Arousal Units: A Framework for Measuring and Tracking Levels of Consciousness During Recovery

Background & Unmet Need

• Each year, millions of patients experience unconsciousness across a range of care settings, including the ICU, operating room, postoperative care unit (PACU), and emergency medical services
• Current consciousness assessments, such as behavioral diagnostic scales, neuroimaging, or EEG, are assessed sporadically, limiting their precision due to the dynamic nature of consciousness
• Moreover, implementation of these methods cannot feasibly capture the temporal resolution needed to track transitions between states of consciousness
• As a result, critical care decisions are often made without objective data about potential recovery; for instance, a study in several Canadian Trauma centers found that 70% of ICU deaths are related to life support withdrawal, with 65% occurring within 72 hours due to uncertainty in prognosis1
• Unmet Need: Objective and quantitative methods for measuring and tracking consciousness levels

Technology Overview

• The Technology: "Arousal Units" (AU), a biomarker for quantitative assessment and monitoring of consciousness levels using EEG
• AUs are repeated, temporally discrete cortical patterns that link to behavioral and breathing changes
• These cortical patterns consist of interactions between three spectral variables: fractional gamma, delta, and gamma power that can be sequentially identified within specific windows
• PoC Data: Arousal indices reflected arousal levels and predicted dominant motor movements in mice during recovery from hypoglycemic coma (accuracy of ~89%, sensitivity of ~75%) and brain injury (accuracy of ~ 87%, sensitivity ~76%)
• Arousal indices also reflected arousal levels in human patients, including neonates and older patients emerging from anesthesia

Technology Applications

• Real-time monitoring of consciousness levels for patients recovering from anesthesia, a disorder of consciousness (DOC), or brain injury
• Prognosing recovery trajectory in patients with long-term DOC to predict patient outcomes and inform treatment decisions
• Assessing treatment efficacy for DOC patients
• Remote assessment of patient consciousness

Technology Advantages

• AUs can measure the transition from one state of consciousness to another
• Provides objective and quantitative measurements
• Continuous monitoring capability versus sporadic behavioral assessments
• Applicable across multiple conditions and causes of consciousness disorders
• Can be used remotely on telemedicine platforms

Figure: Arousal Units represent a pattern of increased breathing frequency aligned to a cortical switch, which precedes a movement. Within these EEG spans, a peak in total gamma power or gamma burst directly links to the movement.