Linear and nonlinear analysis of trunk sway time series in office workers with and without chronic spinal pain

• Autor(a) principal: Júlio, Afonso Manuel Caetano
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/161075
• topic: Chronic Spinal Pain; Office work; Prolonged sitting; Linear metrics; Nonlinear metrics; Postural sway; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Office workers are likely to spend increasingly more time seated in their daily work but also throughout their personal lives. Public administration workers, particularly those working for tax authorities, are vulnerable to developing chronic spinal pain as a result of prolonged sitting (that affects their trunk variability). This study presents an analysis of trunk sway time series in office workers (Tax Authority), with or without chronic spinal pain, to characterize and verify potential kinematic differences between these groups and the impact of prolonged sitting periods in the postural sway of these subjects. This analysis includes measures of variability and is carried out by applying two methods: linear (amount of variability) and nonlinear (complexity of variability). Using a smartphone, the acceleration and rotation vector time series were recorded from 16 workers. A dashboard was created to visualize subjects’ pain reports. An algorithm was developed to remove non-seated subjects’ periods. Another algorithm was developed to convert the rotation vector into center of pressure displacement time series from which the time series of postural sway is extracted, based on the limits defined in the literature for the range of postural sway. Linear and nonlinear analysis is applied to these series, calculating various metrics to characterize the differences between chronic spinal pain and healthy subjects. Results showed few statistically significant differences within and between groups. Higher values of variability for chronic spinal pain subjects were observed. Linear metrics suggested that chronic spinal pain and healthy subjects increased the trunk’s variability as the day progressed, and decreased trunk’s variability over the week. Results for Nonlinear metrics were inconclusive.