Modelling and analysis of changes in muscle dynamics during the rehabilitation process in adolescent idiopathic scoliosis patients

Adolescent idiopathic scoliosis (AIS) is a condition of lateral curvature and rotation of the spine of unknown cause. This type of scoliosis occurs between childhood and adolescence (10-18 years). AIS is the most common type of scoliosis and is usually characterised by rapid progression of spinal curvature. Rapid progression of spinal curvature can lead to a critical clinical picture. Therefore, early diagnosis of subjects with AIS is important. Skeletal imaging techniques, particularly radiography and tomography, are widely used in the diagnostic process. At present, the diagnostic procedure including muscle dynamics is not used. However, dimensional changes are possible, particularly in the upper body muscles (chest, abdominal, back, lumbar and arm muscles) due to spinal curvature in people with AIS. Literature studies suggest that muscle activation changes in subjects with scoliosis and that asymmetry of muscle dynamics occurs between the right and left sides. Radiological studies are also used to determine the physical rehabilitation processes that are applied as a result of the diagnosis and to monitor recovery. In this study, 18-channel surface EMG (sEMG) was recorded, analysed and evaluated from the upper body muscles of subjects with AIS during Schroth exercises. The aims of our study were to determine the change in muscle dynamics in AIS patients due to spinal curvature, to examine the harmony between the right and left muscles, to enable evaluation of the rehabilitation process of the subject and to determine the effectiveness of Schroth exercises on muscle dynamics. Healthy subjects and subjects with AIS were included in the study. The healthy subjects were adolescents (age range 11-16 years) and there were 16 of them. Healthy subjects should have no spinal problems and no symptoms associated with any chronic disease or disorder. The healthy subjects were similar to the AIS subjects in terms of age, gender and other demographic factors. A total of 17 people with AIS were included in the study. Classification of the spinal curves of the AIS subjects was used to select common Schroth exercises for all subjects. In the recording phase, 6 exercises were selected. Ethics committee approval was obtained prior to recording. An interface was designed to make the exercises as stable as possible during recording. On this interface, visual and auditory commands were given to the person performing the exercise on the screen. sEMG recordings were performed at a sampling frequency of 2000 Hz. Butterworth (6th order), 5 Hz high pass and 500 Hz low pass filters were applied to the raw sEMG data. The Wavelet Packet Transform (WPT) method was used to analyse the filtered sEMG data. Wavelet Packet Energy (WPE) values were calculated depending on the scaling and translation parameters to determine the detailed frequency ranges. For each movement, 3D and 2D plots were generated for the mean values of the healthy and AIS subjects. The axes of the 3D plots are frequency, sEMG electrode and WPE values. The axes of the 2D graphs are the sEMG electrode and DPE mean values. The normalisation values of the DPE averages were processed on the human model we created. The Mann-Whitney U test was used to determine statistically significant differences in the results. When the results were analysed, low muscle activation and a difference in right-left muscle dynamics, i.e. asymmetry, were observed in AIS subjects compared to healthy subjects during movements A and B, which require symmetrical muscle activation. It was found that these two movements were postural and that the shoulder and pelvic alignment of AIS subjects was problematic and supported by different muscle dynamics in the exercise. The other exercises were asymmetric exercises performed according to the direction of spinal curvature of the Schroth exercise. The effectiveness of the Schroth exercise was determined from the muscle activation results of the other exercises. In both groups, muscle activation was measured in the direction of the spinal curvature. In people with AIS, muscle activation was also found in muscle regions on the opposite side of the spinal curvature. We expect the abdominal muscles to be activated during the plank exercises. While the abdominal region was active in healthy subjects, activation in the back muscles was observed in AIS subjects. In conclusion, asymmetric muscle activation, balance problems, abdominal muscle weakness and the effectiveness of Schroth exercises were identified. We believe that knowledge of muscle dynamics provides important information for the diagnosis and treatment of people with scoliosis.