Study Results
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View full resultsBasic Information
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COMPLETED
PHASE4
40 participants
INTERVENTIONAL
2016-10-31
2017-07-31
Brief Summary
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Detailed Description
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Currently, effective therapies for tinnitus remain limited. Examples of therapies include external sound therapy to mask the perceived sound, behavioral therapy to habituate the patient to the perceived sound, and counseling such as cognitive behavioral therapy to address the bother and impact that tinnitus has on people's lives. Surgical treatment such as nerve transection remains controversial given its lack of efficacy and adverse event profile. There are no drugs approved by the FDA for the treatment of tinnitus. Antidepressant and antianxiety medications are prescribed to patients with tinnitus with limited benefit.
Nitrous oxide is an N-methyl-D-aspartate (NMDA) receptor antagonist, a class of drugs shown to have antidepressant effects. A previous trial examined the use of nitrous oxide as a treatment for major depressive disorder (MDD). Generally, NMDA receptors promote excitation at synapses throughout the auditory pathway and play diverse roles in synaptic development and auditory information processing. In the setting of chronic damage to the auditory system, overactivation of NMDA receptors leads to aberrant spontaneous neuronal firing in the cochlea and auditory brainstem structures, which can further perpetuate damage and disease in a feed-forward mechanism. Studies by Guitton et al. and Puel et al. showed that administration of NMDA receptor antagonists prior to the administration of salicylate was effective in preventing acute excitotoxic tinnitus, establishing that salicylate induces tinnitus through its action on NMDA receptors. Thus, NMDA receptors are thought to be implicated in the generation and perpetuation of several auditory diseases including tinnitus. The investigators hypothesized that the administration of nitrous oxide, an NMDA receptor antagonist, may be a therapeutic strategy in the treatment of tinnitus.
The study was a randomized placebo-controlled crossover trial. Each participant attended two intervention sessions, one "treatment" and one "placebo". Participants eligible to participate in the study were randomly assigned to receive either placebo followed by nitrous oxide or nitrous oxide followed by placebo, according to a computer-generated randomization sequence. Only the statistician and the anesthesiology team directly involved in administration of nitrous oxide and placebo had access to the group assignments. All participants and other study team members administering survey assessments remained blinded. The two intervention sessions were held at least two weeks apart and were indistinguishable in setting, setup, and monitoring in order to maintain blinding for the participants and study team members. All intervention sessions were performed at the Washington University Clinical Research Unit, a component of the Center for Applied Research Sciences.
Conditions
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Keywords
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Study Design
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RANDOMIZED
CROSSOVER
TREATMENT
DOUBLE
Study Groups
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Placebo
Placebo was defined as 50% nitrogen and 50% oxygen for 40 minutes.
Participants are blinded to the order of interventions administered. Participants have been informed prior to consent that one session will contain the nitrous oxide gas mixture, and the other session will contain the placebo gas mixture.
Placebo gas for inhalation
Placebo gaseous mixture (50% nitrogen and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.
Nitrous oxide
Nitrous oxide treatment was defined as 50% nitrous oxide and 50% oxygen for 40 minutes.
Participants are blinded to the order of interventions administered. Participants have been informed prior to consent that one session will contain the nitrous oxide gas mixture, and the other session will contain the placebo gas mixture.
Nitrous oxide gas for inhalation
Nitrous oxide gaseous mixture (50% nitrous oxide and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.
Interventions
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Nitrous oxide gas for inhalation
Nitrous oxide gaseous mixture (50% nitrous oxide and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.
Placebo gas for inhalation
Placebo gaseous mixture (50% nitrogen and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.
Eligibility Criteria
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Inclusion Criteria
* Subjective, unilateral or bilateral, non-pulsatile tinnitus scoring "Bothered more than a little but not a lot", "Bothered a lot", or "Extremely bothered" on the Global Bothersome scale
* Able to give informed consent
* Must be able to read, write, and understand English
Exclusion Criteria
* Schizophrenia
* Schizoaffective disorder
* Substance abuse or dependence (except for remote substance abuse or dependence with remission at least 1 year prior to the study and except for nicotine use disorders)
* Acute medical illness that may pose subject at risk during nitrous oxide administration
* Active psychotic symptoms
* Patients with significant pulmonary disease and/or requiring supplemental oxygen
* Contraindication against the use of nitrous oxide:
* Pneumothorax
* Bowel obstruction
* Middle ear occlusion
* Elevated intracranial pressure
* Chronic cobalamin and/or folate deficiency treated with folic acid or vitamin B12
* Pregnant patients
* Breastfeeding women
* Previous administration of NMDA-receptor antagonists (e.g., ketamine) within the last 3 months
* Tinnitus related to cochlear implantation, retrocochlear lesion, Meniere's Disease, or other known anatomic lesions of the ear or temporal bone
* Tinnitus related to a Workman's Compensation claim or litigation-related event that is still pending.
* Any medical condition, which, in the opinion of the PI, confounds study results or places the subject at greater risk
18 Years
65 Years
ALL
Yes
Sponsors
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Washington University School of Medicine
OTHER
Responsible Party
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Principal Investigators
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Jay F Piccirillo, MD
Role: PRINCIPAL_INVESTIGATOR
Washington University School of Medicine
Locations
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Washington University School of Medicine
St Louis, Missouri, United States
Countries
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References
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Shargorodsky J, Curhan GC, Farwell WR. Prevalence and characteristics of tinnitus among US adults. Am J Med. 2010 Aug;123(8):711-8. doi: 10.1016/j.amjmed.2010.02.015.
Pierce KJ, Kallogjeri D, Piccirillo JF, Garcia KS, Nicklaus JE, Burton H. Effects of severe bothersome tinnitus on cognitive function measured with standardized tests. J Clin Exp Neuropsychol. 2012;34(2):126-34. doi: 10.1080/13803395.2011.623120. Epub 2011 Dec 14.
Tunkel DE, Bauer CA, Sun GH, Rosenfeld RM, Chandrasekhar SS, Cunningham ER Jr, Archer SM, Blakley BW, Carter JM, Granieri EC, Henry JA, Hollingsworth D, Khan FA, Mitchell S, Monfared A, Newman CW, Omole FS, Phillips CD, Robinson SK, Taw MB, Tyler RS, Waguespack R, Whamond EJ. Clinical practice guideline: tinnitus. Otolaryngol Head Neck Surg. 2014 Oct;151(2 Suppl):S1-S40. doi: 10.1177/0194599814545325.
Langguth B, Elgoyhen AB. Current pharmacological treatments for tinnitus. Expert Opin Pharmacother. 2012 Dec;13(17):2495-509. doi: 10.1517/14656566.2012.739608. Epub 2012 Nov 4.
Beebe Palumbo D, Joos K, De Ridder D, Vanneste S. The Management and Outcomes of Pharmacological Treatments for Tinnitus. Curr Neuropharmacol. 2015;13(5):692-700. doi: 10.2174/1570159x13666150415002743.
Jevtovic-Todorovic V, Todorovic SM, Mennerick S, Powell S, Dikranian K, Benshoff N, Zorumski CF, Olney JW. Nitrous oxide (laughing gas) is an NMDA antagonist, neuroprotectant and neurotoxin. Nat Med. 1998 Apr;4(4):460-3. doi: 10.1038/nm0498-460.
Nagele P, Duma A, Kopec M, Gebara MA, Parsoei A, Walker M, Janski A, Panagopoulos VN, Cristancho P, Miller JP, Zorumski CF, Conway CR. Nitrous Oxide for Treatment-Resistant Major Depression: A Proof-of-Concept Trial. Biol Psychiatry. 2015 Jul 1;78(1):10-18. doi: 10.1016/j.biopsych.2014.11.016. Epub 2014 Dec 9.
Sanchez JT, Ghelani S, Otto-Meyer S. From development to disease: diverse functions of NMDA-type glutamate receptors in the lower auditory pathway. Neuroscience. 2015 Jan 29;285:248-59. doi: 10.1016/j.neuroscience.2014.11.027. Epub 2014 Nov 25.
Kaltenbach JA, Zhang J, Finlayson P. Tinnitus as a plastic phenomenon and its possible neural underpinnings in the dorsal cochlear nucleus. Hear Res. 2005 Aug;206(1-2):200-26. doi: 10.1016/j.heares.2005.02.013.
Sahley TL, Nodar RH, Musiek FE. Endogenous dynorphins: possible role in peripheral tinnitus. Int Tinnitus J. 1999;5(2):76-91.
Nicolas-Puel C, Faulconbridge RL, Guitton M, Puel JL, Mondain M, Uziel A. Characteristics of tinnitus and etiology of associated hearing loss: a study of 123 patients. Int Tinnitus J. 2002;8(1):37-44.
Guitton MJ, Dudai Y. Blockade of cochlear NMDA receptors prevents long-term tinnitus during a brief consolidation window after acoustic trauma. Neural Plast. 2007;2007:80904. doi: 10.1155/2007/80904.
Puel JL. Cochlear NMDA receptor blockade prevents salicylate-induced tinnitus. B-ENT. 2007;3 Suppl 7:19-22.
Guitton MJ, Caston J, Ruel J, Johnson RM, Pujol R, Puel JL. Salicylate induces tinnitus through activation of cochlear NMDA receptors. J Neurosci. 2003 May 1;23(9):3944-52. doi: 10.1523/JNEUROSCI.23-09-03944.2003.
Guitton MJ. Tinnitus: pathology of synaptic plasticity at the cellular and system levels. Front Syst Neurosci. 2012 Mar 8;6:12. doi: 10.3389/fnsys.2012.00012. eCollection 2012.
Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001 Sep;16(9):606-13. doi: 10.1046/j.1525-1497.2001.016009606.x.
Standards for Basic Anesthetic Monitoring. Committee of Origin: Standards and Practice Parameters (Approved by the ASA House of Delegates on October 21, 1986, last amended on October 20, 2010, and last affirmed on October 28, 2016) https://www.asahq.org/~/media/Sites/ASAHQ/Files/Public/Resources/standards-guidelines/standards-for-basic-anesthetic-monitoring.pdf
Meikle MB, Henry JA, Griest SE, Stewart BJ, Abrams HB, McArdle R, Myers PJ, Newman CW, Sandridge S, Turk DC, Folmer RL, Frederick EJ, House JW, Jacobson GP, Kinney SE, Martin WH, Nagler SM, Reich GE, Searchfield G, Sweetow R, Vernon JA. The tinnitus functional index: development of a new clinical measure for chronic, intrusive tinnitus. Ear Hear. 2012 Mar-Apr;33(2):153-76. doi: 10.1097/AUD.0b013e31822f67c0.
Andersson G, Westin V. Understanding tinnitus distress: introducing the concepts of moderators and mediators. Int J Audiol. 2008 Nov;47 Suppl 2:S106-11. doi: 10.1080/14992020802301670.
Duckert LG, Rees TS. Placebo effect in tinnitus management. Otolaryngol Head Neck Surg. 1984 Dec;92(6):697-9. doi: 10.1177/019459988409200618.
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Hong HY, Karadaghy O, Kallogjeri D, Brown FT, Yee B, Piccirillo JF, Nagele P. Effect of Nitrous Oxide as a Treatment for Subjective, Idiopathic, Nonpulsatile Bothersome Tinnitus: A Randomized Clinical Trial. JAMA Otolaryngol Head Neck Surg. 2018 Sep 1;144(9):781-787. doi: 10.1001/jamaoto.2018.1278.
Provided Documents
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Document Type: Study Protocol and Statistical Analysis Plan
Other Identifiers
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201606104
Identifier Type: -
Identifier Source: org_study_id