• Cervico-ocular reflex upregulation in dizzy patients with asymmetric neck pathology.

      Zamysłowska-Szmytke, Ewa; Adamczewski, Tomasz; Ziąber, Jacek; Majak, Joanna; Kujawa, Jolanta; Śliwińska-Kowalska, Mariola; Nofer Institute of Occupational Medicine (2019-10-16)
      Objectives: The aim of this study was to investigate whether the restriction in neck rotation and increased neck muscle tension could be causally related to vertigo and dizziness. Material and Methods: Seventy-one patients reporting vertigo and/or imbalance were divided into 2 groups: 45 subjects with unilateral restriction (R+) and 26 without restriction (R–) of cervical rotation and muscle tension in the clinical flexion-rotation test. The normal caloric test was the inclusion criterion. The control group comprised 36 healthy volunteers with no history of vertigo. The vestibulo-ocular reflex (VOR) and the cervico-occular reflex (COR) were measured through the videonystagmography (VNG) sinusoidal pendular kinetic test in the conditions of not inactivated head and immobilized head, respectively. The VNG-head torsion test (VNG-HTT) nystagmus was recorded. Results: Among the reported complaints, neck stiffness, headaches and blurred vision were more frequent in the R+ group than in both the R– group and the control group. VNG revealed an increased COR gain and the presence of VNG-HTT nystagmus in the R+ group only. Similarly, only in the R+ group a positive relationship between COR and VOR was observed. Conclusions: Patients with asymmetric restriction in neck rotation and increased neck muscle tension reveal the tendency to have an increased response of the vestibular system, along with co-existing COR upregulation. Further research is needed to investigate the relationships between the activation of cervical mechanoreceptors and dizziness pathomechanisms.