Differential cytokine profiles in pediatric patients with PFAPA syndrome and recurrent tonsillitis.

Objective : An attempt was made to identify characteristic cytokine profiles to distinguish periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPAS) from recurrent tonsillitis, of which clinical manifestations are similar to those of PFAPAS in children. Methods : Serum concentrations of IL-6, IL-4 and IFN-γ were measured during febrile episodes in pediatric patients. Results : The levels of IL-6 during febrile episodes were markedly increased above the upper limit of normal ranges in patients with both PFAPAS and recurrent tonsillitis, but there were no significant differences between groups. The levels of IL-4 during febrile episodes in PFAPAS patients were significantly lower than those in recurrent tonsillitis patients. The levels of IFN-γ during febrile episodes in PFAPAS patients were significantly higher than those in recurrent tonsillitis patients. Conclusion : In pediatric patients with PFAPAS, despite an increase of IL-6, IL-4 was suppressed with a marked increase of IFN-γ during febrile episodes. On the contrary, in febrile pediatric patients with recurrent tonsillitis, both IL-6 and IL-4, but not IFN-γ were increased. The characteristic cytokine profiles of IL-6, IL-4 and IFN-γ can be used for differential diagnosis of PFAPAS from recurrent tonsillitis in children in clinical ear, nose and throat (ENT) settings. J. Med. Invest. 68 : 38-41, February, 2021.

The effect of visual-vestibulosomatosensory conflict induced by virtual reality on postural stability in humans.

In this study, we examined the effects of sensory inputs of visual-vestibulosomatosensory conflict induced by virtual reality (VR) on subjective dizziness, posture stability and visual dependency on postural control in humans. Eleven healthy young volunteers were immersed in two different VR conditions. In the control condition, subjects walked voluntarily with the background images of interactive computer graphics proportionally synchronized to their walking pace. In the visual-vestibulosomatosensory conflict condition, subjects kept still, but the background images that subjects experienced in the control condition were presented. The scores of both Graybiel's and Hamilton's criteria, postural instability and Romberg ratio were measured before and after the two conditions. After immersion in the conflict condition, both subjective dizziness and objective postural instability were significantly increased, and Romberg ratio, an index of the visual dependency on postural control, was slightly decreased. These findings suggest that sensory inputs of visual-vestibulosomatosensory conflict induced by VR induced motion sickness, resulting in subjective dizziness and postural instability. They also suggest that adaptation to the conflict condition decreases the contribution of visual inputs to postural control with re-weighing of vestibulosomatosensory inputs. VR may be used as a rehabilitation tool for dizzy patients by its ability to induce sensory re-weighing of postural control.

Autonomic responses during motion sickness induced by virtual reality.

OBJECTIVE: To examine the development of subjective symptoms and heart rate variability (HRV) during motion sickness induced by virtual reality (VR). METHODS: Subjects were 10 healthy young volunteers. During VR immersion, subjects were immersed in a visual-vestibular conflict produced by VR. The levels of the subjective symptoms were assessed by Graybiel's and Hamilton's criteria. HRV was determined by measuring microvascular blood flow or electrocardiogram. RESULTS: Subjective symptoms evaluated by Graybiel's and Hamilton's criteria were gradually worsened during VR. Power spectrum analysis of HRV demonstrated a gradual increase in the low frequency but no change in the high frequency during VR. In this study, individual subjective symptoms were not correlated with the individual result of power spectrum analysis. CONCLUSION: These findings indicate that there was an increase in sympathetic nervous activity, but no change in parasympathetic nervous activity during motion sickness induced by VR. Given the large inter-individual variability and the reliability of subjective measures, it is not surprising that there is scarcely a relation between the subjective symptoms and the results of power spectrum analysis.

Effects of immersion in virtual reality on postural control.

In the present study, we examined the effects of the time lag between visual scene and the head movement in the virtual reality (VR) world on motion sickness and postural control in healthy volunteers. After immersion in VR with additional time lags (from 0 to 0.8 s) to the inherent delay (about 250 ms), the visual-vestibular conflict induced a slight motion sickness in experimental subjects, but no change was noticed in the body sway path with eyes open and closed. However, Romberg ratio of body sway path with eyes closed divided by that with eyes open after immersion in VR was significantly decreased in comparison with that before immersion in VR. Since Romberg ratio is an index of visual dependency on postural control, this finding indicates that the immersion in VR decreases the visual dependency on postural control. It is suggested that adaptation to visual-vestibular conflict in VR immersion increases the contribution of vestibular and somatosensory inputs to postural control by ignoring the conflicting delayed visual input in the VR world. VR may be a promising treatment for visual vertigo in vestibular patients with unsuccessful compensation by its ability to induce vestibular and somatosensory reweighing for postural control.