Estimation of phase signal change in neuronal current MRI for evoke response of tactile detection with realistic somatosensory laminar network model

Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm³. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.     

Barriers and characteristics for successful transition to adult healthcare for individuals with cerebral palsy: a systematic review

Abstract

Background: Cerebral palsy (CP) is a common childhood disability. However, these individuals are now living longer lives, participating in adult roles, and seeking healthcare services. The transition from pediatric to adult healthcare for adolescents with CP is a challenging yet significant time. Adolescents experience several barriers during transition.

Objectives: To utilize the environmental and personal dimensions of the ICF model in order to explore barriers when transitioning to adulthood as well as discuss characteristics and physical therapy implications needed to succeed within transition.

Methods: Electronic searching of PubMed, CINAHL, ERIC, Scopus, ProQuest, and the Cochrane Library databases was concluded on January 9, 2019 for studies including transition between pediatric and adult healthcare in individuals diagnosed with CP. Two independent reviewers agreed upon inclusion, eligibility, and quality assessment of each study using the Mixed-Methods Appraisal Tool (MMAT).

Results: Seven studies were included in the systematic review. Results for each study were separated based on the personal and environmental contextual factors of the ICF model and solutions to the barriers were then discussed.

Conclusions: Research has provided proposed solutions to select barriers, however, other barriers have yet to be addressed. More research is needed to address these barriers and provide a model program that can be implemented within the healthcare systems to promote a successful transition for adolescents with CP from pediatric to adult services.     

Severe lumbar spinal stenosis combined with Guillain-Barré syndrome: A case report

BACKGROUNDGuillain-Barré syndrome (GBS) is a rare disorder that typically presents with ascending weakness, pain, paraesthesias, and numbness, which mimic the findings in lumbar spinal stenosis. Here, we report a case of severe lumbar spinal stenosis combined with GBS.CASE SUMMARYA 70-year-old man with a history of lumbar spinal stenosis presented to our emergency department with severe lower back pain and lower extremity numbness. Magnetic resonance imaging confirmed the diagnosis of severe lumbar spinal stenosis. However, his symptoms did not improve postoperatively and he developed dysphagia and upper extremity numbness. An electromyogram was performed. Based on his symptoms, physical examination, and electromyogram, he was diagnosed with GBS. After 5 d of intravenous immunoglobulin (0.4 g/kg/d for 5 d) therapy, he gained 4/5 of strength in his upper and lower extremities and denied paraesthesias. He had regained 5/5 of strength in his extremities when he was discharged and had no symptoms during follow-up.CONCLUSIONGBS should be considered in the differential diagnosis of spinal disorder, even though magnetic resonance imaging shows severe lumbar spinal stenosis. This case highlights the importance of a careful diagnosis when a patient has a history of a disease and comes to the hospital with the same or similar symptoms.