Pediatric Anoxic Brain Injury - A Possible Locked-In Syndrome

Abstract

Abstract INTRODUCTION Although drowning is a leading cause of death and neurological morbidity in young children, clinical management and prognostication following injury is poor. The most devastating disability from drowning results from anoxic brain injury (ABI). Standard-of-care imaging and assessment methods have proven inadequate in the evaluation of brain damage and prediction of functional sequelae, and thus, have had minimal clinical impact in these patients and other patients with disorders of consciousness. METHODS A total of 11 children with drowning-related ABI and 11 age- and gender-matched neurotypical controls (4-12 yr) were scanned during mildly sedated sleep; T1-weighted, DTI, and resting-state fMRI blood oxygen level dependent (BOLD) data were acquired. Voxel-based morphometry (VBM) was implemented on T1 data, tract-based spatial statistics (TBSS) was implemented on DTI data, and independent components analysis (ICA) was implemented at group and per-subject levels on fMRI data to investigate the integrity of resting-state networks (RSNs). Extensive functional evaluations were conducted and a systematic behavioral evaluation form and scoring system were developed to correlate imaging and behavioral measures. RESULTS VBM investigations of grey and white matter respectively revealed predominant central subcortical pathology in the basal ganglia and posterior limbs of the internal capsule (PLIC). White matter microstructural investigation with TBSS of DTI data revealed focal damage in bilateral PLICs. ICA of resting-state fMRI data revealed principal impairment of motor-related cortical networks (basal ganglia, cerebellum) and striking preservation of networks involved in perception (visual, auditory, sensorimotor), cognition, and emotion. These findings closely agreed with neurobehavioral assessments. CONCLUSION Together, our observations suggest that motor deficits underlie the inability to communicate and convey relatively intact cognitive, perceptual, and emotive capabilities in pediatric post-drowning ABI, depicting a locked-in-type syndrome. Several prognostic, therapeutic, and ethical correlates follow. Furthermore, the developed imaging protocol is suitable for clinical use and highly applicable to other patient populations and disorders of consciousness.