  This work presents the application of Multifractal Detrended Fluctuation
Analysis for the surface electromyography signals obtained from the patients
suffering from rectal cancer. The electrical activity of an external anal
sphincter at different levels of medical treatment is considered. The results
from standard MFDFA and the EMD--based MFDFA method are compared. Two distinct
scaling regions were identified. Within the region of short time scales the
calculated spectra exhibit the shift towards higher values of the singularity
exponent for both methods. In addition obtained spectra are shifted towards the
lower values of singularity exponent for the EMD--based MFDFA.
