# Globus Pallidus Iron Relates to Cognitive Impairment in Alzheimer's Disease: Evidence From MRI‐Based Meta‐Analysis

## TL;DR

This study finds that higher iron levels in the globus pallidus are linked to worse cognitive performance in Alzheimer's patients, based on a meta-analysis of MRI data.

## Contribution

The study provides the first meta-analytic evidence linking globus pallidus iron levels to cognitive impairment in Alzheimer's disease.

## Key findings

- AD patients showed significantly higher iron levels in basal ganglia structures compared to healthy controls.
- Globus pallidus iron levels were uniquely correlated with worse cognitive performance in AD patients.
- Putamen and caudate showed the most pronounced iron level increases in AD patients.

## Abstract

Iron is essential for brain metabolism and cognitive functioning, but excessive levels during healthy and pathological aging can have detrimental effects. Although this notion was supported by several single studies, meta‐analytic evidence in Alzheimer's disease (AD) is still scarce. Therefore, we performed a meta‐analysis of 23 MRI experiments with, in total, 715 AD patients and 1130 healthy controls (HC). All studies employed iron sensitive markers in basal ganglia structures, thalamus, and hippocampus, together with the Mini‐Mental‐Status‐Examination (MMSE) to quantify cognitive performance. In all regions of interest, significantly higher iron levels were present in people with AD compared to HC, with the most pronounced effects in the putamen followed by the caudate. Importantly, only globus pallidus iron levels were negatively correlated with MMSE performance in AD patients. Our results provide unique evidence that increases in iron levels, especially within basal ganglia structures, which provide a hub for cognitive information processing, are a characteristic hallmark of AD.

Iron is crucial for brain functioning, but excessive levels can harm brain health. While previous studies support this, meta‐analytic evidence in Alzheimer's disease (AD) is limited. We performed a meta‐analysis of 23 MRI studies with 715 AD patients and 1130 healthy controls. Higher iron levels in the basal ganglia were found in AD, with globus pallidus iron levels negatively correlating with cognitive performance, emphasizing iron's role in AD.