Welcome to our library

The Pediatric Epilepsy Surgery Alliance library includes publications and presentations based on our work in epilepsy surgery research.  Our library includes both our own research and research we have inspired or funded. 

Since 2011, we have funded over $1.2 million in research. In addition to our current research projects, including the Global Pediatric Epilepsy Surgery Registry, the following discoveries were made by scientists where we have either inspired, funded, and/or assisted with participant recruitment and/or travel costs for their studies:

Vladislav Ayzenberg, Michael C. Granovetter, Sophia Robert, Christina Patterson, Marlene Behrmann, Differential functional reorganization of ventral and dorsal visual pathways following childhood hemispherectomy, Developmental Cognitive Neuroscience, Volume 64, 2023.

In their study, the researchers aimed to discover how specific brain regions, namely the ventral and dorsal visual pathways, adjust and relocate functions to the opposite side of the brain after a child undergoes hemispherectomy. They employed fMRI, a brain imaging technique, to observe patients who had either the left or right hemisphere removed. These individuals were engaged in tasks that typically activate the ventral pathway (like recognizing words and faces) or the dorsal pathway (such as understanding tools and complex shapes).

The team found that the ventral pathway, responsible for tasks like word and face recognition, demonstrated a greater ability to reorganize itself in the remaining hemisphere, in contrast to the dorsal pathway, which is involved in processing the location and movement of objects. This variation in adaptability was not attributed to personal differences such as the nature of the illness, the age at which surgery was performed, or the age during testing.

The findings indicated that the dorsal pathway, which develops earlier, might have a limited developmental window for adaptability, rendering it less flexible than the ventral pathway in adjusting to disruptions like surgery.

Why this research matters

This study provides insights into how the brain can adapt after such a major surgery. Knowing that certain brain functions can reorganize and relocate to the other hemisphere is important for parents and educators to understand. Understanding that the ventral pathway (involved in recognizing words and faces) may be more adaptable than the dorsal pathway (involved in understanding the location and movement of objects) can guide rehabilitation efforts. Therapies can be tailored to focus more on the areas where recovery is more challenging, potentially leading to better outcomes.

Puka K, Jones M, Mathern GW. Functional cognitive and language outcomes after cerebral hemispherectomy for hemimegalencephaly. Epilepsia. 2021 Dec;62(12):2932-2940. doi: 10.1111/epi.17088. Epub 2021 Oct 4. PMID: 34608636.

Hemispheric surgeries are an effective treatment option to control seizures for children with hemimegalencephaly; however, not enough is known about their cognitive outcomes after surgery.

This study addressed the cognitive and language outcomes after hemispherectomy for hemimegalencephaly. It identified and identify the clinical characteristics associated with cognition and language. Using parent-reported data from our Global Pediatric Epilepsy Surgery Registry, it identified the characteristics associated with cognition and language after surgery.

Data from 45 children was analyzed. The authors found that:

  • 43% had average or mildly impaired cognition,
  • 26% could speak age appropriately, and 21% had satisfactory reading skills.
  •  55% children first babbled, 43% spoke their first words, and 17% started speaking in sentences at an age-appropriate period, respectively.
  • Children who had undergone a right hemisphere resection and those who were older when seizures started were more likely to have better cognitive and language outcomes.

AES poster 2020 Hemimegalencephaly

Christodoulou JA, Halverson K, Meegoda O, Beckius H, Moser S, Imhof A, Maguire A. Literacy-related skills among children after left or right hemispherectomy. Epilepsy Behav. 2021 Aug;121(Pt A):107995. doi: 10.1016/j.yebeh.2021.107995. Epub 2021 May 15. PMID: 34004523.

In 2017, researchers attended our family conference and gave various reading tests to children who had hemispherectomy surgery. They grouped their results into left v. right hemispherectomy.

  • Both groups scored below average on standardized measures of reading.
  • Children after right hemispherectomy learned to read sooner than those after left hemispherectomy, regardless of age at surgery.
  • Children after right hemispherectomy scored higher on untimed real word and pseudoword reading measures.
  • Children after right hemispherectomy did somewhat better on measures of phonological awareness and both untimed and timed word and pseudoword reading.
  • Children who had a shorter time between when their seizures started and hemispherectomy surgery, and who started reading at a younger age, had higher reading and language test scores.

Dr. Andrew Gordon, Ph.D.,  is a Professor of Movement Science and Neuroscience & Education at Teachers College, Columbia University. He is the Project Director of the Center For Cerebral Palsy Research In Hand Motor Control at the university, and has been intimately involved in studies of hand motor control in healthy individuals and cerebral palsy since 1990.   Dr. Gordon has authored more than 90 publications to date. He has focused the knowledge gained from these studies into modifying and testing constraint induced use therapy for use in children with hemiplegic cerebral palsy since 1998, and has been the Principal Investigator on a CI therapy trial funded by the National Institutes of Health.

Hand/Arm Bimanual Intensive Training (HABIT) is a new therapy developed at Columbia University.  Its primary aim is to improve the use and coordination of both arms in daily living.  Unlike constraint-induced movement therapy, which focuses on only the use of the hemiparetic arm and hand, HABIT focuses on improving the ability to perform bimanual activities.

This study, commenced in the summer of 2013, included thirteen children post-hemispherectomy who received 90 hours of Hand-Arm Bimanual Intensive Training (HABIT).  Children had clinical hand testing three months before and immediately before attending a camp, and then immediately and three months after camp.  The study also include neuro-imaging.

The research concluded:

  • Completion of Hand-Arm Bimanual Intensive Therapy (HABIT) appears to be feasible in individuals who have had a hemispherectomy, and could be complimentary or a viable alternative to CIMT.
  • Lateralization could not be used as a predictor for hand function (small sample size)
  • Improvement of bimanual function and functional goals can be related to the nature of activities prioritized in HABIT
  • Future work should focus on bimanual performance and the neural substrates underlying these improvements in a larger sample of individuals.

STATUS:  Completed and manuscript submitted for publication.

  • View the scientific poster abstract summarizing the results of the study (Downloadable pdf)
  • Try Hand Arm Bimanual Training at home with this new How-To guide (Downloadable PDF)

Epilepsy surgery can disrupt endocrine function in children, as discussed in a recent scientific abstract from our Global Pediatric Epilepsy surgery registry. Read the abstract here.

Reading is of particular importance to us, because children with epilepsy are at substantial risk of reading poorly. Only 42% of children after hemispherectomy, for example, can read. We know that reading in healthy children depends on well-described “building blocks” such as the ability to manipulate phonemes and match them to written letters in a process known as phonological awareness, vocabulary and verbal memory.  Because all these skills are mostly in the left hemisphere, our research to date has targeted acquisition of reading skills after left hemispherectomy.

Joanna Christodolou, PhD, of the MGH Institute of Health Professions, Stella de Bode, PhD, and Tami Katzir, PhD, of the University of Haifa, discovered that despite having the same pre-surgical condition (left hemisphere stroke) and same surgery (left hemispherectomy), children after these procedures had different skills when reading. Because each child have different individual strengths and weaknesses, the authors of this study concluded that each child after hemispherectomy should have flexible literacy instruction based on standardized assessments that analyze individual strengths and are used to generate intervention strategies.

STATUS: Completed and published

In another study, Mari Chanturidze, PhD, of the University of Oldenburg, Dr. Gary Mathern of the University of California at Los Angeles, Stanley Dubinsky, PhD, of the University of South Carolina, and Stella de Bode, PhD, investigated what happens when the left hemisphere is resected very early in life and concluded that the isolated right hemisphere uses the same reading “building blocks” as its left counterpart. They did, however, note that there was variability even among children with similar underlying conditions, further supporting the need for flexible literacy instruction and standardized assessments that analyze individual strengths in order to generate intervention strategies.

STATUS: Completed and published.

Language is primarily a function of the left side of the brain. This network typically comprised inferior frontal gyrus, superior temporal sulcus, and premotor regions. In this study, Anna Ivanova and Lucina Uddin, PhD, of the University of Miami, Eran Zaidel, PhD, Dr. Noriko Salamon, and Susan Bookheimer, PhD, of the University of California at Los Angeles, and Stella de Bode, PhD, investigated the pattern of functional connectivity within language networks in the right hemisphere after the left hemisphere has been removed. They found that the functional connectivity is at least partially preserved in the right hemisphere.

STATUS: Completed and published.

31 participants were recruited by The Brain Recovery Project at the 2015 and 2016 Hemispherectomy Conference and Family Reunion and travel and lodging costs were provided to the researchers. Forced Choice Card Task showed that children who had surgery for hemimegalencephaly or cortical dysplasia had  71% accurate rate, while those who had surgery for Rasmussen’s encephalitis had a 93% accuracy rate recognizing happy, sad, angry, and scared faces. The Social Responsiveness Scale was also provided. Results showed that 60% of children assessed had mild social deficits in social interaction, with children with Rasmussen’s encephalitis more likely to fall within the normal range than children who had hemimegalencephaly or cortical dysplasia. A manuscript is in preparation for this study.

STATUS: Completed and manuscript in preparation for publication.

A reliable set of functional resting state brain networks is found in healthy people and thought to underlie our cognition, emotion, and behavior. Here, researchers investigated these  networks by quantifying intrinsic functional connectivity in six individuals who had undergone surgical removal of one hemisphere. Hemispherectomy subjects and healthy controls were scanned with identical parameters on the same scanner and compared to a large normative sample (n = 1,482). Surprisingly, hemispherectomy subjects and controls all showed strong and equivalent intrahemispheric connectivity between brain regions typically assigned to the same functional network. Connectivity between parts of different networks, however, was markedly  increased for almost all hemispherectomy participants and across all networks. These results support the hypothesis of a shared set of functional networks that underlie cognition and suggest that between-network interactions may characterize functional reorganization in hemispherectomy.

STATUS: Completed and published

  • Read the published research paper about this study (Downloadable PDF)
  • Read the New York Times story about this research here.

Certain severe epilepsy conditions require treatment with hemispherectomy, a surgery that removes or disconnects the affected cerebral hemisphere, but leaves the individual with many impairments including significant hemiparesis. Limited data exists on rehabilitative techniques or the process of neural plasticity and neural reorganization after hemispherectomy.

This study evaluates the feasibility and efficacy of high-intensity task-oriented rehabilitation, delivered by robot-assisted therapy in an enriched day-camp setting, for improving motor function in patients after cerebral hemispherectomy, as well as the anatomic changes in the brain as a result of the paradigm.

STATUS: This study is ongoing. Rancho Los Amigos Institutional Review Board study #165. Early data shows that a high-intensity, short-duration regimen of robot-assisted rehabilitation:

  • Improved upper extremity function and gait endurance;
  • Increased cortical thickness in motor areas (primary motor cortex and supplementary motor area);
  • Elicited functional improvements and neuroanatomical changes after just eight days of training;
  • Elicited improvements even though participants were out of the acute recovery period;
  • Was feasible and efficacious delivered in an enriched day-camp setting.

This is the first study to show an increase in functional task performance associated with an increase in cortical thickness in post-hemispherectomy individuals. This study used robot-assisted rehabilitation in a program of short-duration, high-intensity, task-specific training.

  • Read a summary of early results of this study from the American Academy of Neurology meeting poster presentation, 2015 (AAN Poster 2015 Robocamp PDF)
  • Read a summary of more recent results of this study from the American Congress of Rehabilitation Medicine meeting 2019 (ACRM 2019 poster PDF)
  • Learn more about Robocamp, including participant requirements here.

Neuropsychology studies the structure and function of the brain as they relate to specific psychological processes and behaviors.  It is seen as a clinical and experimental field of psychology that aims to study, assess, understand and treat behaviors directly related to brain functioning. The purpose of this study at the California Institute of Technology and Travis Research Institute at Fuller Theological Seminary is to understand how childhood hemispherectomy impacts cognitive and social functioning in adulthood. Participants take a variety of tests and puzzles, and complete questionnaires about personal preferences and activities. This testing will be conducted in 3-4 hour sessions across several days, the exact amount of testing time varies from person to person; participants will also be asked to do a series of MRI studies taking 1-1.5 hours.

Status:  This study is ongoing. Interested participants should contact our Executive Director, Monika Jones, at mjones@brainrecoveryproject.org

This first-of-its-kind research meeting convened patients, parents, researchers, and clinicians to discuss the state of research on functional outcomes after large resective or disconnective epilepsy surgeries in childhood, identified research gaps, and set patient-centered outcomes research priorities.

  • A complete summary of this research meeting is found here.

We convened clinicians and researchers to discuss various aspects of neurorehabilitation after cerebral hemispherectomy in childhood.