What Is Cerebellar Hypoplasia?

Nov 1

When someone meets my Weebles for the first time, a confused look almost immediately appears on their face.

To answer their unspoken question, I explain that the girls have something called cerebellar hypoplasia—a neurological condition affecting balance and coordination. CH, for short, has been recognized since the late 19th century.[1]

What does CH actually mean?

The cerebellum, just like yours and mine, sits toward the back and lower part of the brain. It helps coordinate balance, posture, and precise movements. In cats with cerebellar hypoplasia, this part of the brain is underdeveloped.[1, 2]

Signs can include:

Ataxia: uncoordinated, wobbly movements, sometimes described as a “drunken sailor” gait.
A wide-based stance: standing with the legs farther apart to help maintain balance.
Hypermetria: exaggerated, high-stepping movements.
Intention tremors: shaking that becomes more noticeable during purposeful movements, such as reaching for food or playing with a toy. (Think: really cute bobbleheads.)[1, 2]

CH can also affect how accurately a cat controls the distance of a movement. This is called dysmetria: a movement may overshoot or fall short of its intended target. That is different from saying the cat cannot visually perceive distance.[3]

In my own experience, Corkie and Onyx sometimes appear to have trouble judging distance—for example, when someone walks toward them or when they follow a moving toy during play. To me, it looks like difficulty with depth perception. I can’t say whether that reflects visual depth perception, coordination, or a combination of factors, but it is something I notice when interacting with my girls.

Signs of CH often become noticeable when kittens begin walking, around two to three weeks old.[1]

Are they in pain? Will it get worse?

When a concerned look follows my explanation, I reassure people that CH itself is not painful. They don’t really know any different. Injuries from falls or bumps can still hurt, though, so supporting their safety matters.[4]

Both Corkie and Onyx have chipped canine teeth, although Onyx’s chips are less extensive than Corkie’s. This is one reason I want to distinguish CH itself from injuries or other problems that can still cause pain. Chipped teeth and new or concerning symptoms should be assessed by a veterinarian.[6, 7]

The good news? CH is non-progressive: the condition itself does not worsen over time. Some cats become better at navigating their surroundings as they adapt, but they do not simply outgrow CH.[1]

New or worsening wobbliness deserves a conversation with a veterinarian rather than an assumption that it is “just their CH.” Other neurological conditions can cause similar signs, including conditions that do progress.[1, 5]

What causes it?

CH most commonly occurs when a pregnant mama cat becomes infected with feline panleukopenia virus (FPV) and passes the infection to her unborn kittens. Infection very shortly after birth can also interfere with cerebellar development.[2, 4]

The virus targets rapidly dividing cells. Because the cerebellum is still developing during this period, damage to those cells can prevent it from developing properly.[2]

Other possible causes include severe malnutrition during the mother’s pregnancy or injury to the kitten’s brain while the cerebellum is developing.[4]

Does every CH cat look the same?

Not at all. People often describe CH as mild, moderate, or severe, though each cat’s abilities and support needs are individual.

Even kittens from the same litter can be affected differently.[1] My twins are a good example of this: they are from the same litter and have varying degrees of wobbliness.

Onyx has a milder case of CH and is steadier on her feet than Corkie. I’d describe Corkie’s CH as being toward the more pronounced end of moderate. Both can walk independently, but each has her own way of moving through the world.

Most of what I share here comes from caring for the two of them. I do not have firsthand experience caring for a CH cat who cannot walk, and I want to be honest about the limits of my experience.

Getting to know the cat behind the wobble

What the Weebles keep teaching me is when to step forward and when to step back. I’m learning to notice where they need support while also trusting their abilities and giving them room to adapt. They’re still cats—and the cutest little chaos gremlins to have bopping around my home.

If you’re new to CH, I hope this gives you a place to start. When I first adopted Onyx Grace and Corkie May, I felt like a fish out of water. I’m hoping to help alleviate some of that stress for other new wobbly cat parents.

I also want to share with the world just how wonderfully wobbly my two girls are.

Sources