An investigation into the spatial relationship between complexity and motility within the oesophagus

Nonlinear analysis techniques have recently been used in the characterization of complex physiological signals seen in pathological disorders such as epilepsy and cardiac fibrillation. In this study a series of controlled swallows from an asymptomatic demonstration group was investigated using oesophageal manometry. The nonlinear measure of complexity, largest Lyapunov exponents and phase portraits were then used to explore the complexity of motility patterns at different points within the oesophagus. Results indicate greater complexity within the region of the striated muscle in the upper oesophagus than that observed within the region of smooth muscle in the lower oesophagus. Phase portraits showed that manometry patterns within the asymptomatic demonstration group could be quite different, highlighting the problems in clinical diagnosis. The characterization of motility disorders associated with complex manometry patterns such as diffuse oesophageal spasm (DOS) and nonspecific motility disorder (NOMD) still represents a diagnostic challenge. The use of nonlinear techniques enabling the quantitative and qualitative measurement of oesophageal complexity is considered in the classification of such disorders.