Cognitive-Motor Dissociation Following Pediatric Brain Injury: What About the Children?
Nayoung Kim1, James O'Sullivan1, Emily Olafson1
1Department of Radiology (NK, JOS, EO, HUV, JI, SAS) and Department of Rehabilitation Medicine (EC, RL), Weill Cornell Medicine, New York; Blythedale Children's Hospital (SN, WDW), Valhalla, NY; Division of Medical Ethics (JJF), Weill Cornell Medicine and New York Presbyterian Weill Cornell Medical Center; Department of Neurology and BMRI (NDS), Weill Cornell Medicine, New York; National Center for Adaptive Neurotechnologies (NJH), Stratton VA Medical Center; and Department of Electrical and Computer Engineering (NJH), State University of New York at Albany, NY.
Insights
Two adolescents with severe brain injuries showed preserved cognitive function despite appearing to have none. This covert cognition, or cognitive-motor dissociation (CMD), was detected using advanced neuroimaging and neurophysiology, highlighting a need for better diagnostic methods in pediatric medicine.
Area of Science:
- Neuroscience
- Pediatric Neurology
- Cognitive Science
Background:
- Severe brain injury can lead to cognitive-motor dissociation (CMD), where cognitive abilities persist despite lack of clinical signs.
- Up to 16% of adults exhibit CMD, but pediatric guidelines and prevalence data are lacking.
- Covert cognition in children post-brain injury remains underdiagnosed and undertreated.
Purpose of the Study:
- To investigate the presence of covert cognition in adolescents with severe brain injuries.
- To apply neuroimaging and neurophysiologic methods to identify cognitive-motor dissociation (CMD) in pediatric patients.
- To establish preliminary methods for diagnosing CMD in children.
Main Methods:
- Evaluated two adolescents (15 and 18 years old) with no clinical evidence of preserved cognition post-brain injury.
- Utilized a battery of neuroimaging (fMRI) and neurophysiologic (EEG) tests.
- Clinical assessments indicated minimally conscious state (minus) and vegetative state.
Main Results:
- EEG and fMRI indicated that both participants could understand commands and make voluntary decisions.
- EEG revealed enhanced responses to auditory stimuli and intact semantic processing in both participants.
- Evidence suggests preserved cognitive function dissociated from motor output in both cases.
Conclusions:
- Both adolescents demonstrated cognitive-motor dissociation (CMD), with preserved cognitive function despite severe motor impairment.
- The findings underscore the ethical imperative for accurate CMD diagnosis in children.
- This study provides initial methods for identifying covert cognition in pediatric brain injury survivors, aiding therapeutic approaches.
Background And Objectives:
Following severe brain injury, up to 16% of adults showing no clinical signs of cognitive function nonetheless have preserved cognitive capacities detectable via neuroimaging and neurophysiology; this has been designated cognitive-motor dissociation (CMD). Pediatric medicine lacks both practice guidelines for identifying covert cognition and epidemiologic data regarding CMD prevalence.
Methods:
We applied a diverse battery of neuroimaging and neurophysiologic tests to evaluate 2 adolescents (aged 15 and 18 years) who had shown no clinical evidence of preserved cognitive function following brain injury at age 9 and 13 years, respectively. Clinical evaluations were consistent with minimally conscious state (minus) and vegetative state, respectively.
Results:
Both participants' EEG, and 1 participant's fMRI, provided evidence that they could understand commands and make consistent voluntary decisions to follow them. Both participants' EEG demonstrated larger-than-expected responses to auditory stimuli and intact semantic processing of words in context.
Discussion:
These converging lines of evidence lead us to conclude that both participants had preserved cognitive function dissociated from their motor output. Throughout the 5+ years since injury, communication attempts and therapy had remained uninformed by such objective evidence of their cognitive abilities. Proper diagnosis of CMD is an ethical imperative. Children with covert cognition reflect a vulnerable and isolated population; the methods outlined here provide a first step in identifying such persons to advance efforts to alleviate their condition.
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