Serienstimulation oder Einzelfaser
DIES IST EINE BAUSTELLE; VIELLEICHT MÖCHTEN SIE JA SCHON MAL DIESE WENIGEN BAUSTEINCHEN ANSCHAUEN:
Withholding medications
Withholding anticholinesterase medications was mentioned in 4 studies. [2,16,19,22] Twelve hours was
recommended as the length of time to withhold the medications.[16,19] One study did withhold medications from 4 to 18 h. [16,22].
Repetitive Nerve Stimulation
Twelve of 15 articles mentioned specifically comparing the baseline-to-peak or peak-to-peak amplitude of
the first potential to the fourth or fifth waveform within each volley. Two studies discussed measurement
of area.10,30 Postexercise volleys were measured every 30 s to 2 min in 7 papers. The degree of decrement
with a stimulation rate of 2 to 5 Hz was considered significant at 10% in 5 studies. The percent increment
considered abnormal in LEMS was 25% or 42% in 2 papers.15,19 Due to the fact that up to 92% increment
can be seen in MG, 100% increment is considered diagnostic.31 The frequency of stimulation for detecting
decrement was recommended to be 2 to 5 Hz in 13 publications. High frequencies of stimulation ranging
from 10 to 50 Hz were used in 9 studies. Isometric muscle contraction exercise was recommended for
activation instead of high frequency stimulation in 3 publications.
CONCLUSIONS
This literature review has provided scientific evidence that RNS and SFEMG are valid clinical laboratory
studies for confirming a clinical diagnosis of MG or LEMS.
SUMMARY OF HARMS, BENEFITS, AND COSTS OF INTERVENTIONS CONSIDERED
The risks of electrodiagnostic testing to the patient include transient discomfort, bruise, hematoma, and
infection from the needle insertion required to perform both single fiber and needle EMG. The risks of
EMG to the EDX consultant include inadvertent needle puncture of the consultant by the needle used to
evaluate the patient and subsequent infection by hepatitis, human immunodeficiency virus (HIV), or other
communicable disease. The risks of RNS include transient discomfort and accidental electric shock. The
latter is avoided by excluding patients with pacemakers and central lines, as well as avoiding electrical
storms and placing dual ground electrodes on the patient.
This statement is provided as an educational service of the AAEM