Does cognitive decline influence signing?

Area of Science:

• Neurology
• Cognitive Science
• Forensic Science

Background:

• Neurodegenerative diseases like Alzheimer's disease (AD) and frontotemporal dementia (FTD) can affect motor skills and cognitive functions.
• Handwritten signatures require fine motor control and cognitive processing, making them potentially sensitive to neurological changes.

Purpose of the Study:

• To investigate changes in handwritten signatures among patients with AD and FTD.
• To determine if signature analysis, using a rater-based approach, can serve as an indicator of neurodegeneration.

Main Methods:

• Four independent raters assessed signature pairs from 103 AD/FTD patients and 31 healthy controls (HC).
• Signatures were collected with an average of 5 years between them, with one pre-diagnosis for patient groups.
• Raters used a 0-1 scale to judge similarity/difference and identify specific feature changes (e.g., spatial layout, letter shapes).

Main Results:

• Signature changes were reported in 36% of AD patients and 44% of FTD patients, versus 17% of HC.
• Significant differences in reported changes were found between patient groups and HC (p < .01).
• No distinctive signature feature change marker was identified for dementia patients, and changes were unrelated to clinical/demographic factors.

Conclusions:

• Handwritten signatures exhibit resistance to change in neurodegenerative diseases and normal aging.
• Subjective evaluation of signature changes is an unreliable indicator of cognitive status in AD and FTD.