Background: Music is considered a valuable method for stimulating patients with disorders of consciousness (DOC) by enhancing their awareness and arousal. Although biographical music and auditory relative stimulation has been shown, responses to other types of music has not yet been addressed. The purpose of this study was to assess the brain responses in critically ill patients under sedo-analgesia to music that is highly different in features. Methods: We measured the individual responses to three types of music: classical (ClassM, Mozart), dodecaphonic (DodecM, Schönberg), and heavy metal (HeavyM, Volbeat) in six critically ill patients (one male, five female, all between 53 and 82 years old) with primary brain pathology under sedo-analgesia. We analyzed the changes in each patient’s electroencephalogram (EEG) band composition (delta, 1–4 Hz, theta 4–8 Hz, alpha 8–13 Hz, and beta 13–30 Hz) and synchronization throughout the scalp. Results: In spite of the heterogeneity in the responses, ClassM did not change the basal activity, although there was a tendency toward a decrease in brain activity. DodecM increased the alpha and beta bands from the right hemisphere. However, HeavyM increased the delta and theta bands from the frontal lobes and the alpha and beta bands from most of the scalp. No significant changes in synchronization were observed. Conclusions: Different types of music induce heterogeneous responses in the brain, suggesting that music interventions could affect the brain state of patients. HeavyM induced the greatest changes in brain responses, whereas ClassM showed a tendency to reduce brain activity. The result of this study opens the possibility of using different types of music as tools during the rehabilitation process.