The Unsteady Return of Bedside Motor Command-Following After Acute Brain Injury

Area of Science:

• Neurology
• Critical Care Medicine
• Neuroscience

Background:

• Bedside command-following signifies recovery of consciousness post-acute brain injury.
• The timing, stability, and sedation effects on command-following are not well-understood at scale.

Purpose of the Study:

• To characterize the timing and stability of command-following after acute brain injury.
• To investigate the influence of sedation on command-following.
• To validate findings across different patient cohorts.

Main Methods:

• Retrospective analysis of adult patients with acute brain injury from the MIMIC-IV database.
• Glasgow Coma Scale motor response "Obeys Commands" used to define command-following.
• Cumulative incidence estimated with competing risks; instability quantified by transient recovery and threshold crossings.
• Concurrent sedation data analyzed; findings validated in the eICU Collaborative Research Database.

Main Results:

• Of 13,900 patients, 39.6% did not follow commands initially.
• 14-day cumulative incidence of command-following was 65.0%, varying by injury type (e.g., 36.9% anoxic vs. 77.2% ischemic stroke).
• 22.2% of recoveries were transient, and 62.4% showed repeated threshold crossings; non-following strongly correlated with sedation.

Conclusions:

• Command-following after acute brain injury returns early but is unsteady.
• Recovery timing is phenotype-dependent and significantly influenced by sedation.
• A single command-following assessment is an unreliable indicator of a patient's underlying neurological state.