Reference values for the nerve conduction studies used in the evaluation of Carpal Tunnel Syndrome.
| Study | Onset-to-peak amplitude: LLN (3rd percentile) | Peak latency: ULN (97th percentile) (ms) | Onset latency: ULN (97th percentile) (ms) | Conduction velocity: LLN (3rd percentile) (m/s) |
|---|---|---|---|---|
| Digit 2 median antidromic sensory | 11 mv* | 4.0 | 3.3 | NA |
| Digit 5 ulnar antidromic sensory | 10 mv* | 4.0 | 3.1 | NA |
| Digit 2 median vs digit 5 ulnar peak latency difference | NA | <0.5 | NA | NA |
| Digit 4 median vs digit 4 ulnar peak latency difference | NA | <0.5 | NA | NA |
| Palmar orthodromic peak latency difference. | NA | <0.3 | NA | NA |
| Median motor | 4.1 mv* | NA | 4.5 | 49 |
| Ulnar mot | 7.9 mv* | NA | 3.7 | 52 (below elbow) 43 (across elbow) 50 (above elbow) |
LLN - lower limit normal, ULN - upper limit normal, NA - not applicable.
↵* Values represent all ages. For stratification by age and body mass index, we refer the reader to the paper of Chen et al11