The tandem gait test: kinematics and temporal parameters for normal children and for posterior fossa tumor survivors

Background: Tandem Gait (TG) testing is known as a clinical method for studying the walking function with complicated coordination. The precise biomechanical walking parameters in this test remain poorly investigated. Moreover, TG is a modified locomotion of walking. In general, walking is a highly automated movement. TG introduces a component of voluntary control into it. Aims: A study of functional and biomechanical symptoms in children after the treatment for the posterior fossa tumor in the long term. Methods: The study involved 15 healthy subjects aged 12 to 35 years (20.4±7.2), among them 4 men and 11 women - control group. The group of patients comprised 33 children who had a tumor of the posterior cranial fossa (HF) at the age of 7 to 17 years (12.3±3.1), of these 15 boys and 18 girls, who were admitted for rehabilitation treatment to the "Russkoe pole" Rehabilitation Center. A study on the TG kinematics was performed with the Optitrack system. Results: The results showed asymmetry in the duration of the step cycle and an increase in its duration proportional to the severity of the functional state. The pelvic movements showed different abnormalities. The flexion-extension movements in the hip joints were characterized by an extension lag at the end of the transfer period and a slight decrease in the amplitude, which probably became more pronounced with an increase in the degree of the motor impairment. The movements in the knee joints demonstrated two main phenomena: an increase in the flexion setting of the joint and a decrease in the amplitude of the main swing flexion. In addition, there was a delay in the maximum of the swing flexion. The kinematic parameters of the TG of the examined patients, in contrast to the control group, are not stable. This is, presumably, due to the fact, that normally such a modification of walking is easily automated and does not require voluntary control. In patients with SCF, each step in the TG mode requires additional voluntary control, and under these conditions, the stability and repeatability of a movement are dramatically reduced. Conclusions: In contrast to the routine clinical version of the test, the analysis of the movement biomechanics allows one to present an accurate qualitative and quantitative characterization of functional disorders. According to our research, motor function disorders develop at various levels of the musculoskeletal system. The degree of their severity is in a good agreement with the expert assessment of the patient's functional state.