FEATURE SELECTION OF ELECTROMYOGRAPHY SIGNALS FOR AUTISM SPECTRUM DISORDER CHILDREN DURING GAIT USING MANN-WHITNEY TEST

Autism Spectrum Disorder is a lifelong neurodevelopmental impairment that affects brain growth and individual functional capabilities that associates with unusual movement and gait disturbance. The aim of this study is to investigate the significant features of EMG signals for lower limbs and arms muscle between Autism Spectrum Disorder (ASD) and Typical Development (TD) Children during walking. In this study, 30 ASD and 30 Typical Development (TD) children aged between 6 to 13 years old were asked to walk on the walkway naturally. The Electromyography (EMG) signals of Biceps Femoris (BF), Rectus Femoris (RF), Tibialis Anterior (TA), Gastrocnemius (GAS), Biceps Brachii (BB) and Tricep Brachii (TB) muscles of the ASD and TD children were recorded by using surface EMG sensors. The BF muscle is located at the posterior compartment of the thigh whereas the RF muscle located in the anterior compartment of the thigh. On the other hand, the TA muscle originates within the anterior compartment of the leg, and Gas muscle originates at the posterior compartment of the calf. Meanwhile, the BB muscle is in the front of the upper arm between shoulder and elbow, and TB muscle is a large muscle on the back of the upper arm limb. The data consists of 42 features from 7 walking phases of 6 muscles during one gait cycle were obtained from the data collection. Firstly, the data will be normalized to one gait cycle to standardize the length of EMG signals used for all subjects. Then, the feature selection method using Mann-Whitney Test is applied to find the significant features to differentiate between ASD and TD children from the EMG signals. Out of 42 features, 5 were found to be the most significant features of EMG signals between ASD and TD children, there are TA muscle at 30% of gait cycle, Gas muscle at 50% and 60% of gait cycle, and BB muscle at 10% and 80% of gait cycle with significant values of 0.017, 0.049, 0.034, 0.021 and 0.003, respectively. These findings are useful to both clinicians and parents as the lower limbs and arm muscles can be valuable therapeutic parameter for ASD children's rehabilitation plan. The findings of this research also suggest that the significant difference of EMG signals obtained can be a parameter to differentiate between ASD and TD children.