Abstract
Introduction Biomechanical reference values for healthy gait patterns have been widely reported in the peer-reviewed literature for various genders and ages. Gait is considered pathological when observed variables in individuals deviate from healthy reference points. The process of identifying gait characteristics may reveal distinct neurological disorders. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) was first identified in 2001, and has since been extensively researched in the fields of genetics and neurobiology. However, to date, no gait studies to our knowledge have been performed on individuals affected with FXTAS. Therefore, the purpose of this pilot case study was to initiate a descriptive gait profile on an individual clinically diagnosed with FXTAS. Purpose The purpose of this study was to conduct a biomechanical gait analysis on individuals affected with Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS). Methods One 68-year old male participant clinically diagnosed with FXTAS participated in a biomechanical gait analysis. The participant was required to walk at a self-selected pace across 5 meters in a straight line over a force plate imbedded in the ground. A 34 joint marker system was placed on the participant to generate a stick figure model that calculates kinematic variables. An eight infra-red camera motion capture system was used to recognize the reflective joint markers and a Vicon Nexus software program was used to synchronize the force plate data with the reflective joint markers. After the participant completed the self-selected speed walking trials, the participant completed 3 tandem walking trials, 2 30-second standing feet-together balance tasks, and 1 30-second single-leg balance task. For statistical analyses, each variable was averaged with standard deviations. Results During a basic walking task, our participant had an average velocity of 103.7 cm/s compared to healthy age-matched referenced males with an average velocity of 133.84 cm/s. The average cadence in our study was 101.7 steps per minute compared to healthy populations with an average of 114.84 steps per minute. The stance and swing times between the two populations were the same with approximately 60% of the gait cycle dedicated to stance and 40% of the gait cycle dedicated to swing time. The average step length in our FXTAS participant was 56.5 cm compared to average healthy populations of 66.02 cm. There was a small difference of distance in step width between the FXTAS and healthy population with the average step width values being 10.7 cm and 11.77 cm, respectively. The average stride length in the FXTAS population was 118.4 cm compared to the average of 137.32 cm in age-matched health males. The hip angles between the two populations were comparable. The average knee angle of the FXTAS was 56.7 degrees compared to healthy populations showing averages of 63.51 degrees. The average ankle angle of our study was 22.79 degrees compared to the average of 27.23 degrees in healthy populations. Peak joint moments were reported for a normal walking trial. The average peak hip extension moment for healthy populations and FXTAS were -0.65 and -0.97 N-m/kg, respectively. The average peak hip flexion moment for the same populations listed before were 0.63 and 0.74 N-m/kg, respectively. The average knee extension moment for healthy and FXTAS populations were 0.40 and 0.31 N-m/kg, respectively. The average knee flexion moment for the previously mentioned populations were -0.35 and -0.49 N-m/kg. The average ankle dorsiflexion moment for healthy and FXTAS populations were 0.92 and 1.64 N-m/kg, respectively. The average ankle plantarflexion moment for the previously mentioned populations were -0.08 and -0.077 N-m/kg, respectively. During the tandem walk, our study showed the FXTAS velocity to be 11.10 cm/s compared to healthy populations of 27.0 cm/s. The cadence in our study was 25.86 steps per minute compared to 69.7 steps per minute in healthy populations. The step width was 0.4 cm in healthy populations compared to 2.66 cm in our study. The number of missteps showed an average of 0.2 missteps/minute in healthy populations and 6.25 missteps/minute in FXTAS. Conclusion There is a difference in gait variables in our FXTAS population compared to healthy and age-matched males. Our FXTAS participant most similarly mimics ataxic and Parkinson’s Disease populations. For most variables, our participant was in between values of healthy, age-matched males and Parkinson’s Disease and Ataxic populations. This could be due to our participant being in the earlier stages of development in the FXTAS disease.