Table 1.
Serial nerve conduction studies and electromyography
| Time from onset | Right | Left | Ref. | Right | Left | Ref. | Right | Left | Ref. | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 m | 2 m | 2y | 1 m | 2 m | 2y | 1 m | 2 m | 2y | 1 m | 2 m | 2y | 1 m | 2 m | 2y | 1 m | 2 m | 2y | |||||
| Sensory nerve conduction study | Onset latency (ms) | Amplitude (mV) | Conduction velocity (m/s) | |||||||||||||||||||
| Median | 1.7 | 1.0 | 1.8 | <3.5 | 32.3 | 34 | 25.7 | >13 | 71 | 50 | 65 | >50 | ||||||||||
| Ulnar | 1.8 | 1.6 | 1.6 | 1.6 | <3.1 | 50 | 35.7 | 41 | 55.5 | >12 | 60 | 63 | 73 | 63 | >50 | |||||||
| Sural | 2.5 | 3.1 | 2.3 | 2.9 | <3.6 | 17.0 | 9.6 | 16.6 | 19.8 | >9 | 56 | 45 | 61 | 48 | >38 | |||||||
| Motor nerve conduction study | Onset latency (ms) | Amplitude (mV) | Conduction velocity (m/s) | |||||||||||||||||||
| Median | Wrist | 2.9 | 2.7 | 2.9 | 2.8 | 2.7 | <4.2 | 2.8 | 4.3 | 3.0 | 3.7 | 10.7 | >6 | |||||||||
| Elbow | 6.7 | 6.5 | 6.6 | 6.3 | 2.8 | 3.1 | 2.8 | 10.6 | 57.9 | 55 | 59.5 | 61 | >50 | |||||||||
| Ulnar | Wrist | 2.4 | 2.1 | 2.3 | 1.8 | 2.0 | <3.4 | 2.0 | 6.0 | 3.3 | 5.3 | 13.4 | >5.5 | |||||||||
| Below elbow | 5.8 | 5.2 | 5.2 | 5.2 | 0.99 | 6.1 | 2.3 | 13.4 | ||||||||||||||
| Above elbow | 7.6 | 6.7 | 6.6 | 7.0 | 0.68 | 5.9 | 2.0 | 12.8 | 55.6 | 67 | 71.4 | 56 | >50 | |||||||||
| Deep peroneal | Ankle | 4.2 | 4.1 | 4.3 | 3.9 | 3.1 | 3.9 | <5.5 | 1.5 | 0.8 | 0.4 | 0.98 | 0.5 | 1.6 | >2 | |||||||
| Below fibular‐head | 10.8 | 10.7 | 11.5 | 10.2 | 9.9 | 19.3 | 0.78 | 0.6 | 0.5 | 0.89 | 0.4 | 0.8 | ||||||||||
| Above fibular‐head | 12.6 | 13.0 | 13.6 | 12.2 | 12.4 | 22.1 | 0.25 | 0.2 | 0.5 | 0.7 | 0.6 | 0.6 | 44.4 | 43 | 40 | 40 | 40 | 36 | >40 | |||
| Tibial | Ankle | 2.9 | 3.6 | 3.9 | 3.3 | 3.5 | 3.2 | <7 | 11.3 | 9.1 | 15.9 | 7.0 | 4.6 | 15.1 | >4 | |||||||
| Popliteal fossa | 9.8 | 11.4 | 12.0 | 10.2 | 11.2 | 11.1 | 9.7 | 7.5 | 10.8 | 6.7 | 4.5 | 9.4 | 50.7 | 49 | 47 | 47 | 49 | 49 | >40 | |||
| Electromyography a | Fibrillations | Positive sharp waves | Recruitment | |||||||||||||||||||
| First dorsal interosseous m | +++ | +++ | ↓ | |||||||||||||||||||
| Biceps m | + | ↓ | ||||||||||||||||||||
| Anterior tibialis m | ++ | ++ | ↓ | |||||||||||||||||||
| Vastus medialis m | ↓ | |||||||||||||||||||||
| Late responses | Latency (ms) | |||||||||||||||||||||
| Median F‐wave | 23.4 | 31.5 | 25.4 | 24.8 | <29 | |||||||||||||||||
| Ulnar F‐wave | 23.1 | 23.4 | 22.3 | <30 | ||||||||||||||||||
| Deep peroneal F‐wave | NR | NR | NR | NR | <50 | |||||||||||||||||
| Tibial F‐wave | 45.5 | 45.7 | 43.8 | 45.0 | <51 | |||||||||||||||||
| H‐reflex | NR | NR | NR | 29.7 | <31 | |||||||||||||||||
Ref., referential normal value; m, month; y, year; NR, no response. The numbers listed in bold were abnormal data. The gray numbers in italic were normal values for reference.
The nerve conduction studies (NCS) revealed diffusely decreased amplitudes of motor nerve conductions and poor responses of F‐wave and H‐reflex in the first 2 months (column 1 m and 2 m). There is normal sensory conduction. The electromyography performed at the second month showed fibrillations and positive sharp waves with severely reduced recruitment and normal motor unit potentials of tested muscles, which suggested an active denervation of motor neuropathy (column 2 m). In the first month, the patient was unconscious, quadriplegic with generalized areflexia. At the second‐year follow‐up, she was alert and oriented. Muscle power of all limbs returned to full. The NCS 2 years after onset revealed only peroneal neuropathy (column 2y).
The motor unit potentials of electromyography were normal.