WASHINGTON — Researchers at Georgetown University have pinpointed why some stroke survivors struggle with reading, finding that damage to specific brain areas prevents them from using word meanings to recognize words. The discovery, based on brain imaging and reading tests, highlights a potential path for targeted therapies to restore reading abilities.
The National Institutes of Health-funded study, published Aug. 13 in the journal Brain, examined 56 individuals who had left-hemisphere strokes and 68 without strokes. Scientists focused on how strokes disrupt the link between a word’s meaning and its recognition during reading aloud. Participants read words varying in “imageability,” a measure of how easily a word evokes a mental picture. High-imageability words like “hammer” or “cow” are simpler to visualize, while low-imageability ones like “justice” are abstract.
Results showed that damage along the superior temporal sulcus—a brain region involved in speech processing and short-term auditory memory—diminished the benefit of high-imageability words in reading. This damage impairs the integration of semantics, or word meanings, with phonology, the sounding out of words. Phonological deficits are common after strokes, but semantic impairments were less frequent and milder in the group studied.
“We usually think of reading in our daily lives as a way to gain meaning, but the opposite is also true: We rely on a word’s meanings to help us recognize it when reading,” said Peter E. Turkeltaub, MD, PhD, director of the Cognitive Recovery Lab at Georgetown University as well as the Aphasia Clinic at MedStar National Rehabilitation Hospital, and senior author of the study. “Some people recovering from stroke can’t use the meanings of words to help recognize them, making it harder to read.”
The study targeted left-hemisphere strokes because language processing occurs there. Researchers used magnetic resonance imaging to map stroke damage and correlate it with reading performance. An overlapping brain area linked semantic deficits to phonological issues, confirming that reading problems stem from failed connections between meaning and sound.
“Our findings clarify the neurobiology of reading and provide the strongest evidence to date for a form of reading disorders that can occur after a left hemisphere stroke,” said the study’s co-first author Ryan Staples, PhD, a postdoctoral fellow in Turkeltaub’s lab.
About 800,000 Americans experience strokes each year, with higher rates among marginalized groups. Strokes rank as the fifth-leading cause of death nationwide and a major source of disability. In Maryland, stroke is the third-leading cause of death, following heart disease. Statewide, age-adjusted stroke mortality stands at around 38.3 per 100,000 for whites and 45.1 per 100,000 for Blacks, reflecting disparities.
In Southern Maryland, encompassing Calvert, Charles and St. Mary’s counties, stroke rates vary but remain a concern. Charles County reports a 3.0% prevalence among adults who have experienced a stroke, based on behavioral risk factor data. Among Medicare enrollees, Charles County has an age-adjusted stroke rate of 30 per 1,000, ranking seventh highest in Maryland. St. Mary’s County follows with 27 per 1,000, and Calvert County with 25 per 1,000. Calvert County data indicate 3.0% of adults have had a stroke, aligning with state trends. These figures underscore the need for awareness, as early intervention can reduce long-term effects.
Local facilities address stroke care comprehensively. University of Maryland Charles Regional Medical Center in La Plata earned the American Heart Association’s Stroke Gold Plus award for meeting high standards in treatment, including rapid response protocols. The center’s stroke program, redesignated for five years by the Maryland Institute for Emergency Medical Services Systems, focuses on coordinated care from emergency arrival through rehabilitation. MedStar Southern Maryland Hospital Center in Clinton holds primary stroke center designation, emphasizing detection and recovery to minimize disability. CalvertHealth Medical Center in Prince Frederick received national recognition for improving stroke outcomes via guidelines that prioritize timely imaging and therapy.
Rehabilitation options in the region could integrate the study’s insights. Speech-language therapy targets post-stroke impairments like aphasia, which often includes reading deficits. Providers such as Total Speech Therapy offer specialized adult stroke services in Maryland, addressing language and cognitive recovery. Integra Speech provides in-home therapy for speaking, reading and other functions affected by neurological damage. Adventist HealthCare and MedStar Health deliver outpatient programs for speech disorders post-stroke, including evaluations and tailored plans.
The Georgetown team plans further research under a new five-year NIH grant comparing reading in normal aging to post-stroke cases. This could refine understanding of brain plasticity and inform therapies. For Southern Maryland residents, where proximity to Washington allows access to institutions like Georgetown and MedStar, such advancements may enhance local recovery protocols. Stroke prevention remains key, with experts recommending blood pressure management, healthy diets and exercise to lower risks.
