A subset of patients in a minimally conscious state show improved behavioral responsiveness after transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex, while those who are unresponsive show limited benefit. Among 131 patients, 32% of minimally conscious patients responded to tDCS, compared to 10% of unresponsive patients. A regression model using baseline diagnosis, Coma Recovery Scale-Revised Index, age, sex, and time since injury correctly identified responders 77% of the time. Patients in a minimally conscious state with better cognitive profiles and longer time since injury appear to respond better to tDCS, suggesting they are better candidates for this treatment.
Patients with disorders of consciousness, such as those in a minimally conscious state or with unresponsive wakefulness syndrome, often face misdiagnosis because standard assessments rely on motor responses that can be absent due to cognitive-motor dissociation. This study tested whether heart rate variability (HRV) responses to personalized videos of acquaintances differ from responses to videos of strangers. In 17 healthy subjects, HRV measures significantly differed between personalized and non-personalized stimuli, but 11 patients with disorders of consciousness showed no such differences. Significant differences in HRV measures also emerged between the two groups. These findings suggest impaired emotional processing in patients with disorders of consciousness, and that integrating HRV measures may improve diagnosis.