# Differences in Finger Dexterity in Patients With Mild and Moderate Alzheimer's Disease—A Study of Cognitive Function by Disease Severity

## TL;DR

This study shows that finger dexterity worsens as Alzheimer's disease progresses, with moderate cases showing slower and fewer finger taps than mild cases.

## Contribution

The study introduces finger-tapping metrics as a potential tool for assessing Alzheimer's severity.

## Key findings

- Moderate AD patients tapped fewer times than mild AD patients (p = 0.005).
- Moderate AD patients had longer tapping intervals than mild AD patients (p = 0.007).
- Finger function metrics correlated weakly with cognitive scores (MMSE).

## Abstract

This study aimed to estimate the relationship between finger function and cognitive function in patients with Alzheimer's disease (AD).

Patients diagnosed with AD at the Outpatient Center for Comprehensive Care and Research on Memory Disorder of the National Center for Geriatrics and Gerontology underwent a 15‐s bimanual alternating tapping task to measure finger movements. After finger movement measurements, we classified the severity of AD into mild and moderate and compared the finger movements. The Mann–Whitney U test and effect size were used to compare parameter values between the two groups (mild and moderate AD), and the calculated p values were corrected using the Bonferroni method. The Spearman rank correlation coefficient was calculated to determine the association between finger parameters and cognitive function (Mini‐Mental Examination [MMSE]).

Data from 163 patients with AD were analyzed. When comparing finger parameters between the mild AD (64 individuals) and moderate AD (99 individuals) groups, the moderate AD group demonstrated fewer taps (p = 0.005; r = 0.22) and a longer interval between taps with the thumb and index finger (p = 0.007; r = 0.21) than the mild AD group. The correlation between the MMSE score and finger function was weakly positive for the number of taps and weakly negative for the average of tapping interval.

These parameters reflect the decline in finger function associated with the advanced stages of dementia and may help assess the severity of AD. Additionally, these findings may have clinical utility in assessing the severity of AD, potentially enhancing diagnostic accuracy for differentiating stages of AD.

This study examines the relationship between finger dexterity and cognitive function in patients with Alzheimer's disease (AD). The results indicate that patients with moderate AD demonstrate significantly fewer taps and longer tapping intervals compared to those with mild AD, suggesting a progressive decline in motor function. These findings highlight the potential of finger‐tapping assessments as a complementary tool for evaluating AD severity.