Cognitive Motor Dissociation in Disorders of Consciousness: An Individual Participant Data Meta-Analysis

Area of Science:

• Neuroscience
• Neurology
• Clinical Neurophysiology

Background:

• Behavioral assessments in disorders of consciousness (DoC) may underestimate awareness due to unreliable motor output.
• Cognitive motor dissociation (CMD) describes patients with apparent unresponsiveness but volitional brain responses detected via neurodiagnostics.

Purpose of the Study:

• To characterize clinical and methodological factors influencing the detection of cognitive motor dissociation (CMD) in patients with disorders of consciousness (DoC).
• To analyze the impact of etiological factors and clinical states on CMD detection rates.

Main Methods:

• Systematic literature search of MEDLINE, Embase, and Scopus (2000-2026) for studies on CMD detection.
• Individual participant data meta-analysis using mixed-effects logistic regression.
• Quality assessment of included studies using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool.

Main Results:

• Fifty-six studies including 1248 patients were analyzed; 44.5% had unresponsive wakefulness syndrome (UWS).
• CMD detection was significantly lower in patients with anoxic and cerebrovascular etiologies compared to traumatic brain injury.
• Minimally conscious state minus (MCS-) was associated with higher CMD detection rates compared to UWS; time since injury, diagnostic modality, and task paradigms did not independently affect detection.

Conclusions:

• Cognitive motor dissociation (CMD) is a common phenomenon in disorders of consciousness (DoC), with prevalence varying by etiological factors and clinical status.
• The detection of CMD is not influenced by the time since injury, diagnostic modality, or specific task paradigms used.
• Standardized protocols and longitudinal studies are crucial for accurate CMD assessment and understanding its implications in DoC.