Original Article Temporal Gait Measures Associated With Overground and Treadmill Walking in Rett Syndrome Charles Shannon Layne, PhD 1,2,3 , Beom-Chan Lee, PhD 1,2 , David Ryan Young, MS 1,2 , Daniel Gordon Glaze, MD 4,5,6 , Aloysia Schwabe, MD 5,6 , and Bernhard Suter, MD 4,5,6 Abstract Rett syndrome is a severe neurodevelopmental disorder leading to intellectual impairment and global developmental delays, including difficulty or inability to walk. Assessing differences in temporal parameters and associated variability between over- ground and treadmill walking is important if gait training is to be incorporated into intervention protocols. Fourteen female patients with Rett syndrome (mean age 10.4 years + SD 5.1) were evaluated during overground and treadmill walking. Stride, stance, swing, and double support times, and the variance of these measures, were obtained. Wilcoxon signed-rank tests were used to assess for potential differences between overground and treadmill measures. Treadmill gait resulted in decreases in swing and double support times. When normalized to stride time, treadmill gait displayed an increase in stance time with decreases in swing and double support times. Excepting stance time, treadmill gait resulted in decreased variability, indicating a more reg- ularized gait while walking on the treadmill. These results suggest that treadmill walking can be beneficial for ambulatory patients with Rett syndrome and could be incorporated into a therapeutic protocol designed to maintain the maximum degree of mobility and overall general health as part of a comprehensive health management approach. Keywords quality of life, developmental disability, genetics, mutation, rehabilitation Received December 5, 2017. Received revised April 9, 2018. Accepted for publication May 7, 2018. Rett syndrome is a neurodevelopmental disorder that affects approximately 1 in 10 000 live-born females worldwide, and *95% of those diagnosed with typical Rett syndrome carry a mutation in the gene coding for methyl-CpG-binding protein 2 (MECP2). The condition is characterized by seemingly normal developmental progression up to ages 6 to 18 months, at which point distinct regression in motor, prelanguage, growth, and socialization skills occurs, which is then followed by relative stabilization. Several prominent disabilities in fine and gross motor skills are frequently observed. These include stereotypi- cal hand movements, particularly midline “handwashing” motions, breathing difficulties, bruxism, rigidity/hypertonia, apraxia, ataxia, poor transitions from sitting to standing, and disordered gait and postural control. To date, there is no cure for Rett syndrome and a great need to develop effective phar- macologic and therapeutic interventions. Additionally, the development of reproducible, quantitative clinical measures that can be employed and compared across multiple research sites will be necessary to accurately assess the potential effec- tiveness of any intervention. 1-3 The inability to walk often leads to a series of additional physical problems, including contractures of the limbs associ- ated with spasticity and lack of movement, muscle atrophy, scoliosis, and a general lack of physical fitness, including car- diorespiratory fitness. Several authors have suggested physical or movement therapy programs designed to improve overall 1 Health and Human Performance, University of Houston, Houston, TX, USA 2 Center for Neuromotor and Biomechanics Research, University of Houston, Houston, TX, USA 3 Center for Neuro-Engineering and Cognitive Science, University of Houston, Houston, TX, USA 4 Blue Bird Circle Rett Center, Houston, TX, USA 5 Texas Children’s Hospital, Houston, TX, USA 6 Baylor College of Medicine, Houston, TX, USA Corresponding Author: Charles Shannon Layne, PhD, Health and Human Performance, University of Houston, 3875 Holman Street, 104 Garrison Gymnasium, Houston, TX 77204, USA. Email: clayne2@uh.edu Journal of Child Neurology 1-8 ª The Author(s) 2018 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0883073818780471 journals.sagepub.com/home/jcn