Duration Of Aspiration Research Articles

Effects of endotracheal suctioning duration cerebral oxygenation in preterm infants.

This study evaluates the effects of endotracheal suctioning duration on cerebral oxygenation and physiological parameters in preterm infants in intensive care. Prospective and observational s tudy. In this study, 51 preterm infants born at 28-34 weeks of gestation in NICU were evaluated. Cerebral oxygenation was measured before, during, and after endotracheal suctioning with near-infrared spectroscopy. Pain levels of the infants were with N-PASS scale. A negative correlation was found between the lowest cerebral oxygenation value during endotracheal suctioning and the duration of endotracheal suctioning. Cerebral oxygenation levels during endotracheal suctioning were lower than pre- and post-endotracheal suctioning levels. Higher cerebral oxygenation was observed in infants whose endotracheal aspiration time was less than 13 s. The duration of endotracheal suctioning was positively correlated with pain and cerebral oxygenation stabilization time. Prolonged endotracheal suctioning duration negatively affects cerebral oxygenation in preterm infants. The study suggests an optimal endotracheal suctioning duration under 13 s. Properly executed endotracheal suctioning, with the correct technique and knowledge, can alleviate the adverse physiological effects observed in preterm infants and contribute to routine nursing care in intensive care units. This study has been reported in line with STROBE checklists. No patient or public contribution was required to design or undertake this research. Patients contributed only to the data collection. This study contributes to defining the ideal endotracheal aspiration duration, as there is not enough data so far. It showed the effect of prolonged endotracheal aspiration time on cerebral oxygenation, pain and physiological parameters in preterm infants.

Laryngeal realism and the voicing contrast in Khuzestani Arabic stops

In laryngeal realism (LR), laryngeal specification of stops is explained by direct maps of cues (e.g. VOT) onto privative phonological laryngeal features [voice] or [spread glottis]. Phonetic realization of the segments and speakers’ ‘control’ (e.g. the degree of intervocalic voicing and speech rate manipulation effects on VOT duration) are used as diagnostics of phonological specification. Similar to some Arabic vernacular dialects (e.g. Qatari Arabic), Khuzestani Arabic in Iran presents a case where three voiced stops /b d ɡ/ are in contrast with voiceless stops /p t k/, but two voiceless guttural plosives /tˁ q/ have no voiced homorganic counterparts. In this paper we examine the phonetic realization of voicing in these stops at word-initial and intervocalic position, as well as the effects of speech rate manipulation on VOT and closure voicing. The data came from 12 native speakers recorded in Khorramshahr, Iran. Our findings suggest an over-specified voicing system in this Arabic variety. We found that voiced /b d ɡ/ were produced with voicing lead in initial position and complete closure voicing word medially, voiceless /p t k/ had long lag VOT, while guttural /tˁ q/ had short lag VOT. Speech rate manipulation revealed that only duration of (pre)voicing and duration of aspiration increased in slower speech. Also, f0, F1, and F2 were measured at vowel onset to evaluate the glottal state in production of stops. The results support the predictions of LR that voiced stops are specified by [voice], voiceless stops are [sg], while gutturals lack underlying specification for voice.

The promoting effect of adaptive persistence aspiration on the cooperation based on the consideration of payoff and environment in prisoner's dilemma game

This work explores whether holding the last aspiration for a period of time can promote cooperation. Specifically, an evolutionary spatial prisoner's dilemma game mode is proposed, in which the players adjust strategies and aspirations by considering the payoff and environment. Therefore, the core is to allow players to hold the current aspiration for a period of time. Through numerical calculation, this study finds that the existence of an appropriate duration of aspiration can promote cooperation when b is less than a certain value. Moreover, the cooperation is gradually enhanced with the increase of T-max (maximum aspiration duration) when b is greater than it, but the enhancing effect is limited. It is also found that an appropriate value α (sensitivity to environmental change) can promote cooperation at different b intervals. Besides, this system indicates good robustness. Overall, this study provides a new perspective on exploring cooperative evolution based on aspiration.

External photoglottography, intra-oral air pressure, airflow and acoustic data on the Korean fricatives /s’, s/

From simultaneous recordings of the external photoglottography, intra-oral air pressure (P_io), airflow and acoustic data from four native Seoul Korean speakers (2 male and 2 female), we have found that the two fricatives are not significantly different in glottal opening peak and airflow peak height either word-initially or word-medially and that the duration of aspiration is significantly reduced in word-medial /s/, compared to those in word-initial /s/, not in /s’/. We have also found that the duration of a high P_io plateau is significantly longer in /s/ than in /s’/ both word-initially and word-medially and that airflow resistance (R=P_io/U) at the onset and offset of a P_io plateau and at the time of airflow peak height is significantly higher in /s’/ than in /s/ across the contexts. However, the differences in P_io peak and F0 are not significant. In addition, the transition time to reach airflow peak height from the offset of a P_io plateau is found to be significantly longer in /s/ than /s’/ in both word-initial and word-medial positions. No significant differences in glottal opening peak and airflow peak height confirm that /s/ is specified as [–spread glottis] like /s’/. As for the other significant differences, we propose that /s/ is [–tense], and /s’/ [+tense].

Aspiration depends on environmental factors and aspiration duration promotes cooperation in the spatial prisoner’s dilemma game

This paper mainly investigates the impact of the duration of aspiration and environmental factors on cooperation using the weak prisoner’s dilemma game. In real life, people’s aspiration levels are often related to the development levels of areas where they work or live. They will attempt to change the status quo when their income is below the aspiration or expectation level, and learn neighbors’ behaviors based on differences in payoffs, moreover, duration levels of aspiration are heterogeneous for different people. This research used this problem as basis to study the impact of people’s duration levels of aspiration on cooperation using the Monte Carlo simulation method. Numerous simulations show that a dynamic adjustment of aspiration at each Monte Carlo step will lead to the complete disappearance of cooperation, appropriately raising the duration level of aspiration to enhance cooperation. We also find that appropriate reference to the external environment in setting aspirations can promote cooperation. Our analytical conclusions and methods provide a new perspective for exploring the emergence and maintenance of human cooperation.

Phonetic cue competition within multiple phonological contrasts

Abstract This work examines Seoul Korean listeners’ perception of the five Korean sibilants: affricates /c′, c, ch/ and fricatives /s′, s/. Natural productions of the consonants were manipulated to vary orthogonally along several phonetic parameters relevant to the place/manner contrast ((denti)alveolar fricative vs. (palato)alveolar affricate) and the laryngeal contrast (fortis vs. lenis vs. aspirated). Of particular interest was listeners’ representation of /s/, whose laryngeal status is ambiguous. All manipulated parameters (baseline consonant and vowel affiliation, fundamental frequency at vowel onset, frication duration, and aspiration duration) influenced categorization, with consonant and vowel spectral information playing the primary role in distinguishing most sibilants. However, f0, a laryngeal cue, trumped place and manner cues in affricate vs. fricative classification, highlighting the increasing importance of f0 in Korean segmental phonology.

Aspiration Adjustment Based on Environmental Factors and Aspiration Duration Promote Cooperation in Spatial Prisoner's Dilemma Game

Aspiration Adjustment Based on Environmental Factors and Aspiration Duration Promote Cooperation in Spatial Prisoner's Dilemma Game

Do adults produce phonetic variants of /t/ less often in speech to children?

The surface phonetic details of an utterance affect how ‘native’a speaker sounds. However, studies have shown that children’s acquisition of context-appropriate variation (sometimes called allophones) is late. This study’s goal was to understand how caregivers use phonetic variation in the production of American English /t/ in child-directed speech (CDS), compared to in adult-directed speech (ADS). We hypothesized that mothers modify their input to children in order to produce more limited variation in CDS than in ADS, to potentially assist children in the development of contrastive phonemic categories. To this end, we recorded eight mothers of children under the age of 2 years in both ADS and CDS conditions. Results reveal that CDS contains significantly more canonical cues to /t/ than ADS does, and fewer non-canonical cue patterns, including fewer unreleased tokens and fewer glottalized tokens in utterance-medial position. Also, we found larger aspiration duration differences in CDS between aspirated singleton [th] vs. unaspirated [t] in /st/ contexts, suggesting that mothers exaggerate this cue to the phonemic context in which the /t/ occurs. Overall, the findings suggest that CDS more clearly signals the phonemic category, which could in turn assist children learn the relationship between the underlying and surface forms.

Generative Adversarial Phonology: Modeling Unsupervised Phonetic and Phonological Learning With Neural Networks.

Training deep neural networks on well-understood dependencies in speech data can provide new insights into how they learn internal representations. This paper argues that acquisition of speech can be modeled as a dependency between random space and generated speech data in the Generative Adversarial Network architecture and proposes a methodology to uncover the network's internal representations that correspond to phonetic and phonological properties. The Generative Adversarial architecture is uniquely appropriate for modeling phonetic and phonological learning because the network is trained on unannotated raw acoustic data and learning is unsupervised without any language-specific assumptions or pre-assumed levels of abstraction. A Generative Adversarial Network was trained on an allophonic distribution in English, in which voiceless stops surface as aspirated word-initially before stressed vowels, except if preceded by a sibilant [s]. The network successfully learns the allophonic alternation: the network's generated speech signal contains the conditional distribution of aspiration duration. The paper proposes a technique for establishing the network's internal representations that identifies latent variables that correspond to, for example, presence of [s] and its spectral properties. By manipulating these variables, we actively control the presence of [s] and its frication amplitude in the generated outputs. This suggests that the network learns to use latent variables as an approximation of phonetic and phonological representations. Crucially, we observe that the dependencies learned in training extend beyond the training interval, which allows for additional exploration of learning representations. The paper also discusses how the network's architecture and innovative outputs resemble and differ from linguistic behavior in language acquisition, speech disorders, and speech errors, and how well-understood dependencies in speech data can help us interpret how neural networks learn their representations.

AngioJet Aspiration Thrombectomy Combined with Transcatheter Thrombolysis in Treatment of Acute Portal Venous Systemic Thrombosis

This study set out to assess the feasibility, effectiveness, and safety of percutaneous AngioJet aspiration thrombectomy combined with transcatheter thrombolysis for treating acute portal venous systemic thrombosis (APVST). Clinical data of 13 patients with APVST who were treated by AngioJet aspiration thrombectomy combined with transcatheter thrombolysis from March 2017 to July 2018 were analyzed retrospectively. The effect of portal venous recanalization was evaluated by intraoperative angiography and postoperative surveillance of clinical findings, portal venous ultrasound, or computed tomography. Successful puncture of the portal vein (PV) was performed in all patients. The PV was punctured successfully in 7 patients via the transjugular intrahepatic route, 2 patients failed to be punctured and then had successful percutaneous transhepatic puncture, and 4 patients underwent percutaneous transhepatic PV puncture directly. The duration of thrombus aspiration was 238.46±89.89sec (range, 120-360), and the amount of urokinase in thrombus aspiration was 353,000±87,700 IU (range, 200,000-400,000). Portal venous thrombosis was dissolved by the AngioJet thrombectomy device (Boston Scientific, Marlborough, MA) in all patients. After aspiration, angiography showed that grade III lysis was achieved in 8 patients, grade II lysis in 1 patient, and grade I lysis in 4 patients. The length of transcatheter thrombolysis was 3.07±1.75days (range, 1-7), and the total urokinase dose via an indwelling catheter was 1,230,000±706,000 IU (range, 200,000-2,800,000). Four patients had a transjugular intrahepatic portosystemic shunt, 1 patient with stenosis of the superior mesenteric vein (SMV) achieved balloon angioplasty, and 1 patient with stenosis of the SMV was stented. Operative complications were transient hematuria (4 patients), palpitation (1 patient), and bowel resection (1 patient). No patients died within 30days. Patients were discharged at 12.00±5.83days (range, 6-27) after admission. All patients survived, and no recurrence developed during the follow-up of 9.15±3.18months (range, 4-15). Percutaneous AngioJet aspiration thrombectomy combined with thrombolytic therapy is feasible and effective for APVST. This treatment is beneficial for APVST in dissolving thrombus, improving SMV flow, and relieving symptoms of PV hypertension.

Acoustic analysis of Korean stop sounds in patients with dysarthrias

Purpose Korean ‘stops’ are considered an especially good acoustic variable since they are sensitive to speech intelligibility and reflect physiological coordination between laryngeal and supra-laryngeal mechanisms. The purpose of the study was to evaluate the acoustic characteristics of both the dysarthria and control groups in the production of nine Korean stops, /p, p′, ph, t, t′, th, k, k′, kh/, in VCV contexts. Methods The participants comprised eight patients with dysarthria and eight age- and gender-matched normal adults. After the acoustic analysis of the closure duration, aspiration duration, and the ratio of closure duration to closure-aspiration combined duration, the results were compared among three types of phonation and places of articulation for Korean stops. Results The dysarthria group (DG) had longer closure durations, suggesting slower articulatory movements of the DG than the normal control group (NC). Although statistically not significant except for /ap′a/ and /at′a/, the absolute aspiration durations of the DG were still longer than those of the NC. This resulted in the normal levels of ratios in the DG between closure duration and closure-aspiration combined durations. Furthermore, the DG could change the durational aspects of stop production distinctively according to types of phonation more than they could according to the places of articulation. This trend was more prominent during the closure duration than during the aspiration duration. Conclusions This finding suggested that while the DG has centralized tongue positions, they control the tenseness and the timing coordination between laryngeal and supra-laryngeal articulators to distinctively produce different types of phonation of stops. Keywords: Dysarthria; Acoustic analysis; Korean stops; Closure duration; Aspiration duration

Effects of aspiration time on immediate viability of adipocyte cell in ultrasound-assisted liposuction (UAL) and in traditional suction-assisted lipectomy (SAL)

We aimed to determine the effect of aspiration periods following liposuction procedure on vascular structures, fibrocollagenous tissues and viability of adipose cells at different minutes, respectively in UAL and SAL. Abdominoplasty materials were divided into two equal parts from middle following excusion during the operations. Traditional SAL was performed to the right part of the abdominoplasty materials therewithal. Each side of the material was then divided into five parts enumarated from one to five and aspiration procedure time for each area was defined according to this ranking. The aspiration periods for each area were as follows: the transition intervals of 30 seconds between each zone were calculated as preoperative preparation time for surgical equipment in every area, and for discharging the lipoaspirates from collecting container. Red blood cell amount, a rate of degeneration in vasculary tissues, adipocyte cell amount with nuclear conformation, a rate of septal structure loss in fibroblast cells and septal fibroblast amount were the histopatological parametres of the study which observed and analysed by the pathologists. Based on the results of statistically analysis we proved that obtaining more surviving fat graft is possible by keeping aspiration period less than 2 minute in operation zone. In case of elongation of stated period clinical accomplishment of fat graft application reduces due to the downward of viable adipocyte cell amount and accelerating injury on tissues. Consequently, keeping the aspiration duration less than two minutes in planned liposuction area in both liposuction methods is favourable for providing maximum viable autologous fat graft.

Plosive voicing acoustics and voice quality in Yerevan Armenian

Yerevan Armenian is a variety of Eastern Armenian with a three-way voicing contrast that includes voiced, voiceless unaspirated, and voiceless aspirated stops, but previous work has not converged on a description of how voice quality is involved in the contrast. We demonstrate how voice quality can be assessed in a two-dimensional acoustic space using a spectral tilt measure in conjunction with a measure of spectral noise. Eight speakers produced a list of words with prevocalic word-initial and postvocalic word-final plosives. The results suggest that Yerevan Armenian has breathy-voiced plosives which are produced with closure voicing and a relatively spread glottis that is maintained into a following vowel. These qualitatively differ from some Indic ones in that they do not have an extended interval of voiced aspiration after the closure. For the voiceless unaspirated plosives, most speakers produced acoustically modal voiceless plosives, although two showed evidence for some glottal constriction and tensing. Many acoustic cues contribute to overall reliable discriminability of the three-way contrast in both initial and final position. Nevertheless, closure voicing intensity and aspiration duration together provide a robust separation of the three categories in both positions. We also find that back vowels are fronted after the breathy-voiced plosives, which supports a historical analysis in which early Armenian voiced stops were also breathy, rather than plain voiced.

In vitro study for the evaluation of transluminal aspiration as a novel treatment option for thrombosis in the HeartWare HVAD.

Pump thrombosis of left ventricular assist devices remains a devastating complication with high morbidity and mortality. Despite the improvements made, the matter affects many patients and the treatment options are limited to thrombolysis and surgical replacement. An alternative approach using the aspiration Indigo catheter was tested. An Indigo thrombectomy catheter was used within an in vitro model to assess the direct aspiration of prefabricated clots from three different positions within the HeartWare HVAD (inlet, outlet, and housing). The experiments were conducted with a straight and an angled catheter. The aspiration pressure was constant. The flow, power consumption, and pressure head of the left ventricular assist devices were measured at pre-defined measuring points. The device was more effective (success rate 71%) at inlet and outlet of the left ventricular assist device. In addition, the duration of aspiration and the aspiration volume were shorter in comparison to the aspiration in the housing (inlet M = 19.75 s, outlet M = 60.50 s, and housing M = 38.75 s). Moreover, the aspiration volume was associated with the aspiration duration and the weight of thrombi but not with their volume. Noteworthy, the angled catheter showed an improved performance compared to the straight one (67%-33%). The recorded parameters showed no major changes during the use of the catheter. After application of the Indigo catheter, flow and pressure head of the pump could be restored. The aspiration system showed promising results under specific conditions for the treatment of pump thrombosis in an in vitro model. However, further examination, including in vivo experiments, will justify its effectiveness.

Pre-coda vowel duration in Nepali

Many previous studies have found that vowels are longer before voiced consonants than voiceless (Chen 1970). Fewer studies have examined vowel duration preceding aspirated vs. unaspirated stops, and results are inconsistent (Maddieson & Grandour 1976, Ohala & Ohala 1992). Durvasala and Luo (2012) find that both voicing and aspiration have a lengthening effect on the preceding vowel in Hindi, and that the voiced aspirated class has the longest preceding vowel duration. In the present study, I measure the duration of vowels preceding word final codas in Nepali, an Indo-Aryan language with the same four-way contrast as Hindi. A phonetic study of final stop realization has not yet been reported in the literature, though Nepali is described as variably neutralizing voiced aspirated to the plain voiced. I present an acoustic analysis of cues in word-final position including voicing, burst, and preceding vowel duration. I find evidence of neutralization of voiced and voiced aspirated stops in terms of aspiration duration, but also find results consistent with Durvasala and Luo (2012), that the voiced aspirated stops have longer preceding vowel than the voiced. The difference in vowel duration between the voiced and voiced aspirated classes suggests incomplete neutralization of voiced aspirated to voiced.Many previous studies have found that vowels are longer before voiced consonants than voiceless (Chen 1970). Fewer studies have examined vowel duration preceding aspirated vs. unaspirated stops, and results are inconsistent (Maddieson & Grandour 1976, Ohala & Ohala 1992). Durvasala and Luo (2012) find that both voicing and aspiration have a lengthening effect on the preceding vowel in Hindi, and that the voiced aspirated class has the longest preceding vowel duration. In the present study, I measure the duration of vowels preceding word final codas in Nepali, an Indo-Aryan language with the same four-way contrast as Hindi. A phonetic study of final stop realization has not yet been reported in the literature, though Nepali is described as variably neutralizing voiced aspirated to the plain voiced. I present an acoustic analysis of cues in word-final position including voicing, burst, and preceding vowel duration. I find evidence of neutralization of voiced and voiced aspirated stops in terms of aspiration...

Retrospective analysis of the effects of continuous intraluminal aspiration on postoperative intestinal fistulas

Aim: The aim of this study was to present the effectiveness of continuous intraluminal aspiration for treating postoperative intestinal fistulas. Methods: Continuous intraluminal aspiration was conducted on nine patients who underwent surgery for upper or lower Gastrointestinal (GI) tract diseases in our General Surgery clinic from January 2014 to March 2016 and developed an intestinal fistula after the surgery. The clinical and demographic results of the patients were analyzed retrospectively. A double-lumen system consisting of a nasogastric catheter and an implanted endoscopic retrograde cholangiopancreatography cannula was used for aspiration. Results: Seven of the nine patients (age range: 28-71 y) were males. Nine patients had complications: six in the upper GI tract and three in the lower GI tract. The first session was technically successful in all patients. Mean hospital stay was 41.77 ± 15.74 d and mean aspiration duration was 14.12 ± 2.84 d. Neoadjuvant chemotherapy (CRT) was performed in four patients. Eight patients recovered and were discharged but one patient, who underwent laparoscopic Ivor Lewis esophagectomy after neoadjuvant CRT for esophageal cancer and developed esophagomediastinal and tracheomediastinal fistulas, died at 20th d after surgery. Clinical success was achieved in five of six patients (83%) who had a fistula and leakage in the upper GI tract, and in three patients (100%) who had a fistula and leakage in the lower GI tract system. Conclusions: Although treatment duration is longer when using continuous intraluminal double-lumen catheter aspiration, it is an effective method to treat postoperative intestinal fistulas with a low mortality rate and cost.

The Mechanism and Representation of Korean Three-Way Phonation Contrast: External Photoglottography, Intra-Oral Air Pressure, Airflow, and Acoustic Data

This paper aims to refine our understanding of the speech mechanism and laryngeal features involved in the Korean lenis (/p t k/), aspirated (/ph th kh/), and fortis (/p' t' k'/) plosives. For this purpose we made measurements using a new noninvasive technique called external lighting and sensing photoglottography (ePGG) as well as intra-oral air pressure (Pio) above the glottis, airflow, and acoustic data. From simultaneous recordings of the experimental data, we were ableto quantify the laryngeal-oral coordination of glottal opening and a consonant release, and the covariance of airflow peak and duration of aspiration with glottal opening. The phasing of glottal opening and the 3-way phonation contrast occurs in the order, from early to late, fortis, lenis < aspirated plosives, and the glottal opening peak ranges from low to high in the same order. We also found that a Pio peak, the durations of a high Pio plateau and an oral closure, and F0 are independent of the glottal opening mechanism, varying in the order lenis < aspirated and fortis plosives. From these findings, we propose that the 2 independent patterns are accounted for by the articulator-based features [±spread glottis] and [±tense], respectively.

Comparison of cough reflex testing with videoendoscopy in recently extubated intensive care unit patients

PurposeOrotracheal intubation is known to impair cough reflex, but the validity of cough reflex testing (CRT) as a screening tool for silent aspiration in this population is unknown. Material and methodsOne hundred and six participants in a tertiary-level intensive care unit (ICU) underwent CRT and videoendoscopic evaluation of swallowing (VES) within 24 hours of extubation. Cough reflex threshold was established for each participant using nebulized citric acid. ResultsThirty-nine (37%) participants had an absent cough to CRT. Thirteen (12%) participants aspirated on VES, 9 (69%) without a cough response. Sensitivity of CRT to identify silent aspiration was excellent, but specificity was poor. There was a significant correlation between intubation duration and presence of aspiration on VES (P= .0107). There was no significant correlation between silent aspiration on VES and length of intubation, age, sex, diagnosis at intensive care unit admission, indication for intubation, Acute Physiology and Chronic Health Evaluation III score, morphine equivalent dose, or time of testing postextubation. ConclusionsIntensive care unit patients are at increased risk of aspiration in the 24 hours following extubation, and an impaired cough reflex is common. However, CRT overidentifies risk of silent aspiration in this population.

Laser-assisted posterior cordotomy for bilateral vocal fold paralysis: Our experience

Introduction: Bilateral vocal fold paralysis (BVFP) is a relatively uncommon cause of respiratory distress. The goals of surgical treatment are an improvement in airway size by enlarging the glottis, thus, eliminating the need for tracheostomy, while at the same time avoiding a breathy voice and aspiration. Striking this balance is extremely important. Unilateral laser-assisted posterior cordotomy provides sufficient airway at posterior glottis while preserving phonatory and protective functions of the larynx. Aims: To evaluate long-term acoustic, aerodynamic and functional results of laser-assisted unilateral posterior cordotomy in BVFP. Materials and Methods: The prospective study includes seven patients of BVFP who underwent unilateral laser-assisted posterior cordotomy. Surgical success was evaluated regarding decannulation rate, time to decannulation and need for the second procedure. Voice assessment was done using voice handicap index (VHI), grade, roughness, breathiness, asthenia, strain and measurement of maximum phonation time (MPT). Effect of deglutition was assessed by the presence or absence and duration of aspiration. Observations and Results: Of seven patients, four had been tracheostomized at some time during their treatment. They were successfully decannulated within an average of 1 week after the surgery. The postoperative respiratory function was adequate for more than routine activity in all patients. None of the patients required a second procedure. VHI values demonstrated that while four patients had no/mild degree of voice handicap, two had moderate and one had a severe degree of handicap. While five patients had a normal MPT, two had a reduced MPT. Perceptual rating by a speech pathologist revealed that while two patients had mild dysphonia, four had moderate dysphonia. None of the patients complained of aspiration postoperatively. Conclusion: Unilateral CO2laser posterior cordotomy is a simple, safe and short surgical technique that creates a satisfactory glottic airway to improve respiration while avoiding aspiration and having minimal to the mild effect on the voice.

Diachronic change in perception of Korean sibilants

The laryngeal contrast in the Seoul dialect of Korean is in a state of flux: the increasing importance of f0 (relative to VOT) in both perception and production of the three-way stop contrast in younger (vs. older) Seoul speakers has been well-documented. The current work turns to perception of the Korean sibilant series, comprised of a three-way affricate contrast, (fortis vs. lenis vs. aspirated, parallel to the stop contrast) and a phonologically ambiguous two-way fricative contrast (fortis vs. “nonfortis”). We map younger (mean 33 years old) and older (mean 66) Seoul listeners’ perceptual spaces for the sibilant class using a five-way forced-choice task, with stimuli manipulated to vary independently across multiple acoustic dimensions (consonantal spectral information, vocalic spectral information, frication duration, aspiration duration, and f0). Hierarchical classification tree analyses reveal systematic age-related differences in cue-weighting. While both age groups make use of a combination of sp...