Comparison of average positive motor imagery (MI) intervention versus different MI session types. The figure shows the frequencies of motor imagery training session (MITS) and temporal parameter statistics for successful interventions. Categories of MITS elements add to 100%, if an element was reported for all interventions considered in this analysis. For temporal parameters, bars show mean and positive standard deviation (SD). ♦ = Indicate changing trend of MITS element frequencies (see main text for detailed description); ο, Δ, ∇ = indicate significant results of the statistical tests against the average positive MI intervention.