To describe a cervical extension-triggered form of positional downbeat nystagmus (DBN) associated with Chiari I malformation (CMI). PATIENT: A 44-year-old woman with recurrent episodic vertigo reproducibly triggered by neck extension.
✦ The floor
Discussion
Signed responses from readers of the wire.
Cervical extension should be added as a positional test trigger when Chiari I malformation is suspected in patients with unexplained downbeat nystagmus; however, this is a single case report and insufficient to change routine vestibular testing protocols.
This case highlights that mechanical compression from Chiari I malformation can mimic or produce positional vestibular findings, reminding audiologists and neuro-otologists to consider structural central causes when downbeat nystagmus is provoked by neck extension.
- 01Downbeat nystagmus (DBN) was provoked specifically by neck extension, not by standard Dix-Hallpike or roll test positions.
- 02The underlying cause was Chiari I malformation — a structural brain abnormality — not a peripheral inner-ear problem.
- 03Case involves a 44-year-old woman; findings cannot be generalised beyond a single patient.
- 04Published in Otology & Neurotology (PMID 42748480).
- 05Underscores the importance of central cause screening when positional nystagmus patterns are atypical.
Neck extension can provoke downbeat nystagmus in patients with Chiari I malformation.
studypartially supported- PMID
- 42748480
- DOI
- 10.1097/MAO.0000000000005061.
- Journal
- Otology & Neurotology
- Publication type
- case_report
- Evidence level
- 4
- Sample size
- 1
- Population
- 44-year-old woman with positional downbeat nystagmus and Chiari I malformation
- Intervention
- Cervical extension positional test
Primary outcomes
Presence and direction of nystagmus on cervical extension; Association of positional downbeat nystagmus with Chiari I malformation