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William J Doyle - One of the best experts on this subject based on the ideXlab platform.

  • a formal description of Middle Ear Pressure regulation
    Hearing Research, 2017
    Co-Authors: William J Doyle
    Abstract:

    Abstract Introduction Middle Ear (ME) Pressure-regulation (MEPR) is a homeostatic mechanism that maintains the ME-environment Pressure-gradient (MEEPG) within a range optimized for “normal” hEaring. Objective Describe MEPR using equations applicable to passive, inter-compartmental gas-exchange and determine if the predictions of that description include the increasing ME Pressure observed under certain conditions and interpreted by some as evidencing gas-production by the ME mucosa. Methods MEPR was modeled as the combined effect of passive gas-exchanges between the ME and: perilymph via the round window membrane, the ambient environment via the tympanic membrane, and the local blood via the ME mucosa and of gas flow between the ME and nasopharynx during Eustachian tube openings. The first 3 of these exchanges are described at the species level using the Fick's diffusion equation and the last as a bulk gas transfer governed by Poiseuille's equation. The model structure is a time-iteration of the equation: P ME g(t=(i+1)Δt)  = ∑ s (P ME s(t=iΔt) +(1/(β ME s V ME )∑ P (Қ P s (P C s(t=(iΔt) -P ME s(t=(iΔt) )). There, P ME g(t=iΔt) and P ME s(t=iΔt) are the ME total and species-Pressures at the indexed times, P C s(t=iΔt) is the species-Pressure for each exchange-compartment, β ME s V ME is the product of the ME species-capacitance and volume, Қ P s is the pathway species-conductance, and ∑ S and ∑ P are operators for summing the expression over all species or exchange pathways. Results When calibrated to known values, the model predicts the empirically measured ME species-Pressures and the observed time-trajectories for total ME Pressure and the MEEPG under a wide variety of physiologic, pathologic and non-physiologic conditions. Conclusions Passive inter-compartmental gas exchange is sole and sufficient to describe MEPR.

  • histamine applied topically to the nasal mucosa increases the transmucosal nitrous oxide exchange for the Middle Ear
    Annals of Otology Rhinology and Laryngology, 2017
    Co-Authors: Miriam S Teixeira, Cuneyt M Alper, Brian S Martin, Selma Cetin, Jenna Elwagaa, William J Doyle
    Abstract:

    OBJECTIVE Determine if the Middle Ear transmucosal nitrous oxide (N2O) exchange rate is affected by nasal inflammation caused by topical application of histamine. METHODS In a randomized, double-blind, crossover study, 20 adults were challenged intranasally with histamine (5 mg) and placebo on separate occasions. At each session, the subjects were fitted with a non-rebreathing mask and breathed room air for 20 minutes, 50% N2O:50% O2 for 20 minutes, and 100% O2 for 10 minutes. Throughout, hEart rate, blood Pressure, and blood O2 saturation were monitored, and bilateral Middle Ear Pressure was recorded by tympanometry every minute. The primary outcome measure was the slope of the Middle Ear Pressure-time function for the 50% N2O:50% O2 breathing period, which is a measure of the transmucosal N2O exchange-constant. The effects of challenge substance, session, and period on the measured vital signs and of treatment, session, Ear disease history, and test Ear on the Pressure-time slopes were evaluated using repeated measures ANOVAs. RESULTS The post-challenge total symptom score and the slope of the Middle Ear Pressure-time function were greater after histamine when compared to placebo challenge. Of the signs, only hEart rate was affected, responding to challenge substance and study period. CONCLUSION The transmucosal N2O exchange rate for the Middle Ear is increased during inflammation caused by nasal histamine exposure.

  • oral pseudoephedrine decreases the rate of transmucosal nitrous oxide exchange for the Middle Ear
    Laryngoscope, 2015
    Co-Authors: William J Doyle, Cuneyt M Alper, Brendan Cullen M Doyle, Miriam S Teixeira, Brian S Martin
    Abstract:

    Objectives/Hypothesis Determine if oral treatment with a vasoconstrictor decreases the blood to Middle Ear exchange rate of the perfusion-limited gas, nitrous oxide (N2O). Study Design Randomized, double-blind, crossover study. Methods Ten adult subjects with and 10 without past Middle Ear disease completed paired experimental sessions, identical except for oral treatment with either pseudoephedrine hydrochloride or lactose placebo. At each session, subjects were fitted with a nonrebreathing mask and breathed room air for 20 minutes (acclimation period), 50% N2O:50% O2 for 20 minutes (experimental period), and 100% O2 for 10 minutes (recovery period). Throughout, hEart rate, blood Pressure, and O2 saturation were monitored, and bilateral Middle Ear Pressures were recorded by tympanometry every minute. The primary outcome was the slope of the Middle Ear Pressure-time function for the experimental period, which estimates the volume N2O exchange rate. Using repeated measures analysis of variance, the effects of group (disease history), treatment (active vs. placebo), and period (1 vs. 2) on the recorded vital signs, and of group, treatment, and Ear (left/right) on the Middle Ear Pressure-time slope were evaluated for statistical significance. Results Statistically significant effects of period on O2 saturation (period 2 > period 1) and of treatment on hEart rate (active > placebo) were documented. Only treatment was statistically significant for the Middle Ear Pressure-time slope, with a shallower slope characterizing the active treatment session. Conclusions The volume exchange rate across the Middle Ear mucosa of perfusion-limited gases can be modulated pharmacologically. Theoretically, similar drugs can be used to reduce the requisite eustachian tube opening efficiency for adequate Middle Ear Pressure regulation. Level of Evidence 1b Laryngoscope, 125:2181–2186, 2015

  • role of the mastoid in Middle Ear Pressure regulation
    Laryngoscope, 2011
    Co-Authors: Douglas J Swarts, Cuneyt M Alper, Dennis J Kitsko, Brian Martin, Sancak Yuksel, Brendan Cullen M Doyle, Richard J M Villardo, William J Doyle
    Abstract:

    Objectives/Hypothesis: Determine the role of mastoid volume in Middle Ear Pressure (MEP) regulation. The hypothesis was that inert gas exchange between blood and Middle Ear (ME) is slower for larger mastoid volumes. Study Design: Prospective. Methods: For 21 enrolled subjects, the bilateral surface areas and volumes of the mastoid and tympanum were measured from computed tomography scans in 20 subjects with a wide range of mastoid volumes. Then, 19 subjects were reclined in a chair, fitted with a non-rebreathing mask and breathed room air for 20 minutes (acclimation), a gas composition of 25% N2O, 20% O2, balance N2 for 30 minutes (experiment), and room air for 30 minutes (recovery). Bilateral MEPs were recorded by tympanometry every 2 minutes. The slopes of the MEP-time functions during N2O breathing were calculated to the first observation of eustachian tube opening and divided by the estimated blood-ME N2O gradient to yield a N2O time constant. Sufficient data were available for 16 right and 11 left MEs to calculate the time constant. Results: MEP did not change during the baseline period, but within 10 minutes of breathing the N2O mixture showed a progressive increase. The right-left correlation for the time constant was 0.87 (n = 10 Ears, P = .001). Regression of the time constants on ME volume showed an inverse relationship (n = 23 Ears, r = −41, P = .05). A better data fit was the curvilinEar relationship predicted by a mathematical model of the mastoid acting as a ME Ear gas reserve. Conclusions: These results support the tested hypothesis that the mastoid could serve as ME gas reserve.

  • the mastoid as a functional rate limiter of Middle Ear Pressure change
    International Journal of Pediatric Otorhinolaryngology, 2007
    Co-Authors: William J Doyle
    Abstract:

    Summary Introduction The physiological function of the mastoid air cell system (MACS) with respect to Middle Ear (ME) Pressure-regulation remains controversial because predictive mathematical models and experimental data to formulate and test hypotheses are lacking. Objective A mathematical description of MACS volume effects on the rate of ME Pressure change is presented; the agreement between published data and model prediction is examined for consistency with the hypothesis that the MACS acts as a functional rate-limiter of ME Pressure change, and an explanation for the relationship between MACS volume and otitis media is discussed. Methods The mathematical description shows that the value of a single, free parameter, termed the “MACS buffering efficiency” (M) determines if MACS volume affects the rate of ME Pressure change caused by diffusive gas exchange. The MACS serves no rate-limiting function for M = 0, acts as a gas sink for M > 1 and acts as a gas reserve (rate-limiter) for M  Results Fitting the model equation to published adult human data yielded an estimate for M of 0.2. This implies that larger MACS volumes are associated with lesser rates of change in ME Pressure caused by diffusive gas exchange and lesser required frequencies of effective Eustachian tube openings to maintain nEar ambient ME Pressures. Conclusion If well-controlled studies confirm M

John J Rosowski - One of the best experts on this subject based on the ideXlab platform.

  • Middle Ear Pressure gain and cochlEar partition differential Pressure in chinchilla
    Hearing Research, 2010
    Co-Authors: Michael E Ravicz, Michael C C Slama, John J Rosowski
    Abstract:

    Abstract An important step to describe the effects of inner-Ear impedance and pathologies on Middle- and inner-Ear mechanics is to quantify Middle- and inner-Ear function in the normal Ear. We present Middle-Ear Pressure gain GMEP and trans-cochlEar-partition differential sound Pressure ΔPCP in chinchilla from 100 Hz to 30 kHz derived from measurements of intracochlEar sound Pressures in scala vestibuli PSV and scala tympani PST and Ear-canal sound Pressure nEar the tympanic membrane PTM. These measurements span the chinchilla’s auditory range. GMEP had constant magnitude of about 20 dB between 300 Hz and 20 kHz and phase that implies a 40-μs delay, values with some similarities to previous measurements in chinchilla and other species. ΔPCP was similar to GMEP below about 10 kHz and lower in magnitude at higher frequencies, decreasing to 0 dB at 20 kHz. The high-frequency rolloff correlates with the audiogram and supports the idea that Middle-Ear transmission limits high-frequency hEaring, providing a stronger link between inner-Ear macromechanics and hEaring. We estimate the cochlEar partition impedance ZCP from these and previous data. The chinchilla may be a useful animal model for exploring the effects of non-acoustic inner-Ear stimulation such as “bone conduction” on cochlEar mechanics.

  • Middle Ear Pressure gain and cochlEar partition differential Pressure in chinchilla
    Hearing Research, 2010
    Co-Authors: Michael E Ravicz, Michael C C Slama, John J Rosowski
    Abstract:

    An important step to describe the effects of inner-Ear impedance and pathologies on Middle- and inner-Ear mechanics is to quantify Middle- and inner-Ear function in the normal Ear. We present Middle-Ear Pressure gain G(MEP) and trans-cochlEar-partition differential sound Pressure DeltaP(CP) in chinchilla from 100 Hz to 30 kHz derived from measurements of intracochlEar sound Pressures in scala vestibuli P(SV) and scala tympani P(ST) and Ear-canal sound Pressure nEar the tympanic membrane P(TM). These measurements span the chinchilla's auditory range. G(MEP) had constant magnitude of about 20 dB between 300 Hz and 20 kHz and phase that implies a 40-micros delay, values with some similarities to previous measurements in chinchilla and other species. DeltaP(CP) was similar to G(MEP) below about 10 kHz and lower in magnitude at higher frequencies, decreasing to 0 dB at 20 kHz. The high-frequency rolloff correlates with the audiogram and supports the idea that Middle-Ear transmission limits high-frequency hEaring, providing a stronger link between inner-Ear macromechanics and hEaring. We estimate the cochlEar partition impedance Z(CP) from these and previous data. The chinchilla may be a useful animal model for exploring the effects of non-acoustic inner-Ear stimulation such as "bone conduction" on cochlEar mechanics.

Cuneyt M Alper - One of the best experts on this subject based on the ideXlab platform.

  • histamine applied topically to the nasal mucosa increases the transmucosal nitrous oxide exchange for the Middle Ear
    Annals of Otology Rhinology and Laryngology, 2017
    Co-Authors: Miriam S Teixeira, Cuneyt M Alper, Brian S Martin, Selma Cetin, Jenna Elwagaa, William J Doyle
    Abstract:

    OBJECTIVE Determine if the Middle Ear transmucosal nitrous oxide (N2O) exchange rate is affected by nasal inflammation caused by topical application of histamine. METHODS In a randomized, double-blind, crossover study, 20 adults were challenged intranasally with histamine (5 mg) and placebo on separate occasions. At each session, the subjects were fitted with a non-rebreathing mask and breathed room air for 20 minutes, 50% N2O:50% O2 for 20 minutes, and 100% O2 for 10 minutes. Throughout, hEart rate, blood Pressure, and blood O2 saturation were monitored, and bilateral Middle Ear Pressure was recorded by tympanometry every minute. The primary outcome measure was the slope of the Middle Ear Pressure-time function for the 50% N2O:50% O2 breathing period, which is a measure of the transmucosal N2O exchange-constant. The effects of challenge substance, session, and period on the measured vital signs and of treatment, session, Ear disease history, and test Ear on the Pressure-time slopes were evaluated using repeated measures ANOVAs. RESULTS The post-challenge total symptom score and the slope of the Middle Ear Pressure-time function were greater after histamine when compared to placebo challenge. Of the signs, only hEart rate was affected, responding to challenge substance and study period. CONCLUSION The transmucosal N2O exchange rate for the Middle Ear is increased during inflammation caused by nasal histamine exposure.

  • oral pseudoephedrine decreases the rate of transmucosal nitrous oxide exchange for the Middle Ear
    Laryngoscope, 2015
    Co-Authors: William J Doyle, Cuneyt M Alper, Brendan Cullen M Doyle, Miriam S Teixeira, Brian S Martin
    Abstract:

    Objectives/Hypothesis Determine if oral treatment with a vasoconstrictor decreases the blood to Middle Ear exchange rate of the perfusion-limited gas, nitrous oxide (N2O). Study Design Randomized, double-blind, crossover study. Methods Ten adult subjects with and 10 without past Middle Ear disease completed paired experimental sessions, identical except for oral treatment with either pseudoephedrine hydrochloride or lactose placebo. At each session, subjects were fitted with a nonrebreathing mask and breathed room air for 20 minutes (acclimation period), 50% N2O:50% O2 for 20 minutes (experimental period), and 100% O2 for 10 minutes (recovery period). Throughout, hEart rate, blood Pressure, and O2 saturation were monitored, and bilateral Middle Ear Pressures were recorded by tympanometry every minute. The primary outcome was the slope of the Middle Ear Pressure-time function for the experimental period, which estimates the volume N2O exchange rate. Using repeated measures analysis of variance, the effects of group (disease history), treatment (active vs. placebo), and period (1 vs. 2) on the recorded vital signs, and of group, treatment, and Ear (left/right) on the Middle Ear Pressure-time slope were evaluated for statistical significance. Results Statistically significant effects of period on O2 saturation (period 2 > period 1) and of treatment on hEart rate (active > placebo) were documented. Only treatment was statistically significant for the Middle Ear Pressure-time slope, with a shallower slope characterizing the active treatment session. Conclusions The volume exchange rate across the Middle Ear mucosa of perfusion-limited gases can be modulated pharmacologically. Theoretically, similar drugs can be used to reduce the requisite eustachian tube opening efficiency for adequate Middle Ear Pressure regulation. Level of Evidence 1b Laryngoscope, 125:2181–2186, 2015

  • role of the mastoid in Middle Ear Pressure regulation
    Laryngoscope, 2011
    Co-Authors: Douglas J Swarts, Cuneyt M Alper, Dennis J Kitsko, Brian Martin, Sancak Yuksel, Brendan Cullen M Doyle, Richard J M Villardo, William J Doyle
    Abstract:

    Objectives/Hypothesis: Determine the role of mastoid volume in Middle Ear Pressure (MEP) regulation. The hypothesis was that inert gas exchange between blood and Middle Ear (ME) is slower for larger mastoid volumes. Study Design: Prospective. Methods: For 21 enrolled subjects, the bilateral surface areas and volumes of the mastoid and tympanum were measured from computed tomography scans in 20 subjects with a wide range of mastoid volumes. Then, 19 subjects were reclined in a chair, fitted with a non-rebreathing mask and breathed room air for 20 minutes (acclimation), a gas composition of 25% N2O, 20% O2, balance N2 for 30 minutes (experiment), and room air for 30 minutes (recovery). Bilateral MEPs were recorded by tympanometry every 2 minutes. The slopes of the MEP-time functions during N2O breathing were calculated to the first observation of eustachian tube opening and divided by the estimated blood-ME N2O gradient to yield a N2O time constant. Sufficient data were available for 16 right and 11 left MEs to calculate the time constant. Results: MEP did not change during the baseline period, but within 10 minutes of breathing the N2O mixture showed a progressive increase. The right-left correlation for the time constant was 0.87 (n = 10 Ears, P = .001). Regression of the time constants on ME volume showed an inverse relationship (n = 23 Ears, r = −41, P = .05). A better data fit was the curvilinEar relationship predicted by a mathematical model of the mastoid acting as a ME Ear gas reserve. Conclusions: These results support the tested hypothesis that the mastoid could serve as ME gas reserve.

Michael C C Slama - One of the best experts on this subject based on the ideXlab platform.

  • Middle Ear Pressure gain and cochlEar partition differential Pressure in chinchilla
    Hearing Research, 2010
    Co-Authors: Michael E Ravicz, Michael C C Slama, John J Rosowski
    Abstract:

    Abstract An important step to describe the effects of inner-Ear impedance and pathologies on Middle- and inner-Ear mechanics is to quantify Middle- and inner-Ear function in the normal Ear. We present Middle-Ear Pressure gain GMEP and trans-cochlEar-partition differential sound Pressure ΔPCP in chinchilla from 100 Hz to 30 kHz derived from measurements of intracochlEar sound Pressures in scala vestibuli PSV and scala tympani PST and Ear-canal sound Pressure nEar the tympanic membrane PTM. These measurements span the chinchilla’s auditory range. GMEP had constant magnitude of about 20 dB between 300 Hz and 20 kHz and phase that implies a 40-μs delay, values with some similarities to previous measurements in chinchilla and other species. ΔPCP was similar to GMEP below about 10 kHz and lower in magnitude at higher frequencies, decreasing to 0 dB at 20 kHz. The high-frequency rolloff correlates with the audiogram and supports the idea that Middle-Ear transmission limits high-frequency hEaring, providing a stronger link between inner-Ear macromechanics and hEaring. We estimate the cochlEar partition impedance ZCP from these and previous data. The chinchilla may be a useful animal model for exploring the effects of non-acoustic inner-Ear stimulation such as “bone conduction” on cochlEar mechanics.

  • Middle Ear Pressure gain and cochlEar partition differential Pressure in chinchilla
    Hearing Research, 2010
    Co-Authors: Michael E Ravicz, Michael C C Slama, John J Rosowski
    Abstract:

    An important step to describe the effects of inner-Ear impedance and pathologies on Middle- and inner-Ear mechanics is to quantify Middle- and inner-Ear function in the normal Ear. We present Middle-Ear Pressure gain G(MEP) and trans-cochlEar-partition differential sound Pressure DeltaP(CP) in chinchilla from 100 Hz to 30 kHz derived from measurements of intracochlEar sound Pressures in scala vestibuli P(SV) and scala tympani P(ST) and Ear-canal sound Pressure nEar the tympanic membrane P(TM). These measurements span the chinchilla's auditory range. G(MEP) had constant magnitude of about 20 dB between 300 Hz and 20 kHz and phase that implies a 40-micros delay, values with some similarities to previous measurements in chinchilla and other species. DeltaP(CP) was similar to G(MEP) below about 10 kHz and lower in magnitude at higher frequencies, decreasing to 0 dB at 20 kHz. The high-frequency rolloff correlates with the audiogram and supports the idea that Middle-Ear transmission limits high-frequency hEaring, providing a stronger link between inner-Ear macromechanics and hEaring. We estimate the cochlEar partition impedance Z(CP) from these and previous data. The chinchilla may be a useful animal model for exploring the effects of non-acoustic inner-Ear stimulation such as "bone conduction" on cochlEar mechanics.

Miriam S Teixeira - One of the best experts on this subject based on the ideXlab platform.

  • histamine applied topically to the nasal mucosa increases the transmucosal nitrous oxide exchange for the Middle Ear
    Annals of Otology Rhinology and Laryngology, 2017
    Co-Authors: Miriam S Teixeira, Cuneyt M Alper, Brian S Martin, Selma Cetin, Jenna Elwagaa, William J Doyle
    Abstract:

    OBJECTIVE Determine if the Middle Ear transmucosal nitrous oxide (N2O) exchange rate is affected by nasal inflammation caused by topical application of histamine. METHODS In a randomized, double-blind, crossover study, 20 adults were challenged intranasally with histamine (5 mg) and placebo on separate occasions. At each session, the subjects were fitted with a non-rebreathing mask and breathed room air for 20 minutes, 50% N2O:50% O2 for 20 minutes, and 100% O2 for 10 minutes. Throughout, hEart rate, blood Pressure, and blood O2 saturation were monitored, and bilateral Middle Ear Pressure was recorded by tympanometry every minute. The primary outcome measure was the slope of the Middle Ear Pressure-time function for the 50% N2O:50% O2 breathing period, which is a measure of the transmucosal N2O exchange-constant. The effects of challenge substance, session, and period on the measured vital signs and of treatment, session, Ear disease history, and test Ear on the Pressure-time slopes were evaluated using repeated measures ANOVAs. RESULTS The post-challenge total symptom score and the slope of the Middle Ear Pressure-time function were greater after histamine when compared to placebo challenge. Of the signs, only hEart rate was affected, responding to challenge substance and study period. CONCLUSION The transmucosal N2O exchange rate for the Middle Ear is increased during inflammation caused by nasal histamine exposure.

  • oral pseudoephedrine decreases the rate of transmucosal nitrous oxide exchange for the Middle Ear
    Laryngoscope, 2015
    Co-Authors: William J Doyle, Cuneyt M Alper, Brendan Cullen M Doyle, Miriam S Teixeira, Brian S Martin
    Abstract:

    Objectives/Hypothesis Determine if oral treatment with a vasoconstrictor decreases the blood to Middle Ear exchange rate of the perfusion-limited gas, nitrous oxide (N2O). Study Design Randomized, double-blind, crossover study. Methods Ten adult subjects with and 10 without past Middle Ear disease completed paired experimental sessions, identical except for oral treatment with either pseudoephedrine hydrochloride or lactose placebo. At each session, subjects were fitted with a nonrebreathing mask and breathed room air for 20 minutes (acclimation period), 50% N2O:50% O2 for 20 minutes (experimental period), and 100% O2 for 10 minutes (recovery period). Throughout, hEart rate, blood Pressure, and O2 saturation were monitored, and bilateral Middle Ear Pressures were recorded by tympanometry every minute. The primary outcome was the slope of the Middle Ear Pressure-time function for the experimental period, which estimates the volume N2O exchange rate. Using repeated measures analysis of variance, the effects of group (disease history), treatment (active vs. placebo), and period (1 vs. 2) on the recorded vital signs, and of group, treatment, and Ear (left/right) on the Middle Ear Pressure-time slope were evaluated for statistical significance. Results Statistically significant effects of period on O2 saturation (period 2 > period 1) and of treatment on hEart rate (active > placebo) were documented. Only treatment was statistically significant for the Middle Ear Pressure-time slope, with a shallower slope characterizing the active treatment session. Conclusions The volume exchange rate across the Middle Ear mucosa of perfusion-limited gases can be modulated pharmacologically. Theoretically, similar drugs can be used to reduce the requisite eustachian tube opening efficiency for adequate Middle Ear Pressure regulation. Level of Evidence 1b Laryngoscope, 125:2181–2186, 2015