Human brain distinctiveness based on EEG spectral coherence connectivity.

The use of EEG biometrics, for the purpose of automatic people recognition, has received increasing attention in the recent years. Most of the current analyses rely on the extraction of features characterizing the activity of single brain regions, like power spectrum estimation, thus neglecting possible temporal dependencies between the generated EEG signals. However, important physiological information can be extracted from the way different brain regions are functionally coupled. In this study, we propose a novel approach that fuses spectral coherence-based connectivity between different brain regions as a possibly viable biometric feature. The proposed approach is tested on a large dataset of subjects (N = 108) during eyes-closed (EC) and eyes-open (EO) resting state conditions. The obtained recognition performance shows that using brain connectivity leads to higher distinctiveness with respect to power-spectrum measurements, in both the experimental conditions. Notably, a 100% recognition accuracy is obtained in EC and EO when integrating functional connectivity between regions in the frontal lobe, while a lower 97.5% is obtained in EC (96.26% in EO) when fusing power spectrum information from parieto-occipital (centro-parietal in EO) regions. Taken together, these results suggest that the functional connectivity patterns represent effective features for improving EEG-based biometric systems.

Objective measurement of motor speech characteristics in the healthy pediatric population.

OBJECTIVE: To obtain objective measurements of motor speech characteristics in normal children, using a computer-based motor speech software program. METHODS: Cross-sectional, observational design in a university-based ambulatory pediatric otolaryngology clinic. Participants included 112 subjects (54 females and 58 males) aged 4-18 years. Participants with previously diagnosed hearing loss, voice and motor disorders, and children unable to repeat a passage in English were excluded. Voice samples were recorded and analysed using the Motor Speech Profile (MSP) software (KayPENTAX, Lincoln Park, NJ). The MSP produced measures of diadochokinetics, second formant transition, intonation, and syllabic rates. RESULTS: Demographic data, including sex, age, and cigarette smoke exposure were obtained. Normative data for several motor speech characteristics were derived for children ranging from age 4 to 18 years. A number of age-dependent changes were indentified, including an increase in average diadochokinetic rate (p<0.001) and standard syllabic duration (p<0.001) with age. There were no identified differences in motor speech characteristics between males and females across the measured age range. Variations in fundamental frequency (Fo) during speech did not change significantly with age for both males and females. CONCLUSIONS: To our knowledge, this is the first pediatric normative database for the MSP progam. The MSP is suitable for testing children and can be used to study developmental changes in motor speech. The analysis demonstrated that males and females behave similarly and show the same relationship with age for the motor speech characteristics studied. This normative database will provide essential comparative data for future studies exploring alterations in motor speech that may occur with hearing, voice, and motor disorders and to assess the results of targeted therapies.

Nasopharyngeal polymorphous low-grade adenocarcinoma in a patient with nonfunctioning pituitary macroadenoma.

BACKGROUND: Polymorphous low grade adenocarcinoma (PLGA) is a rare malignant neoplasm of the minor salivary glands occurring in the fifth and sixth decade with a 2:1 female predominance. The nasal cavity is involved in less than 1% of cases. The incidence of clinically recognisable pituitary adenoma is 15 cases/million/year. The prevalence of non-functioning pituitary adenoma (NFPA) is estimated to be 70-90 cases/million. Both types of adenoma represent 20-45% of pituitary tumours. CASE REPORT: The report describes the first case of PLGA associated with NFPA, both incidentally diagnosed. Three months after the exeresis of the NFPA using a trans-sphenoidal approach, an endoscopic resection of the PLGA was performed. No recurrence was observed during a 13 months follow-up. CONCLUSIONS: Complete surgical excision is the preferred management for PLGA. Radiotherapy has not been demonstrated to be effective in treating PLGA. The prognosis is good with a very low rate of metastasis and local recurrence.

Acoustic analysis of voice in cochlear implant recipients with post-meningitic hearing loss.

The objective of this study was to evaluate the critical time period between the onset of sensorineural hearing loss and cochlear implantation with respect to normal voice production in children with post-meningitic hearing loss. Acoustic measures of voice production were obtained from ten paediatric cochlear implant recipients with post-meningitic hearing loss. Acoustic measures were obtained utilising the Multi-Dimensional Voice Program and Computerized Speech Laboratory (Kay Elemetrics Corp.). Measures were based on sustained phonation of the vowel /a/. Acoustic parameters included fundamental frequency, short- and long-term frequency perturbation, and short- and long-term amplitude perturbation. Measures of fundamental frequency and short-term frequency and amplitude perturbation were comparable to values of children with normal hearing. Long-term control of frequency was within normal limits for subjects with a period of auditory deprivation of less than four months. Measures of long-term amplitude perturbation were normal for all patients except those with cochlear ossification. Early restoration of auditory feedback with cochlear implantation, the absence of cochlear ossification, residual aided hearing following meningitis, and auditory-verbal therapy were identified as factors in preserving the long-term control of frequency and amplitude in the setting of post-meningitic hearing loss.

Fatal peri-operative acute tumour lysis syndrome precipitated by dexamethasone.

A 3-year-old patient presented for elective adenotonsillectomy to treat symptomatic obstructive sleep apnoea. The patient had not been assessed at a pre-operative anaesthesia clinic but had undergone uneventful general anaesthesia twice in the previous two years. An uneventful operative course was complicated by the development of clinical instability over the first 6 h postoperatively culminating in cardiorespiratory arrest. Subsequent investigation demonstrated the acute development of tumour lysis syndrome in the setting of a new onset, undiagnosed acute leukaemia. The patient died on the third postoperative day. The use of dexamethasone for prophylaxis against postoperative nausea and vomiting was the likely aetiology of the acute tumour lysis syndrome in this case. This is the first documented peri-operative death due to tumour lysis syndrome after administration of dexamethasone. We discuss the various problems encountered with this case and review the recent literature and case reports on tumour lysis syndrome in the operating theatre.

Accuracy of CT-guided transthoracic needle biopsy of lung lesions: factors affecting diagnostic yield.

PURPOSE: This study was performed to analyse the variables affecting the diagnostic accuracy of computed tomography (CT)-guided transthoracic needle biopsy of pulmonary lesions. MATERIALS AND METHODS: A retrospective study of 612 consecutive procedures with confirmed final diagnoses was undertaken. Benign and malignant needle biopsy results were compared with final outcomes to determine diagnostic accuracy. A statistical analysis of factors related to patient characteristics, lung lesions and biopsy technique was performed to determine possible influences on diagnostic yield. A p value less than 0.05 was interpreted as statistically significant. RESULTS: There were 508 (83%) malignant and 104 (17%) benign lesions. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for a diagnosis of malignancy were 90.2%, 99.0%, 99.8%, 67.3% and 91.7%, respectively. Overall diagnostic accuracy was 83.3%. Variables affecting diagnostic accuracy were the final diagnosis (benign 67%, malignant 92%; p<0.001) and lesion size (lesions<1.5 cm 68%, lesions 1.5-5.0 cm 87%, lesions>5 cm 78%; p<0.05). CONCLUSIONS: In CT-guided transthoracic needle biopsy, the final diagnosis and lesion size affect diagnostic accuracy: benign lung lesions and lesions smaller than 1.5 cm or larger than 5.0 cm in diameter provide lower diagnostic yield.

[On-site evaluation and triage for endoscopic ultrasound-guided fine needle aspiration cytology. The Turin experience]. / Valutazione on-site e triage per la citologia agoaspirativa sotto guida ecoendoscopica. L'esperienza torinese.

AIM: Evaluation of the importance of the on-site presence of a skilled cytopathologist during endoscopic ultrasound-guided fine needle aspiration at determining samples' adequacy and performing ancillary techniques which can be helpful for the diagnosis. METHODS: A retrospective analysis of our institute's experience with EUS-FNA sampling is presented. From January 2001 to May 2007, 404 patients underwent the EUS-FNA evaluation. From 2003 a cytopathologist was present during the procedure and started making an extemporary evaluation of the samples' adequacy. RESULTS: Before 2003, a final cytological diagnosis was available in only 70% of the cases (without an on-site cytopathologist). After 2003, in 90% of the cases (with an on-site cytopathologist). It is possible planning and performing: immunocytochemistry on cell block material including evaluation of the proliferation index; to obtain a sample for the flow cytometry in cases of lymphomas or a microbiologic workup in cases of infective lesions. CONCLUSION: The quality of the specimens and the proper handling of the aspirated sample are very important to succesfully obtain a definitive cytological diagnosis in EUS-FNA. On-site evaluation and triage of the material allow to improve the accuracy of the diagnosis.

The current state of congenital tracheal stenosis.

Congenital tracheal stenosis (CTS) is an uncommon condition that has challenged pediatric surgeons for decades. Patients with CTS can present with a wide spectrum of symptoms and varying degrees of severity. In addition, a variety of techniques have been devised to repair this malformation. A review of these procedures and our suggestions for clinical standards and practice guidelines will be presented in this paper. A retrospective review of the literature on CTS from 1964 to 31 March, 2006. There is not one standard technique for the repair of CTS, as individualized approach to each patient and airway lesion is necessary to optimize patient management; nevertheless there is a consensus about segmental resection and anastomosis being best for short segment stenosis while slide tracheoplasty is most effective for the long-segment ones. Conservative management is also an option for select group of patients with careful and close follow up. Survival following surgery over the years has improved, but mortality remained high, particularly in a specific subset of patients presenting at the age less than 1 month with associated cardiac malformations. In conclusion, CTS remains a significant challenge for pediatric surgeons. Additional research is required to improve our understanding of the pathogenesis of CTS, and to develop evidence-based treatment protocols for the entire spectrum of presentation including conservative management.

Severity of juvenile onset recurrent respiratory papillomatosis is not associated with socioeconomic status in a setting of universal health care.

BACKGROUND: Juvenile onset recurrent respiratory papillomatosis (JORRP) results from HPV transmission. Cervical cancer, also transmitted via HPV, is known to be correlated with socioeconomic status (SES). This study aims to determine if an association exists between SES and severity of JORRP. METHODS: Cross-sectional study of all active JORRP patients at the Hospital for Sick Children in Toronto in 2005. SES information from Hollingshead surveys, Postal walk Census data, and Low Income Cutoff Data were compared with Derkay-Wiatrak disease severity scores, peak annual surgical frequency, and age of diagnosis. Statistical analysis was performed using Spearman, Mann-Whitney, and linear regression analyses. RESULTS: Twenty-one patients were surveyed. Hollingshead results were as follows: two patients (10%) were class I (major business and professional); 11 patients (52%) were class II (medium business, minor professional, technical); 4 patients (19%) were class III (skilled craftsmen, clerical, sales workers); 4 patients (19%) were class IV (machine operators, semiskilled workers); 0% were from class V (unskilled laborers, menial service workers). Interestingly, based on postal code data nine patients (45%) were below the low income cutoff as compared to the Toronto (metropolitan) and Ontario (provincial) rates of low income (17% and 14%, respectively). There was significant correlation between each of the SES measures and between disease severity measures. However, analysis of the SES measures versus disease severity measures did not demonstrate any significant relationship. CONCLUSIONS: Though almost half the patients lived below the low income cutoff, this study did not demonstrate a significant correlation between socioeconomic status and severity of disease in JORRP. One possible explanation is that universal access to the Canadian health care system is able to provide support despite a large proportion of patients being socioeconomically vulnerable. A national level study is underway to further detect any relationship between SES and JORRP severity in the general population.

Mitek QuickAnchor fixation of cochlear implants using a minimal access technique.

RATIONALE: In children with thick cortical bone, surgical exposure for cochlear implant fixation is difficult when using a minimal access technique. We report our experience in these children using the Mitek QuickAnchor system. METHODS: A retrospective review of all children undergoing cochlear implantation over a 12-month period was performed to identify those children in which a Mitek QuickAnchor was used. Measurements of cortical bone thickness at the receiver-stimulator well site were obtained from pre-operative CT scans of temporal bones of all children. The application of the Mitek QuickAnchor system was also reviewed. RESULTS: Cochlear implant fixation using the Mitek QuickAnchor system was performed in 14 children (mean age 12 years) during the study period. The mean cortical bone thickness was 5.6mm in patients receiving the Mitek QuickAnchor system and 3.2mm in patients undergoing conventional fixation. The difference in cortical thickness was highly statistically significant. Successful secure fixation was obtained in all cases. CONCLUSIONS: The Mitek QuickAnchor system provides an effective method of cochlear implant fixation when using a minimal access technique in children with thick cortical bone.

Acoustic analysis of the voice in pediatric cochlear implant recipients: a longitudinal study.

OBJECTIVE: To characterize inherent acoustic abnormalities of the deaf pediatric voice and the effect of artificially restoring auditory feedback with cochlear implantation. DESIGN: Inception cohort. SETTING: Academic referral center. PATIENTS: Twenty-one children with severe to profound hearing loss (15 prelingually deaf, 6 postlingually deaf) accepted into the cochlear implant program were followed for up to 6 months. Patients unable to perform the vocal exercises were excluded. INTERVENTIONS: Objective voice analysis was performed using the Computerized Speech Laboratory (Kay Elemetrics) prior to cochlear implantation, at the time of implant activation and at 2 and 6 months postactivation. Assessments were based on sustained phonations and dynamic ranges. MAIN OUTCOME MEASURE: Fundamental frequency, long-term control of fundamental frequency (vF0) and long-term control of amplitude (vAM) were derived from sustained phonations. The dynamic frequency range was derived from scale exercises. Formant frequencies (F1, F2, F3) were determined using linear predictive coding. RESULTS: Fundamental frequency was not altered by implant activation or experience (P = 0.342). With profoundly deaf subject, the most prevalent acoustic abnormality was a poor long-term control of frequency (vF0, 2.81%) and long-term control of amplitude (vAm, 23.58%). Implant activation and experience had no effect on the long-term control of frequency (P = 0.106) but normalized the long-term control of amplitude (P = 0.007). The mean frequency range increased from 311.9 Hz preimplantation to 483.5 Hz postimplantation (P = 0.08). The F1/F2 ratio remained stable (P = 0.476). CONCLUSION: In children, severe to profound deafness results in poor long-term control of frequency and amplitude. Cochlear implantation restores control of amplitude only and implies the need for additional rehabilitative strategies for restoration of control of frequency.

Cochlear implant positioning in children: a survey of patient satisfaction.

INTRODUCTION: The past decade has been witness to significant diminution in incision size and placement for pediatric cochlear implantation at our institution. Furthermore, the orientation of the long axis of the implant relative to the skull base plane has generally evolved from a retro-verted to ante-verted direction to accommodate the ear level receiver stimulator and the new minimal access technique. OBJECTIVE: To characterize the cosmetic, functional and clinical implications of this evolution in cochlear implant positioning by means of a patient satisfaction survey. METHODS: A survey of patient satisfaction was administered to 100 cochlear implant recipients or their parents. The survey elicits the patient's level of satisfaction with respect to implant position and functional limitations. In addition, the angle formed by the long axis of the implant and the skull base plane (implant angle) was determined from lateral skull radiographs to detect the temporal evolution in implant positioning. RESULTS: Analysis of the radiographs revealed an implant angle of 65.4-125 degrees in patients implanted prior to 1997, an implant angle of 56.3-87.5 degrees in patients implanted from 1997 to 2001, and an implant angle of 35.1-78.1 degrees after 2002. In spite of this evolution in positioning, the patient satisfaction survey did not reveal any change in incidence of cosmetic, functional or clinical problems. DISCUSSION: The significant changes in incision and implant positioning represent a technical evolution in pediatric cochlear implant surgery. The fact that patients have been consistently satisfied over time suggests that the cosmetic, functional and clinical implications are minimal.

Hyalinizing trabecular adenoma versus papillary thyroid carcinoma in a child.

Hyalinizing trabecular adenoma (HTA) of the thyroid gland is a rare, benign neoplasm predominantly diagnosed in middle-aged women. There is mounting evidence in the medical literature, however, to suggest that HTA may represent an encapsulated variant of papillary thyroid carcinoma (PTC). This report describes an unusual case of PTC in a child initially diagnosed as HTA. Establishing an accurate diagnosis has important management implications for the pediatric patient.

Sequential parapharyngeal abscesses.

Deep neck infections are not unusual in either the pediatric or adult populations. Multiple, and recurrent abscesses are found not infrequently, especially in immunocompromised and debilitated persons. It is very rare to find sequential parapharyngeal abscesses without identifiable etiology in an otherwise healthy pediatric patient while receiving appropriate, culture-directed, intravenous antibiotics. This could be due to underestimation of the extent of the infection by CT scanning. The use of intravenous clindamycin as a first-line therapy may not be sufficient if a large phlegmon exists. We describe a case of sequential, bilateral parapharyngeal abscesses in a 3-year-old patient.

MultiDimensional Voice Program analysis in children with vocal cord nodules.

Computer-assisted voice analysis has recently been introduced as a noninvasive approach to the management of paediatric dysphonia. The aim of this study was to determine which parameters of voice analysis distinguish vocal cord nodules from normal patterns. Following diagnosis by flexible nasolaryngoscopy, 12 male children with vocal cord nodules, aged 7 to 12, underwent voice analysis by MultiDimensional Voice Program (MDVP; Kay Elemetrics, Lincoln Park, NJ, USA). These subjects were divided into two age groups (7-9 years, n = 5; 10-12 years, n = 7) and compared to age-matched controls. Results suggest that across all age groups, subjects with vocal cord nodules had statistically significant (p < .01) elevations in absolute jitter, jitter percent, relative average perturbation, pitch period perturbation quotient, smoothed amplitude perturbation quotient, and fundamental frequency variation. Further studies are required to assess the role of MDVP in the diagnosis of other voice pathologies and the monitoring of voice therapy.

Foreign body aspiration following unconventional use of a metered dose inhaler.

PURPOSE: Aspiration of a foreign body may be life-threatening. This report describes laryngeal obstruction after inhalation of a piece of a Turbuhaler which resulted from a patient tampering with the device. CLINICAL FEATURES: A 27-yr-old man disassembled a Turbuhaler and inadvertently aspirated a plastic dispensing medication disc (22 mm diameter) while attempting to inhale the remnant terbutaline sulfate which accumulated on it. Although the patient was hoarse, he was not in acute respiratory distress. X-ray revealed the disc lodged in the larynx below the vocal cords. The patient was immediately transferred to an operating theatre, and a drying agent (glycopyrrolate), judicious sedation (midazolam and fentanyl) and O2 were administered. The airway was anesthetized with lidocaine 4% delivered using high-flow O2 through an atomizer. Direct laryngoscopy revealed a partially obstructed view of the disc lodged distal to the vocal cords which was inaccessible for retrieval. Loss of consciousness was subsequently induced by spontaneous mask ventilation with sevoflurane (in O2). The airway was visualized using a suspension laryngoscope and the foreign body was removed with grasping forceps. The patient was awakened, transferred to the ICU and given 4 mg decadron i.v. every eight hours (two doses). Laryngoscopy prior to discharge indicated good mobility of the vocal cords and normal glottic structure. CONCLUSION: Aspiration of a foreign body is a potentially life-threatening situation requiring coordination between anesthesiologist, surgeon, and nursing staff. Anesthetic goals include avoidance of upper airway obstruction and maintenance of adequate ventilation while the foreign body is retrieved. Provisions must be made for tracheostomy if these goals cannot be realized.

Reduced complexity modeling and reproduction of colored textures.

An unsupervised color texture synthesis-by analysis method is described. The texture is reproduced to appear perceptually similar to a given prototype by copying its statistical properties up to the second order. The synthesized texture is obtained at the output of a single-input three-output nonlinear system driven by a realization of a white Gaussian random field. Significant complexity reduction is gained by exploiting the rank deficiency of the cross power spectral density matrix of the color texture samples.

A perceptually lossless, model-based, texture compression technique.

In natural scenes, still images as well as sequences, backgrounds, and objects' surfaces usually have a textural structure. Therefore, in order to efficiently code images it is crucial to investigate the texture compression problem. In this paper, a perceptually lossless, synthesis-by-analysis texture coding method is presented. The proposed approach is model based; the parameters of the model consist of a binary excitation signal and the parsimonious representation of the reconstruction filter. The estimated parameters, which allow to one synthesize, at the decoder site, a texture that is perceptually indistinguishable from the original one, are then compressed using a lossless strategy, which is based on a fast binary wavelet transformation specifically tailored to binary images. The proposed method leads to very good perceptual results superior to those of existing techniques.