Handedness and dementia: New research shows surprising connections!

Handedness and dementia: New research shows surprising connections!

On September 8, 2025, Dr. Annakarina Mundorf, Sarah Merklein and Jette Borawski from the University of Health (MSH) as well as Prof. Dr. Sebastian Ocklenburg from the Institute for Cognitive Neuroscience (ICAN) carried out a comprehensive meta-analysis. This appeared in the specialist journalNeuroscience & Biobehavioral Reviewsand looks in detail at a fascinating connection between handedness and neurodegenerative diseases, particularly dementia.

The focus of the analysis is the differences in handedness between people suffering from dementia, including Alzheimer's, compared to healthy controls. The researchers noted that atypical handedness, including both left-handedness and mixed-handedness, is linked to changes in brain asymmetry. This interesting result could provide starting points for future studies to better understand early signs of neurodegenerative processes, particularly in Alzheimer's disease.

Relationship between handedness and neurological diseases

In a parallel study published in the journalPsychological Bulletinpublished on May 2, 2025, the connection between aberrant handedness and certain neurological diseases is further discussed. An international research collaboration from Bochum, Hamburg, Nijmegen and Athens found that left- or mixed-handedness often occurs in patients with early-onset disorders such as dyslexia, schizophrenia and autism. These results support the hypothesis that language and handedness are unilaterally anchored in the brain, leading to a connection between these two aspects.

Dr. Julian Packheiser from the Institute for Cognitive Neuroscience at the Ruhr University Bochum has also confirmed the significantly higher occurrence of left-handedness and mixed-handedness in people with dyslexia. A similar cluster is also seen in autism and schizophrenia, with research suggesting that aberrant handedness is closely linked to the early symptoms of these disorders. However, no connection was found with depression, as this usually only occurs around the age of 30.

Research implications and the way forward

The findings of these two studies open up new perspectives for research in neuropsychology. Studying differences in handedness can not only contribute to the early detection of dementia, but also to a better understanding of neurodevelopmental disorders. In the future, such studies could help to better understand the complexity of brain development and enable early interventions.

Overall, the results demonstrate both diversity and complexity in the relationships between handedness and neurological diseases. By shedding light on these aspects, the current research invites the formulation of new hypotheses and further exploration of the mechanisms behind these connections. Such findings are crucial to developing better diagnostic and treatment approaches for those affected.

For detailed information about the meta-analysis on handedness and dementia, read Medical School Hamburg, or learn more about the connection between handedness and neurological diseases at RUB and Univadis.