Upper Extremity Rehabilitation Using Fully Immersive Virtual Reality Games With a Head Mount Display: A Feasibility Study.

BACKGROUND: Rehabilitation therapy using a virtual reality (VR) system for stroke patients has gained attention. However, few studies have investigated fully immersive VR using a head-mount display (HMD) for upper extremity rehabilitation in stroke patients. OBJECTIVE: To investigate the feasibility, preliminary efficacy, and usability of a fully immersive VR rehabilitation program using a commercially available HMD for upper-limb rehabilitation in stroke patients. DESIGN: A feasibility study. SETTING: Two rehabilitation centers. PARTICIPANTS: Twelve stroke patients with upper extremity weakness. INTERVENTIONS: Five upper extremity rehabilitation tasks were implemented in a virtual environment, and the participants wore an HMD (HTC Vive) and trained with appropriate tasks. Participants received a total of 10 sessions two to three times a week, consisting of 30 minutes per session. MAIN OUTCOME MEASURES: Both patient participation and adverse effects of VR training were monitored. Primary efficacy was assessed using functional outcomes (Action Research Arm Test, Box and Block Test, and modified Barthel Index), before and after the intervention. Usability was assessed using a self-reported questionnaire. RESULTS: Three patients discontinued VR training, and nine patients completed the entire training sessions and there were no adverse effects due to motion sickness. The patients who received all sessions showed significant functional improvement in all outcome measures after training (P < .05 for all measures). The overall satisfaction was 6.3 ± 0.8 on a 7-point Likert scale in all participants. CONCLUSIONS: A fully immersive VR rehabilitation program using an HMD for rehabilitation of the upper extremities following stroke is feasible and, in this small study, no serious adverse effects were identified. LEVEL OF EVIDENCE: IV.

The natural course of passive tenodesis grip in individuals with spinal cord injury with preserved wrist extension power but paralyzed fingers and thumbs.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To investigate the natural course of passive tenodesis grip in individuals with spinal cord injury (SCI) with no experience of tenodesis splint application and the related factors for success of the grip. SETTING: Community-dwelling persons with chronic SCI in South Korea. METHODS: Individuals with cervical SCI with preserved wrist extensor power, but completely paralyzed fingers and thumbs, were recruited. For each hand, success or failure of passive tenodesis lateral grip was assessed both in the opening and closing phase. The key task in the Graded and Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) test was also assessed. RESULTS: Fifty-eight hands of 37 individuals with SCI were analyzed. In 35 of the 58 hands, both opening and closing phases of the grip were achieved. During the closing phase of the passive tenodesis lateral grip, the mean (s.d.) value of the second MP joint flexion angle (°) in the success group was 55.1 (13.6), compared to 38.6 (17.8) in the failure group. The key task in GRASSP was completed in only 14 out of 58 hands. Hands with a wrist extensor power of grade 4 or 5 on a manual muscle test showed higher GRASSP scores than those with a grade 3 wrist extensor power. CONCLUSIONS: The passive tenodesis lateral grip can be achieved in a large number of hands without splint application after SCI, but its use in the key task of the GRASSP is limited.

Controlled multiple neutral planes by low elastic modulus adhesive for flexible organic photovoltaics.

To protect brittle layers in organic photovoltaic devices, the mechanical neutral plane strategy can be adopted through placing the brittle functional materials close to the neutral plane where stress and strain are zero during bending. However, previous research has been significantly limited in the location and number of materials to protect through using a single neutral plane. In this study, multiple neutral planes are generated using low elastic modulus adhesives and are controlled through quantitative analyses in order to protect the multiple brittle materials at various locations. Moreover, the protection of multiple brittle layers at various locations under both concave and convex bending directions is demonstrated. Multilayer structures that have soft adhesives are further analyzed using the finite element method analysis in order to propose guidelines for structural design when employing multiple neutral planes.

Cell type-specific genetic and optogenetic tools reveal hippocampal CA2 circuits.

The formation and recall of episodic memory requires precise information processing by the entorhinal-hippocampal network. For several decades, the trisynaptic circuit entorhinal cortex layer II (ECII)→dentate gyrus→CA3→CA1 and the monosynaptic circuit ECIII→CA1 have been considered the primary substrates of the network responsible for learning and memory. Circuits linked to another hippocampal region, CA2, have only recently come to light. Using highly cell type-specific transgenic mouse lines, optogenetics and patch-clamp recordings, we found that dentate gyrus cells, long believed to not project to CA2, send functional monosynaptic inputs to CA2 pyramidal cells through abundant longitudinal projections. CA2 innervated CA1 to complete an alternate trisynaptic circuit, but, unlike CA3, projected preferentially to the deep, rather than to the superficial, sublayer of CA1. Furthermore, contrary to existing knowledge, ECIII did not project to CA2. Our results allow a deeper understanding of the biology of learning and memory.

Altered cortical synaptic morphology and impaired memory consolidation in forebrain- specific dominant-negative PAK transgenic mice.

Molecular and cellular mechanisms for memory consolidation in the cortex are poorly known. To study the relationships between synaptic structure and function in the cortex and consolidation of long-term memory, we have generated transgenic mice in which catalytic activity of PAK, a critical regulator of actin remodeling, is inhibited in the postnatal forebrain. Cortical neurons in these mice displayed fewer dendritic spines and an increased proportion of larger synapses compared to wild-type controls. These alterations in basal synaptic morphology correlated with enhanced mean synaptic strength and impaired bidirectional synaptic modifiability (enhanced LTP and reduced LTD) in the cortex. By contrast, spine morphology and synaptic plasticity were normal in the hippocampus of these mice. Importantly, these mice exhibited specific deficits in the consolidation phase of hippocampus-dependent memory. Thus, our results provide evidence for critical relationships between synaptic morphology and bidirectional modifiability of synaptic strength in the cortex and consolidation of long-term memory.

Translational control by MAPK signaling in long-term synaptic plasticity and memory.

Enduring forms of synaptic plasticity and memory require new protein synthesis, but little is known about the underlying regulatory mechanisms. Here, we investigate the role of MAPK signaling in these processes. Conditional expression of a dominant-negative form of MEK1 in the postnatal murine forebrain inhibited ERK activation and caused selective deficits in hippocampal memory retention and the translation-dependent, transcription-independent phase of hippocampal L-LTP. In hippocampal neurons, ERK inhibition blocked neuronal activity-induced translation as well as phosphorylation of the translation factors eIF4E, 4EBP1, and ribosomal protein S6. Correspondingly, protein synthesis and translation factor phosphorylation induced in control hippocampal slices by L-LTP-generating tetanization were significantly reduced in mutant slices. Translation factor phosphorylation induced in the control hippocampus by memory formation was similarly diminished in the mutant hippocampus. These results suggest a crucial role for translational control by MAPK signaling in long-lasting forms of synaptic plasticity and memory.

Bilateral Breast Cancer

Bilateral breast cancer is not a common clinical problem, and its occurance is not suprising in this paired organ. Bilateral breast cancer is categorized as synchronous or metachronous. We propose to evaluate clinical and biological characteristics in bilateral breast cancer. Previous cancer in one breast is the strongest known risk factor for cancer to develop in the second breast, and a young age at dignosis of a breast cancer and lobular type of tumor are additional risk factors related to bilaterality. Seventeen cases of bilateral breast cancer have been admitted to the department of General surgery, Samsung Cheil general Hospital from 1980 till 1995. We report the analysis of these cases with the references. The incidence of bilateral breast cancer among all case of total breast cancer was 2.1%(17/827). Synchronous breast cancer was 3 cases(0.4%) and metachronous breast cancer was 14cases (1.7%). The median age was 41 years. The mean age at diagnosis of the primary tumor in the metachronous group was 40 years. Among metachronous cases, the mean interval between the treatment of the primary cancer and the detection of secondary cancer was 37months. The clinical stage was 0-I in 12%, II in 50%, III in 32%, and IV in 6% of tumors. The majority of patients (88%) were clinically node positive. Out of a total of 34 tumors, the clinical tumor size Tis-T1 in 8 tumors, T2 in 21 tumors, and T3 in 5 tumors. Histopathologic type of the pimary tumor was the same with the second in 70%(12/17). The location of secondary breast cancer was in the upper outer quadrant in 9 cases, and in the upper medial quadrant of breast in 2 cases. The premenopausal primary cancer was in 50% of the patients, and postmenopausal primary cancer was in 50% of patients for whom this information was available. Median survival period was 57 months, and 5 year survival rate was 80%. Bilateral breast cancers have similar biological features to unilateral breast cancer more freqently than would be predicted by chance alone. The similarity in clinical aspects of unilateral and bilateral breast cancers should be considered in clinical management of patients with breast cancer. Further investigation is required to know these similaritics and differences between unilateral and bilateral breast cancer.