P3a from visual stimuli: typicality,task, and topography

A visual three-stimulus (target, nontarget, standard) paradigm was employed in which subjects responded only to the target. Nontarget stimulus properties were varied systematically to evaluate how stimulus typicality (non-novel vs. novel) across task discrimination (easy vs. difficult) conditions affects P3a scalp topography. Nontarget stimuli consisted of letters, small squares, large squares, and novel patterns; discrimination difficulty between the target and standard was varied across conditions. When the discrimination was easy, P300 amplitude was larger for the target than the nontarget with parietal maximums for both. In contrast, when the discrimination was difficult, nontarget amplitude (P3a) was larger and earlier than the target P300 over the frontal/central electrode sites, whereas target amplitude (P3b) was larger parietally and occurred later. P3a was largest when elicited by either the large square or novel pattern stimuli. The findings suggest that stimulus context as defined by the target/standard discrimination difficulty rather than stimulus novelty determines P3a generation.     

Congenital Lipedematous Alopecia: Adding to the Differential Diagnosis of Congenital Alopecia

Lipedematous alopecia is a rare condition of unknown etiology characterized by a thick boggy scalp with varying degrees of hair loss. It is usually seen in adult African-American females, and a case in a 9-year-old was the youngest patient reported thus far. We report on the appearance of this condition in two children, a 6-year-old child and a 10-year-old child. Each presented with congenital patchy hair loss on the occipital area and the left temple. A boggy hairless scalp with soft swelling was detected in both patients. Histological examination showed increased thickness of the subcutaneous fat tissue with a decrease in hair follicles. These features were consistent with a diagnosis of lipedematous alopecia. We report two cases of congenital lipedematous alopecia, which has not been reported previously. Although congenital, these distinct clinical features should be kept in mind in the diagnosis of alopecic hair loss.     

儿童头皮深在性红斑狼疮五例

目的 探讨儿童头皮深在性红斑狼疮（LEP）临床及病理学特征。 方法 回顾性分析5例LEP患儿临床、组织病理特点及治疗和预后情况。 结果 5例儿童头皮LEP,男2例,女3例;中位发病年龄5个月（范围2 ～ 38个月）;中位病程15个月（范围4 ～ 72个月）。皮损为头部弧形或环形紫红色萎缩性斑块伴脱发,枕部及颞部最常受累。1例患儿抗核抗体（ANA）1 ∶ 100,4例患儿ANA抗Ro/SSA、La/SSB抗体检查均为阴性。组织病理学改变主要为脂肪透明变性,黏蛋白沉积及脂肪小叶淋巴细胞灶状聚集。2例口服泼尼松（1.5 ~ 2） mg·kg-1·d-1, 1例口服羟氯喹5 mg·kg-1·d-1,1例口服泼尼松1.5 mg·kg-1·d-1并联合羟氯喹5 mg·kg-1·d-1;1例患儿仅外用卤米松乳膏及0.03%他克莫司软膏。患儿皮损于治疗后2 ~ 3月均获得缓解,6个月消退,新发生长,随访1.5年未见病情反复。 结论 头皮LEP对泼尼松及羟氯喹治疗反应良好,患儿可选用强效糖皮质激素及钙调磷酸酶抑制剂外用治疗。     

头皮电烧伤骨外露带毛发皮瓣修复

目的：探讨头皮电烧伤骨外露用头皮扩张皮瓣移植修复的临床效果。方法：采用早期扩创,保留部分坏死骨质,用邻近头皮扩张使带毛发的头皮面积扩大后移植覆盖创面,电性失活骨质在血循环良好的皮瓣覆盖下,为周边及基底健康骨质生长起到支架作用,皮瓣扩张到一定面积后移植到裸露骨质上,使其得以修复。结果：在治疗的9例中,除1例皮瓣边缘在1．5cm×1．5cm坏死外,其余皮瓣全部成活,未发生感染坏死,创面均一次性封闭。结论：头皮电烧伤骨外露扩张后皮瓣带毛发修复,可缩短创面愈合时间,外形较好,易掌握,效果较为满意。     

Cirsoid aneurysms of the scalp

This study reviewed the surgical management of cirsoid aneurysms of the scalp, which are rarely encountered in the neurosurgical practice, and compares the results with embolization. 21 patients with cirsoid aneurysm underwent surgery. There were 1 female and 20 male patients. Trauma was present in four patients. Selective internal and external carotid artery angiograms and cranial magnetic resonance imaging studies were performed on all patients. All angiograms were staged according to published procedures. There were 15 (71.4%) Stage 1a, 4 (19.1%) Stage 1b, and 2 (9.5%) Stage 3 patients.Total excision of the lesion was achieved in 19 patients (90.5%). We operated on only one patient for a second time, because of a residual lesion, and we resected the lesion totally. Only two patients developed necrosis of the scalp (button hole). Both scalp necroses were on the frontal area. Other patients all had good cosmetic results. Surgical resection of cirsoid aneurysms seems to be the most effective treatment with good results. There may be a tendency for the occurrence of necrosis on the frontal area. Staging of the scalp aneurysms has no effect on surgical outcome.     

Supragaleal placement of tissue expander for post-burn alopecia.

Supragaleal placement of tissue expander for management of alopecia of scalp excludes tough galeal layer so that easier and faster expansion of scalp may be achieved.     

High‐frequency oscillations: The state of clinical research

Modern electroencephalographic (EEG) technology contributed to the appreciation that the EEG signal outside the classical Berger frequency band contains important information. In epilepsy, research of the past decade focused particularly on interictal high‐frequency oscillations (HFOs) > 80 Hz. The first large application of HFOs was in the context of epilepsy surgery. This is now followed by other applications such as assessment of epilepsy severity and monitoring of antiepileptic therapy. This article reviews the evidence on the clinical use of HFOs in epilepsy with an emphasis on the latest developments. It highlights the growing literature on the association between HFOs and postsurgical seizure outcome. A recent meta‐analysis confirmed a higher resection ratio for HFOs in seizure‐free versus non–seizure‐free patients. Residual HFOs in the postoperative electrocorticogram were shown to predict epilepsy surgery outcome better than preoperative HFO rates. The review further discusses the different attempts to separate physiological from epileptic HFOs, as this might increase the specificity of HFOs. As an example, analysis of sleep microstructure demonstrated a different coupling between HFOs inside and outside the epileptogenic zone. Moreover, there is increasing evidence that HFOs are useful to measure disease activity and assess treatment response using noninvasive EEG and magnetoencephalography. This approach is particularly promising in children, because they show high scalp HFO rates. HFO rates in West syndrome decrease after adrenocorticotropic hormone treatment. Presence of HFOs at the time of rolandic spikes correlates with seizure frequency. The time‐consuming visual assessment of HFOs, which prevented their clinical application in the past, is now overcome by validated computer‐assisted algorithms. HFO research has considerably advanced over the past decade, and use of noninvasive methods will make HFOs accessible to large numbers of patients. Prospective multicenter trials are awaited to gather information over long recording periods in large patient samples.     

Fast and effective removal of contamination from scalp electrical recordings

ObjectiveTo present a new, automated and fast artefact-removal approach which significantly reduces the effect of contamination in scalp electrical recordings.MethodWe used spectral and temporal characteristics of different sources recorded during a typical scalp electrical recording in order to improve a fast and effective artefact removal approach. Our experiments show that correlation coefficient and spectral gradient of brain components differ from artefactual components. We trained two binary support vector machine classifiers such that one separates brain components from muscle components, and the other separates brain components from mains power and environmental components. We compared the performance of the proposed approach with seven currently used alternatives on three datasets, measuring mains power artefact reduction, muscle artefact reduction and retention of brain neurophysiological responses.ResultsThe proposed approach significantly reduces the main power and muscle contamination from scalp electrical recording without affecting brain neurophysiological responses. None of the competitors outperformed the new approach.ConclusionsThe proposed approach is the best choice for artefact reduction of scalp electrical recordings. Further improvements are possible with improved component analysis algorithms.SignificanceThis paper provides a definitive answer to an important question: Which artefact removal algorithm should be used on scalp electrical recordings?     

Source imaging of seizure onset predicts surgical outcome in pediatric epilepsy

ObjectiveTo assess whether ictal electric source imaging (ESI) on low-density scalp EEG can approximate the seizure onset zone (SOZ) location and predict surgical outcome in children with refractory epilepsy undergoing surgery.MethodsWe examined 35 children with refractory epilepsy. We dichotomized surgical outcome into seizure- and non-seizure-free. We identified ictal onsets recorded with scalp and intracranial EEG and localized them using equivalent current dipoles and standardized low-resolution magnetic tomography (sLORETA). We estimated the localization accuracy of scalp EEG as distance of scalp dipoles from intracranial dipoles. We also calculated the distances of scalp dipoles from resection, as well as their resection percentage and compared between seizure-free and non-seizure-free patients. We built receiver operating characteristic curves to test whether resection percentage predicted outcome.ResultsResection distance was lower in seizure-free patients for both dipoles (p = 0.006) and sLORETA (p = 0.04). Resection percentage predicted outcome with a sensitivity of 57.1% (95% CI, 34–78.2%), a specificity of 85.7% (95% CI, 57.2–98.2%) and an accuracy of 68.6% (95% CI, 50.7–83.5%) (p = 0.01).ConclusionIctal ESI performed on low-density scalp EEG can delineate the SOZ and predict outcome.SignificanceSuch an application may increase the number of children who are referred for epilepsy surgery and improve their outcome.