Feline Audiogenic Reflex Seizures (FARS)

Melissa Boldan, DVM
Written by:
Published: November 8, 2022
Feline Audiogenic Reflex Seizures (FARS)

What Are Feline Audiogenic Reflex Seizures?

Feline audiogenic reflex seizures (FARS) are a medical condition where loud sounds can trigger seizures in cats. FARS is more common in senior cats, with the average patient being 15 years old when diagnosed. It is also a genetic disorder in the Birman cat breed.

There are three types of FARS seizures:

  • Myoclonic Seizure: This is the most common type and is considered one of the hallmark clinical signs. Myoclonic seizures look like muscle spasms or jerking, and usually last only a few seconds. Cats experiencing this type of seizure look like they are conscious, but they have muscle twitches across their body.

  • Generalized Tonic-Clonic Seizure (GTCS): This is what most people think of when they hear the word “seizure.” When a cat has GTCS, they fall over on their side, paddle their feet, shake, chomp their jaw, possibly lose control of their bladder or bowels, and are not mentally aware. Usually, these episodes last a couple of minutes. Cats are confused and disoriented for a few minutes afterward.

  • Absence Seizure: Commonly called a petit mal seizure, an absence seizure is a subtle seizure where the patient seems to be briefly unaware. This type of seizure is more commonly described in humans because it is more obvious. A person may be sitting and talking to you one minute, and the next minute they are not responsive to questions. In pets, an absence seizure can be difficult to recognize, but it looks like the animal has lost awareness for a short period of time.

FARS is not commonly diagnosed in cats. It is believed to have a genetic link and may be triggered by hearing loss. As a senior cat loses their hearing, first they lose the ability to hear lower tones. High- pitched and loud sounds are the last to go. Cats with FARS are startled by these loud sounds, and that can trigger a seizure.

When a cat is diagnosed with a seizure disorder, it may not be possible to eliminate their seizures altogether. Managing seizures by reducing their frequency and severity might be the only option.

A seizure is considered a medical emergency when it lasts more than 5 minutes, or if your cat has a cluster of seizures (more than three seizures in 24 hours). If your cat is having a protracted (prolonged) seizure or is clustering, they need to be taken to an emergency veterinarian as soon as possible.

Clinical Signs of Feline Audiogenic Reflex Seizures

The following are general signs of various types of seizures, but they are considered clinical signs of FARS after exposure to a high-frequency sound:

  • Muscle twitches, spasms, or jerks

  • Loss of awareness

  • Stiffening up and falling over

  • Leg paddling or kicking while on side

  • Jaw chomping/chewing

  • Hypersalivation 

  • Loss of control of bladder or bowels

Causes of Feline Audiogenic Reflex Seizures

FARS seizures are triggered by interrupted, high-frequency sounds. Researchers who characterized this syndrome linked the following sounds to onset of seizures:

  • Crinkling tin foil, plastic, or paper bags

  • Dropping metal spoon into ceramic bowl

  • Chinking or tapping of glass

  • Tapping on computer keyboard

  • Clicking on computer mouse

  • Computer printers

  • Clinking of keys or coins

  • Hammering nails

  • Clacking together of wooden blocks

  • Splitting firewood

  • Clicking tongue

  • Texting ding

  • Mobile phone ring

  • Alarms

  • Clicking of gas burner while igniting

  • Running water

  • Dog scratching

  • Jingling metal dog tags

  • Walking on wooden floors with bare feet or squeaky shoes

  • Children’s screams or peals of laughter

The most common sounds to cause seizures are tin foil crinkling, dropping a metal spoon into a ceramic bowl, and tapping or chinking of glass.

Why Do Sharp Sounds Lead to Seizures in Cats?

Researchers have found that more than half of cats that have FARS are either deaf or have some hearing loss. When hearing loss occurs, low-toned sounds are lost before high-pitched ones.

The high-pitched sounds break through the quiet in the hearing-impaired cat and startle them. This causes a reflex seizure. Reflex seizures are triggered by specific environmental stimuli, in this case, a startling noise.

How Veterinarians Diagnose Feline Audiogenic Reflex Seizures

To determine if your cat has FARS, your veterinarian will ask you about your cat’s history of possible seizures. They will want to know exactly what behaviors your cat displayed when they had the episode, and might ask these questions:

  • Did they fall over on their side, paddle their legs, and chomp their jaws?

  • Did they have muscle twitches?

  • Did they lose control of their bladder?

  • How long did the episode last?

  • Did you notice anything different right before the episode started?

If your pet is having seizure episodes, it is recommended that you start keeping a journal and include as much information as possible about the seizures. If you notice any patterns or specific stimuli that seem to trigger your cat, share those with your veterinarian so they can determine if it is FARS or spontaneous seizures.

After a thorough history, your veterinarian will perform a physical exam. They may run bloodwork or do an x-ray or CT scan to rule out any underlying medical conditions.

It is helpful if you can provide your veterinarian with a video of your cat when they are having an episode. This will help them diagnose the type of seizure your cat is experiencing. Your veterinarian may recommend that you see a veterinary neurologist for advanced diagnostics.

Treatment of Feline Audiogenic Reflex Seizures

FARS disorder is treated with prescription medication to reduce the severity and likelihood of seizures. Levetiracetam (Keppra) is a drug that demonstrates good control of both the myoclonic and the generalized tonic-clonic types of seizures.

Avoiding or minimizing the seizure-triggering noises can also be helpful in reducing the frequency of episodes.

Recovery and Management of Feline Audiogenic Reflex Seizures

FARS is not curable, but cats may find some relief from frequency of seizure episodes with medical management. All treatment is geared toward management and keeping your cat comfortable and having less seizures.

FARS is a condition that affects senior cats and is a genetic disorder in the Birman cat breed. Because most cats diagnosed with FARS are senior cats, they may also have concurrent diseases that come with age. Prognosis is good for seizure control itself, but most cats diagnosed with FARS typically have additional underlying diseases or are seniors, and therefore they may not live much longer for reasons unrelated to the FARS diagnosis.

References

  1. Blake A. DVM 360. High-frequency sounds can lead to seizures in some older cats. (2015).
  2. Lowrie M, et al. Journal of Feline Medicine and Surgery. Audiogenic reflex seizures in cats. (2015).

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