Gerstmann's Syndrome: Agraphia, Acalculia, Finger Agnosia and Left-Right Disorientation

Imagine being unable to write your name or distinguish your fingers – challenges faced by those with Gerstmann's Syndrome, a rare neurological disorder. This condition, marked by agraphia, acalculia, finger agnosia, and left-right disorientation, offers a unique glimpse into the brain's functioning. In this post, we'll explore the symptoms, causes, and neurological basis of Gerstmann's Syndrome, highlighting the intricate connections within our brain that govern our daily abilities.
Frederika Malichová

Frederika Malichová

Neuroscientist at the University Of Cambridge.

An illustration of a human brain, centrally placed with numbers and directions.

Gerstmann's syndrome: An Overview

Gerstmann syndrome is characterized by a cluster of four fascinating, yet debilitating primary symptoms: finger agnosia (inability to distinguish fingers), agraphia (difficulty writing), acalculia (difficulty with arithmetic), and right-left disorientation [1].

The occurrence of the syndrome is rare and it causes controversy in neurology, largely because the syndrome often shows as incomplete and the patients clinically show only some of the symptoms [2].

The exact cause of the syndrome is still debated, with some suggesting it may be due to a disturbance in verbally mediated spatial operations or a disconnection of separate cortical networks. However, it is most likely associated with damage to the left angular gyrus of the brain [2].

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These symptoms of Gerstmann's syndrome can occur on their own, and are individually considered as neurological disorders.


Agraphia is a condition characterized by the loss or impairment of the ability to write, often occurring alongside other neurological deficits [3].

It can be divided into "central" agraphia, which involves disruptions in the processes of understanding and organizing letters and words, and "peripheral" agraphia, which involves impairments in the motor planning or action of writing.

There are also specific types of agraphia, such as phonological text agraphia, which involves difficulty writing well-formed sentences, and apraxic agraphia, which is due to a loss of access to motor engrams that program the movements necessary to produce letters [3].

Unlike dysgraphia, which refers to one's difficulty with writing, agraphia is caused by damage to brain tissue and results in a complete disability to write.


Acalculia is a condition that affects a person's ability to perform calculations. A simple question for some: "What is 2+2?" can be a tough one for those affected by acalculia.

It can be acquired due to brain injuries or developmental disturbances. It can manifest in several ways, including difficulty with oral and written calculations, and can be associated with aphasia, a language disorder.

Acalculia can have a significant impact on a person's daily life, affecting tasks like managing money or making appointments. It is usually associated with damage to the left posterior parietal region of the brain [4].

Finger agnosia

Finger agnosia is a condition where a person is unable to distinguish between their fingers, often seen in conditions like Alzheimer's disease and stroke [5,6].

It can be seen in patients with Alzheimer's disease as well, and is associated with cognitive dysfunction [7].

Right-left disorientation

Right-left disorientation refers to a defect in right-left discrimination when using language and spatial orientation, which can be due to an impairment in verbally mediated spatial operations. If a patient with Gerstmann's syndrome exhibits right-left disorientation symptoms, they may accurately identify sides from their own perspective, but encounter difficulties when considering the perspectives of others.

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Gerstmann's syndrome is typically associated with damage to the left angular gyrus of the brain. In other words, lesions in the left hemisphere posterior parietal lobe cause the syndrome [1,2].

This damage can be caused by various factors such as stroke, brain injury, or neurodegenerative diseases.

However, the exact cause of the syndrome is still debated and may vary from person to person.

Additionally, it's important to note that while these factors can lead to Gerstmann's syndrome, not everyone with these conditions will develop the syndrome.


Unfortunately, there is no specific cure for Gerstmann syndrome. Treatment generally focuses on managing symptoms and improving the individual's quality of life.

This can involve rehabilitation therapies such as occupational therapy, speech therapy, and counselling.

However, It's important to note that the effectiveness of treatments can vary from person to person.

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This article does not offer health advice. Always consult a medical professional regarding your condition.

Frederika Malichová

Frederika Malichová

Frederika is a postgraduate researcher at the University of Cambridge, where she investigates new biomarkers for Frontotemporal Dementia and other tauopathies. Her research has been published at prestigious conferences such as the Alzheimer’s Association International Conference 2023. She obtained her BSc in Biomedical Sciences from UCL, where she worked closely with the UK Dementia Research Institute.