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Downbeat nystagmus associated with dolichoectasia of the vertebrobasilar artery
1Department of Neurology, Marshfield Clinic, WI 54449.
Insights
Vertebrobasilar artery dolichoectasia may cause downbeat nystagmus in some idiopathic cases. This study investigated the link between this vascular abnormality and unexplained nystagmus.
Area of Science:
- Neurology
- Vascular Neurology
- Ophthalmology
Background:
- Downbeat nystagmus (DBN) is an involuntary eye movement disorder.
- The etiology of DBN remains unknown in a significant percentage of patients.
- Vertebrobasilar artery dolichoectasia (VAD) involves abnormal widening and elongation of these arteries.
Purpose of the Study:
- To investigate the potential association between VAD and idiopathic DBN.
- To determine if VAD is an identifiable cause in cases where DBN etiology is unclear.
Main Methods:
- Retrospective review of 41 patients diagnosed with primary position DBN over a 5-year period.
- Analysis of patient case records and radiographic studies.
- Identification of VAD as a potential causative factor.
Main Results:
- The cause of DBN was undetermined in 12 patients (29%).
- Two of these idiopathic DBN cases exhibited VAD as the sole abnormality.
- One additional case had VAD alongside other potential contributing factors.
Conclusions:
- VAD may be an underrecognized cause of idiopathic DBN.
- Compression of the caudal brainstem by dolichoectatic vertebrobasilar arteries could explain some DBN cases.
- Further research is warranted to confirm VAD as a cause of DBN.
Abstract:
We reviewed the case records and radiographic studies of 41 patients with primary position downbeat nystagmus seen during a 5-year period to investigate whether a relationship existed between dolichoectasia of the vertebrobasilar artery and cases of unknown cause. The cause of downbeat nystagmus could not be determined in 12 cases (29%). Two of these cases had dolichoectasia of the vertebrobasilar artery as the only identifiable abnormality. One other case had a dolichoectatic vertebrobasilar artery, but other potential etiologic factors for the development of downbeat nystagmus were present. Compression of the caudal brain stem by an enlarged and tortuous vertebrobasilar arterial system may be the cause of downbeat nystagmus in some cases unassociated with more commonly recognized causes.