The feasibility of mixed reality-based upper extremity self-training for patients with stroke-A pilot study.

Mixed reality (MR), which combines virtual reality and tangible objects, can be used for repetitive training by patients with stroke, allowing them to be immersed in a virtual environment while maintaining their perception of the real world. We developed an MR-based rehabilitation board (MR-board) for the upper limb, particularly for hand rehabilitation, and aimed to demonstrate the feasibility of the MR-board as a self-training rehabilitation tool for the upper extremity in stroke patients. The MR-board contains five gamified programs that train upper-extremity movements by using the affected hand and six differently shaped objects. We conducted five 30-min training sessions in stroke patients using the MR-board. The sensor measured hand movement and reflected the objects to the monitor so that the patients could check the process and results during the intervention. The primary outcomes were changes in the Box and Block Test (BBT) score, and the secondary outcomes were changes in the Fugl-Meyer assessment and Wolf Motor Function Test (WMFT) scores. Evaluations were conducted before and after the intervention. In addition, a usability test was performed to assess the patient satisfaction with the device. Ten patients with hemiplegic stroke were included in the analysis. The BBT scores and shoulder strength in the WMFT were significantly improved (p < 0.05), and other outcomes were also improved after the intervention. In addition, the usability test showed high satisfaction (4.58 out of 5 points), and patients were willing to undergo further treatment sessions. No safety issues were observed. The MR-board is a feasible intervention device for improving upper limb function. Moreover, this instrument could be an effective self-training tool that provides training routines for stroke patients without the assistance of a healthcare practitioner. Trial registration: This study was registered with the Clinical Research Information Service (CRIS: KCT0004167).

Injury of the Thalamocingulate Tract in the Papez Circuit in Patients with Mild Traumatic Brain Injury.

The thalamocingulate tract between the anterior thalamic nuclei and the cingulate gyrus is a part of the Papez circuit. Using diffusion tensor tractography, injury of the thalamocingulate tract was investigated in patients with mild traumatic brain injury. Two patients (patient 1: a 58-yr-old woman and patient 2: a 49-yr-old man) with head trauma resulting from a car accident were enrolled. They were classified as mild traumatic brain injury and no specific lesion was observed on brain magnetic resonance imaging. These patients complained of memory impairment after head trauma. The entire Papez circuits, including thalamocingulate tract, fornix, mammillothalamic tract, and cingulum, were reconstructed in both hemispheres except for the left thalamocingulate tract: patient 1, it was thinner and discontinued compared with the right thalamocingulate tract; and patient 2, it was not reconstructed. The injury of the left thalamocingulate tract appeared to be related to the memory impairment in these patients.

Anatomical location and somatotopic organization of the corticospinal tract in the corona radiata of the normal human brain: a diffusion tensor tractography study.

The anatomical location and somatotopic organization of the corticospinal tract (CST) in the corona radiata (CR) of the normal human brain have not been studied using diffusion tensor tractography so far. In this study, the anatomical location and somatotopic organization of the CST in the CR were evaluated by determining the highest probabilistic locations and distances between the upper and lower extremities in the slices of upper and lower CR in the brain. In the mediolateral direction, the average of the highest probabilistic locations for the upper and lower extremities were 40.27 and 37.16% at the upper CR level and 38.19 and 37.14% at the lower CR level, respectively. In the anteroposterior direction, the average of the highest probabilistic locations for the upper and lower extremities were 62.52 and 75.65% at the upper CR level and 60.19 and 68.12% at the lower CR level, respectively. The average distances between upper and lower extremities for the mediolateral direction were 2.41 mm at the upper CR level and 1.21 mm at the lower CR level. The average distances between upper and lower extremities for the anteroposterior direction were 5.23 mm at the upper CR level and 4.47 mm at the lower CR level, respectively. Our findings suggest that the anatomical location and somatotopic organization for the upper extremity are located anterolaterally to the lower extremity in the CR of a normal human brain and distances between the upper and lower extremities become decreased as the CST descends from the upper to the lower CR level.

Usefulness of the combined motor evoked and somatosensory evoked potentials for the predictive index of functional recovery after primary pontine hemorrhage.

OBJECTIVE: To investigate the predictive index of functional recovery after primary pontine hemorrhage (PPH) using the combined motor evoked potential (MEP) and somatosensory evoked potential (SEP) in comparison to the hematoma volume and transverse diameter measured with computerized tomography. METHODS: Patients (n=14) with PPH were divided into good- and poor-outcome groups according to the modified Rankin Score (mRS). We evaluated clinical manifestations, radiological characteristics, and the combined MEP and SEP responses. The summed MEP and SEP (EP sum) was compared to the hematoma volume and transverse diameter predictive index of global disability, gait ability, and trunk stability in sitting posture. RESULTS: All measures of functional status and radiological parameters of the good-outcome group were significantly better than those of the poor-outcome group. The EP sum showed the highest value for the mRS and functional ambulatory category, and transverse diameter showed the highest value for "sitting-unsupported" of Berg Balance Scale. CONCLUSION: The combined MEP and SEP is a reliable and useful tool for functional recovery after PPH.

Influence of abutment materials on the implant-abutment joint stability in internal conical connection type implant systems.

PURPOSE: This study evaluated the influence of abutment materials on the stability of the implant-abutment joint in internal conical connection type implant systems. MATERIALS AND METHODS: Internal conical connection type implants, cement-retained abutments, and tungsten carbide-coated abutment screws were used. The abutments were fabricated with commercially pure grade 3 titanium (group T3), commercially pure grade 4 titanium (group T4), or Ti-6Al-4V (group TA) (n=5, each). In order to assess the amount of settlement after abutment fixation, a 30-Ncm tightening torque was applied, then the change in length before and after tightening the abutment screw was measured, and the preload exerted was recorded. The compressive bending strength was measured under the ISO14801 conditions. In order to determine whether there were significant changes in settlement, preload, and compressive bending strength before and after abutment fixation depending on abutment materials, one-way ANOVA and Tukey's HSD post-hoc test was performed. RESULTS: Group TA exhibited the smallest mean change in the combined length of the implant and abutment before and after fixation, and no difference was observed between groups T3 and T4 (P>.05). Group TA exhibited the highest preload and compressive bending strength values, followed by T4, then T3 (P<.001). CONCLUSION: The abutment material can influence the stability of the interface in internal conical connection type implant systems. The strength of the abutment material was inversely correlated with settlement, and positively correlated with compressive bending strength. Preload was inversely proportional to the frictional coefficient of the abutment material.

Chronic traumatic spinal epidural hematoma in a child.

Spinal epidural hematoma (SEH) can lead to progressive neurological deficits that are the result of spinal cord compression. Most of the reported cases of SEH had nontraumatic origins, and they were mainly in the acute stage. Traumatic SEH in a child is rare, and it is also difficult to diagnose because of the nonspecific pain and irritability of the child. We present here the first reported case of chronic traumatic SEH in a 3-yr-old boy. He was admitted with axillary pain and slowly progressive weakness after a fall that had occurred 4 wks before. On admission, he could not stand or hold a spoon. Magnetic resonance imaging revealed epidural hematomas from C5 to C7; these hematomas showed high signal intensity on the T1-weighted images and heterogeneous high-iso signal intensity on the T2-weighted images. After the surgical decompression, the patient showed a complete resolution of symptoms without any neurological sequelae. Our study suggests that a child with unexplained pain and motor weakness should undergo magnetic resonance imaging for making an early diagnosis. Chronic traumatic SEH in a child can be successfully treated by a surgical operation.

Identification of the medial lemniscus in the human brain: combined study of functional MRI and diffusion tensor tractography.

The medial lemniscus (ML) plays a critical role in sensory function and skillful movement. Using combined functional MRI (fMRI) and diffusion tensor tractography (DTT), we attempted to identify the ML pathway and quantify the characteristics of the ML compared to the corticospinal tract (CST). Eleven young healthy subjects without any history of neurological disorder were recruited for this study. For tracking of the ML, a seed region of interest (ROI) was determined using the fMRI activation in the primary sensorimotor cortex (SM1) following proprioceptive input, and a target ROI was given in the ML area of the pons. We were able to locate the ML in 9 out of 11 subjects. All ML started from the ML area just posterior to the transpontine fiber in the pons, and ascended to the SM1 posterolaterally to the cerebral peduncle of the midbrain, the posterior limb of the internal capsule (PLIC), and the corona radiata along with the CST. The fractional anisotropy (FA) value of the ML was similar to that of the CST. We could identify the ML pathway in the human brain using the combined fMRI/DTT method. These results and technique will be helpful for research about the ML in the human brain.

Motor outcome prediction using diffusion tensor tractography in pontine infarct.

We investigated whether the integrity of the corticospinal tract classified by diffusion tensor tractography (DTT) can predict the motor outcome in 25 patients with pontine infarct. DTTs were obtained in the early stage of stroke (5-30 days) and were classified into two groups (type A: the integrity of corticospinal tract was preserved around the infarct; type B: corticospinal tract was interrupted). DTT type A patients showed better motor function than the type B patients at 6 months after onset. DTT obtained at the early stage of pontine infarct appears to have predictive value for motor outcome in patients with pontine infarct.