An algorithm for real-time extraction of population EPSP and population spike amplitudes from hippocampal field potential recordings

A new method is presented for extracting the amplitude of excitatory post synaptic potentials (EPSPs) and spikes in real time. It includes a low pass filter (LPF), a differentiator, a threshold function, and an intelligent integrator. It was applied to EPSP and population spike data recorded in the Dentate Gyrus and the CA1 hippocampus in vitro. The accuracy of the extraction algorithm was evaluated via the extraction normalized mean square error (eNMSE) and was found to be very high (eNMSE < 5%). The preservation of neuronal information was confirmed using the Volterra-Poisson modeling approach. Volterra-Poisson kernels were computed using amplitudes extracted with both proposed and traditional methods. The accuracy of the computed kernels and the resulting model was evaluated via the prediction normalized mean square error (pNMSE) and was found to be very high (pNMSE < 5%). The similarity between the kernels computed when the proposed method was used to extract the field potential amplitude and their counterparts when the traditional method was used to extract the field potential amplitude confirms the preservation of the neuronal dynamics. The proposed method represents a new class of real time field potential amplitude extraction algorithms with complexity that can be included in hardware implementations.     

Management of hydrocephalus in posterior fossa tumors: how,what, when?

Object The aim of this work is to analyze the current management of hydrocephalus associated with posterior fossa (PF) tumors.Methods The personal perspectives of experienced pediatric neurosurgeons were presented at a virtual round table.Discussion Preoperative hydrocephalus has been reported in about 80% of patients with PF tumors and postoperative treatment is required for persistent or progressive hydrocephalus in about 25–30% of the cases. Preoperative management includes external ventricular drainage (EVD), endoscopic third ventriculostomy (ETV), shunt insertion, and no treatment at all, while ETV and ventriculo-peritoneal (V-P) shunt are recommended as treatment after PF craniotomy.Conclusion There is no consensus on the way hydrocephalus should be managed before, during, and after PF surgery. While awaiting prospective multicenter trials of various management schemes the perioperative management of hydrocephalus in the context of posterior fossa tumors should be considered as options.     

Neonatal hearing loss in the indigent

OBJECTIVE: To compare the risk factor profile for neonatal hearing loss (HL), and the follow-up rate of those identified with HL in an indigent population with those in an insured population. STUDY DESIGN: Retrospective review. METHODS: We studied 4526 neonates from the high-risk nursery or neonatal intensive care unit from two adjacent hospitals in Houston, Texas. Ben Taub General Hospital (BTGH) is a county public hospital that serves mainly the indigent. Texas Children's Hospital (TCH) is a private tertiary care center that serves patients with private insurance and Medicaid. RESULTS: Overall, 133 infants failed the screening test. Follow-up diagnostic testing identified 48 patients with definite HL. Although nearly twice as many patients at BTGH failed screening compared with TCH (88 vs. 45), four times as many patients at BTGH did not return for diagnostic testing (43 vs. 10). When a hearing aid was needed, there was a delay in getting one at BTGH (P <.05). There was a higher prevalence of dysmorphic facial features and central nervous system disease and a lower prevalence of long-term ventilatory support at BTGH (P <.05). There were no differences between BTGH and TCH in the prevalence of low birth weight, neonatal asphyxia, syndromic stigmata, neonatal infection, family history of HL, or neonatal transfusion (P >.1). CONCLUSIONS: Significant differences in the risk factor profile for neonatal HL exist between the indigent and the general population. A worrisome problem exists with the timely intervention in hearing-impaired indigent neonates.     

Intestinal obstruction and perforation--the role of the surgeon

Intestinal obstruction and perforation are always a challenge for the surgeon, not only in respect to the surgical option offered to the patient, but also to the ability to accurately diagnose and stage the disease. The understanding of the underlying pathophysiological mechanism is also very important in order to classify each patient in order to receive the more appropriate treatment. Mechanisms of obstruction and perforation, methods of diagnosis as well as prevention and treatment of the disease were reviewed.     

Neuropsychological testing in the screening for cochlear implant candidacy

OBJECTIVE: To demonstrate the utility of neuropsychological assessment in the screening process for pediatric cochlear implant candidacy. STUDY DESIGN: Prospective and ongoing evaluation of children with profound bilateral hearing loss using age-specific neuropsychological test batteries. METHODS: Eighteen children who met audiological criteria for cochlear implantation were evaluated by two age-specific neuropsychological tests. The Vineland Adaptive Behavior Scales survey assesses several domains of behavioral functions (communication, daily living skills, socialization, and gross motor skills). The Mullen Scales of Early Learning assesses the child's visual perception, speech and language, and motor abilities. The Leiter International Performance Scale-Revised assesses intellectual ability. RESULTS: All patients underwent the Vineland Adaptive Behavior Scales survey. Overall scores were lower than normative means with a mean composite score in the 7th percentile. In addition, there was a strong inverse correlation between score and age of testing. Ten children were assessed using the Mullen Scales of Early Learning, and, again, there was a strong inverse correlation between score and age of testing. Intellectual ability was assessed in seven children using the Leiter International Performance Scale-Revised and was found to be lower than normative means with a mean score in the 13th percentile. CONCLUSIONS: Neuropsychological testing of profoundly deaf children provides a detailed and accurate assessment of the child's cognitive, behavioral, and motor functions. The profoundly deaf child does not develop at the same rate as normal children in cognitive and behavioral domains. Neuropsychological testing is a useful tool for screening for cochlear implant candidacy and has the potential to track changes before and after implantation.     

Bowel preparation increases the diagnostic yield of capsule endoscopy: a prospective, randomized, controlled study

BACKGROUND: The aim of this study was to determine the value of small-bowel preparation for patients undergoing capsule endoscopy. METHODS: The study design was prospective, randomized, and controlled. Eighty patients referred for capsule endoscopy were randomized into two equal groups. Patients in Group A (mean age 54.40 [15.65] years) ingested 2 L of a polyethylene glycol/electrolyte solution 16 hours before the test, whereas patients in Group B (mean age 59.85 [14.58] years) prepared for the procedure by taking only clear liquids during the prior day. The primary outcome evaluated was the effect of bowel preparation on the quality of capsule images, as assessed with an objective scoring system in which cleansing was graded as "adequate" or "inadequate" by blinded examiners. A secondary outcome was the effect of bowel preparation on diagnostic yield. For this purpose, the results of capsule endoscopy were classified as positive findings, findings of uncertain significance, and no findings. RESULTS: Cleansing of the small intestine was considered "adequate" in 36 patients in Group A (90%) vs. 24 patients of Group B (60%) (p = 0.004). A diagnosis was established in 26 patients in Group A (65%) compared with 12 patients in Group B (30%) (p = 0.003). CONCLUSIONS: Bowel preparation before capsule endoscopy improves visualization of the small intestine, which may lead to an improvement in diagnostic yield.