Electrodiagnostic Decision Support

Nerve Injury Calculator

Estimate axonal loss, demyelinating loss, and intact or ischemic axons from CMAP amplitudes using a structured, clinic-ready workflow.

Clinical Inputs

Enter the normal contralateral motor amplitude and the affected-side distal and proximal amplitudes.

The calculator flags impossible negative percentages and recommends normative controls when needed.

Input

CMAP Data Entry

Values should be entered in the same units for all fields, typically mV.

Calculation Logic

  • Axonal loss = (normal distal amplitude - affected distal amplitude) / normal distal amplitude
  • Demyelinating loss = (affected distal amplitude - affected proximal amplitude) / normal distal amplitude
  • Intact or ischemic axons = 100% - axonal loss% - demyelinating loss%
  • Negative percentages suggest an abnormal contralateral control; use normative control values instead.

Output

Injury Pattern Summary

Pie chart values update after each calculation and can be copied for reports or presentations.

Ready for Calculation

Enter CMAP values to generate the injury profile and chart.