Table 1

Control values in the healthy subjects for tibialis anterior (TA) muscle recordings

MUP analysisMean amplitude (μV)Mean area (μVms)Mean duration (ms)Polyphasics (%)Phases (n)Turns (n)
Mean+SD661.5±92851.5±158.79.35±0.93Range 5–403.47±0.363.35±0.52
ULN845.51168.911.235%4.194.39
JitterMean jitter μs% unstable potentials% blocking
 Mean+SD37.0±5.6Range 0–200–10
 ULN48.220%10%
  • The data for amplitude, area, duration, number of phases and number of turns and mean jitter are normally distributed (Kolmogorov-Smirnov statistic). The % polyphasic potentials; and the number of unstable potentials and number of blocking potentials were not normally distributed. For normally distributed data the upper limit of normal (ULN) was calculated as the mean+2 SD; and for non-normally distributed data the 95% range of the distribution frequency was used as a cut-off. The ULN for neuromuscular jitter in an isolated potential pair was taken as 58 μs, representing the 95% CI in the control population.

  • MUP, motor unit potential.