Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_statfun_diff_itc”.

  FT_STATFUN_DIFF_ITC computes the difference in the inter-trial
  coherence between two conditions. The input data for this test
  should consist of complex-values spectral estimates, e.g. computed
  using FT_FREQANALYSIS with method=mtmfft, wavelet or mtmconvcol.
  The ITC is a measure of phase consistency over trials. By randomlly
  shuffling the trials  between the two consitions and repeatedly
  computing the ITC difference, you can test the significance of the
  two conditions having a different ITC.
  A difference in the number of trials poer condition will affect the
  ITC, however since the number of trials remains the same for each
  random permutation, this bias is reflected in the randomization
  Use this function by calling 
    [stat] = ft_freqstatistics(cfg, freq1, freq2, ...)
  with the following configuration options
    cfg.method    = 'montecarlo'
    cfg.statistic = 'diff_itc'
  and optionally the options
   cfg.complex    = 'diffabs' to compute the difference of the absolute ITC values (default), or
                    'absdiff' to compute the absolute value of the difference in the complex ITC values.
  NOTE: For this specific statistic there is no known parametric distribution, hence
  the probability and critical value cannot be computed. This specific statistic can
  therefore only be used with cfg.method='montecarlo'. If you want to do this in combination
  with cfg.correctm='cluster', you need cfg.clusterthreshold='nonparametric_common' or