Summary: Sickle cell disease (SCD) is widely recognized as a blood disorder, but new research reveals its profound impact on the brain’s architecture. Using advanced MRI imaging and analytical tools originally developed for economics, the team found that the brains of SCD patients “rewire” themselves to compensate for chronic oxygen shortages.
While patients may appear to function normally in daily tasks, their brains are working significantly harder—recruiting extra support from attention networks to keep higher cognitive functions like decision-making on track. This study underscores the critical need for specialized neurological care for adults living with SCD.
Key Facts
- The Compensation Hub: To maintain decision-making (executive control), the SCD brain actively recruits support from the attention networks—a phenomenon not seen in healthy individuals.
- Severity-Based Adaptation: Patients with mild complications rely on the dorsal attention network (focusing attention), while those more severely impacted recruit the ventral attention network (responding to unexpected events).
- Speed vs. Accuracy: While task accuracy in SCD patients often matches healthy controls, their neural and behavioral response speeds are significantly slower, revealing the “hidden cost” of brain compensation.
- Economic Analysis: This is the first study to apply “effective connectivity” (an economic-style directional analysis) to SCD brain networks, allowing researchers to see exactly which networks are influencing others.
- Healthcare Equity: The findings highlight a gap in adult care for SCD, an illness that primarily affects underserved communities and often lacks adequate neurological support beyond childhood.
Source: Carnegie Mellon University
Sickle cell disease is often thought of solely as a blood disorder, but new research from the Wood Neuro Research Group provides measurable evidence that it can reshape how brain networks function.
Previous neuroimaging studies have relied on functional connectivity to show that adults with sickle cell disease may experience changes in how brain networks communicate among one another, potentially compensating for reduced oxygen delivery. However, this method is limited in determining the directionality or influence between networks.
“Red blood cells that carry oxygen to the brain are altered by the disease, resulting in reduced oxygen delivery to all regions of the brain and long-term changes in how it functions,” outlined Nahom Mossazghi, biomedical engineering Ph.D. student and the study’s first author.
“The brain actively recruits other regions to help process information, which we do not see in people without the disease.”
The study used MRI and advanced analytical tools originally developed in economics to examine how different brain networks influence one another. Instead of functional connectivity, effective connectivity was used to address a gap in the field and interpret how specific networks support one another in response to the disease-related changes.
Results showed that the executive control network, responsible for higher cognitive functions like decision-making, recruits support from attention networks.
Patients with milder complications of sickle cell disease rely on the dorsal attention network, which focuses attention, while patients more severely impacted by the condition rely on the ventral attention network, which responds to unexpected events.
“This shows the brain is compensating for oxygen shortages by reorganizing its network to maintain function,” Mossazghi said.
The findings also highlight why cognitive challenges in adults with sickle cell disease have been overlooked.
“Even if patients seem to function normally, their brain is networked and rewired differently,” emphasized Sossena Wood, assistant professor of biomedical engineering.
“Their task accuracy may match healthy controls, but their behavioral and neural response speed is slower, showing unseen compensation. We hope that this evidence paired with novel therapeutics helps alleviate some of the rewiring caused by the disease.”
Traditionally, sickle cell disease care focuses on children and hematology, and in many regions, adult care clinics are not available or commutable from patients’ homes. Pittsburgh has one of the few adult sickle cell disease clinics in the United States.
This new research underscores the need for more involved neurology in adult care and raises awareness of cognitive impacts that affect daily life, school, and work. It also emphasizes healthcare equity, since sickle cell disease primarily affects underserved communities.
Looking forward, the Wood Neuro Research Group is studying how these networks respond during specific cognitive tasks. Combining MRI with simultaneous EEG, researchers hope to identify neural circuits that could be targeted with noninvasive interventions to improve cognitive function.
“This could transform how adults with sickle cell disease are cared for and help us understand how the brain compensates for chronic conditions more broadly,” Mossazghi added.
The study, supported by NIH and internal funding, is the first to apply this economic-style analytical approach to sickle cell disease brain networks. It provides a new framework for understanding compensation in adult patients and sets the stage for future research to improve quality of life.
Key Questions Answered:
A: It’s all about oxygen. Sickle-shaped red blood cells can’t deliver oxygen as efficiently as healthy ones. Because the brain is an oxygen-hungry organ, it has to find workarounds. The study shows the brain literally “calls for backup” from attention systems just to perform basic thinking and decision-making tasks.
A: Not necessarily. Many patients match the accuracy of healthy individuals on cognitive tests. However, the study shows they have to use more brain “fuel” and different pathways to get there. Their response speed is often slower because their brain is taking a more complex, rewired route to solve the same problem.
A: Currently, SCD care mostly focuses on blood health in children. This research proves that adult patients need neurological support as well. By identifying the specific “circuits” that are working overtime, doctors can develop non-invasive interventions (like targeted brain stimulation) to help the brain function more efficiently and reduce cognitive fatigue.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this sickle cell disease and neurology research news
Author: Sara Pecchia
Source: Carnegie Mellon University
Contact: Sara Pecchia – Carnegie Mellon University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Investigating Disruptions in Information Flow due to Sickle Cell Disease Using Granger Causality” by Nahom Mossazghi, Helmet T. Karim, Nadim Farhat, Tales Santini, Enrico M. Novelli, Tamer Ibrahim, Sossena Wood. Human Brain Mapping
DOI:10.1002/hbm.70407
Abstract
Investigating Disruptions in Information Flow due to Sickle Cell Disease Using Granger Causality
Sickle cell disease (SCD) is an inherited blood disorder caused by a mutation in the beta-globin gene, resulting in chronic complications, including cognitive decline—particularly in executive functions.
Neuroimaging studies have identified structural and functional abnormalities associated with SCD; however, the directionality of information flow between brain networks and how disruptions in these interactions contribute to cognitive deficits remains poorly understood.
This study employed Granger causality (GC) analysis to investigate effective connectivity and information flow between brain regions and resting-state networks using ultra-high-field 7T MRI in adult patients with SCD (n = 51) and age-, sex-, and race-matched controls (n = 44).
We first performed a whole-brain network analysis, followed by an examination of specific brain regions within the default mode network (DMN), executive control network (ECN), dorsal attention network (DAN), and ventral attention network (VAN). For each analysis, we computed both the magnitude and directionality of information flow to capture the strength and directional influence of connectivity between brain regions.
While patients with SCD exhibited a higher magnitude of information flow compared to controls, this difference was only statistically significant when computed at the brain region level, not at the resting-state network level. In terms of directionality, afferent flow from DAN and VAN to ECN was significantly greater in patients with SCD than in controls.
Subtype analysis revealed that patients with severe SCD demonstrated significantly higher magnitude of information flow than those with mild SCD and controls. We also observed subtype-specific differences in afferent flow to ECN: mild SCD patients showed significant flow from VAN, while severe SCD patients showed significant flow from DAN.
Additionally, multiple regression analyzes assessing correlations between information flow and cognitive performance showed that controls had higher R2 values than patients with SCD, suggesting reduced network efficiency in SCD.
This study is the first to apply GC-based effective connectivity analysis in SCD, revealing unique pathways of information exchange in patients with SCD, potentially as compensatory mechanisms for disease-related structural and functional disruptions.
These findings provide novel insights into how SCD impacts brain network organization and cognitive function, emphasizing the importance of investigating network-level dynamics in this population.
