Contribution of the Pedunculopontine Nucleus on Walking in Stroke Patients

Abstract

Objectives: We attempted to investigate changes of the pedunculopontine nucleus (PPN) according to walking ability in chronic stroke patients, using diffusion tensor imaging (DTI). Methods: 55 consecutive chronic stroke patients who were not able to walk due to injury of the corticospinal tract (CST) at stroke onset and 22 age-matched normal control subjects were recruited. We measured the values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the PPN and assessed the walking ability of each patient. Results: In patients who were able to walk independently, the FA value of the PPN in the affected hemisphere was increased without change of the ADC value (p < 0.05). Increase of the FA value was positively correlated with the degree of walking ability (p < 0.05). In contrast, the ADC value was increased in the affected hemisphere of patients who could not walk, without change of the FA value (p < 0.05). This increase of the ADC value was negatively correlated with the degree of walking ability (p < 0.05). Conclusion: We found that the neuronal activity of the PPN in the affected hemisphere was increased in stroke patients who were able to walk independently. Therefore, we think that the PPN in the affected hemisphere contributed to walking ability in stroke patients with CST injury.