S92 Abstracts of the 20 th National Congress of Digestive Diseases / Digestive and Liver Disease 46S (2014) S1–S144 basal impedance may reflect impaired mucosal integrity and increased acid sensitivity. We compared baseline impedance levels in patients with heart- burn and pathophysiological characteristics related to functional heartburn (FH) divided into two groups on the basis of symptom relief after proton pump inhibitors (PPIs). Moreover, we aimed to compare these results with a group of patients affected by hypersensitive esophagus (HE) and with healthy volunteers (HVs). Material and methods: Patients with heartburn and negative endoscopy were treated with PPI 40 mg daily for 8 weeks. According to MII-pH (off-therapy) analysis, patients with normal acid exposure time (AET), normal reflux num- ber and lack of association between symptoms and refluxes were selected. Out of them, 30 patients with a symptom relief higher than 50% after PPIs composed Group A, and 30 patients, matched for sex and age, without symp- tom relief composed FH group. Moreover, 30 patients with normal AET and reflux number but positive correlation between symptoms and refluxes (HE) and 20 HVs were enrolled. For each patient and HVs, we evaluated baseline impedance levels at channel 3, during the overnight rest, at three different times and PSPW index. Results: Data are summarized in the Table. Compared to FH group, Group A showed a higher mean AET (1.4%±0.8 vs 0.5%±0.6, p<0.05), mean reflux number (30.4±8.7 vs 24±6.9, p<0.05), and acid reflux number (17.9±6.1 vs 10.7±6.9, p<0.05). Patients with HE showed mean AET (1.8%±0.8) and total reflux number (34.4±8.2) similar to those recorded in Group A (p=ns). Baseline impedance levels were lower in Group A and in patients with HE then in FH and in HVs (p<0.001). PSPW index was similar between Group A and HE (p=ns). Conclusions: Patients with negative MII-pH studies who respond to PPI therapy present similar MII-pH features of patients with HE. Measuring esophageal baseline impedance levels in these patients might allow to identify reflux patients who are not confirmed by MII-pH monitoring likely due the day-to-day variability or the limitations of the current reflux-symptom association indexes. P.10.22 EVALUATION OF SLEEP DISRUPTIONS BY MEANS OF IMPEDANCE-PH MONITORING IN PATIENTS WITH NERD N. De Bortoli *,1 , I. Martinucci 1 , E. Savarino 2 , R. Franchi 1 , S. Russo 1 , L. Bertani 1 , M.T. Urbano 1 , M. Furnari 3 , M. Bellini 1 , V. Savarino 3 , S. Marchi 1 1 Gastroenterology Unit, University of Pisa, Pisa, Italy; 2 Gastroenterology Unit, University of Padova, Padova, Italy; 3 Gastroenterology Unit, University of Genova, Genova, Italy Background and aim: Gastroesophageal reflux disease (GERD) adversely impacts on sleep, representing a major cause of disrupted sleep mainly due to reflux symptoms. This may lead to a impaired quality of life. Impedance and pH monitoring (MII-pH) is the gold standard technique for GERD diagnosis. During the sleep period, impedance values remain stable unless the occurrence of arousals. We aimed to evaluate sleep disruptions in patients with heartburn and negative endoscopy by means of MII-pH. Material and methods: A group (33) of endoscopy negative patients with heartburn underwent MII-pH and were classified accordingly: 18 with non- erosive reflux disease (NERD) (i.e., pathological acid exposure time, AET); 15 with functional heartburn (FH) (i.e., normal AET and reflux number, negative symptom association). MII-pH tracings were reviewed manually using a 5-min window. During recumbent time, we identified sleep disruptions when at least 2 swallows were observed in a 5-min window. This data was evaluated in each group. We also calculated the overnight swallowing breaking sleep (OSBS) index (i.e., number of windows with swallows/total number of 5-min windows during the sleep period). All patients performed a validated questionnaire to assess the quality of sleep. Results: Male/female ratio was 7/11 in NERD and 3/12 in FH patients. Mean age was 51.3±12.4 in NERD and 49.3±9.7 in FH. The quality of a restful sleep was 64.3±8.3% in NERD and 67.3±7.8% in FH (p=0.299). Mean AET was higher in NERD (5.4±0.4) than in FH (0.4±0.4) (p<0.05). NERD group recorded higher total reflux number and acid reflux number (p<0.05). The total recumbent time was 541.4±64.7 min in NERD and 547.3±59.3 min in FH (p=0.39). During the sleep period, NERD patients recorded higher reflux number (9.8±8.7) than FH patients (0.6±0.9) (p<0.05). Moreover, the total number of 5-min windows presenting at least 2 swallows was higher in NERD patients (49.7±6.4) compared to those with FH (27±5.3; p<0.01). The OSBS index was 46.2±4.0 in NERD and 25.3±5.5 in FH (p=0.023). Conclusions: The manual analysis of the MII-pH tracings during the recum- bent period might be useful to estimate sleep disruptions in patients with NERD, thus helping to identify those patients in whom GERD is perceived more severe and quality of life is much more impaired. P.10.23 THE EFFECT OF GLUTEN ON GALLBLADDER AND GASTRIC EMPTYING IN HEALTHY VOLUNTEERS M. Di Stefano, C. Mengoli, P. Formagnana, M. Bergonzi * , A. Zanaboni, M. De Amici, G. Carnevale Maffè, G. Marseglia, G.R. Corazza IRCCS S. Matteo Hospital Foundation, Pavia, Italy Background and aim: The physiopathology of Non Celiac Gluten Sensitivity (NCGS) is largely unknown and few data are available on the effect of gluten on sensorimotor activity of the gastrointestinal (GI) tract. It was previously shown that gluten powder may have an endorphin-like activity in healthy volunteers (HV) but we have no information on the effect of gluten contained in foods. The aim was to study stomach and gallbladder emptying after the ingestion of a gluten-containing and gluten-free (GF) meal in a group of HV. Material and methods: A group of 18 HV (6 F, mean age 25 ys, range 22–30) was enrolled. In a double-blind, cross-over protocol, gastric and gallbladder emptying was evaluated by ultrasonography (US) after oral administration of two different meals, at least one week apart: (a) 100 g pasta and 1 scrambled egg; (b) 100 g GF pasta (BiAglut) and 1 scrambled egg. The different content between the meals was offset. A questionnaire to check for gluten content recognition was administered. Basal measurements of the antral area and gallbladder volume were taken at fasting. After the meals, the gastric area was measured every 30 min for 360 min (or until the gastric area returned to basal values), and gallbladder volume every 15 min for 120 min. Gastric emptying time and gallbladder ejection fraction were evaluated. At the same intervals as ultrasound measurements, the presence and severity of headache and GI symptoms was evaluated by a visuo-analogic scale. Results: 7 out of 18 HV correctly recognized the GF and gluten-containing meals. After the gluten-containing meal, gastric emptying time was longer than after the GF meal, but the results didn’t reach statistical significance (243±21 vs 231±14 min, p=0.08). No significance different between gallblad- der ejection fraction after the gluten-containing meal and after the GF meal (52-67% vs 57 to 64%, 25-75 percentile). The occurrence of symptoms and their severity not different between the two tests. Conclusions: Gluten-containing foods didn’t modify gastric and gallbladder motility. However, by increasing the sample studied, we will verify if the trend towards a prolongation of gastric emptying time becomes statistically significant. On a theoretical basis, this motility alteration could be important to explain the origin of dyspeptic symptoms associated with NCGS.