Effectiveness of Familiar Voices and Nature Sounds Among Critically Ill Comatose Patients

The recovery of consciousness in critically ill comatose persons is influenced by both internal factors, such as the severity of the critical illness, and external factors, such as sensory stimulation. Regular exposure to sensory stimuli can promote neuronal dendritic growth, improve synaptic connections, and enhance peripheral stimulation of the brain, which controls cognitive function. This supports the recovery of critically ill comatose person's consciousness. Sensory stimulation has also been found to be effective in reducing pain and anxiety for critically ill comatose persons.

Among sensory stimuli, auditory stimulation is the most feasible intervention because it is non-invasive, easy to perform, less expensive, and most importantly, hearing is the last sense to be lost when a person is in a coma state. Auditory stimulation can be delivered in various forms, such as the voice of caregivers or loved ones, natural sounds, or music. These non-invasive interventions have shown potential in improving patients' health outcomes and are safe for nurses to proactively implement.

Some studies have provided evidence that intense and repeated auditory stimulation can help to awaken persons from coma earlier or reduce pain. However, these studies have been limited by small sample sizes, with only comparisons between single stimulation and routine care or other types of sensory stimulation, or with the reporting of only some parameters. As a results, there is a lack of strong evidence regarding the specific type of auditory stimulation that is most effective for critically ill comatose person's recovery. This makes it difficult for nurses to identify the best stimulus to use for these persons. Therefore, further well-designed research studies should be conducted to observe significant differences regarding the effectiveness of familiar voices and nature sounds among critically ill comatose persons. This approach will enable a comprehensive evaluation and comparison of the effectiveness of these two auditory stimulation.

The investigators hypothesize that auditory stimulation is more effective in recovering critically ill comatose persons than routine care. Additionally, the investigators will also test the hypothesis that the effectiveness of auditory stimulation generated by familiar voices is higher than that provided by nature sounds.