Objectives To test the hypothesis that vertebral artery hypoplasia (VAH) may affect the lateralisation of vestibular neuropathy (VN), probably through haemodynamic effect on the vestibular labyrinth.
Methods 69 patients with unilateral VN were examined with a magnetic resonance angiographic (MRA) and caloric test. 50 healthy subjects served as controls. The diagnosis of intracranial VAH was based on MRA if <0.22 cm in VA diameter and a diameter asymmetry index >40%. The authors then correlated the canal paretic side with the VAH side.
Results MRA study revealed 29 VAH (right/left: 23/6) in VN subjects and six VAH in controls (right/left: 5/1). The RR of VAH in VN subjects compared with controls was elevated (RR=2.2; 95% CI 1.8 to 2.8). There was a high accordance rate between the side of VAH and VN. Among 29 patients with unilateral VAH, 65.5% (N=19) had an ipsilateral VN, in which left VAH showed a higher accordance rate (83.3%) than the right side (60.9%). VN subjects with vascular risk factors also had a higher VAH accordance rate (81%) than those without (25%).
Conclusions VAH may serve as a regional haemodynamic negative contributor and impede blood supply to the ipsilateral vestibular labyrinth, contributing to the development of VN, which could be enhanced by atherosclerotic risk factors and the left-sided location.
- Vertebral artery hypoplasia
- magnetic resonance angiogram
- vestibular neuropathy or neuronitis
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Funding This study was funded by a research grant (DOH94-TD-I-111-012) from the Office of National Science and Technology Program for Biotechnology and Pharmaceuticals, Department of Health, the Executive Yuan, Taiwan, Republic of China.
Competing interests None.
Patient consent Obtained.
Ethics approval Ethics approval was provided by the Taipei Veterans General Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.