Table 1:

Nerve conduction studies from a 63-year-old man with Guillain–Barré syndrome*

SitesLatency, msAmplitude, mVNegative area, ms*mVMinimum F-wave latency, msDistance, cmCV, m/s
Motor sites
Left median (APB)
Left ulnar (ADM)
 Below elbow8.35.021.82757
 Above elbow11.44.821.51135
Left radial (EIP)
 Upper arm8.93.817.92643
Left fibular (EDB)
Left fibular (tibial anterior)
 Fibular head4.53.824.4-
 Popliteal fossa7.53.8-1033
Left tibial (AHB)
Left facial (nasalis)
Onset latency, msPeak latency, msAmplitude of onset potential, μVNegative area, ms*μVDistance, cmCV, m/s
Sensory sites
Left median
 Wrist-digit IINRNRNRNR14NR
Left ulnar
 Wrist-digit VNRNRNRNR12NR
Left sural
 Calf-latency mallNRNRNRNR14NR
Left superficial peroneal
  • Note: ADM = abductor digiti minimi, AHB = abductor hallucis brevis, AMM = anterior medial malleolar, APB = abductor pollicis brevis, CV = conduction velocity, EDB = extensor digitorum brevis, EIP = extensor indicis proprius, NR = no response.

  • * Latency is the time it takes for the impulse to generate a response. In demyelination, this is prolonged, as shown in the latency times for the wrist (normal < 2.2 ms) and elbow (normal < 4.4 ms) of the left median APB, and at the wrist of the left ulnar ADM (normal < 2.2 ms). F-wave is a measure of motor conduction time of the entire nerve. In demyelination, this is prolonged, as shown in the left ulnar ADM.