Why many stroke survivors struggle with numbers

Numbers are all around us. In the morning, we wake up to an alarm that tells us it’s time to get out of bed. When deciding what to wear, we often check the temperature outside. We count out the vitamins or prescription pills we need to take while eating our breakfast, we estimate how long it will take to get to the station and then check what platform we need to be on to catch the train to work.

Every single one of these examples involves using and understanding numbers. Being able to carry out such small calculations and estimations makes our life possible.

This is why acalculia, a neurological condition that impairs the ability to process and understand numbers, can have a devastating effect on a person’s life. The condition commonly afflicts people who have had a stroke or suffered a brain injury. It’s estimated that it affects between 30%-60% of stroke survivors.

The brain is a complex organ that controls both our movements and senses. It enables us to receive signals from the environment, process information and execute motor actions.

But a stroke or brain injury interrupts blood supply to the brain. If this stroke or injury happens on the left side of the brain, it can cause problems with language processing and other cognitive functions, such as memory. It can also affect movement on the right side of the body.

If it happens on the right side of the brain, movement on the left side of the body will be affected. There may also be cognitive deficits—typically those involved with processing visual information.

But acalculia can occur regardless of which area of the brain has been damaged. This is because processing numbers and performing calculations are done using many different areas of the brain.

This includes the left hemisphere, which helps us process language; the right hemisphere, which is involved in visuospatial processing; the posterior part of the brain, which is involved in comprehending magnitude (which of two numbers is smaller or bigger); and the front of the brain, which controls executive function.

Lesions or damage to any of these areas can cause problems in how a person processes numbers.

For people with acalculia, sometimes the processing problem can just be surface level. They may feel that they know a number but can’t say it out loud. Or, a person may mean to say or write one number and instead another comes out.

In severe cases, a patient can altogether lose the meaning of numbers. So they may know a number has been mentioned or is written down, but they just can’t figure out what it actually means or how to make sense of it.

Effect on daily life

To understand the impacts of acalculia, my colleagues and I interviewed people with the condition alongside some of their caregivers to learn how it affected their lives and what support they received.

Stroke and brain injury survivors with acalculia reported being unable to manage their money. Some interviewees spoke of needing to depend on their caregiver to handle their money or having trouble accessing their internet banking because they struggled with common login questions such as “enter the third character of your pin”.

Worryingly, many participants reported difficulties managing their medications—with several totally relying on their pharmacist.

Simply managing their everyday lives was also made more difficult by the condition. Telling the time was difficult because of the digits. Even using the microwave was difficult because cooking times “are a jumble with numbers,” as one participant put it.

Importantly, acalculia had a detrimental effect on independence and well-being. As one participant said, “I feel dumb, embarrassed and frustrated.”

Overall, our findings highlighted just how substantial an effect acalculia had on stroke and brain injury survivors’ independence and quality of life. Acalculia left some unable to return to work, and many unable to live independently or manage their everyday lives, leaving them vulnerable. Our research also pointed out important gaps in how the condition is currently assessed and treated.

Acalculia awareness

One in four adults over the age of 25 are at risk of experiencing a stroke in their lifetime. Although we’re getting better equipped to help people recover from a stroke, acalculia remains overlooked in stroke rehabilitation guidelines. It’s not routinely tested for after a stroke (despite several dedicated assessments available) and there are currently no clinically-tested treatments for the condition.

The condition doesn’t appear to be taught in clinical training at present. One patient we interviewed in our study recalled asking their therapists for help with acalculia, saying: “What can you do to help me with my math? Every therapist I’ve met says ‘I can’t help you’. Why? Because it’s not part of their training.”

This means health care workers aren’t able to recognize the problem—let alone be able to support patients who have it.

People with acalculia are currently left to support themselves. Many may not even know there’s a name for their condition. It’s clear more needs to be done to raise awareness so that it can be better assessed—and so patients can receive the help and support they need in overcoming acalculia.

This article is republished from The Conversation under a Creative Commons license. Read the original article.