Single Water Swallows Research Articles

Assessing the diagnostic yield of achalasia using provocative testing in high-resolution esophageal manometry: Serial diagnostic study.

Chicago Classification v4.0 recommends that if achalasia is demonstrated with single water swallows (SWS); provocative testing is not required. We determine whether provocative testing in patients with suspected achalasia can change manometric findings and reproduce symptoms. Between 2016 and 2022, 127 consecutive manometry studies of patients with achalasia were retrospectively analyzed. All patients underwent SWS, a solid meal (SM) and/or a rapid drink challenge (RDC). Demographic data, fluoroscopy, gastroscopy, and pre-and post-treatment Eckardt scores were collated. Of 127 achalasia patients (50.6 ± 16.6 years and 54.6% male), all completed a SM and 116 (91.3%) completed RDC; overall 83 were naïve (65.4%) to previous therapy. 15.4% patients with normal integrated relaxation pressure (IRP) on SWS demonstrated obstruction with RDC. SM gave a different achalasia phenotype in 44.9% of patients (p ⟨ 0.001). Twelve patients with normal IRP during SWS had persistent/recurrent obstruction during provocative testing; 83.3% had previous achalasia therapy. None of 13 patients with Type III (TIII) achalasia with SWS exhibited a change in manometric findings with provocative testing. Impedance bolus heights were lower in patients with TIII achalasia and those with normal IRP with SWS. During the SM, symptoms were reproduced in 56.7% of patients. Forty-six of 103 patients (44.7%) underwent therapy based upon the final achalasia subtype which was defined by the provocative test result of the high-resolution manometry (HRM) study. All treatments were effective, regardless of the achalasia subtype. Manometric findings remain unchanged when TIII achalasia is diagnosed with SWS. In patients with normal IRP, Type I, or Type II achalasia during SWS, provocative testing can alter achalasia phenotype or uncover achalasia where diagnosis is unclear. Further, it can reproduce symptoms. Such findings can personalize and guide effective therapeutic decisions.

Diagnostic yield of adding solid food swallows during high-resolution manometry in esophageal motility disorders.

High-resolution manometry (HRM) is a key method to evaluate esophageal motility disorders. Current evaluation is usually performed with single water swallows (SWS) that may not challenge esophageal function or reproduce symptoms. Solid food swallows (SFS) could increase the diagnostic yield for clinically relevant disorders. Patients with dysphagia referred for esophageal HRM during a 2-year period in a single center were reviewed retrospectively and included if SFS was performed during HRM. Chicago classification v3.0 was used to define esophageal motility disorders. One hundred and four patients with dysphagia were included (59% women, mean age 57years). Ineffective esophageal motility was the most frequent motility disorder. Compared to SWS, the diagnosis changed after SFS in 33 patients (31.7%) including a change from normal or minor diagnosis toward major motility disorders in 14 (13.4%). Fifteen subjects (14.4%) shifted from a minor disorder on SWS to normal after SFS. SFS changed the diagnosis in 53.8% of patients with previous surgery versus 29.5% of those without (p=0.023). Pressurization during rapid drink challenge was more frequent when SFS changed the diagnosis to major motility disorders (69.2% vs. 37.3%, p=0.033). Twenty-nine percent of patients reported symptoms during SFS, mostly those with diagnostic change to major disorders after SFS (71.4% of patients with changes to major disorders vs. 22.2% of patients without, p<0.0001). Solid food swallows is a simple way to improve the diagnostic yield of HRM in patients with dysphagia and should be added to manometry protocol in daily clinical practice.

Application of a novel straight leg raise test during high-resolution manometry can predict esophageal contractile reserve in patients with gastroesophageal reflux disease.

Increased intra-abdominal pressure from abdominal compression augments esophageal peristalsis during high-resolution manometry (HRM), and straight leg raise (SLR) while supine increases intra-abdominal pressure. We determined if water swallows performed during SLR can mimic contraction reserve seen with multiple rapid swallows (MRS). Consecutive patients evaluated for GERD symptoms completed validated GERD questionnaires, esophageal HRM, and upper endoscopy. Distal contractile integral (DCI) was analyzed during single water swallows (10×5mL), MRS (5×2mL), and during SLR (5x5mL). Peristaltic breaks were measured using software tools with a 20mmHg isobaric contour. Univariate correlational analyses were performed to compare esophageal motor patterns and DCI values during single water swallows, MRS, and SLR. Of 103 study patients (mean age: 46.7±12.3years, 56.3% female), 50 (48.5%) had ineffective esophageal motility (IEM). Contraction reserve was observed on MRS in 62% with IEM, and 35.8% with normal motility (p=0.008). DCI was significantly higher during SLR compared to mean single swallow DCI in both IEM and normal motility patients (p<0.001 for each comparison). In IEM patients, SLR significantly reduced swallows with peristaltic breaks (6.1±3.7 vs 3.6±3.6; p<0.001) and shortened the length of the largest break (4.8±3.4 vs 3.0±3.0cm; p<0.001). DCI response following MRS correlated with DCI with swallows during SLR, with a correlational coefficient (Pearson's r) of 0.70 (p<0.001). Swallowing against the resistance of increased intra-abdominal pressure from SLR improves esophageal body peristaltic performance and predicts esophageal body contraction reserve.

Impaired motility in Barrett's esophagus: A study using high-resolution manometry with physiologic challenge.

Esophageal dysmotility may predispose to Barrett's esophagus (BE). We hypothesized that high-resolution manometry (HRM) performed with additional physiologic challenge would better delineate dysmotility in BE. Included patients had typical reflux symptoms and underwent endoscopy, HRM with single water swallows and adjunctive testing with solids and rapid drink challenge (RDC) before ambulatory pH-impedance monitoring. BE and endoscopy-negative reflux disease (ENRD) subjects were compared against functional heartburn patient-controls (FHC). Primary outcome was incidence of HRM contractile abnormalities with standard and adjunctive swallows. Secondary outcomes included clearance measures and symptom association on pH-impedance. Seventy-eight patients (BE 25, ENRD 27, FHC 26) were included. Water swallow contractility was reduced in both BE (median DCI 87mmHg/cm/s) and ENRD (442mmHg/cm/s) compared to FHC (602mmHg/cm/s; P<.001 and .04, respectively). With the challenge of solid swallows and RDC, these parameters improved in ENRD (solids=1732mmHg/cm/s), becoming similar to FHC (1242mmHg/cm/s; P=.93), whereas abnormalities persisted in BE (818mmHg/cm/s; P<.01 c.f. FHC). In BE and ENRD, reflux events (67 vs 57 events/24hour) and symptom frequency were similar; yet symptom correlation was significantly better in ENRD compared to BE, which was comparable to FHC (symptom index 30% vs 4% vs 0%, respectively). Furthermore, bolus clearance and exposure times were more pronounced in BE (P<.01). Reduced contractile effectiveness persisted in BE with the more representative esophageal challenge of swallowing solids and free drinking; while in ENRD and FHC peristalsis usually improved, demonstrating peristaltic reserve. Furthermore, symptom association and refluxate clearance were reduced in BE. These factors may underlie BE pathogenesis.

Variation in esophageal physiology testing in clinical practice: Results from an international survey.

Advances in clinical measurement of esophageal motility and function have improved the assessment of swallowing disorders and reflux symptoms. Variation in data acquisition, analysis, and reporting exists and impacts on diagnosis and management. This study examined variation in esophageal manometry methodology between institutions to establish the status in current practice. A structured survey was distributed through international NGM societies using an Internet-based platform. Questions explored infrastructure, technology, analysis, and reporting. Responses were received from 91 centers from 29 countries. Eighteen (20%) centers used "conventional" manometry, 75 (82%) high-resolution manometry, and 53 (58%) HR impedance manometry. All centers documented motility for single water swallows. The Chicago Classification was applied by 65 (71.4%) centers. In contrast, analysis of EGJ morphology varied widely. Adjunctive testing was often applied: multiple rapid swallows (77%), rapid drink challenge (77%), single solid swallows (63%), and a standard test meal (18%). Of 86 (94.5%) units that offered pH impedance (pH-Z) studies, approximately half (53.5%) performed tests on acid-suppressant medication in patients with a high pretest probability (eg, erosive esophagitis). Most (75.6%) centers manually reviewed every reflux event. Others examined pH-Z data only prior to symptoms. To assess symptom association with reflux events, 73.6% centers analyzed each symptom separately, whereas 29.7% centers pooled symptoms. There is marked variation in the data acquisition, analysis, and reporting of esophageal manometry studies. Further efforts to improve quality and uniformity in testing and reporting are required. This survey provides information upon which best-practice guidelines can be developed.

Diagnostic yield of high-resolution manometry with a solid test meal for clinically relevant, symptomatic oesophageal motility disorders: serial diagnostic study

The use of high-resolution manometry (HRM) to diagnose oesophageal motility disorders is based on ten single water swallows (SWS); however, this approach might not be representative of oesophageal function during the ingestion of normal food. We tested whether inclusion of a standardised solid test meal (STM) to HRM studies increases test sensitivity for major motility disorders. Additionally, we assessed the frequency and cause of patient symptoms during STM. Consecutive patients who were referred for investigation of oesophageal symptoms were recruited at Nottingham University Hospitals (Nottingham, UK) in the development study and at University Hospital Zürich (Zürich, Switzerland) in the validation study. HRM was done in the upright, seated position with a solid-state assembly. During HRM, patients ingested ten SWS, followed by a standardised 200 g STM. Diagnosis of oesophageal motility disorders was based on the Chicago Classification validated for SWS (CCv3) and with STM (CC-S), respectively. These studies are registered with ClinicalTrials.gov, numbers NCT02407938 and NCT02397616. The development cohort included 750 patients of whom 360 (48%) had dysphagia and 390 (52%) had reflux or other symptoms. The validation cohort consisted of 221 patients, including 98 (44%) with dysphagia and 123 (56%) with reflux symptoms. More patients were diagnosed with a major motility disorder by use of an STM than with SWS in the development set (321 [43%] patients diagnosed via STM vs 163 [22%] via SWS; p<0·0001) and validation set (73 [33%] vs 49 [22%]; p=0·014). The increase was most evident in patients with dysphagia (241 [67%] of 360 patients on STM vs 125 [35%] patients on SWS in the development set, p<0·0001), but was also present in those referred with reflux symptoms (64 [19%] of 329 patients vs 32 [10%] patients in the development set, p=0·00060). Reproduction of symptoms was reported by nine (1%) of 750 patients during SWS and 461 (61%) during STM (p<0·0001). 265 (83%) of 321 patients with major motility disorders and 107 (70%) of 152 patients with minor motility disorders reported symptoms during the STM (p=0·0038), compared with 89 (32%) of 277 patients with normal motility as defined with CC-S (p<0·0001). The diagnostic sensitivity of HRM for major motility disorders is increased with use of the STM compared with SWS, especially in patients with dysphagia. Observations made during STM can establish motility disorders as the cause of oesophageal symptoms. None.

Pharyngeal swallowing and oesophageal motility during a solid meal test: a prospective study in healthy volunteers and patients with major motility disorders

The factors that determine how people eat when they are healthy or have disease have not been defined. We used high resolution manometry (HRM) to assess pharyngeal swallowing and oesophageal motility during ingestion of a solid test meal (STM) in healthy volunteers and patients with motility disorders. This study was based at University Hospital Zurich (Zürich, Switzerland). Healthy volunteers who responded to an advertisement completed HRM with ten single water swallows (SWS) in recumbent and upright positions followed by a 200 g rice STM in the upright position. Healthy volunteers were stratified for age and sex to ensure a representative population. For comparison, consecutive patients with major motility disorders on SWS and patients with dysphagia but no major motility disorders on SWS (disease controls) were selected from a database that was assembled prospectively; the rice meal data were analysed retrospectively. During STM, pharyngeal swallows were timed and oesophageal contractions were classified as representing normal motility or different types of abnormal motility in accordance with established metrics. Factors that could potentially be associated with eating speed were investigated, including age, sex, body-mass index, and presence of motility disorder. We compared diagnoses based on SWS findings, assessed with the Chicago Classification v3.0, with those based on STM findings, assessed with the Chicago Classification adapted for solids. These studies are registered with ClinicalTrials.gov, numbers NCT02407938 and NCT02397616. Between April 2, 2014, and May 13, 2015, 72 healthy volunteers were recruited and underwent HRM. Additionally, we analysed data from 54 consecutive patients with major motility disorders and 53 with dysphagia but no major motility disorders recruited between April 2, 2013, and Dec 18, 2014. We found important variations in oesophageal motility and eating speed during meal ingestion in healthy volunteers and patients. Increased time between swallows was accompanied by more effective oesophageal contractions (in healthy volunteers, 20/389 [5%] effective swallows at <4 s between swallows vs 586/900 [65%] effective swallows at >11 s between swallows, p<0·0001). Obstructive, spastic, or hypercontractile swallows were rare in healthy volunteers (total <1%). Patients with motility disorders ate slower than healthy volunteers (14·95 g [IQR 11-25] per min vs 32·9 g [25-40] per min, p<0·0001) and pathological oesophageal motility were reproduced when patients consumed the STM. In healthy volunteers, eating speed was associated only with frequency of swallows (slope 2·5 g per min per pharyngeal swallow per min [95% CI 1·1-4·0], p=0·0009), whereas in patients with dysphagia, it was correlated with frequency of effective oesophageal contractions (6·4 g per min per effective contraction per min [4·3-8·5], p<0·0001). Diagnostic agreement was good between the HRM with SWS and rice STM (intra-class correlation coefficient r=0·81, 95% CI 0·74-0·87, p<0·0001). Our results show normative values for pharyngeal swallowing and oesophageal motility in healthy volunteers. Detailed analysis of HRM data acquired during an STM shows that the rate-limiting factor for intake of solids in health is the frequency of pharyngeal swallowing and not oesophageal contractility. The reverse is true in patients with oesophageal motility disorders, in whom the frequency of effective oesophageal contractions determines eating speed. University Hospital Zurich.

Sa1657 - Achalasia Despite Normal Integrated Relaxation Pressure with 5ml Water Swallows

Introduction Resistance to bolus flow across the lower esophageal sphincter (LES) is a hallmark of achalasia. Presently the gold standard of diagnosis is by high-resolution manometry (HRM) demonstration of raised integrated relaxation pressure (IRP) following ten 5 mL water swallows; however, this does not replicate normal swallowing behaviour. It has been demonstrated that the addition of adjunctive tests improves sensitivity of identifying relevant dysmotility. Such tests include multiple water swallows (MWS; 200 mL water drunk freely) and solid swallows. In addition, the timed barium esophagram (TBE) measures esophageal emptying. This study describes a cohort of patients who have been treated as having achalasia based on resistance to flow not exhibited with single water swallows. Method Inclusion criteria were all patients between October 2014–2016 with normal mean and median IRP with 5 mL water swallows but considered to have achalasia due to resistance to flow demonstrated by pan-esophageal pressurisation (PEP) during MWS or solid swallows and/or a persistent column at 5 min during TBE. Outcome post-treatment was based on Eckardt score (ES). Results 14 patients (9 male) fulfilled inclusion criteria. 7 were treatment-naive and 7 treatment-experienced (3 myotomy, 4 dilatation). Mean resting LES pressure was 14.6±7.4 mmHg. In all patients, mean and median IRP values for ten 5 mL water swallows were non-raised (mean 9.1±4.3 and 8.7±4.5 mmHg respectively). Of the 7 treatment-naive patients, 5 demonstrated PEP on MWS, 3 on solid swallows and 6 had a positive TBE at 5 min. In treatment-experienced patients, 5 had PEP on MWS, 1 on solid swallows and all had a positive TBE. Of the 13 who had resistance to flow on TBE, 10 (77%) also had resistance demonstrated during MWS and/or solid swallows. Mean height of the 5 min column of barium at baseline was 16.5±8.9 cm. 8 patients underwent therapy based on these findings; one POEM and 7 pneumatic dilatations. Median baseline ES was 7.5 (IQR 5–8). Median ES at minimum 3 months following treatment was 1 (IQR 0–2.5; p Conclusion A normal IRP for water swallows does not preclude a diagnosis of achalasia. The addition of free drinking/solids during HRM or the TBE can identify pathology that might have been missed with standard 5 mL water swallows alone. Patients treated based on this algorithm exhibit excellent treatment outcomes, validating this approach. Disclosure of Interest None Declared

Rapid Drink Challenge in high-resolution manometry: an adjunctive test for detection of esophageal motility disorders.

The Chicago Classification for diagnosis of esophageal motility disorders by high-resolution manometry (HRM) is based on single water swallows (SWS). Emerging data suggest that a "Rapid Drink Challenge" (RDC) increases sensitivity for motility disorders. This study establishes normal values and diagnostic thresholds for RDC in clinical practice. Two cohort studies were performed in patients with dysphagia or reflux symptoms (development and validation sets). Healthy subjects and patient controls provided reference values. Ten SWS and two 200-mL RDC were performed. Primary diagnosis for SWS was established by the Chicago Classification. Abnormal RDC was defined by impaired esophagogastric junction (EGJ) function (elevated integrated relaxation pressure during RDC [IRP-RDC]); incomplete inhibition of contractility during and ineffective contraction after RDC. Diagnostic thresholds identified in the development set were prospectively tested in the validation set. Normal values were determined in healthy (n=95; age 37.8±12) and patient controls (n=44; age 46.4±15). Development and validation sets included 178 (54±17years) and 226 (53±16years) patients, respectively. Integrated relaxation pressure during RDC was higher for SWS than RDC in all groups (overall P<.001), except achalasia. Rapid Drink Challenge suppressed contractility, except in achalasia type III, spasm, and hypercontractile motility disorders (P<.001). An effective after-contraction was present more often in health than disease (P<.001). Optimal diagnostic thresholds identified in the development set (IRP-RDC ≥12mmHg achalasia, IRP-RDC ≥8mmHg "all cause" EGJ dysfunction), were confirmed in the validation set (both, sensitivity ~85%, specificity >95%). Rapid Drink Challenge contributes clinically relevant information to routine HRM studies, especially in patients with EGJ dysfunction.

Investigation of Dysphagia After Antireflux Surgery by High-resolution Manometry: Impact of Multiple Water Swallows and a Solid Test Meal on Diagnosis, Management, and Clinical Outcome

Management of patients with dysphagia, regurgitation, and related symptoms after antireflux surgery is challenging. This prospective, case-control study tested the hypothesis that compared with standard high-resolution manometry (HRM) with single water swallows (SWS), adding multiple water swallows (MWS) and a solid test meal increases diagnostic yield and clinical impact of physiological investigations. Fifty-seven symptomatic and 12 asymptomatic patients underwent HRM with SWS, MWS, and a solid test meal. Dysphagia and reflux were assessed by validated questionnaires. Diagnostic yield of standard and full HRM studies with 24-hour pH-impedance monitoring was compared. Pneumatic dilatation was performed for outlet obstruction on HRM studies. Clinical outcome was assessed by questionnaires and an analogue scale with "satisfactory" defined as at least 40% symptom improvement requiring no further treatment. Postoperative esophagogastric junction pressure was similar in all groups. Abnormal esophagogastric junction morphology (double high pressure band) was more common in symptomatic than in control patients (13 of 57 vs 0 of 12, P= .004). Diagnostic yield of HRM was 11 (19%), 11 (19%), and 33 of 57 (58%), with SWS, MWS, and solids, respectively (P < .001); it was greatest for solids in patients with dysphagia (19 of 27, 70%). Outlet obstruction was present in 4 (7%), 11 (19%), and 15 of 57 patients (26%) with SWS, MWS, and solids, respectively (P < .009). No asymptomatic control had clinically relevant dysfunction on solid swallows. Dilatation was performed in 12 of 15 patients with outlet obstruction during the test meal. Symptom response was satisfactory, good, or excellent in 7 of 12 (58%) with no serious complications. The addition of MWS and a solid test meal increases the diagnostic yield of HRM studies in patients with symptoms after fundoplication and identifies additional patients with outlet obstruction who benefit from endoscopic dilatation.

Malingering dysphagia and odynophagia electromyographic assessment

Objective The article discusses the usefulness and investigation technique of suspected malingering dysphagia/odynophagia by surface electromyography (sEMG) of deglutition. Methods Forty patients with suspected malingering dysphagia (group 1), 40 patients with dysphagia/odynophagia due to tonsillectomy (group 2), and 40 healthy individuals (group 3) were involved in the study. The timing, amplitude, and graphic patterns of activity of the masseter, submental, and trapezius muscles were examined during voluntary single water swallows (“normal”) and continuous drinking of 100 mL of water. The muscle activity in oral, pharyngeal, and initial esophageal stages of swallowing was measured, and graphic records were evaluated in relation to timing and voltage. Results The main sEMG patterns of malingering dysphagia/odynophagia are prolonged time of the voluntary oral phase of a swallow (80% of cases, n = 32, P < .01 vs healthy volunteers) with normal timing of the reflex pharyngeal and initial esophageal phases and normal amplitude voltage. In 42.5% of cases (n = 17, P < .05 vs healthy volunteers), tension of skeletal muscles normally not involved in deglutition was observed during single swallowing being at the same time absent during continuous drinking. Conclusion Dysphagia due to malingering has no pathologic sEMG patterns associated with deglutition. Skeletal muscle tension during deglutition, being observed in some cases, has no connection with the act of swallowing itself. Prolonged oral phase of a swallow is factitious, nonpathologic. Surface EMG, being noninvasive, nonradiographic and inexpensive, can be used for patients with suspected malingering dysphagia, thus avoiding expensive and time-consuming investigation.

The electrodiagnostic examination of psychogenic swallowing disorders

The article discusses the usefulness and technique of investigation of suspected psychogenic dysphagia by surface electromyography (sEMG) of deglutition. Thirty-two patients with suspected psychogenic dysphagia (Group 1) and 40 healthy individuals (Group 2) were involved in the study. The timing, amplitude and graphic patterns of activity of the masseter, submental, infrahyoid and trapezius muscles were examined during voluntary single water swallows ("normal"), and continuous drinking of 100 cc of water. The muscle activity in oral, pharyngeal and initial oesophageal stages of swallowing was measured, and graphic records were evaluated in relation to timing and voltage. Globus hystericus was found in only 14 patients of the Group 1 (43.75%). The main sEMG pattern of psychogenic dysphagia is a lack of any pathologic changes of timing, voltage and graphic patterns of deglutition. In 28% of cases tension of skeletal muscles not involved in deglutition was observed during single swallowing (vs. 0% in controls). Psychogenic/hysteria-conversion dysphagia has no pathologic sEMG patterns associated with deglutition. Skeletal muscle tension during deglutition, being observed in some cases has no connection with the act of swallowing itself. Surface EMG, being non-invasive and non-radiographic, can be used for screening purposes for patients with dysphagia thus avoiding expensive and time-consuming investigation.

Surface Electromyography in Preoperative Evaluation and Postoperative Monitoring of Zenker’s Diverticulum

Patients with Zenker's diverticulum (ZD) underwent surface electromyography (sEMG) evaluation to determine sEMG patterns specific for ZD. Group 1 comprised patients with proven long-standing ZD that refused surgical treatment (n = 11, age mean = 55.7 years). Group 2 comprised surgically operated on patients with ZD (n = 6, age mean = 61 years). The timing, amplitude, and graphic patterns of activity of the masseter, submental, and laryngeal strap muscles were examined during voluntary single water swallows ("normal"), single swallows of excessive amounts of water (20 ml, "stress test"), and continuous drinking of 100 cc of water. The muscle activity in pharyngeal and initial esophageal stages of swallowing was measured, and graphic records were evaluated in relation to timing and voltage. The data were compared with the previously established normative database. The main sEMG patterns of ZD are (1) duration of swallowing and drinking is longer than normal (p < 0.05), (2) electric amplitude of laryngeal strap muscles during swallowing activity is higher than normal (p < 0.05), and (3) regurgitation peaks immediately after swallow followed by secondary swallow of the regurgitated portion of a bolus as seen at the sEMG records are specific graphic patterns for the ZD. Zenker's diverticulum has its own specific sEMG patterns. Surface EMG, being an important screening method for patients with dysphagia, is a valuable additional diagnostic tool for ZD. Because it is noninvasive and nonradiographic, it can be used for monitoring of long-standing cases of the disease as well as monitoring of postsurgical recovery.

Swallow-induced alterations in breathing in normal older people.

Respiratory parameters in 29 normal older subjects (mean age-73 years, SD = 5.7) were studied at rest, during single water swallows, and in continuous drinking. Respiration was recorded by intranasal air pressure changes and the moment of swallowing by pharyngoesophageal manometry. Compared with respiration at rest, respiratory rate increased immediately after 5 mL swallows as duration of breath cycles decreased from a mean of 3.8 s at rest to 3.5 s after swallowing (p = 0.003), but regularity of respiration was maintained. Deglutition apnea showed a trend toward increasing duration from a median of 1.06 to 1.24 s (p = 0.096) as bolus volume increased from 5 to 20 mL. Oxygen saturation levels were also compared, with a median fall of 2% during swallowing, but with larger and unexplained falls in several subjects. Direction of airflow monitoring showed 91% of single 5 mL swallows were followed by expiration, with postswallow inspiratory breaths occurring in 41% of subjects. Continuous swallowing of 100 mL of water from a cup and straw was typically performed with a pattern of multiple swallows per breath, with expiration occurring after 78.5% (cup) and 63.5% (straw) of swallows. This definition of swallowing-induced respiratory changes in normal older people forms a valuable basis for future comparison with elderly dysphagic patients.