Long-term recovery from a minimally responsive state with recovery of an injured ascending reticular activating system: A case report

Relationship between Coma Recovery Scale-Revised and the Thalamocortical Tract of Ascending Reticular Activating System in Hypoxic-Ischemic Brain Injury: A Pilot Study

BACKGROUND

This pilot study examined the relationship between the Coma Recovery Scale-Revised (CRS-R) and the five subparts of the thalamocortical tract in chronic patients with hypoxic-ischemic brain injury by diffusion tensor tractography (DTT).

METHODS

Seventeen consecutive chronic patients with hypoxic-ischemic brain injury were recruited. The consciousness state was evaluated using CRS-R. The five subparts of the thalamocortical tract (the prefrontal cortex, the premotor cortex, the primary motor cortex, the primary somatosensory cortex, and the posterior parietal cortex) were reconstructed using DTT. Fractional anisotropy and the tract volume of each subpart of the thalamocortical tract were estimated.

RESULTS

The CRS-R score showed a moderate positive correlation with the tract volume of the prefrontal cortex part of the thalamocortical tract (p < 0.05). In addition, the tract volume of the prefrontal cortex component of the thalamocortical tract could explain the variability in the CRS-R score (p < 0.05).

CONCLUSION

The prefrontal cortex part was closely related to the CRS-R score in chronic patients with hypoxic-ischemic brain injury. In addition, the change in the remaining number of neural fibers of the prefrontal cortex part appeared to be related to the change in conscious state.

Relationship between the consciousness level and the structural neural connectivity of the medial prefrontal cortex in hypoxic-ischemic brain injury: a pilot study

This pilot study investigated the relationship between the consciousness level and the structural neural connectivity of the medial prefrontal cortex (mPFC SNC) in patients with hypoxic-ischemic brain injury (HI-BI), using diffusion tensor tractography (DTT). Twenty-three patients with HI-BI were recruited into the study based on predefined inclusion criteria. Their consciousness levels were evaluated using the Glasgow Coma Scale (GCS) and the Coma Recovery Scale-Revised (CRS-R). Using DTT, the mPFC SNC was reconstructed for each patient. The average of the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and voxel number (VN) for the mPFC SNC in both hemispheres were determined. The GCS score showed moderate positive correlations with the FA value and VN of the mPFC SNC [(FA) r = 0.439; (VN) r = 0.466; P < 0.05], and a strong negative correlation with ADC value ( r = -0.531; P < 0.05). The CRS-R score had a strong positive and negative correlation with the FA and ADC values of the mPFC SNC, respectively, [(FA) r = 0.540; (ADC) r = -0.614; P < 0.05] and a moderate positive correlation with the VN of the mPFC SNC ( r = 0.488; P < 0.05). We found that the severity of the injury to the mPFC SNC was closely related to the consciousness level. Our results suggest that the mPFC SNC appears to be a neural correlate for the control of consciousness in patients with HI-BI. Based on these results, we believe that the mPFC could be a target area for noninvasive neurostimulation therapies for patients with impaired consciousness following HI-BI.

Preliminary Study of Vagus Nerve Magnetic Modulation in Patients with Prolonged Disorders of Consciousness

BACKGROUND

The number of patients with prolonged disorders of consciousness (pDOC) is increasing. However, its clinical treatment remains challenging. To date, no studies have reported the effect of vagus nerve modulation (VNM) using repetitive transcranial magnetic stimulation (rTMS) in patients with pDOC. We aimed to evaluate the effect of vagus nerve magnetic modulation (VNMM) on pDOC patients.

METHODS

We performed VNMM in 17 pDOC patients. The Revised Coma Recovery Scale (CRS-R), Glasgow scale (GCS), somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) were assessed before and after treatment.

RESULTS

Both CRS-R and GCS results showed significant improvement in p DOC patients after VNMM treatment. The CRS-R improved from 7.88 ± 2.93 to 11.53 ± 4.94. The GCS score also improved from 7.65 ± 1.9 to 9.18 ± 2.65. The number of BAEP grades I increased from 3 to 5 after treatment. The number of BAEP grades I increased from 3 to 5, grade II increased by 1, and grade III decreased from 4 to 1.

CONCLUSION

This study provides a preliminary indication of the potential of VNMM in the rehabilitation of pDOC patients. It provides the basis for a Phase 2 or Phase 3 study of VNMM in patients with pDOC.

Recovery of the ascending reticular activating system and consciousness following comprehensive management in a patient with traumatic brain injury

We report on changes in the ascending reticular activating system (ARAS) concurrent with the recovery of impaired consciousness following rehabilitation and cranioplasty in a patient with traumatic brain injury (TBI), which were demonstrated on diffusion tensor tractography (DTT). A 34-year-old male patient was diagnosed with a traumatic intracerebral hemorrhage after falling from a height of approximately 7 m and underwent a right frontoparietotemporal decompressive craniectomy and hematoma removal. At 5 months after onset, when starting rehabilitation, the patient showed impaired consciousness, with a Glasgow Coma Scale (GCS) score of 4. Comprehensive rehabilitative therapy was provided until 14 months after onset, and his GCS score improved to 8. Cranioplasty was performed using auto-bone at 14 months after onset. One month after cranioplasty, his GCS score improved to 12. On the 15-month DTT, the deviated lower dorsal ARAS was restored on both sides, and the right side had become thicker. The right lower ventral ARAS was reconstructed, and increased neural connectivity of the upper ARAS was detected in both the prefrontal cortices. Thus, changes in the ARAS were demonstrated in a patient with TBI during recovery of consciousness following rehabilitation and cranioplasty.