Parent – environmental interactions shape acoustic signatures in tree swallows: a cross-fostering experiment.

Acoustic signatures are common components of avian vocalizations and are important for the recognition of individuals and groups. The proximate mechanisms by which these signatures develop are poorly understood, however. The development of acoustic signatures in nestling birds is of particular interest, because high rates of extra-pair paternity or egg dumping can cause nestlings to be unrelated to at least one of the adults that are caring for them. In such cases, nestlings might conceal their genetic origins, by developing acoustic signatures through environmental rather than genetic mechanisms. In a cross-fostering experiment with tree swallows Tachycineta bicolor, we investigated whether brood signatures of nestlings that were about to fledge were attributable to their genetic/maternal origins or to their rearing environment. We found that the calls of cross-fostered nestlings did not vary based on their genetic/maternal origin, but did show some variation based on their rearing environment. Control nestlings that were not swapped, however, showed stronger brood signatures than either experimental group, suggesting that acoustic signatures develop through an interaction between rearing environment and genetic/maternal effects.

Swallowing Activity Assessed by Ambulatory Impedance-pH Monitoring Predicts Awake and Asleep Periods at Night

INTRODUCTION: Voluntary muscle activity, including swallowing, decreases during the night. The association between nocturnal awakenings and swallowing activity is under-researched with limited information on the frequency of swallows during awake and asleep periods. AIM: The aim of this study was to assess nocturnal swallowing activity and identify a cut-off predicting awake and asleep periods. METHODS: Patients undergoing impedance-pH monitoring as part of GERD work-up were asked to wear a wrist activity detecting device (Actigraph(®)) at night. Swallowing activity was quantified by analysing impedance changes in the proximal esophagus. Awake and asleep periods were determined using a validated scoring system (Sadeh algorithm). Receiver operating characteristics (ROC) analyses were performed to determine sensitivity, specificity and accuracy of swallowing frequency to identify awake and asleep periods. RESULTS: Data from 76 patients (28 male, 48 female; mean age 56 ± 15 years) were included in the analysis. The ROC analysis found that 0.33 sw/min (i.e. one swallow every 3 min) had the optimal sensitivity (78 %) and specificity (76 %) to differentiate awake from asleep periods. A swallowing frequency of 0.25 sw/min (i.e. one swallow every 4 min) was 93 % sensitive and 57 % specific to identify awake periods. A swallowing frequency of 1 sw/min was 20 % sensitive but 96 % specific in identifying awake periods. Impedance-pH monitoring detects differences in swallowing activity during awake and asleep periods. Swallowing frequency noticed during ambulatory impedance-pH monitoring can predict the state of consciousness during nocturnal periods

Inter-observer agreement for diagnostic classification of esophageal motility disorders defined in high-resolution manometry

High-resolution esophageal manometry (HRM) is a recent development used in the evaluation of esophageal function. Our aim was to assess the inter-observer agreement for diagnosis of esophageal motility disorders using this technology. Practitioners registered on the HRM Working Group website were invited to review and classify (i) 147 individual water swallows and (ii) 40 diagnostic studies comprising 10 swallows using a drop-down menu that followed the Chicago Classification system. Data were presented using a standardized format with pressure contours without a summary of HRM metrics. The sequence of swallows was fixed for each user but randomized between users to avoid sequence bias. Participants were blinded to other entries. (i) Individual swallows were assessed by 18 practitioners (13 institutions). Consensus agreement (≤2/18 dissenters) was present for most cases of normal peristalsis and achalasia but not for cases of peristaltic dysmotility. (ii) Diagnostic studies were assessed by 36 practitioners (28 institutions). Overall inter-observer agreement was 'moderate' (kappa 0.51) being 'substantial' (kappa > 0.7) for achalasia type I/II and no lower than 'fair-moderate' (kappa >0.34) for any diagnosis. Overall agreement was somewhat higher among those that had performed >400 studies (n = 9; kappa 0.55) and 'substantial' among experts involved in development of the Chicago Classification system (n = 4; kappa 0.66). This prospective, randomized, and blinded study reports an acceptable level of inter-observer agreement for HRM diagnoses across the full spectrum of esophageal motility disorders for a large group of clinicians working in a range of medical institutions. Suboptimal agreement for diagnosis of peristaltic motility disorders highlights contribution of objective HRM metrics.

The contribution of intrabolus pressure to symptoms induced by gastric banding

BACKGROUND & AIMS Mechanisms that ultimately lead to dysphagia are still not totally clear. Patients with laparoscopic gastric banding (LAGB) often complain about dysphagia, regurgitation and heartburn. Our aim was to evaluate the contribution of intrabolus pressure to symptoms of gastric banding. METHODS This study investigated 30 patients with LAGB before and 3 months after conversion to Roux-en-Y gastric bypass (RYGB), evaluating symptoms with a 7-point-Likert-scale and esophageal peristalsis, esophageal bolus transit and intrabolus pressure changes using combined impedance-manometry. RESULTS Conversion from LAGB to RYGB leads to a significant reduction in dysphagia (1.9 +/- 0.4 vs. 0.0 +/- 0.0; p< 0.01) and regurgitation (4.2 +/- 0.4 vs. 0.1 +/- 0.1; p< 0.01) symptom scores. For liquid swallows we found a modest but significant correlation between the intensity of dysphagia and intrabolus pressure (r=0.11; p<0.05) and the intensity of regurgitation and intrabolus pressure for viscous swallows (r=0.12, p<0.05) in patients with LAGB. There was a significant (p< 0.05) reduction in intrabolus pressure at 5 cm above LES before (liquid 10.6 +/-1.0; viscous 13.5 +/- 1.5) and after (liquid 6.4 +/- 0.6; viscous 10.5 +/- 0.9) conversion from LAGB to RYGB. CONCLUSION Current data suggest that intraesophageal pressure during bolus presence in the distal esophagus contributes to the development but not to the intensity of dysphagia and regurgitation.

Characteristics of Consecutive Esophageal Motility Diagnoses After a Decade of Change

BACKGROUND AND AIMS Combined multichannel intraluminal impedance and esophageal manometry (MII-EM) measures concomitantly bolus transit and pressure changes allowing determination of the functional impact of esophageal motility abnormalities. Ten years ago our laboratory reported MII-EM results in 350 consecutive patients. Since then high-resolution impedance manometry (HRIM) became available and the definitions of ineffective esophageal motility (IEM) and nutcracker esophagus were revised. The aim of this study was to assess the impact of these developments on esophageal function testing. METHODS From August 2012 through May 2013, HRIM was performed in 350 patients referred for esophageal function testing. Each patient received 10 liquid and 10 viscous swallows. While taking advantage of the new technology and revised criteria, HRIM findings were classified according to the conventional criteria to allow more appropriate comparison with our earlier analysis. RESULTS Compared with the study performed 10 years ago, the prevalence of normal manometry (36% vs. 35%), achalasia (7% vs. 8%), scleroderma (1% vs. 1%), hypertensive lower esophageal sphincter (LES) (7% vs. 7%), and hypotensive LES (1% vs. 2%) remained the same, whereas the prevalence of distal esophageal spasm (9% vs. 3%), nutcracker esophagus (9% vs. 3%), and poorly relaxing LES (10% vs. 3%) decreased and the prevalence of IEM increased (20% vs. 31%) significantly. Compared with the early study, normal liquid bolus transit was significantly different in patients with hypertensive LES (96% vs. 57%) and poorly relaxing LES (55% vs. 100%). CONCLUSIONS This study brings to light the increase in prevalence of IEM. In addition, it suggests that the hypertensive LES and poorly relaxing LES may each affect bolus transit in about half of these patients.