Browse our latest publications and discover the research, insights, and contributions shaping our work.
2026
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Akshay Tangutur, Phoebe K. Yu, Mathias Basner, Brendan T. Keenan, and Raj C. Dedhia
This study investigated whether active hypoglossal nerve stimulation improves cognitive function and sleep-related quality of life in patients with obstructive sleep apnea.
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Chau Phung, Tice Harkins, Linda C. Magaña, Yash Dixit, Eric Thuler, Muskaan Aggarwal, Andrew Wiemken, Everett Seay, Brendan T. Keenan, Bruno Saconi, Richard J. Schwab, and Raj C. Dedhia
Are CT-derived anatomic measures, particularly relative tongue volume and other upper airway anatomical features, associated with successful response to hypoglossal nerve stimulation in patients with obstructive sleep apnea?
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Tice R. Harkins, Everett G. Seay, Eric Thuler, and Raj C. Dedhia
The purpose of this study was to develop a novel physiologic DISE platform to quantify hypoglossal nerve stimulation (HGNS)-related changes in tongue motion, airway patency, pharyngeal pressure, and airflow, and to better understand why some patients respond to HGNS while others do not.
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Jordan S. Weiner, Eugene G. Chio, Raj C. Dedhia, Colin T. Huntley, Michael J. Hutz, Phillip Huyett, Daniel J. Lee, Philip LoSavio, Ilya Perepelitsyn, Ryan J. Soose, and David T. Kent
This study was conducted to determine whether supine pharyngeal width, neck circumference, and body mass index are associated with complete concentric collapse (CCC) and could be used to help determine hypoglossal nerve stimulation candidacy instead of requiring drug-induced sleep endoscopy (DISE).
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Jing Xu, Zohreh Hajipour, Mark S. Aloia, Sara Op de Beeck, Olivier M. Vanderveken, Phillip Huyett, Ryan J. Soose, Raj Dedhia, Patrick J. Strollo Jr, and Ali Azarbarzin
Is hypoglossal nerve stimulation (HGNS) associated with reduced hypoxic burden in patients with obstructive sleep apnea?
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Brendan T. Keenan and Raj C. Dedhia
Do measures such as lateral oropharyngeal wall collapse and airflow shape truly predict hypoglossal nerve stimulation success in obstructive sleep apnea, or are they merely associated with treatment outcomes?
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Vasilikia Triantafillou, Raj C. Dedhia, and Julianna G. Rodin
What is the current role of drug-induced sleep endoscopy (DISE) in the evaluation and management of obstructive sleep apnea, and how might emerging physiologic and imaging adjuncts improve patient selection and treatment outcomes?
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B. Tucker Woodson, David T. Kent, Colin Huntley, Melyssa K. Hancock, Douglas J. Van Daele, Maurits S. Boon, Tod C. Huntley, Sam Mickelson, M. Boyd Gillespie, Maria V. Suurna, Ashutosh Kacker, Asim Roy, Stuart MacKay, Kirk P. Withrow, Raj C. Dedhia, Phillip Huyett, Clemens Heiser, Sylvie di Nicola, Fatima Makori, Olivier M. Vanderveken, Tapan A. Padyha, Ulysses J. Magalang, Eugene Chio, Eric J. Kezirian, and Richard Lewis
The authors evaluated whether a novel bilateral hypoglossal nerve stimulation system can safely and effectively treat obstructive sleep apnea in PAP-intolerant patients, examining its impact on objective measures of disease severity, patient-reported outcomes, treatment adherence, and device-related adverse events over 12 months.
2025
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Linda C. Magaña, Tice Harkins, Yash Dixit, Andrew Weimken, Brendan T. Keenan, Everett G. Seay, Eric Thuler, Alan R. Schwartz, and Raj C. Dedhia
Herein, we sought assess whether differences exist between ascending pharyngeal opening pressure (PhOPA) and descending pharyngeal opening pressure (PhOPD) obtained from positive airway pressure (PAP) titrations during drug-induced sleep endoscopy (DISE) and to identify the associations between the physiologic and anatomic constituents of these differences.
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Akshay Tangutur, Katherine K. Brown, and Raj C. Dedhia
We sought to answer if the results of objective skin patch testing offer clinical guidance prior to reimplantation of a hypoglossal nerve stimulation (HGNS) device.
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Julianna G. Rodin, Tice Harkins, Erica Kent, Chau Phung, Rafa Khan, Everett Seay, Brendan T. Keenan, and Raj C. Dedhia
Surgical treatment of non obstructive sleep apnea (OSA) pathology poses the risk of inappropriate surgical indications. Herein, we sought to determine the prevalence of non-OSA respiratory disorders, specifically central sleep apnea (CSA), in new referrals to a Sleep Surgery Clinic.
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Tice R. Harkins, Leonard J. M. Soh, Everett G. Seay, Eric Thuler, Alan R. Schwartz, and Raj C. Dedhia
How does the timing of HGNS influence nasal airflow, and what are the recommended next steps for a patient experiencing persistent symptoms due to asynchronous stimulation?
2024
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Tice R. Harkins, Julianna G. Rodin, Chau M. Phung, Everett Seay, Eric Thuler, and Raj C. Dedhia
Our findings advocate for a more patient-specific approach to DISE interpretations, emphasizing the physiological and anatomical aspects of airway collapse.
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Tice Harkins, Akshay Tangutur, Brendan T. Keenan, Everett G. Seay, Eric Thuler, Raj C. Dedhia, and Alan R. Schwartz
We sought to assess collapse sites in patients with OSA undergoing DISE and whether number and location are associated with differences in airway collapsibility; and to quantify differences in collapsibility between primary and secondary sites in multilevel collapse.
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Manan H. Parekh, Eric Thuler, Vasiliki Triantafillou, Everett Seay, Chandra Sehgal, Susan Schultz, Brendan T. Keenan, Alan R. Schwartz, and Raj C. Dedhia
Examine factors accounting for differences in hyoid motion during obstructive breathing events amongst obstructive sleep apnea (OSA) patients.
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Tice R. Harkins, Everett Seay, Alan R. Schwartz, Eric Thuler, and Raj C. Dedhia
This case highlights the ability of drug-induced sleep endoscopy with PAP to determine the mechanistic cause of oronasal mask failure.
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Yi Cai, Manan H. Parekh, Julianna Rodin, Akshay Tangutur, Jason L. Yu, Brendan T. Keenan, Alan R. Schwartz, and Raj C. Dedhia
There are disparities between Black and White patients in the utilization of positive airway pressure (PAP) alternatives for obstructive sleep apnea (OSA). Given low utilization rates among Black patients, there is limited knowledge of PAP alternative outcomes in this group. Therapeutic PAP levels are clinically accessible measures that have been shown to predict PAP alternative outcomes. Herein, we examined differences in PAP requirements between Black and White patients in a large clinical sample.
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Tice R. Harkins, Vasiliki Triantafillou, Everett G. Seay, Alan R. Scwartz, and Raj C. Dedhia
This case report illustrates how quantitative airflow and pressure measurements can complement the standard DISE exam and aid in surgical decision-making.
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Eric R. Thuler, Manan H. Parekh, Jules G. Rodin, Everett G. Seay, Andrew Wiemken, Brendan T. Keenan, Richard J. Schwab, Alan R. Schwartz, and Raj C. Dedhia
Positive airway pressure (PAP) titration during drug-induced sleep endoscopy (DISE) provides objective measures of upper airway collapsibility. While skeletal measurements relate to collapsibility measures on DISE, the influence of soft tissue dimensions on upper airway collapsibility is not known. We analyzed the relationship of measures of upper airway soft tissue volumes, specifically soft palate, pharyngeal lateral walls, and tongue, with metrics of collapsibility.
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Akshay Tangutur, Yi Cai, Everett G. Seay, Erica R. Thaler, Brendan T. Keenan, and Raj C. Dedhia
Determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA).
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Julianna G. Rodin, Manan H. Parekh, Yi Cai, Brendan T. Keenan, Eric R. Thuler, Everett Seay, Joshua H. Atkins, Alan R. Schwartz, and Raj C. Dedhia
With the recent addition of airflow and respiratory effort channels, our group has observed central and mixed apnea events during drug-induced sleep endoscopy (DISE). We measured the frequency and timing of sentinel central and/or mixed events (SCents), as well as assessed for differences in velum, oropharynx, tongue, and epiglottis (VOTE) classification compared to obstructive events.
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Michael J. Hutz, Eric Thuler, Crystal Cheong, Chau Phung, Marianna Evans, John Woo, Brendan T. Keenan, and Raj C. Dedhia
Recent evidence suggests that environmental factors impact craniofacial development. Specifically, the height and width of the maxilla may impact the degree of septal deviation. We sought to determine the relationship between transverse maxillary deficiency and severity of septal deviation.
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Manan Parekh, Vasiliki Triantafillou, Brendan T. Keenan, Everett G. Seay, Eric Thuler, Alan R. Schwartz, and Raj C. Dedhia
Increased pharyngeal collapsibility leads to obstructive sleep apnea (OSA). Positive airway pressure titration during drug-induced sleep endoscopy (DISE-PAP) provides objective collapsibility metrics, the pharyngeal opening pressure (PhOP), and active pharyngeal critical pressure (PcritA ). We examined the interrelationships between risk factors of OSA, airway collapsibility measures, and clinical manifestations of the disease.
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Sebastian M. Jara, Eric R. Thuler, Michael J. Hutz, Jason L. Yu, Crystal S. Cheong, Normand Boucher, Marianna Evans, and Raj C. Dedhia
Surgically assisted rapid palatal expansion (SARPE) addresses transverse maxillary deficiency, a known contributor to nasal obstruction. The purpose of this study was to assess the feasibility, preliminary outcomes, and safety of posterior palatal expansion via subnasal endoscopy (2PENN), a modified SARPE procedure, aimed at achieving anterior and posterior maxillary expansion.
2023
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Manan H. Parekh, Eric Thuler, Vasiliki Triantafillou, Everett Seay, Chandra Sehgal, Susan Schultz, Brendan T. Keenan, Alan R. Schwartz, and Raj C. Dedhia
The significance of hyoid dynamics in OSA pathophysiology remains unclear. Drug-induced sleep endoscopy (DISE) is often used for evaluating patients intolerant to positive airway pressure (PAP) therapy. We performed DISE with concurrent hyoid-focused ultrasonography to quantify hyoid dynamics during obstructive and non-obstructive breathing.
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Eric Thuler, Everett G. Seay, John Woo, Jane Lee, Niusha Jafari, Brendan T. Keenan, Raj C. Dedhia, and Alan R. Schwartz
Examine the relationship between craniofacial skeletal anatomy and objective measures of pharyngeal collapse obtained during drug-induced sleep endoscopy. We hypothesized that transverse maxillary deficiency and an increased pharyngeal length will be associated with higher levels of pharyngeal collapsibility.
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Jason L. Yu, Eric Thuler, Everett G. Seay, Alan R. Schwartz, and Raj C. Dedhia
Examine the accuracy and interrater reliability of a visually assessed vs airflow-based measure of pharyngeal collapsibility obtained in patients with obstructive sleep apnea undergoing drug-induced sleep endoscopy (DISE).
2022
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Jason L. Yu, Eric Thuler, Everett G. Seay, Alan R Schwartz, and Raj C. Dedhia
Examine the accuracy and interrater reliability of a visually assessed vs airflow-based measure of pharyngeal collapsibility obtained in patients with obstructive sleep apnea undergoing drug-induced sleep endoscopy (DISE).
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Jason L. Yu, Akshay Tangutur, Eric Thuler, Marianna Evans, and Raj C. Dedhia
There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea.
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Crystal S. Cheong, Raj C. Dedhia, Everett G. Seay, Sebastian M. Jara, Jorge L. Mora, Erica R. Thaler, and Alan R. Schwartz
This case report describes a patient originally diagnosed with obstructive sleep apnea (OSA) who was later found to have central sleep apnea (CSA) during drug-induced sleep endoscopy, which was subsequently confirmed on an in-laboratory sleep study. The revised diagnosis resulted in a change in recommended therapy from hypoglossal nerve stimulation to phrenic nerve stimulation. This case report is a reminder that the sleep surgeon must be cognizant of the possibility of CSA being misclassified as OSA especially as home sleep studies become increasingly routine, and discusses ways to more easily distinguish between CSA and OSA.
2021
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Raj C. Dedhia, Everett G. Seay, and Alan R. Schwartz
Alternatives to positive airway pressure therapy, including surgery, represent an important area of research. Specifically, predictors of response to surgical therapy remain underdeveloped. Drug-induced sleep endoscopy (DISE) holds promise as a diagnostic tool to identify patient-specific causes of airway collapse. Herein, we present a novel, standardized approach which combines anatomic and physiologic measurements during DISE. Our DISE platform measures airflow, airway compliance, airway collapsibility, and structural drivers of collapse. Taken together, these inputs provide a comprehensive framework to further inform the surgeon in providing personalized care of the patient with obstructive sleep apnea.
2020
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Phoebe K. Yu, Asitha D. L. Jayawardena, Matthew Stenerson, Margaret B. Pulsifer, Julie A. Grieco, Leonard Abbeduto, Raj C. Dedhia, Ryan J. Soose, Allison Tobey, Nikhila Raol, Stacey L. Ishman, Sally R. Shott, Michael S. Cohen, Brian G. Skotko, Thomas B. Kinane, Donald G. Keamy Jr, and Christopher J. Hartnick
Patients with Down syndrome have a high incidence of obstructive sleep apnea (OSA) and limited treatment options. Hypoglossal stimulation has shown efficacy but has not yet been approved for pediatric populations. Our objective is to characterize the therapy response of adolescent patients with down syndrome and severe OSA who underwent hypoglossal stimulation.
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Jason L. Yu, Yifan Liu, Akshay Tangutur, Monique Arnold, Everett G. Seay, Alan R. Schwartz, and Raj C. Dedhia
Lower therapeutic positive airway pressure (PAP) levels are associated with improved response to non-PAP therapies in the treatment of obstructive sleep apnea. The aim of this study was to evaluate the prevailing notion that patients with apnea-predominant obstructive sleep apnea require higher therapeutic PAP levels compared to patients with hypopnea-predominant obstructive sleep apnea.
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Everett G. Seay, Graeme Mulholland, and Raj C. Dedhia
This is a case report of a 41-year-old male with obesity, severe obstructive sleep apnea (OSA), and an apnea-hypopnea index of 90 events/h, despite high bilevel positive airway pressure (BPAP).
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Everett G. Seay, Brendan T. Keenan, Alan R. Schwartz, and Raj C. Dedhia
Examine the use of therapeutic nasal PAP levels at the soft palate in predicting the outcomes of HGNS for patients with obstructive sleep apnea.
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Graeme B. Mulholland and Raj C. Dedhia
Hypoglossal nerve stimulation (HGNS) effectively treats obstructive sleep apnea in select patients. Drug-induced sleep endoscopy (DISE) is required for HGNS candidacy. Data suggest that mandibular advancement (MA) devices and HGNS share similar target populations. We aimed to test the association between MA’s effect on the velum and lateral walls during DISE in relation to the improvement in the apnea-hypopnea index (AHI) with HGNS.
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Clara H. Lee, Everett G. Seay, James W. Reese, Xin Wu, Richard J. Schwab, Brendan Keenan, and Raj C. Dedhia
Determine if clinically acquired cephalometric measurements, specifically soft palate size, can predict hypoglossal nerve stimulation outcomes.
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Clara H. Lee, Graeme B. Mulholland, and Raj C. Dedhia
Examine the correlation between transoral and awake endoscopic examination and investigate their respective ability to predict outcomes of hypoglossal nerve stimulation (HGNS).
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Raj C. Dedhia and Gary F. Bouloux
The purpose of this study was to determine if submental intubation during maxillomandibular advancement (MMA) reduces the development of nasal obstruction in patients with obstructive sleep apnea (OSA).