OBJECTIVE

To determine the electromyographic patterns of motor tics in children.

MATERIAL AND METHODS

130 patients were examined, which were divided into 3 groups: the 1st group included 21 patients with motor tics; the 2nd group included 87 patients with motor-vocal tics; the 3rd group included 22 patients with Tourette’s syndrome (ST). The control group consisted of 35 healthy children. Clinical methods for assessing the severity and semiotics of tics were used, including the YGTSS scale, hyperkinesis counting in 20 minutes, cutaneous electromyography (EMG) in rest and exercise modes with turn-amplitude analysis.

RESULTS

The following EMG patterns of tic hyperkinesis in the resting mode were found: 1) the amplitude of the background activity exceeds the values in the control group (p<0.05); 2) in case of clonic tics, a high-amplitude volley activity (VA) arises simultaneously in the form of spindles with a duration of 10-30 ms with an amplitude of 500-2500 μV; 3) with dystonic tics, volleys in the form of rhombuses with a duration of 100-1000 ms and an amplitude of 1000-3000 μV; 4) volley-slow wave had a duration of 307.2±109.6 ms and an amplitude of 540.3±238.6 μV. In the mode of physical activity, VA increases, which is maximally expressed in amplitude on the circular muscle of the eye and the superficial flexor of the fingers in patients with CT (p<0.05). Analysis of correlations established an inverse relationship between the amplitude of VA and the number of hyperkinesis in 20 minutes.

CONCLUSION

Qualitative and amplitude-time analysis of EMG makes it possible to objectify the disease, to isolate patients with CT from chronic motor-vocal tics and to model the prognosis. Probably, the tic can act as a compensatory manifestation of excessive impulsation of cortical-subcortical genesis.