Patients With Severe Disturbance Of Consciousness-listen To Stimulate Cortical Reaction Of Fmri Research

Since 2002, severe disorders of consciousness (DOS) have been grouped into the vegetative state (VS) and the minimally conscious state (MCS). The patients with VS unaware of the self and the environment, accompanied by sleep-wake cycles, and those with MCS show definite, but minimal, sign(s) of awareness. The differential diagnosis and prognosis of these two states is one of the key problems in the clinical practice of the DOS. Currently, the judgment of consciousness exclusively comes from bedside behavioral assessment, resulting remarkably high misdiagnosis rate. The advances in the functional brain mapping techniques, such as fMRI and PET, might provide objective evidence for the diagnosis and prognosis of these patients. By using fMRI, we observed the cerebral response to the subject's own name spoken by a familiar voice (SON-FV) and the subject's affective music in a relatively large sample of strictly-diagnosed DOS patients (7 VS and 5 MCS). Main findings in this study are as follows.First, SON-FV elicited activation in primary auditory cortex (typical activation pattern) in seven patients with VS. This finding is in consistent with the previous conclusion that the patients with VS retained the isolated function of primary cortex.Second, two patients with VS and four with MCS not only showed activation in the primary auditory cortex but also in hierarchically higher order associative temporal areas. These two patients with VS showing the most widespread activation subsequently showed clinical improvement into MCS three months after their fMRI scan. In some patients who developed into MCS from VS, the cerebral responses to SON-FV measured by fMRI were earlier several months than clinical diagnosis, thus this method might be a more reliable tool for preclinically distinguish minimally conscious state-like cognitive processing. In addition, our methods could differentiate the patients with VS in transient states during spontaneous recovery from the permanent patients, pointing the potential prognostic value of the atypical activation pattern elicited by SON-FV.Third, in controls, the affective music elicited the activation in MPFC. The MPFC was divided into two subregions, with positive activation in the anterior subregion and negative activation in the posterior subregion. In patients with MCS, the affective music elicited negative activation in MPFC, whereas no MPFC activation showed in patients with VS. These results indicated the diagnostic value of the negative activation elicited by the affective music. And it also provided important evidence for the relationship of the negative activation in the prefrontal cortex and awareness.Fourth, in patients with VS, the effective music elicited activation in the temporal lobe in two patients who emerged to MCS showed by the behavioral assessment 3 months later, and the remain four patients showed no activation. This indicated the signal elicited by the effective music is less stable in patients with VS than that of the SON-FV.By detecting SON-FV or effective music, functional neuroimaging may add valuable information to the standard clinical assessment of awareness in severely brain-damaged patients. Our result indicated that fMRI will become an important ancillary test in determining the diagnosis and prognosis of patients with VS and MCS in the future.