Table 1.
Case 2 Nerve Conduction Study Data.
| Side/nerve | Stimulation site | Recording site | Distal latency (ms) | Amplitude (mV) | Normal amplitude (mV) | Negative waveform duration (ms) | Conduction velocity (m/s) |
|---|---|---|---|---|---|---|---|
| Motor nerve conduction studies | |||||||
| R Median | Wrist | APB | 4.4 | 0.1 | >7 | 17.9 | |
| Elbow | APB | 12.6 | 0.1 | 29.3 | 30 a (≥50) | ||
| R Ulnar | Wrist | ADM | 3.2 | 10.1 | >7 | 15.4 | |
| Below elbow | ADM | 8.9 | 9.4 | 22.7 | 37 a (≥50) | ||
| Above elbow | ADM | 12.1 | 8.5 | 22.7 | 31 | ||
| R Peroneal | Ankle | EDB | NR | >2.5 | |||
| Fibula | EDB | NR | NR (≥40) | ||||
| R Peroneal | Fibula | TA | 4.2 | 2.4 | >4 | 45.8 | |
| Popliteal fossa | TA | 6.3 | 2.4 | 43.7 | 38 (≥40) | ||
| R Tibial | Ankle | AHB | 5.2 | 0.2 | >4 | 24.8 | |
| Popliteal fossa | AHB | NR | NR (≥40) | ||||
| Sensory nerve conduction studies | |||||||
| R Median | Wrist | Digit II | 4.1 | 3.0 | >15 | 1.2 | 30 a (≥50) |
| R Ulnar | Wrist | Digit V | 3.6 | 4.0 | >12 | 1.6 | 28 a (≥50) |
| R Radial | Forearm | Snuff box | 3.0 | 4.0 | >15 | 1.8 | 33 a (≥50) |
| R Sural | Foreleg | Ankle | NR | >3 | NR (≥40) | ||
| R Superficial Peroneal | Foreleg | Ankle | NR | >3 | NR (≥40) | ||
Motor and sensory nerve conduction data from case 2 demonstrate a moderately severe, chronic length-dependent predominantly axonal sensorimotor polyneuropathy with several conduction velocities in the demyelinating range without conduction block, consistent with intermediate forms of CMT neuropathy. Abnormal values indicated in bold type. Brackets indicate normal conduction velocity values.
Abbreviations: R, Right; APB, abductor pollicis brevis; ADM, abductor digiti minimi; EDB, extensor digitorum brevis; NR, not recordable; TA, tibialis anterior; AHB, abductor hallucis brevis; CMT, Charcot-Marie-Tooth.
a
Demyelinating range conduction velocity.