To investigate patient-specific automated epileptic seizure detection from scalp EEG using a new technique: frequency–moment signatures.
Methods
Signatures were calculated from 32 s blocks of data of electrode differences from the right (RH) and left hemisphere (LH). Discrete Fourier transforms of 15 data subsets were calculated per block per hemisphere. The spectral powers at a given frequency from the RH and LH were combined into a single quantity. The signature elements were found by subtracting normalised central moments of the subset distribution from the mean, to measure the consistency of the spectral power at a given frequency over all subsets. The seizure measure was the logarithm of the probability that a signature belonged to a control set of non-seizure signatures.
Results
Following the optimisation of signature parameters using three one-day recordings from each of 12 patients, performance was tested on a separate set of data from the same patients. The method had a sensitivity of 91.0% (total 34 seizures) with 0.020 false positives per hour (total 618 h).
Conclusions
Frequency–moment signatures promise automated seizure detection sensitivities comparable to visual identification and other published methods, with improved false detection rates.
Significance
This technique has the potential to be used more widely in EEG analysis. 相似文献
ObjectiveThe impact of neuronal cell loss associated with Alzheimer’s disease (AD) on the network organization of the brain is poorly understood. Here we investigated whether modifications in resting-state functional connectivity (FC) are associated with cognitive function of AD patients.MethodsHigh-density electroencephalograms (EEGs) were obtained from patients with early stages of AD and elderly healthy controls. Cortical oscillations were reconstructed with an adaptive spatial filter. Maps of imaginary coherence (IC) between brain areas were compared between groups and correlated with cognitive performance.ResultsParietal and medial temporal lobes of AD patients showed a disruption of alpha band FC to the rest of the brain. However, an adaptive extension of the language network to the right hemisphere could be observed in AD patients and was correlated with better verbal fluency. A shift of FC from alpha frequencies to theta frequencies could be observed in a memory network and was associated with better verbal memory performance.ConclusionsNot only dysfunctional but also adaptive network reorganization occurs in early AD.SignificanceThe network mechanisms for preserved cognitive functioning may inform novel treatment strategies for AD in the future. 相似文献
Recovery from stroke-related oro-facial impairment has rarely been investigated. In this longitudinal study chewing efficiency, maximum lip and bite force as well as masseter muscle thickness were evaluated and compared with hand-grip force.
Materials and methods
Thirty-one hospitalized stroke patients and 24 controls were recruited for this cohort study with 2-year follow-up. Chewing efficiency was evaluated with a color mixing ability test, lip forces with a traction dynamometer, bite force with a digital gauge, masseter muscle thickness using ultrasound measurements and grip strength with a hand dynamometer.
Results
During the 2-year observation period, patients were evaluated four times. A total of 21 patients dropped out of the study. Stroke patients showed significantly impaired chewing efficiency and lower lip forces than controls with no significant improvement over time. Bite forces were not different between ipsi- and contralesional sides, in contrast to contralesional hand-grip strength which was significantly impaired and did not improve during the observation period. On the first examination with a median of 40 days after stroke, masseter thickness was reduced contralesional, but did not continue to show significant side-differences during follow-up.
Conclusions
Stroke affects the upper limb and the masseter muscles differently on a functional and morphological level. Further research is needed to evaluate the predictive value of oro-facial parameters on functional outcome after stroke.
Clinical relevance
Impaired chewing efficiency and reduced lip force are quantifiable symptoms in stroke patients which seem not to improve in absence of oro-facial rehabilitation procedures. 相似文献
The Endobronchial Valve for Emphysema Palliation Trial (VENT) was a multi-centre, prospective, randomised, controlled trial conducted to evaluate the safety and effectiveness of unilateral endobronchial valve (EBV) treatment. The purpose of this analysis was to assess outcomes in the previously unreported European VENT study cohort. Patients with advanced emphysema were randomly assigned (2:1) to receive Zephyr? (Pulmonx Inc., Redwood City, CA, USA) EBV treatment (n = 111) or medical management (n = 60). At 6 months, EBV patients demonstrated a significant improvement compared with the controls for mean ± SD change in forced expiratory volume in 1 s (7 ± 20% versus 0.5 ± 19%; p = 0.067), cycle ergometry (2 ± 14 W versus -3 ± 10 W; p = 0.04) and St George's Respiratory Questionnaire (-5 ± 14 points versus 0.3 ± 13 points; p = 0.047). At 12 months, the magnitude of the difference between groups for change from baseline was of similar magnitude to the differences seen at 6 months. Rates for complications did not differ significantly. EBV patients with computed tomography (CT) scans suggestive of complete fissure and lobar occlusion had a mean ± SD lobar volume reduction of -80 ± 30% and >50% met minimal clinical difference thresholds. The degree of emphysema heterogeneity did not preclude excellent outcomes. Unilateral lobar volume reduction using EBV treatment is safe and superior clinical results correlated with CT suggestive of complete fissures and successful lobar occlusion. Emphysema heterogeneity was not critical for determining positive outcomes. 相似文献
Transscleral controlled cyclophotocoagulation (COCO) is a transscleral 810-nm diode laser cyclophotocoagulation that automatically adjusts the applied laser energy utilizing an optical feedback loop. The present study investigates the influence of pseudoexfoliation (PEX) on the efficacy of COCO in a Caucasian study population.
Methods
Retrospective data from 130 consecutive eyes were analyzed during a 2-year follow-up. Baseline characteristics, intraocular pressure (IOP), number of IOP-lowering medications, visual field, best-corrected visual acuity (BCVA), and secondary surgical interventions (SSI) were analyzed. The primary endpoint was IOP reduction at M24 compared to baseline, and the secondary endpoints were IOP course, reduction of IOP-lowering medications, surgical success, and IOP-lowering SSIs stratified by PEX and baseline IOP.
Results
IOP reductions of −35, −39, −25, −25, −23, −34, and −36% could be achieved from baseline to D1, W1, M1, M3, M6, M12, and M24 (all p < 0.001), respectively, while there was a significant overall reduction over time (p < 0.001) in the number of topical IOP-lowering medications postoperatively. The proportion of eyes requiring additional systemic IOP-lowering medication reduced from 31 to 0% at M24 (p = 0.025). Eyes without PEX and IOP < 30 mmHg at baseline had the lowest risk for IOP-lowering SSIs (p < 0.03). BCVA dropped at M12 (0.25 [95% CI: 0.12–0.38]), and the drop persisted during the following 12 months.
Conclusion
The present study demonstrates a midterm IOP-lowering effect after COCO while reducing the burden for topical and systemic IOP-lowering medications. Patients without PEX and IOP < 30 mmHg have a lower risk of SSI. The procedure per se cannot be excluded as causative for the decreased postoperative BCVA. Further prospective investigations are suggested.
Navigation systems potentially facilitate minimally invasive esophagectomy and improve patient outcome by improving intraoperative orientation, position estimation of instruments, and identification of lymph nodes and resection margins. The authors’ self-developed navigation system is highly accurate in static environments. This study aimed to test the overall accuracy of the navigation system in a realistic operating room scenario and to identify the different sources of error altering accuracy.
Methods
To simulate a realistic environment, a porcine model (n = 5) was used with endoscopic clips in the esophagus as navigation targets. Computed tomography imaging was followed by image segmentation and target definition with the medical imaging interaction toolkit software. Optical tracking was used for registration and localization of animals and navigation instruments. Intraoperatively, the instrument was displayed relative to segmented organs in real time. The target registration error (TRE) of the navigation system was defined as the distance between the target and the navigation instrument tip. The TRE was measured on skin targets with the animal in the 0° supine and 25° anti-Trendelenburg position and on the esophagus during laparoscopic transhiatal preparation.
Results
On skin targets, the TRE was significantly higher in the 25° position, at 14.6 ± 2.7 mm, compared with the 0° position, at 3.2 ± 1.3 mm. The TRE on the esophagus was 11.2 ± 2.4 mm. The main source of error was soft tissue deformation caused by intraoperative positioning, pneumoperitoneum, surgical manipulation, and tissue dissection.
Conclusion
The navigation system obtained acceptable accuracy with a minimally invasive transhiatal approach to the esophagus in a realistic experimental model. Thus the system has the potential to improve intraoperative orientation, identification of lymph nodes and adequate resection margins, and visualization of risk structures. Compensation methods for soft tissue deformation may lead to an even more accurate navigation system in the future. 相似文献
Freshly prepared autologous plasma clots may serve as a carrier matrix for expanded multipotent mesenchymal stromal cells (MSCs) or bone marrow cells. By varying the calcium concentration, plasma clots with different properties can be produced. The purpose of this in vitro study was to determine the optimal calcium concentrations for the clotting process, intra-clot cell viability, and clot lysis.
Methods
Different plasma clots were prepared by adding an equal volume of RPMI1640 (with or without MSCs) to citrate plasma (either containing platelets or platelet-free). Clotting was initiated by the addition of CaCl2 (10 g/100 ml H2O, 10 % solution). The final concentration of CaCl2 ranged from 1 to 10 % by volume of plasma. Viability and distribution of the MSCs were analysed by calcein-AM/propidium iodide staining. MSC-embedded plasma clots were dissolved with trypsin (0.25 %), and recovered cells were further incubated for 1 week under cell culture conditions.
Results
The viability of MSCs embedded in clots formed by the addition of 1–8 % by volume CaCl2 was not affected by incubation of up to 1 week. In contrast, clots produced by higher volumes of CaCl2 solutions (9–10 % by volume of plasma) showed decreased numbers of viable cells. Intra-clot cell proliferation was highest in clots produced by addition of 5 % CaCl2 by plasma volume. Osteocalcin release was not influenced in platelet-free plasma but decreased in platelet-containing plasma. Morphological analysis of stained recovered MSCs revealed that lysis of the plasma clot did not affect cell morphology or subsequent spontaneous proliferation.
Conclusions
Clot formation and clot stability can be controlled by changing the concentration of CaCl2 added to plasma. The addition of 5 % CaCl2 produced a plasma clot with optimal results for stem cell delivery. 相似文献
Peripheral neuropathies are well-known complications of primary systemic vasculitides. In rare cases, peripheral neuropathies are among the first symptoms of these diseases. In this prospective study, 89 consecutive adult patients with newly diagnosed primary systemic vasculitis were screened, of whom 22 patients (25 %, 12 men, ten women, mean age, 59 years, range, 26–82 years) suffered from peripheral neuropathy due to systemic vasculitis at initial presentation. Peripheral neuropathy was most frequent in newly diagnosed patients with eosinophilic granulomatosis with polyangiitis (Churg–Strauss syndrome, 12 out of 20 patients, 60 %) and polyarteritis nodosa (three out of six patients, 50 %), and less common in patients with granulomatosis with polyangiitis (six out of 47 patients, 13 %) and microscopic polyangiitis (one out of 16 patients, 6 %). Multiplex mononeuropathy was more frequent (n = 13, 59 %) than symmetric polyneuropathy (n = 9, 41 %). The nerves commonly affected were the peroneal nerve, followed by the sural, posterior tibial, and median nerves. Treatment options were chosen according to current guidelines of the national neurological and rheumatologic societies, with initial corticosteroid monotherapy for patients with a mild disease form and a combination of corticosteroids and intravenously pulsed cyclophosphamide for patients with a more extended organ involvement. During follow-up (mean, 34 months, range, 12–112 months), new neurological complications were rare (9 %): One patient suffered from a cerebral infarct while another patient sustained epileptic seizures. Two patients (9 %) died from sepsis (after 60 months) or severe gastrointestinal bleeding (after 13 months). The degree of neurological disability measured by the functional disability score (described by Prineas) improved in 20 of 22 patients after 12 months of therapy. 相似文献