts, the Guides allow for interpolation of impairment in the corresponding interval. For example, referencing Figure 16-37 on page 474, for an elbow measurement that lacks 35 degrees of supination to the neutral position (i.e. -35 degrees of supination), instead of upward or downward rounding to the next listed value, this motion is more accurately given a 7% upper extremity impairment rating (half-way between the value of 6% for finding of -30 degrees and 8% for the finding of -40 degrees). Another example is a finding of elbow pronation of 15 degrees would be equivalent to 6% upper extremity impairment.

* Finally, because the motions in a pie chart are specific to a joint, the motion units have the same "relative value scale". Therefore, the impairment values obtained can be directly added together.

Brigham is the editor of the Guides Newsletter and Guides Casebook. To view more of these tips visit:

www.impairment.com/tips

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