The following is a summary of “A Focus on Subtle Signs and Motor Behavior to Unveil Awareness in Unresponsive Brain-Impaired Patients,” published in the June 2023 issue of Neurology by Diserens, et al.
For a study, researchers sought to propose the term “clinical cognitive motor dissociation” (CMD) to describe a subset of brain-injured patients who exhibit a lack of command following using conventional neurobehavioral examination tools but demonstrate high levels of awareness and language processing when assessed using advanced imaging and electrophysiology techniques. They aimed to expand the range of motor testing to detect subtle, purposeful movements in the patients, potentially revealing hidden cognitive capabilities and significant potential for a good long-term outcome.
The study involved reviewing cases of brain-injured patients with CMD who appeared behaviorally unresponsive using conventional assessment tools but demonstrated cognitive function using advanced imaging and electrophysiology techniques. Motor testing was expanded across a limb, facial, and ocular motricity to identify subtle, purposeful movements in these patients. A novel approach to classification was presented, utilizing a graphical model to illustrate the range of clinical manifestations and recovery trajectories, distinguishing true disorders of consciousness from the spectrum of CMD.
The study proposed the term “clinical CMD” to describe patients with brain injuries who exhibit slight but determined motor responses and characteristic akinetic motor behavior, differentiating them from individuals with disorders of consciousness. CMD was conceptualized as ranging from complete (no motor response) to partial (subtle clinical motor response) forms, representing a spectrum of progressively better motor output in patients with preserved cognitive capabilities. The graphical model provided a visual representation of the classification approach and the distinct clinical manifestations and recovery trajectories within CMD.
The term “clinical CMD” is proposed to identify brain-injured patients who exhibit behavioral unresponsiveness but demonstrate cognitive capabilities and potential for recovery through expanded motor testing. The classification approach and the graphical model highlight the differentiation between true disorders of consciousness and the spectrum of CMD, emphasizing the importance of recognizing subtle motor responses as indicators of preserved cognitive function and long-term outcome potential.