Background and Objective: Coma due to brain injury is an important complication resulting in unconsciousness and reducing the capacity of responding to the environment. This study aimed at examining the effect of organized voice auditory stimulation, which was performed by a nurse, on the length of coma in the patients suffering from head injury.

  Material and Methods: This clinical-trial study was applied on 40 patients in the critical care unit of Panje Azar Hospital. The patients were randomly recruited to one of the two groups (each group 20 patients). The intervention group was stimulated by the voice of a male nurse. Hearing stimulation was conducted in the morning and night shift about 15 minutes each time for 10 days. The patient consciousness was measured by GCS scale and analyzed by ANOVA and t-test (P<0.05), using SPSS Soft ware.

  Results: ­ The average age of intervention and control group was 28.20 ± 11.49 and 27.8 ± 13.22, respectively. Before stimulation in the first day, there is no significant difference between the GCS of intervention group (5.95 ±0.68) and that of control (5.95 ± 0.64). The results indicate that the intervention group has become consciousness from the 5th day (GCS of 8.25 ± 1.19) and control group (GCS of 7.80 ± 1.96) from the 10th day.

  Conclusion: The study show that the auditory stimulation in the intervention group compared to control group gives rise to the improvement of ­the level of consciousness in comatose patients .