Wavelet-based sparse functional linear model with applications to EEGs seizure detection and epilepsy diagnosis

In epilepsy diagnosis or epileptic seizure detection, much effort has been focused on finding effective combination of feature extraction and classification methods. In this paper, we develop a wavelet-based sparse functional linear model for representation of EEG signals. The aim of this modeling approach is to capture discriminative random components of EEG signals using wavelet variances. To achieve this goal, a forward search algorithm is proposed for determination of an appropriate wavelet decomposition level. Two EEG databases from University of Bonn and University of Freiburg are used for illustration of applicability of the proposed method to both epilepsy diagnosis and epileptic seizure detection problems. For this data considered, we show that wavelet-based sparse functional linear model with a simple classifier such as 1-NN classification method leads to higher classification results than those obtained using other complicated methods such as support vector machine. This approach produces a 100 % classification accuracy for various classification tasks using the EEG database from University of Bonn, and outperforms many other state-of-the-art techniques. The proposed classification scheme leads to 99 % overall classification accuracy for the EEG data from University of Freiburg.     

Pituicytoma: Report of three cases with review of literature

Pituicytoma is a rare low-grade tumor (WHO Grade I) of pituicytes involving the sellar–suprasellar region, and originating from the specialized glial cells of the neurohypophysis. Clinically and radiologically, they closely mimic pituitary adenoma or meningioma. Diagnosis requires histopathological examination of the resected tissue. This uncommon glial neoplasm is a rarity, with only 57 cases reported in the literature so far. We report three cases of pituicytoma (aged between 7 and 24 years) presenting with reduced vision, headache and features of hypercortisolism in one case. Radiologically, these lesions mimicked meningioma, hypothalamic chiasmatic glioma and pituitary microadenoma, respectively. The second case is a 7-year-old girl, the youngest case on record. Since this tumor is uncommon, it is frequently misdiagnosed. Awareness of this entity is essential for planning management and treatment. We present a brief review of all cases reported in the medical literature, and describe the clinical symptomatology, associated endocrinological abnormalities, imaging characteristics, behavior and outcome.     

Accumulation of neurofibrillary tangles and activated microglia is associated with lower neuron densities in the aphasic variant of Alzheimer’s disease

The neurofibrillary tangles (NFT) and amyloid‐ß plaques (AP) that comprise Alzheimer’s disease (AD) neuropathology are associated with neurodegeneration and microglial activation. Activated microglia exist on a dynamic spectrum of morphologic subtypes that include resting, surveillant microglia capable of converting to activated, hypertrophic microglia closely linked to neuroinflammatory processes and AD neuropathology in amnestic AD. However, quantitative analyses of microglial subtypes and neurons are lacking in non‐amnestic clinical AD variants, including primary progressive aphasia (PPA‐AD). PPA‐AD is a language disorder characterized by cortical atrophy and NFT densities concentrated to the language‐dominant hemisphere. Here, a stereologic investigation of five PPA‐AD participants determined the densities and distributions of neurons and microglial subtypes to examine how cellular changes relate to AD neuropathology and may contribute to cortical atrophy. Adjacent series of sections were immunostained for neurons (NeuN) and microglia (HLA‐DR) from bilateral language and non‐language regions where in vivo cortical atrophy and Thioflavin‐S‐positive APs and NFTs were previously quantified. NeuN‐positive neurons and morphologic subtypes of HLA‐DR‐positive microglia (i.e., resting [ramified] microglia and activated [hypertrophic] microglia) were quantified using unbiased stereology. Relationships between neurons, microglia, AD neuropathology, and cortical atrophy were determined using linear mixed models. NFT densities were positively associated with hypertrophic microglia densities (P < 0.01) and inversely related to neuron densities (P = 0.01). Hypertrophic microglia densities were inversely related to densities of neurons (P < 0.01) and ramified microglia (P < 0.01). Ramified microglia densities were positively associated with neuron densities (P = 0.02) and inversely related to cortical atrophy (P = 0.03). Our findings provide converging evidence of divergent roles for microglial subtypes in patterns of neurodegeneration, which includes hypertrophic microglia likely driving a neuroinflammatory response more sensitive to NFTs than APs in PPA‐AD. Moreover, the accumulation of both NFTs and activated hypertrophic microglia in association with low neuron densities suggest they may collectively contribute to focal neurodegeneration characteristic of PPA‐AD.     

Characterization of fibrillar collagen isoforms in infarcted mouse hearts using second harmonic generation imaging

We utilized collagen specific second harmonic generation (SHG) signatures coupled with correlative immunofluorescence imaging techniques to characterize collagen structural isoforms (type I and type III) in a murine model of myocardial infarction (MI). Tissue samples were imaged over a four week period using SHG, transmitted light microscopy and immunofluorescence imaging using fluorescently-labeled collagen antibodies. The post-mortem cardiac tissue imaging using SHG demonstrated a progressive increase in collagen deposition in the left ventricle (LV) post-MI. We were able to monitor structural morphology and LV remodeling parameters in terms of extent of LV dilation, stiffness and fiber dimensions in the infarcted myocardium.     

Improving postoperative pain management in subpectoral tissue expander implant reconstruction of the breast using an elastomeric pump

IntroductionPostoperative pain after breast surgery is one of the major factors contributing to delay in mobilisation and prolonged hospital stay. A retrospective analysis was performed of patients undergoing skin sparing mastectomy and insertion of a subpectoral implant. The aim was to determine whether the use of an elastomeric local anaesthetic pump improved pain control and length of stay.MethodsTwenty-five consecutive patients undergoing the above procedure were sited with an elastomeric local anaesthetic infusion pump intraoperatively, in addition to standard regular and pro re nata analgesia. The control group comprised 25 patients undergoing the same procedure in the same year who received standard analgesia alone. Visual analogue scale scores were recorded for the duration of inpatient stay, as was any further analgesic requirement.ResultsThe median age was 51 years (range: 26–75 years) in the intervention group and 50 years (range: 28–70 years) in the control group. The mean visual analogue scale score was 0.28 (standard deviation [SD]: 0.61) at 24 hours for the intervention group and 1.84 (SD: 0.37) for the control group (p<0.0001). The mean length of stay was 1.8 days (SD: 0.71 days) for the intervention group and 2.28 days (SD: 0.94 days) for the control group (p=0.15). There were no complications involving catheter placement, leakage or toxicity relating to use of the local anaesthetic.ConclusionsThere was significantly reduced pain with the use of the local anaesthetic infusion pump. The elastomeric pump is a step towards enhanced patient recovery after breast surgery in the case of skin sparing mastectomy and subpectoral tissue expander reconstruction.     

Effectiveness of medical thoracoscopy and thoracoscopic talc poudrage in patients with exudative pleural effusion

INTRODUCTION

This study aimed to assess the effectiveness of medical thoracoscopy (MT) and thoracoscopic talc poudrage (TTP) in patients with exudative pleural effusion.

METHODS

We evaluated the diagnostic yields, complications and outcomes of MT and TTP in 41 consecutive patients with symptomatic pleural effusions who were planned to undergo both procedures from 1 December 2011 to 30 November 2012. Data was reviewed retrospectively and prospectively up to March 2013.

RESULTS

Among the 41 patients, 36 underwent MT with the intent of biopsy and talc pleurodesis, 2 underwent MT for pleurodesis only and 3 had failed MT. Aetiologies of pleural effusion included lung cancer (n = 14), tuberculosis (n = 9), breast cancer (n = 7), ovarian cancer (n = 2), malignant mesothelioma (n = 1), congestive cardiac failure (n = 1), peritoneal dialysis (n = 1) and hepatic hydrothorax (n = 1); pleural effusion was undiagnosed in five patients. The overall diagnostic yield of MT, and the yield in tubercular and malignant pleural effusions were 77.8%, 100.0% and 82.6%, respectively; it was inconclusive in 22.2%. Complications that occurred were self-limiting, with no procedure-related mortality. The 30-day mortality rate was 17.1%. A total of 15 patients underwent TTP. The 30-, 60- and 90-day success rates were 77.8%, 80.0% and 80.0%, respectively, with one patient having complications (i.e. empyema). The 30-day mortality was 40.0%.

CONCLUSION

MT is a safe procedure with high diagnostic yields in undiagnosed pleural effusions. TTP is an effective method to stop recurrence of pleural effusions.