High rate repetitive stimulation

1. What is the rate for HRRS? Is there any substitute for this?
2. What is the effect of HRRS?
3. What occurs as a result of HRRS in MG, LEMS, and botulism?
4. What is pseudofacilitation?

Answers:
1. 10-50Hz. May substitute maximal isometric contraction.
2. Accumulation of calcium in the cell.
3. MG shows a decrement, LEMS shows a 200-300% increment, and botulism shows a mild increment.
4. Pseudofacilitation is the progressive increase in CMAP amplitude with HRRS or voluntary contration in a normal patient, which results from synchronicity of muscle fibers (decreased temporal dispersion).