Acalculia After Stroke: When Numbers Stop Making Sense
“In practice, [acalculia] can affect many tasks in everyday life- from reading the time, to making appointments, counting medications, playing games, cooking, banking or using money, using telephone/remote controls, traveling (estimating distances, understanding road signs, using travel timetable or bus numbers), etc. Our work also shows that it can significantly impact a person’s well-being.”
—Yael Benn
Numbers are a fundamental part of our daily lives, woven into everything from managing finances to following recipes. But what happens when the ability to process and utilize these seemingly basic symbols is disrupted? This is the reality for individuals with acalculia, a condition arising after a stroke or brain injury that can significantly impact their independence.
I recently participated in an interdisciplinary stroke (CVA) course and one of the presentations focused strictly on the topic of acalculia and the research around it. The presenter, Dr. Yael Benn, is a leading cognitive neuroscientist whose research focuses on the intersection of numbers and behavior. Dr. Benn's work delves into the fascinating world of numerical cognition, exploring how our brains process numerical information and how this information influences our decisions and actions, however, her research extends beyond the realm of healthy individuals. Dr. Benn is passionate about understanding and addressing the challenges faced by those with acalculia.
In this interview, Dr. Benn will shed light on acalculia, its symptoms, and its impact on daily life. We'll explore the importance of early assessment and the current state of support for individuals with acalculia. Most importantly, Dr. Benn will share her groundbreaking research on novel treatment approaches, offering hope for a brighter future for those living with this condition.
5 Questions About Acalculia
1. What is acalculia, how does it present, and how common is it?
Acalculia is an acquired deficit in numerical skills- this means, that it is not a developmental condition, like dyscalculia, but it is something that people can experience after a stroke or a brain injury. Symptoms vary from a deficit in producing/ understanding number-words (this can be as a result of other deficits such as aphasia too, but often patients notice a difference between, for example, difficulties with number words and difficulties with other words), producing/understanding digits, or even difficulties in understanding the meaning of a number (e.g., is 35 bigger or smaller than 24?). In practice, this can affect many tasks in everyday life- from reading the time, to making appointments, counting medications, playing games, cooking, banking or using money, using telephone/remote controls, traveling (estimating distances, understanding road signs, using travel timetable or bus numbers), etc. Our work also shows that it can significantly impact a person’s well-being.
The prevalence of the condition is not clear, but even the most conservative estimates, suggest that around 30% of stroke survivors experience acalculic symptoms. Some of the work we have done suggests that as many as 65% of stroke/brain injury survivors may experience acalculic symptoms in the first few weeks following the injury.
2. As an outpatient OT, I tend to find acalculia when I'm addressing IADL (e.g. bill paying) and return to work skills. Often times this is many months or years after their initial injury. What do you suggest? Should this be assessed earlier in their care?
I agree that acalculia often goes undiagnosed. It is not the first thing that patients and/or clinicians think about. Naturally, they are first concerned about their language and mobility issues, then perhaps memory and attention, and numbers come last in the list and are often considered an ‘associated problem’ rather than a problem in its own right.
There are several assessments that can be used to check if a patient can confidently use numbers and understand their meaning. For an OT, I would think that the more ‘practical’ assessments can be useful – for example, see the functional numeracy assessment, which is also suitable for individuals with aphasia: Which blueberries are better value? The development and validation of the functional numeracy assessment for adults with aphasia.
4. Recently, I was working with a patient who discovered her acalculia when she was trying to help her 8-year-old son with his math homework. My patient, who works in finance, broke down in her session telling me the moment she realized her skills had devolved. What have you witnessed in others with acalculia and what is the best way to support them?
Indeed, some of the patients we talked to found it very difficult to live with their acalculia. One person, who used to be very good at maths—did a maths degree, worked in marketing using lots of numbers, and used maths in most of his leisure activities—told us that:
“To me, the numbers you know the biggest problem…. I get very upset. and I just feel that the…. If I had more help than that, that would be better…. I'd like my, you know, the Sudoku and (unclear speech). I wish. I wish I could do it again.”
Another participant told us:
“I'll get angry and frustrated and sometimes I say oh god I'm rubbish… I feel, I'm sorry. I feel sad” (starts crying).
The partner then added: “Sometimes you say you're ‘thick’.”
Support for acalculia is currently minimal. In a review we carried out, we found only a handful of papers that developed interventions, but all of these were individually designed to the needs of patients, they were delivered one-to-one with a therapist, and they are very specific to skills, for example, multiplication facts or transcoding (but these have not been done in English, and transcoding in French and German has different rules). The patients we spoke to found that using fingers was helpful, but they stopped doing it because they were embarrassed. My advice is to not stop—this is how children learn, and it should help re-learning too.
Others are using apps, such as tip calculators, but many find these too difficult to use.
One participant, who used to be a math teacher, decided he had to re-teach himself. To do this, he slowly worked his way through books for children, and he did improve. In my work, I am working on developing more interactive interventions, and hopefully one day an app-based intervention too.
5. What has the research found to be the most effective interventions in treating acalculia?
I am currently working on a form of treatment that we call ‘Embodied’. A trial we have conducted with 4 patients showed that it is very effective. We work in a group of 3-5 patients and we develop activities that make the body and mind work in a congruent way. For example, counting up while walking forward, or doing subtraction while walking backward. These ideas are not new, and they are rooted in Education theory, but they have not been previously used for interventions with patients. We found that just after 9 sessions, patients really improved their skills and their confidence. Improving confidence is important because it means they try more outside of the sessions and continue to improve. We are currently seeking funding for larger pilots. Hopefully, we will have more news in a year or two!
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