Sound-triggered myoclonus in the geriatric cat
15-year-old female Birman cat with episodes of sudden 1–2-second jerks of the head and trunk, occurring when foil is crumpled, keys jingle or someone types nearby. It has had one generalised tonic-clonic seizure. Neurological examination between episodes is normal; blood pressure, total T4 and biochemistry are normal.
What is the most likely diagnosis and the treatment with the best evidence?
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A. Feline audiogenic reflex seizures; levetiracetam controls myoclonus better
Correct. These are myoclonic seizures triggered by high-pitched sounds in elderly cats, with Birmans over-represented; generalised seizures may also occur. In a randomised trial, levetiracetam was more effective and better tolerated than phenobarbital in controlling the myoclonus.
B. Feline hyperaesthesia syndrome; gabapentin and environmental enrichment
Feline hyperaesthesia presents with rippling of the dorsal skin, tail chasing or self-mutilation, often in young cats. It is not reproducibly triggered by specific high-pitched sounds.
C. Seizures from a meningioma; do not treat until MRI and surgery are done
A meningioma is reasonable in the differential for an older cat and MRI is useful, but the pattern of sound-triggered reflex myoclonus is characteristic of another syndrome, the examination is normal and delaying treatment is not justified.
D. Intermittent hypertensive encephalopathy; amlodipine even if blood pressure is normal
Hypertensive encephalopathy produces variable signs with very high pressures, not sound-triggered myoclonus. With normal blood pressure there is no basis for amlodipine treatment.
lightbulb Key takeaway
Always ask about the trigger: foil, keys, keyboards or tongue clicking. Avoiding those sounds helps, and many affected cats also have hearing loss. Myoclonus may precede generalised seizures by months.
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Updated: November 1, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.