Surface-EMG analysis of rectus femoris in patients with spastic hemiparesis undergoing rehabilitation treatment.

In the present study a surface-EMG investigation of the rectus femoris muscle was performed in patients with spastic hemiparesis before and after rehabilitation treatment. The EMG activity was detected during 50% of the maximum voluntary contraction by means of FFT automatic analysis; the mean power frequency (MPF) and the time-course of the frequencies of the surface-EMG signals showed significant changes after physiokinesitherapy. In hemiparetic patients a particular distribution of the frequencies of the surface-EMG signals towards the lowest values were observed. These findings could be related to the preferential atrophy of type II fibers which has been demonstrated in morphological studies. Furthermore the surface-EMG analysis after a period of rehabilitation treatment showed some significant modifications of MPF and time-course of the EMG signals. These changes corresponded to an improvement of the spasticity as evaluated by clinical rating-scale. This neurophysiological investigation seem to be a simple and reliable method for better evaluating some effects of the rehabilitation therapy.

Peripheral nerve conduction velocity in normal infants and children.

Maximum motor conduction velocity of the median, ulnar and peroneal nerves and maximum sensory conduction velocity of the median nerve have been studied in 635 children, below 12 years of age, free from peripheral nervous system disease. The children fell into four age-group: from 0 to 1 year; from 1 to 3 years: from 3 to 6 years; from 6 to 12 years. No normal values were recorded for the sensory conduction velocity of the median nerve under the age of one year. The motor conduction velocity values significantly rise for the median and ulnar nerves up to 1 year, for the peroneal nerve up to 3 years. The sensory conduction velocity values of median nerve increase significantly up to 6 years.

Surface EMG evaluation of quadriceps femoris muscle in hemiplegic patients.

The method applied consists of evaluating the power spectra of the electromyographic (EMG) surface signal obtained during maximal isometric effort of the quadriceps femoris muscle. In hemiplegic patients it is possible to observe a particular frequency distribution towards the lowest values of the range considered. This trend might be accounted for by the morphological and enzyme- histochemical studies on the quadriceps femoris showing a selective atrophy of type 2 fibers. During rehabilitation treatment, however, it is imperative to consider parameters such as muscle strength changes and frequency values preferentially activated during the isometric effort (time-course). Observation of the pattern of the power spectra time-course therefore seems to contribute to a better view of the rehabilitation strategies suitable for exploiting the residual motor abilities.