Dorsal Displacement of the Soft Palate Secondary to Persistent Frenulum of the Epiglottis in Neonatal Foal

Dorsal displacement of the soft palate (DDSP) usually occurs in athletic adult horses. Congenital DDSP in foals secondary to the persistent frenulum of the epiglottis is rarely observed. The aim of this report was to describe a case of a seven-day-old female neonate Quarter Horse presenting dysphagia, milk reflux through the nostrils and mouth, and expiratory dyspnea since 4 days. Thoracic auscultation was indicative of aspiration pneumonia. Diagnosis of DDSP associated with local inflammation was made after endoscopic examination of upper respiratory tract. Radiographic examination was performed to rule out hypoplasia of the epiglottis. No clinical improvement was observed after anti-inflammatory treatment with flunixin meglumine. Oral endoscopy under general anesthesia revealed that the displacement of the soft palate was caused by a persistent frenulum of the epiglottis. Using a 30° rigid endoscope and a curved laparoscopic scissors, the frenulum was transected. After surgery, no dysphagia or dyspnea at rest was observed. However, discreet respiratory noise persisted during exercise for 5 days postoperatively. After discharge, the owner reported that the animal was completely normal during exercise. The animal is currently 3 years old and is developing a normal athletic performance. Persistent frenulum of the epiglottis should be considered while examining neonates with nasal milk reflux associated with expiratory dyspnea. This case report emphasizes the importance of the differential diagnosis for DDSP and for DDSP secondary to the persistent frenulum of the epiglottis in neonatal foals. It also underlines the importance of oral endoscopic examination for diagnosis.

Characterization and reduction of cardiac- and respiratory-induced noise as a function of the sampling rate (TR) in fMRI

It has recently been shown that both high-frequency and low-frequency cardiac and respiratory noise sources exist throughout the entire brain and can cause significant signal changes in fMRI data. It is also known that the brainstem, basal forebrain and spinal cord areas are problematic for fMRI because of the magnitude of cardiac-induced pulsations at these locations. In this study, the physiological noise contributions in the lower brain areas (covering the brainstem and adjacent regions) are investigated and a novel method is presented for computing both low-frequency and high-frequency physiological regressors accurately for each subject. In particular, using a novel optimization algorithm that penalizes curvature (i.e. the second derivative) of the physiological hemodynamic response functions, the cardiac- and respiratory-related response functions are computed. The physiological noise variance is determined for each voxel and the frequency-aliasing property of the high-frequency cardiac waveform as a function of the repetition time (TR) is investigated. It is shown that for the brainstem and other brain areas associated with large pulsations of the cardiac rate, the temporal SNR associated with the low-frequency range of the BOLD response has maxima at subject-specific TRs. At these values, the high-frequency aliased cardiac rate can be eliminated by digital filtering without affecting the BOLD-related signal.