Table 1.
Summary of neurophysiological studies
| Motor studies | 1997 | 2013 | ||
|---|---|---|---|---|
| Right | Left | Right | Left | |
| Nerve | ||||
| Tibial | ||||
| Latency (ms) | 5.8 | 5.4 | 6.5 | |
| Amplitude (mV) | 0.8 | 1.1 | 0.05 | |
| Conduction velocity m/s | 36 | 36 | ||
| F Wave (max) ms | 65.5 | Absent | Absent | |
| Peroneal | ||||
| Latency (ms): ankle | 5.45 | |||
| Amplitude (mV): ankle | 0.3 | |||
| Amplitude (mV): above knee | 0.3 | |||
| Conduction velocity (m/s) | 30.5 | |||
| F Wave (max) ms | Absent | |||
| Ulnar | ||||
| Latency (ms): wrist | 3.30 | |||
| Amplitude (mV): wrist | 11.7 | |||
| Amplitude (mV): above elbow | 9.6 | |||
| Conduction velocity (m/s) | 45.6 | |||
| F Wave (min) ms | 33.15 | |||
| Median | ||||
| Latency (ms): wrist | 4.3 | 3.90 | 3.75 | |
| Amplitude (mV): wrist | 18.8 | 16.0 | 14.9 | |
| Amplitude (mV): elbow | 17.3 | 14.8 | 7.1 | |
| Conduction velocity (m/s) | 52 | 48 | 43.3 | |
| F Wave (min) ms | 34.25 | |||
| Sensory studies | 1997 | 2013 | ||
|---|---|---|---|---|
| Right | Left | Right | Left | |
| Nerve | ||||
| Sural | ||||
| Latency (peak) ms | Absent | Absent | Absent | Absent |
| Amplitude (peak–peak) µV | Absent | Absent | Absent | Absent |
| Radial | ||||
| Latency (onset) ms | 1.90 | |||
| Latency (peak) ms | 2.80 | 2.80 | 2.60 | |
| Amplitude (peak–peak) µV | 10.0 | 10.0 | 0.26 | |
| Conduction velocity (onset) m/s | 44.7 | |||
| Ulnar | ||||
| Latency (peak) ms | 3.0 | 3.4 | Absent | Absent |
| Amplitude (peak–peak) µV | 3.1 | 1.0 | Absent | Absent |
| Median | ||||
| Latency (peak) ms | 4.10 | 4.10 | Absent | Absent |
| Amplitude (peak–peak) µV | 2.20 | 2.10 | Absent | Absent |
| Electromyography | 1997 | 2013 |
|---|---|---|
| Muscle | ||
| Right tibialis anterior | No spontaneous activity, Normal pattern of motor unit recruitment with motor units up to 2.5 mV | No abnormal spontaneous activity. Voluntary recruitment moderately severely reduced in density with an excess of slightly unstable irregular motor unit potentials: durations up to 20 ms, amplitude up to 10 mV |
| Right first dorsal interosseous | No spontaneous activity, Normal pattern of motor unit recruitment with motor units up to 2.5 mV | |
The neurophysiological studies were consistent with a length-dependant predominantly axonal motor and sensory peripheral neuropathy. However, the slowing of the conduction velocities, prolonged F waves and conduction block of the median nerve suggest a possible demyelinating component. Sympathetic skin response (performed only in 2013) was absent in the right hand and left foot
Bold values indicate abnormal results
ms milliseconds, mV millivolt, m/s metres per second, µV microvolt