Brief, frequent vertigo attacks responding to carbamazepine
Vignette
A 58-year-old engineer presents with 8 months of brief vertigo attacks. Each attack lasts 5–20 seconds — a sudden sense of spinning or rocking, sometimes provoked by a head turn, sometimes spontaneous. He has 10–20 attacks per day and is between attacks at the time of assessment. There is no associated hearing change, no aura, no headache. Bedside examination is normal: no spontaneous or positional nystagmus, normal head impulse test, normal smooth pursuit and saccades, normal Romberg, normal gait. Audiometry is normal. MRI brain with thin-slice cisternal sequences shows a loop of the anterior inferior cerebellar artery contacting the right vestibulocochlear nerve at the porus acusticus.
CDP findings
SOT pattern vs normalMCT — medium-amplitude backward translationADT — sway energy across five trials per direction
Audiometric findings
Normal hearing — both ears within 20 dB HL across all frequencies.
Healthy adult audiogram. Thresholds sit within the 0–20 dB HL normal range across all tested frequencies, with the small high-frequency rise typical of healthy adults. Paired with a normal CDP, this is the unremarkable baseline.
Single-best-answer
His CDP is normal. What is the most likely diagnosis, and what is the appropriate next step?
Teaching point. Vestibular paroxysmia is a recognised cause of brief, frequent vertigo attacks that the standard vestibular work-up — including CDP — typically misses. The Bárány Society 2016 criteria emphasise the clinical phenotype (brief, recurrent attacks with normal interictal exam), with MRI demonstration of neurovascular cross-compression as a supportive feature and treatment response to carbamazepine or oxcarbazepine as both diagnostic and therapeutic. Like SCD, BPPV, and cervicogenic dizziness, this is a diagnosis CDP doesn't make — recognising that CDP is unhelpful here is itself the clinical skill.