In the neurosurgery department of a university hospital, a 64-year-old male patient underwent craniectomy and hematoma removal for spontaneous intracerebral hemorrhage in the left fronto-parieto-temporal lobes and extraventricular catheterization for intraventricular hemorrhage. Also, left transtentorial and subfalcine herniations were detected on brain computed tomography before surgery (Fig.1-A). Approximately two months after onset, he was transferred to the rehabilitation department of the same university hospital. Brain MRIs at two and three months after onset showed leukomalactic lesions in the left fronto-parieto-temporal lobes (Fig. 1-B). At transfer to the rehabilitation department, the patient was in a minimally conscious state with a Coma Recovery Scale-Revised (CRS-R) score of 14 (auditory function: 3, visual function: 4, motor function: 3, verbal function: 1, communication: 1, and arousal: 2) [15]. He underwent comprehensive rehabilitation, which included the provision of neurotropic drugs (methylphenidate, pramipexole, ropinirole, amantadine, zolpidem, and baclofen) and physical and occupational therapies that included tilt-table standing. Transcranial direct-current stimulation (tDCS) was administered using a neuroConn DC-stimulator (neuroConn, Ilmenau, Germany) as previously described [16]. The battery-driven constant-current stimulator was attached to saline-soaked surface sponge electrodes (7 cm × 5 cm). The anode was placed on the left mPFC area, and the cathode was placed on the opposite supraorbital region. Stimulation intensity was 2 mA, and duration was 20 minutes per session with one session/day and seven sessions/week. In addition, repetitive transcranial magnetic stimulation (rTMS) using a MagPro stimulator (Medtronic Functional Diagnostics, Skovlunde, Denmark) was applied as previously described to the left mPFC at a frequency of 10 Hz with an 80% motor threshold intensity and 160 pulses for 8 minutes per session with one session/day and seven sessions/week [17]. After four weeks of rehabilitation, the patient had recovered to a near-normal consciousness state with a CRS-R score of 22 (auditory function: 4, visual function: 5, motor function: 6, verbal function: 2, communication: 2, arousal: 3). The patient’s brother provided signed informed consent, and the study protocol was approved by our institutional review board.
Diffusion tensor imaging
DTI data were acquired twice (at 8 and 12 weeks after onset) using a 6-channel head coil on a 1.5-T Philips Gyroscan Intera (Philips, Best, Netherlands) with single-shot echo-planar imaging. Imaging parameters were as follows: acquisition matrix = 96 × 96, reconstructed to matrix = 192 × 192, field of view = 240 mm x 240 mm, repetition time = 10,398 ms, echo time = 72 ms, parallel imaging reduction factor (SENSE factor) = 2, echo-planar imaging factor = 59, b = 1000 s/mm2, slice gap = 0 mm, and slice thickness = 2.5 mm. The Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB) Software Library was used for the DTI data analysis. Affine multiscale 2-dimensional registration was used for correction of head motion effects and image distortion due to eddy currents. FMRIB Diffusion Software (Oxford, United Kingdom) with the routines option (0.5 mm step lengths, 5000 streamline samples, and curvature threshold = 0.2) implemented was used for fiber tracking. For analysis of the TCT from the thalamic ILN, the seed and target regions of interest (ROI) were placed on the thalamic ILN.[8] Of the 5000 samples generated from the seed voxel, contact results for the TCT were visualized at a threshold of 10 streamlined through each voxel.
The patient’s 8-week DTT results showed decreased TCT connectivity between the thalamic ILN and the cerebral cortex in both mPFC, as well as the occipital cortex and the left parietal cortex (Fig.1-C). By contrast, on 12-week DTT, the TCT connectivity was shown to have increased in both mPFCs and the right occipital cortex.