• A Novel Design of a Knee Brace for Patients with Spinocerebellar Ataxia: A Comparative Study

      Speece, Brooke; School of Engineering
      Spinocerebellar ataxia (SCA) is an inherited degenerative disease of the central nervous system leading to the deterioration of the cerebellum, the voluntary motor control center of the brain. Patients with SCA are unable to maintain balance and normal posture and have an ataxic gait, resulting in increased abnormalities in gait parameters. Some patients may increase muscle co-activation to provide stability during gait by stiffening their joints. A compensation that typically results in reduced joint range of motion and a decrease of gait parameters. The subject of this study is a 47-year-old female with spinocerebellar ataxia type 2 and presents with difficulty standing, abnormal ataxic gait, and poor balance. The purpose of this study was to design and construct a brace to provide stability and aid the patient in walking as well as standing and sitting. Two braces were designed, constructed, and tested to compare the efficacy of each: a tension brace with an adjustable Velcro tension band attachment on the anterior portion of the brace and a spring brace with a torsional spring and 3D printed housing attached to the brace knee joint. Electromyography analysis determined the knee antagonist co-activation index (CAI) increased by 86.3% during stance and by 168.7% during swing with the spring brace, indicating greater stability and motor control. The tension brace had little to no effect on CAI. During standing, the tension brace increased quadriceps activity by 65.4% and the spring brace increased activity by 37.2%, indicating both braces could help to rehabilitate weak muscle function. Joint angle diagrams obtained in the gait analysis determined both braces aid the knee during the terminal stance and pre-swing. With the spring brace, cadence increased by 8.7% (72.4 steps/min) and velocity by 8% (0.53 m/s), while the tension brace increased cadence 4.9% (69.7 steps/min) and velocity remained unchanged. The F-Scan pressure analysis determined the spring brace decreases abnormal peak force during loading which can indicate balance problems at heel strike. The patient preferred using the spring brace to the tension brace. She felt it provided her more stability and speed and elected to keep the brace after testing.