The current literature on the outcome predictors of the emergence from DoC is in its moderate infancy and nowadays reliable markers have not been fully identified. After traumatic events, the early stages are crucial to determine the severity of the disease and to help clinicians and patients’ family in decision-making processes. Indeed, after discharge from ICUs, a better understanding of clinical evolution is mandatory for guiding decisions about pharmacological treatment and rehabilitation planning . As stated by Guacino et al. , the emergence from MCS is highlighted by the re-emergence of a functional communication system or restoration of the ability to use objects in a functional manner. Operationally, recovery of communication is demonstrated by reliable yes–no responses to questions concerning personal orientation or situational orientation. However, the likelihood of emergence from DoC is highly variable depending on several factors, such as: aetiology, age at onset, duration of DoC or clinical complications. In our Italian sample, the detected amount of full recovery of consciousness (35.5%) was in line with previous studies [17, 18, 31] although a final assessment requires a larger temporal period after injury.
Generally, the clinical evolution in this kind of patients is complicated by several factors (i.e., epileptic seizure, infection, thrombosis), which strongly reduces the likelihood of emergence. However, in the last two decades some clinical variables have been recognized as predictive of a favourable functional improvement. As elegantly summarized by Estraneo and Trojano  the usefulness of neurophysiological markers as extracted by EMG, EEG or fMRI methods have been widely recognized [32,33], although they are rarely used in traditional ICUs. Considering only clinical variables, it has widely been recognized that diagnosis of VS, anoxic aetiology, older age and large temporal interval from the event are the most negative prognostic factors in DoC patients [13, 34,35]. Overall our data are in part in agreement with all previous studies assessing predictive factors of conscious awareness in short-term period [17-19].
However, our most important finding was that the CRS-r scores are the best predictor of clinical improvement as revealed by multivariate survival tree statistical approach. In particular, we found that scores ≥ 12 at admission are highly predictive of emergence in DoC patients after discharge. This finding enlarges previous evidence provided by Estraneo et al., , who only investigated DoC with anoxic aetiology, demonstrating that CRS-r scores higher than 6, was the best predictor of recovery of consciousness. On the other hand, Bodien et al.,  demonstrated that a total CRS-r scores ≥ 10 should be considered as a marker of conscious awareness either for diagnosis of MCS or for assessing the emergence from MCS.
Otherwise, with respect to previous literature, we did not confirm that length of stay in the ICU impacts functional outcome . In this work, the authors evaluated the rehabilitation outcome in 63 DoC patients. They found that younger age, shorter stay in the ICU, and MCS diagnosis at admission were found to be significant predictors for higher functional motor improvement at discharge. However, with respect to our study, they only investigated DOC patients with aneurysmal subarachnoid haemorrhagic aetiology, which basically present a different clinical evolution with respect to traumatic patients.
The main limitation of this study is that the outcomes at 2 months cannot be considered as definitive. Although the detected predictors are similar to those reported in long-term longitudinal studies [9-21], we are aware that this study needs further evaluation before translating to clinical practice. Again, the lack of a deeper evaluation of medical complications might have influenced our data. However, it should bear in mind that endocrine, metabolic or other neurological complications (i.e seizures) are generally often reported in the later phases of the disease .