Alzheimer’s disease (AD) is the most common form of dementia. Handwriting analysis could be one of the potential tools for early detection of the onset of the disease. The dynamics of handwriting changes are also a good indicator of the progression of the disease and the effectiveness of therapy. In many studies, researchers have used handwritten texts. The results show that handwriting problems correlate quite well with the progress level of the disease. Affected people show a diligent but awkward, hesitant writing. Some form of dysgraphia or agraphia is common. This is because automatic writing, as a learned skill, requires cognitive work to retrieve the learned movements from the brain. For this reason, researchers have suggested that handwriting may be affected by the disease in its earliest stages. Although the results of the available publications are promising, their conclusions are methodologically rather limited, as they relate in most studies only to linguistic aspects and the content of written texts or pure motoric problems reflected several obvious handwriting signs.
Based on the meta-analysis of existing publications and original statistical study we developed two tests – AD-HS for the detecting AD markers in the handwriting, and AD-HC – for the evaluation of the handwriting changes with the progress of the disease.
AD-HS includes 39 handwriting characteristics (3 linguistic and 36 handwriting ones). Test evaluates so called Z-factor, measured from 0 to 1. It reflects the number of handwriting characteristics present in the sample related to the total number of them in the test (39).
AD-HC includes as well 36 handwriting signs (mostly the same as in AD-HS).
The pilot study with 16 subject, by whom AD or mild cognitive impairment had been diagnosed, Every subject provided samples of his/her current handwriting and an old (10-20 ago) one. The results demonstrate good validity of both tests. They were compared to the several hundreds evaluated handwriting samples out of HSDetect database. They served as a control group. The correlation between Z-factor and the diagnosed severity level of AD was high (0.62).
Dr. Zhibek Zholdasova, Ph.D., Head of LLP «Universal Brain Center», Almaty, Kazakhstan
Ass. Prof. Gayane Ghazaryan, Ph.D., Medical Psychology, Yerevan State Medical University, Armenia
Prof. Rafal Ciesla, Ph.D., Department of Forensic Sciences, University of Wroclaw, Poland
Ass. Prof. Olga Razumnikova, Dr. Sci, Psychology & Pedagogic, Novosibirsk State Technical University, Russia
Dr. Yury Chernov, Ph.D., Institute for Handwriting Sciences, Zurich, Switzerland