ArticlePDF Available

Nebulized Isotonic Saline Versus Water Following a Laryngeal Desiccation Challenge in Classically Trained Sopranos

Authors:

Abstract and Figures

To examine the effects of nebulized isotonic saline (IS) versus sterile water (SW) on self-perceived phonatory effort (PPE) and phonation threshold pressure (PTP) following a surface laryngeal dehydration challenge in classically trained sopranos. In a double-blind, within-subject crossover design, 34 sopranos breathed dry air (relative humidity < 1%) transorally for 15 min and then nebulized 3 mL of IS or SW, or experienced a no-treatment control condition over 3 consecutive weeks. PPE and PTP were measured every 15 min from baseline through 2 hr postdesiccation. PPE increased significantly following the laryngeal desiccation challenge in all 3 treatment conditions (p < .01). After nebulization, PPE returned to baseline for the IS condition only. For the SW and control conditions, PPE remained above baseline during the 2 hr after desiccation. No statistically significant changes in PTP following laryngeal desiccation were observed, although values for the IS condition remained below baseline for nearly 2 hr after nebulization. PPE and PTP were not significantly correlated. Following a laryngeal surface dehydration challenge, classically trained sopranos reported increased vocal effort that persisted for at least 2 hr. Compared with SW, nebulized IS showed promise as an effective way to remediate the adverse, self-perceived effects of laryngeal desiccation.
Content may be subject to copyright.
Nebulized Isotonic Saline Versus
Water Following a Laryngeal
Desiccation Challenge in Classically
Trained Sopranos
Purpose: To examine the effects of nebulized isotonic saline (IS) versus sterile water
(SW) on self-perceived phonatory effort (PPE) and phonation threshold pressure (PTP)
following a surface laryngeal dehydration challenge in classically trained sopranos.
Method: In a double-blind, within-subject crossover design, 34 sopranos breathed
dry air (relative humidity < 1%) transorally for 15 min and then nebulized 3 mL of IS or
SW, or experienced a no-treatment control condition over 3 consecutive weeks. PPE
and PTP were measured every 15 min from baseline through 2 hr postdesiccation.
Results: PPE increased significantly following the laryngeal desiccation challenge
in all 3 treatment conditions (p< .01). After nebulization, PPE returned to baseline
for the IS condition only. For the SW and control conditions, PPE remained above
baseline during the 2 hr after desiccation. No statistically significant changes in PTP
following laryngeal desiccation were observed, although values for the IS condition
remained below baseline for nearly 2 hr after nebulization. PPE and PTP were not
significantly correlated.
Conclusions: Following a laryngeal surface dehydration challenge, classically trained
sopranos reported increased vocal effort that persisted for at least 2 hr. Compared
with SW, nebulized IS showed promise as an effective way to remediate the adverse,
self-perceived effects of laryngeal desiccation.
KEY WORDS: isotonic saline, laryngeal desiccation, singers, hydration,
voice production
Singers are considered vocal athletes who place rigorous standards
and heavy demands on their voices (Broaddus-Lawrence, Treole,
McCabe, Allen, & Toppin, 2000; Edwin, 1995; Kitch & Oates, 1994;
LeBorgne & Dal Vera, 2009). They rely on optimal vocal health to pro-
mote peak performance. Singers believe hydration is essential to effi-
cient voice production (Armbrust, 2001; Behlau & Oliveira, 2009; Fisher,
Ligon, Sobecks, & Roxe, 2001; Franca, 2006; Gregg, 1995; Henry, 2009;
Timmermans, Vanderwegen, & De Bodt, 2005). Popular remedies to im-
prove the singing voice, at least conceptually, often involve a hydration
component (e.g., drinking herbal tea or lemon juice, use of throat sprays,
steam inhalation; Verdolini-Marston, Sandage, & Titze, 1994). Similarly,
clinical advice is frequently offered to maximize hydration either by in-
creasing fluid consumption or by manipulating ambient humidity levels
in the environment. Yet no studies have examined the effects of drinking
more water or increasing environmental humidity on classical singing.
Singers are often considered to be particularly at risk for vocal health
Kristine Tanner
Nelson Roy
The University of Utah, Salt Lake City
Ray M. Merrill
Brigham Young University, Provo, UT
Faye Muntz
Daniel R. Houtz
Voice Disorders Center,
The University of Utah,
Salt Lake City
Cara Sauder
University of New Mexico
Hospitals, Albuquerque
Mark Elstad
George E. Wahlen Department of Veterans
Affairs Medical Center, Salt Lake City, UT,
and The University of Utah, Salt Lake City
Julie Wright-Costa
The University of Utah, Salt Lake City
Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010 DAmerican Speech-Language-Hearing Association 1555
issuesincluding dehydrationbecause of a variety of
factors, such as frequent airplane travel, erratic sched-
ules, changing performance venues, fluctuating environ-
mental humidity levels, voice demands in the presence
of vocal fatigue or illness, and laryngopharyngeal re-
flux,tonameafew(David,1996;Phyland,Oates,&
Greenwood, 1999; Sapir, Mathers-Schmidt, & Larson,
1996; Webb, 2007; Welham & Maclagan, 2004). Thus,
singers represent one of the principal populations of in-
terest in studying the effects of dehydration and hydra-
tion treatments on the voice.
Two primary biological mechanisms are believed to
be responsible for mediating vocal fold hydration and
the laryngeal water environment. The first, systemic hy-
dration, involves the maintenance of normal cell volume
levels through the bodys homeostatic regulation of ex-
tracellular fluids and is believed to affect voice produc-
tion if inadequately managed (Fisher, Ligon, Sobecks, &
Roxe, 2001; Fisher, Telser, Phillips, & Yeates, 2001). The
second mechanism, surface tissue hydration of the vocal
fold mucosa and airway epithelia, is accomplished through
ion transport mechanisms that govern transepithelial
water fluxes, thereby maintaining the liquid layer re-
quired for laryngeal lubrication and efficient vocal fold os-
cillation (Leydon, Sivasankar, Falciglia, Atkins, & Fisher,
2009). Both of these biological mechanisms are thought
to sustain vocal fold vibratory efficiency and voice qual-
ity, although the specific processes responsible for
their combined influence are not fully understood. Pre-
vious research involving hydration and the voice has
used aeromechanical, acoustic, auditoryperceptual, and
participant-based vocal effort measures to examine the
presumed influence of dehydration and hydration treat-
ments on voice production and vocal fold physiology
(Chan & Tayama, 2002; Erickson & Sivasankar, 2010;
Fisher, Ligon, et al., 2001; Fisher, Telser, et al., 2001;
Hemler, Wieneke, & Dejonckere, 1997; Hemler, Wieneke,
van Riel, Lebacq, & Dejonckere, 2001; Jiang, Ng, & Hanson,
1999; Jiang, Verdolini, Aquin o, Ng, & Hanson, 20 00;
Sivasankar & Blazer-Yost, 2009; Sivasankar & Erickson,
2009; Sivasankar, Erickson, Schneider, & Hawes, 2008;
Sivasankar & Fisher, 2002, 2003, 2007, 2008; Sivasankar,
Nofziger, & Blazer-Yost, 2008; Solomon & DiMattia, 2000;
Solomon, Glaze, Arnold, & van Mersbergen, 2003; Tanner,
Roy, Merrill, & Elstad, 2007; Verdolini et al., 2002;
Verdolini, Titze, & Fennell, 1994; Verdolini-Marston et al.,
1994; Verdolini-Marston, Titze, & Druker, 1990; Vintturi,
Alku, Sala, Sihvo, & Vilkman, 2003; Yiu & Chan, 2003).
These studies have explored hydration mechanisms using
ex vivo and in vivo methodologies, the latter involving
participants with normal voices, vocal attrition, vocal fa-
tigue, structural voice disorders, and asthma, and have
collectively documented the influence of both systemic
and surface tissue hydration on voice production.
Aeromechanical estimates of phonation threshold
pressure (PTP; i.e., the minimum amount of subglottic
pressure required to initiate and sustain vocal fold oscil-
lation) have been widely used in vocal fold hydration
studies and have been considered the gold standard
in quasi-objective measures of vocal effort (Titze, 1988).
The use of PTP to estimate changes in vocal effort asso-
ciated with vocal fold hydration has been well described
(Chan & Titze, 1999; Finkelhor, Titze, & Durham, 1988;
Fisher, Ligon, et al., 2001; Fisher & Swank, 1997; Verdolini
et al., 1994; Verdolini-Marston et al., 1990), with changes
in vocal fold viscosity, presumably related to variations in
systemic or surface tissue hydration, generally resulting
in corresponding changes in PTP. However, the changes in
PTP associated with dehydration challenges and hydra-
tion treatments have been relatively modest. In addition,
issues surrounding observer and participant bias, as
well as PTP measurement variability, have been iden-
tified (Erickson & Sivasankar, 2010; Roy, Tanner, Gray,
Blomgren, & Fisher, 2003; Sivasankar & Fisher, 2002,
2003; Tanner et al., 2007). To complicate matters, the
relationship between PTP and participant-based ratings
of self-perceived phonatory effort (PPE) has also been
questioned, and there is an expanding literature to sug-
gest that PTP and PPE are poorly correlated (Erickson
& Sivasankar, 2010; Leydon et al., 2009; Sivasankar,
Erickson, et al., 2008; Tanner et al., 2007; Verdolini et al.,
2002). The interpretation of PPE findings from previous
hydration studies has been made difficult by diverse meth-
ods related to measurement scales and the vocal tasks
sampled (Erickson & Sivasankar, 2010; Leydon et al.,
2009; Roy et al., 2003; Sivasankar, Erickson, et al., 2008;
Sivasankar & Fisher, 2002, 2003; Solomon & DiMattia,
2000; Solomon et al., 2003; Tanner et al., 2007).
These concerns notwithstanding, several investiga-
tors have attempted to elucidate the effects of systemic
hydration on voice production, either in isolation or com-
bined with presumed surface tissue hydration manipula-
tion(s). Verdolini-Marston and colleagues (1990) observed
differences in PTP for six participants who underwent a
combined systemic and surface tissue dehydration chal-
lenge versus hydration treatment and placebo control
conditions. Two later studies replicated and extended
these results in 12 participants with normal voices
(Verdolini et al., 1994) and six with vocal nodules or pol-
yps (Verdolini-Marston et al., 1994). These double-blind,
placebo-controlled studies reported moderate correlations
between PPE and PTP, based on direct magnitude esti-
mation of vocal effort during conversational speech. A later
investigation by Verdolini and colleagues (2002) confirmed
the influence of systemic hydration on PTP in four non-
singers. However, PPE based on direct magnitude esti-
mation of the PTP task failed to produce similar results.
Solomon and colleagues (Solomon & DiMattia, 2000;
Solomon et al., 2003) also have reported evidence for
1556 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
the influence of systemic dehydration on PTP, when com-
bined with a vocally fatiguing task, in two studies involv-
ing four female and four male nonsingers, respectively.
However, no consistent trends in dehydration were ob-
served for PPE based on visual analog scale ratings of
connected speech. In summary, evidence from small-
group studies exists to support the influence of systemic
hydration on PTP, but the relationship with PPE seems
less clear.
Although earlier research has demonstrated effects
of systemic dehydration and rehydration on the voice,
later studies have focused on the mechanisms responsible
for maintaining surface tissue hydration of the vocal fold
mucosa and airway epithelial tissue. Surface tissue hy-
dration is believed to be regulated by ionic transport
mechanisms across the cell membranes of airway and
vocal fold epithelial cells; specifically, the movement of
sodium (Na
+
) and chloride (Cl
) across the cell membrane
results in transepithelial water fluxes that influence the
depth and viscosity of the layer of liquidincluding a
deeper sol (water) layer and an overlaying, more viscous
mucus blanketthat lubricates the larynx (Fisher, Ligon,
et al., 2001; Leydon et al., 2009). It has been postulated
that reductions in environmental relative humidity (RH)
result in reduced depth and increased viscosity of the sur-
face liquid that covers the airway (Yeates, 1991), ulti-
mately producing corresponding increases in PTP and
PPE (Roy et al., 2003, Sivasankar & Fisher, 2002, 2003;
Tanner et al., 2007). Hemler, Wieneke, and Dejonckere
(1997) confirmed the potential influence of low-percentage
RH exposure on phonatory instability measures in eight
participants with healthy voices. Several studies have also
demonstrated statistically significant differences in PTP
and, to some extent, PPEfollowing short-duration ex-
posure to low environmental RH. Sivasankar and Fisher
(2002) studied the effects of 15 min of oral breathing
on PTP and PPE in 20 females with healthy voices. PTP
increased significantly following the oral breathing chal-
lenge, but only six of 10 participants demonstrated sig-
nificant increases in PPE as measured using direct
magnitude estimation (based on singing Happy Birth-
day). Similar results have been observed in participants
with vocal attrition (Sivasankar & Fisher, 2003). In a
later study, Sivasankar, Erickson, et al. (2008) demon-
strated the differential effects of exposure to various per-
centage RH levels based on an oral breathing challenge
in eight participants with a history of vocal fatigue and
eight control participants with normal voices. Using a
repeated measures, within-subject experimental design,
the authors reported that exposure to extremely low RH
resulted in the greatest increase in PTP following oral
breathing, but PTP and PPE were poorly correlated. Col-
lectively these studies substantiate the deleterious ef-
fects of surface tissue dehydration on phonation, and these
findings warrant further examination in the singing voice.
Only two investigations have studied the potential
temporal effects of surface tissue hydration treatments
in vivo. In the first, Roy and colleagues (2003) examined
the effects of three possible laryngeal lubricants on PTP.
Eighteen healthy females nebulized 2 mL of sterile wa-
ter, mannitol, and Entertainers Secret Throat Relief, a
glycerin-based product, for 3 consecutive weeks. A short-
lived lowering of PTP was observed for mannitol but not
for the other two treatments. The authors hypothesized
that mannitol, a hyperosmotic agent, might influence the
transepithelial water fluxes in the direction of the airway,
thereby increasing laryngeal lubrication. In the second,
later investigation, Tanner et al. (2007) examined the ef-
fects of three nebulized osmotic agentshypertonic sa-
line (7%), isotonic saline (0.9%), and (hyposmotic) sterile
wateron PTP and PPE (measured as the self-perceived
vocal effort required to produce the PTP task) in 60 healthy
female nonsingers using a double-blind, randomized ex-
perimental design. Participants first underwent a laryn-
geal desiccation challenge involving oral breathing of
medical-grade dry air for 15 min and were subsequently
observed for 50 min following the administration of each
nebulized treatment. The results indicated a reversal of
the negative effects of laryngeal desiccation on PTP for
the isotonic saline group and, to a lesser extent, for the
sterile water group. PPE was poorly correlated with PTP
measures. The authors suggested that nebulized isotonic
saline into the airway might be potentially advantageous,
perhaps facilitating short-term laryngeal lubrication with-
out altering the ionic balance maintained by systemic and
surface tissue hydration mechanisms in healthy individ-
uals. However, singers were intentionally excluded from
the study, leaving questions surrounding the generaliz-
ability of the findings to this group of elite voice users.
To date, only one investigation has attempted to ex-
amine the potential influence of hydration on the singing
voice. Yiu and Chan (2003) studied the effects of systemic
dehydration and a vocally fatiguing task in 20 amateur
(untrained) singers. Participants combined extended kar-
aoke singing with either a hydration or dehydration con-
dition. The hydration condition included the ingestion of
100 mL of water and a 1-min rest period between songs.
The acoustic measurement results suggested that am-
ateur singers experienced vocal fatigue less quickly with
frequent vocal rest and ingestion of water, as compared
with withholding rest and water. However, on the basis
of auditoryperceptual ratings, no detectable differences
in voice quality were observed between conditions. This
study did not, however, examine the effects of hydration
in classically trained singers, thus limiting the general-
izability of the findings. Vocal training presumably in-
creases ones ability to mitigate or compensate for factors
such as dehydration that might otherwise influence voice
production; therefore, it is necessary to study the effects
of surface tissue dehydration and potential rehydration
Tanner et al.: Nebulized Isotonic Saline Versus Water 1557
conditions in populations with voice training to deter-
mine the external validity of these treatments.
In summary, previous research has established the
potential of both systemic and surface tissue dehydration
and rehydration treatments to influence voice produc-
tion; however, the effects of hydration on the classical
singing voice have not been directly examined. Singers
represent a unique population who place extreme de-
mands on their voices and are believed to be at risk for
vocal health issues, including dehydration. Surface tis-
sue dehydration studies seem particularly useful in terms
of measuring the negative effects of dehydration on voice
production in individuals with normal voices; however, the
variable relationship between PTP and PPE as previ-
ously reported in the literature is somewhat troubling,
particularly when one considers that the individuals
perception of the relative effects of treatments in miti-
gating dehydration will likely influence overarching treat-
ment compliance and success. Thus issues surrounding
the poor relationship between PTP and PPE in assessing
potential hydration treatment benefits should also be ex-
plored. We therefore undertook the present investigation
to address the following experimental questions: What are
the effects of laryngeal desiccation and subsequent nebu-
lized treatments on PTP and PPE in classically trained
sopranos? What is the relationship between PTP and PPE?
Method
Participants
Thirty-four classically trained female sopranos (M=
30.2 years, SD = 11.9, range = 1856) participated in the
study. Singers were identified and recruited from clas-
sical vocal studios at The University of Utah School of
Music and the greater Salt Lake City area. To maximize
the generalizability (i.e., external validity) of this initial
attempt to study surface tissue hydration in the classical
singing voice, a somewhat heterogeneous group of profes-
sional singers, voice teachers, and college students was
included in the study. Singers ranged in their experience
and years of instruction. However, all participants were
at the university level or greater as verified by their voice
teachers or, in the case of the professional singers, via
self-report. None of the singers were experiencing upper
respiratory symptomsor voice problems at the time of the
study. All singers were nonsmokers and denied a history
of asthma or hearing loss. Participant identification and
recruitment methods, as well as data collection proce-
dures, were approved by The University of Utah insti-
tutional review board.
Design
In a double-blind, within-subject crossover design,
each singer attended three data collection sessions on
3 consecutive weeks. Each session involved a laryngeal
desiccation challenge followed by one of three treat-
ment conditions, including nebulized isotonic saline (IS)
(0.9% NaCl) or nebulized hypotonic sterile water (SW) or
a nontreatment control condition. The order of treatment
administration was counterbalanced across weeks. Ses-
sions were scheduled near the same time of day for each
participant across the 3 weeks. Singers were also asked
to use their voices in a similar manner on the day of
each scheduled session prior to data collection. Each
data collection session was approximately 2.5 hr.
Procedure
Laryngeal desiccation and treatment administration
procedures in this study were identical to previous re-
search involving surface tissue hydration in nonsingers
(Tanner et al., 2007). For purposes of laryngeal desicca-
tion, each singer received medical-grade dry air (<1% RH;
78% nitrogen, 21% oxygen, <350 ppm carbon dioxide, and
<5 ppm water) transorally via an oralnasal mask with
the nose clipped. Dry air was administered at a rate of
8 L per minute for 15 min. Following the laryngeal desic-
cation challenge, singers received 3 mL of nebulized IS
or SW or underwent a control condition (sitting quietly
and breathing naturally without oral or nasal specifica-
tion) during a 10-min period. Treatments were admin-
istered using a Micro Mist Nebulizer (TUp-Draft II,
No. 1883, Hudson/ RCI) at a rate of 8 L per minute, with
the nose clipped to prevent nasal inhalation. PPE and
PTP were measured at baseline, immediately postdesic-
cation, and at 5, 20, 35, 50, 65, 80, 95, and 110 min post-
nebulization (i.e., 10 total observations). We selected the
2-hr postdesiccation observation period to facilitate mea-
surement of recovery from laryngeal desiccation during
the control condition on the basis of previous evidence
that 60 min was inadequate to measure laryngeal desic-
cation recovery in nonsingers (Tanner et al., 2007). Par-
ticipants were instructed to sit quietly and did not eat
or drink during the session. Percentage environmen-
tal relative humidity was measured for each session
using a Mannix wireless thermo-hygrometer (Model
EMR963HG). Average environmental humidity levels
were 17.9% (SD = 2.8%) and were not significantly dif-
ferent amongthe three treatment conditions as indicated
by a one-way analysis of variance (ANOVA), F(2, 99) =
0.83, p= .439.
PPE measurement. Because the purpose of this study
was to examine the effects of surface tissue dehydration
and two nebulized treatments on the classical singing
voice, it was important to base self-perceived vocal effort
measures on a singing task. Therefore, each soprano
sang a five-note ascending-to-descending scale at a self-
determined mezzo-forte loudness level, with vibrato, in
legato style as follows: C5, D5, E5, F5, G5, F5, E5, D5,
1558 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
C5. Following this task, singers sustained a pianissimo
G5, with vibrato, for 5 s. These tasks were selected to
sample the upper passaggio, where voice production is
often more difficult and presumably might be more sus-
ceptible to surface tissue hydration changes (Miller, 1986).
For the purposes of the present investigation, each
singer estimated her vocal effort based on the singing
voice task for each of the 10 observations. PPE ratings
were accomplished using Alvin (Version 1.01), a public do-
main software used for listening experiments (Hillenbrand
& Gayvert, 2005). Participants placed the cursor on a
100-point visual analog scale to indicate self-perceived
phonatory effort for the singing task, with the extreme
left indicating no effort and the extreme right indicat-
ing extreme effort. PPE values reflect the number of
points (0100) from the left of the scale, for each of the
10 observations. Singers were not permitted to view pre-
vious self-rating responses during PPE sampling.
PTP measurement. Consistent with previous research
involving PTP acquisition (Erickson & Sivasankar, 2010;
Sivisankar & Fisher, 2003, 2007; Solomon & DiMattia,
2000; Solomon et al., 2003; Verdolini et al., 1994), the
80th percentile of each singersF
o
range during soft pho-
nation was selected for PTP acquisition. To establish each
singersF
o
range, participants glided softly on the vowel
/i/ from their midrange to the highest and lowest sustain-
able 3-s tone. Pitch range was established by rounding
each pitch to the nearest semitone using a piano key-
board, and the 80th percentile was calculated. Singers
were instructed to practice /pi/ repetitions (<5 trials) us-
ing soft phonation, just above a whisper, at the 80th per-
centile target pitch.
We accomplished PTP measurement using the meth-
odology reported in Tanner et al. (2007) and previously
described and validated by others (Milbrath & Solomon,
2003; Roy et al., 2003; Solomon & DiMattia, 2000; Solomon
et al., 2003). In brief, singers produced three sets of seven-
syllable /pi/ strings, just above a whisper, at a rate of
1.5 per second (Holmberg, Perkell, & Hillman, 1987) into
the oralnasal mask of the PERCI Speech-Aeromechanics
Research System, Version 3.21 (MicroTronics). A heated
pneumotachometer (Hans Rudolph) set at 37 °C was
used for PTP measurement. The PERCI system was cal-
ibrated at the beginning of each data collection session,
and calibration was confirmed every 30 min. Pressure
calibration was accomplished using a U-tube manome-
ter. For calibration purposes, pressure variations of less
than 5% were considered within acceptable limits.
During PTP acquisition, an 8-Fr catheter (Kendall
Co.) was placed just behind the central incisors for pur-
poses of oral pressure measurement. All productions
were monitored by the examiner related to mask and
catheter placement and loudness and pitch requirements.
Resampling was undertaken (fewer than three trials) if
productions failed to meet measurement criteria based
on auditoryperceptual judgment by the examiner (e.g.,
supra- or subthreshold productions). For data analysis,
the central five pressure peaks of the middle syllable string
were identified and pairs of adjacent peaks averaged
(Smitheran & Hixon, 1981) to obtain PTP estimates.
Reliability. Although the PTP calculations involved
in the present study were fairly automatic, we confirmed
each oral pressure peak manually to eliminate the pos-
sibility of peak-skipping.Therefore, 10% of the sam-
ples were reanalyzed by the original examiner and a
second examiner to assess reliability for the measure-
ment analysis procedure. Pearson correlations of 1.0 (mean
difference = 0.000 cmH
2
0) and .99 (mean difference =
0.009 cmH
2
0) were obtained as estimates of interjudge
and intrajudge reliability, respectively.
Statistical Methods
One-way ANOVAs were conducted to establish base-
line equivalence among the three treatment conditions
for PPE and PTP. Paired ttests were used to evaluate
desiccation and treatment effects using a corrected alpha
level of .0125 to control for potential Type I error rate
inflation due to multiple comparisons (i.e., four paired
ttests for PPE and PTP, respectively). Third-order poly-
nomial modeling of each treatment condition for PPE
and PTP was performed to evaluate temporal trends.
The Pearson correlation coefficient was used to evaluate
the relationship between PPE and PTP. Data were ana-
lyzed using SAS for personal computers, Version 9.1.
Results
Baseline Equivalence
Although this study involves a within-subject design,
we undertook testing for each of the three treatment con-
ditions for PPE and PTP measures to assess equivalence
at baseline. The results from one-way ANOVAs confirmed
no differences at baseline among the three conditions
for PPE, F(2, 99) = 0.49, p= .613, or PTP, F(2, 99) = 0.25,
p= .780.
PPE
Mean PPE data for each of the 10 observations are
presented in Table 1. PPE increased significantly fol-
lowing laryngeal desiccation, t(101) = 5.74, p= .001, and
in a similar manner across the three treatment condi-
tions, F(2, 99) = 0.49, p= .613. The IS condition produced
PPE values that approximated baseline by 5 min post-
nebulization and that ultimately returned to baseline by
110 min postnebulization. PPE gradually lowered fol-
lowing SW nebulization but did not return to baseline
Tanner et al.: Nebulized Isotonic Saline Versus Water 1559
within the 2 hr. For the control condition, PPE continued to
worsen gradually over the subsequent 2-hr period, and dif-
ferences between baseline and 110 min postnebulization
remained statistically significant, t(33) = 2.91, p= .006.
Differences between baseline and 110 min postnebuliza-
tion were not significant for the IS condition, t(33) = 0.11,
p= .914, or the SW condition, t(33) = 1.07, p= .292.
PTP
Mean PTP data for each of the 10 observations are
presented in Table 2. PTP did not change significantly
following laryngeal desiccation, t(101) = 0.68, p= .497,
and postdesiccation values were similar across the three
treatment conditions, F(2, 99) = 0.14, p= .869. Although
no significant differences were observed immediately
following the laryngeal desiccation challenge, PTP pro-
gressively increased for the SW and control conditions
throughout subsequent observations. At 110 min post-
nebulization, PTP was significantly above baseline for
the SW condition, t(33) = 3.54, p= .001, but not for the
IS condition, t(33) = 0.58, p= .569, or the control con-
dition, t(33) = 1.23, p= .214. Only the PTP values for the
IS condition remained below baseline through 95 min
postnebulization.
Trend Analysis
Although no statistically significant differences
were observed among the three conditions at baseline,
PPE and PTP raw values were numerically greater for
the IS condition as compared with the SW and control
conditions. We therefore performed trend analyses to ex-
amine the relative changes in PPE and PTP from base-
line to each subsequent observation (i.e., mean change)
for each of the three conditions. Third-order polynomial
models provided the best fit for the temporal effects asso-
ciated with laryngeal desiccation and subsequent nebu-
lization. For PPE, models accounted for 79.4% of the
variance in mean change for the IS condition, 40.8% for
the SW condition, and 51.3% for the control condition
(see Figure 1). For PTP, models accounted for 48.7% of
the variance in mean change for the IS condition, 70.1%
for the SW condition, and 67.8% for the control condition
(see Figure 2).
Relationship Between PPE and PTP
To evaluate the relationship between PPE and PTP,
we calculated a Pearson correlation coefficient based on
all PPE and PTP measures. A nonsignificant and slightly
negative correlation coefficient was observed, r=.20,
p= .319, indicating a poor, and slightly inverse, relation-
ship between PPE and PTP.
Discussion
This investigation examined the effects of nebulized
IS and SW following a laryngeal desiccation challenge
and is the first to directly study surface tissue dehy-
dration in classically trained singers. The double-blind,
Table 1. Self-perceived phonatory effort (in millimeters) means and standard deviations (in parentheses) for the isotonic saline, sterile water,
and control conditions at each observation.
Condition Baseline Postdesiccation
Postnebulization
5 min 20 min 35 min 50 min 65 min 80 min 95 min 110 min
Isotonic saline 39.4 (23.3) 46.7 (24.0) 40.9 (25.1) 40.0 (22.7) 40.4 (23.1) 42.4 (26.1) 40.6 (25.8) 40.5 (24.5) 41.7 (24.3) 39.1 (27.7)
Sterile water 34.4 (24.0) 43.6 (25.1) 42.9 (25.4) 42.7 (25.4) 40.0 (24.4) 41.2 (25.5) 40.1 (25.9) 40.3 (25.0) 43.9 (25.2) 38.6 (24.6)
Control (no treatment) 34.9 (20.4) 42.5 (22.0) 42.9 (21.3) 43.2 (20.6) 41.5 (20.3) 42.6 (22.6) 45.1 (22.5) 44.3 (23.9) 44.0 (24.0) 44.2 (23.9)
Table 2. Phonation threshold pressure (in cmH
2
0) means and standard deviations (in parentheses) for the isotonic saline, sterile water, and control
conditions at each observation.
Condition Baseline Postdesiccation
Postnebulization
5 min 20 min 35 min 50 min 65 min 80 min 95 min 110 min
Isotonic saline 12.3 (3.9) 11.9 (4.2) 11.6 (4.5) 11.8 (4.6) 12.2 (4.9) 12.2 (4.7) 12.2 (5.0) 11.8 (4.7) 12.1 (4.8) 12.6 (5.4)
Sterile water 11.7 (5.1) 12.0 (5.4) 12.8 (5.2) 12.5 (5.6) 12.9 (5.2) 13.2 (5.2) 12.8 (5.4) 12.6 (5.2) 13.0 (5.6) 13.0 (5.6)
Control (no treatment) 11.6 (4.7) 11.4 (4.5) 11.7 (4.7) 12.1 (5.2) 11.7 (4.7) 11.6 (4.5) 11.7 (4.1) 12.0 (4.8) 12.1 (4.9) 12.2 (4.7)
1560 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
within-subject crossover design afforded an optimal ex-
amination of the temporal effects associated with laryn-
geal dryness and subsequent treatment. The results
from this study indicate that nebulized IS has the poten-
tial to reverse the perceived adverse effects associated
with laryngeal dryness in singers, whereas nebulized SW
was inadequate in addressing these effects. Following
a short-duration laryngeal desiccation challenge, vocal
effort continued to worsen progressively without treatment
based on PPE and PTP measures. PPE was more sensi-
tive to the temporal effects associated with the laryngeal
desiccation and subsequent treatment paradigm in clas-
sical singers as compared with PTP.
The results of this study provide confirmatory evi-
denceoftheadverseeffectsassociated with short-duration
exposure to dry air via mouth breathing in classical
Figure 1. Mean change in self-perceived phonatory effort from baseline to each subsequent observation
for the isotonic saline, sterile water, and control conditions. PD = postdesiccation; PN = postnebulization.
Figure 2. Mean change in phonation threshold pressure from baseline to each subsequent observation
for the isotonic saline, sterile water, and control conditions.
Tanner et al.: Nebulized Isotonic Saline Versus Water 1561
singers. The sopranos in this study experienced signif-
icant increases in PPE following a 15-min laryngeal
desiccation challenge, results that were replicated in
this same group of singers across three experimental
conditions. In addition, the nebulized IS treatment in
this study reversed the observed desiccation effect
based on PPE measures. These findings suggest that
nebulized IS provides immediate relief from the per-
ceived negative effects associated with brief exposure
to dry air in the singing voice. The reduction in PPE
associated with nebulized IS in singers was not surpris-
ing given previous research supporting the potential effi-
cacy of this treatment based on nonsingers (Ferreira
& Fujita, 1999; Tanner et al., 2007) and animal studies
(Jiang et al., 1999). Additional evidence for the poten-
tial benefits of a nebulized ionic solution on voice pro-
duction has been offered by more recent studies that
have explored the biological mechanisms responsible
for regulating transepithelial water fluxes in the airway
(Sivasankar & Blazer-Yost, 2009; Sivasankar & Fisher,
2007; Sivasankar, Nofziger, & Blazer-Yost, 2008). In-
creased viscosity of the surface liquid on the vocal fold
mucosa is believed to have deleterious effects on vocal
fold vibration and ease of phonation (Ayache, Ouaknine,
Dejonckere, Prindere, & Giovanni, 2004); thus, treatments
that promote a reduction in the viscosity of the surface
liquid in the airway might reverse or offset the negative
effects associated with surface tissue dehydration. It has
also been posited that ion and water transport mecha-
nisms maintain the homeostatic processes of airway epi-
thelial cells and are responsive to changes in surface
liquid ionic imbalance (Jayaraman, Song, & Verkman,
2001; Leydon et al., 2009). Therefore, the introduction
of a solution that is isotonic to the fluid within the epi-
thelial cells of the airway and vocal fold mucosa might
serve to lubricate the larynx without disrupting the ho-
meostatic processes associated with transepithelial ion
and water transport on the airway surface. In essence,
IS might serve simply as a laryngeal lubricant, decreas-
ing the viscosity of the surface liquid on the vocal folds
and thereby reducing vocal effort and increasing vocal
fold vibratory efficiency.
It is interesting, however, that the observed effects
of laryngeal desiccation and subsequent treatment ad-
ministration on PPE in this study were not strongly sup-
ported by PTP measures. Although a short-lived decrease
in PTP was noted between 5 and 20 min following the
administration of nebulized IS, this difference was modest
(0.25 cm H
2
O) and failed to approach statistical signifi-
cance. In addition, no immediate, statistically signifi-
cant desiccation effect was observed for PTP. It should be
noted, however, that PTP was observed to increase over
time for each of the three treatment conditions, a finding
that is consistent with previous research that examined
the temporal effects associated with laryngeal desiccation
(Tanner et al., 2007). It is possible that these findings in-
dicate a delay in laryngeal response to the desiccation
challenge as measured by PTP, or that the greatest in-
fluence of laryngeal desiccation occurs at a later point in
time. Thus, PTP and PPE may be temporally offset, per-
haps explaining the relatively poor correlation between
these two measures. Previous research has overwhelm-
ingly relied on PTP as the gold standard for estimating
changes in vocal effort associated with hydration manip-
ulation. Many of these studies have attempted to offer
corroborating evidence for observed changes in PTP as-
sociated with laryngeal dehydration using a variety of
PPE measures (e.g., direct magnitude estimation, vi-
sual analog scales) and based on a variety of sample
tasks (e.g., PTP productions, oral reading, singing Happy
Birthday), with mixed success (Sivasankar & Fisher,
2002, 2003, 2007; Tanner et al., 2007; Verdolini et al.,
2002). Although some studies have reported relatively
strong agreement between PTP and PPE (Chang &
Karnell, 2004), recent studies have concluded that these
measures are generally poorly correlated, at least in la-
ryngeal hydration research. Still, both measures con-
tinue to be used, with the majority of emphasis placed on
PTP findings. Caution certainly is warranted when in-
terpreting the PPE results alone in the present inves-
tigation; however, the differences observed in previous
studies of PTP following laryngeal desiccation and the
application of surface tissue hydration treatments have
traditionally been modest and somewhat variable (Roy
et al., 2003; Sivasankar & Fisher, 2002, 2003, 2007;
Tanner et al., 2007). It is possible that the PPE mea-
surement task in this studya psychological measure
of vocal effort (Verdolini et al., 1994)was more sensi-
tive to the adverse effects associated with laryngeal des-
iccation than the physiological measure (i.e., PTP). One
potentialexplanation for this difference might be the sen-
sory alterations associated with throat dryness during
singing. PPE, a presumably multidimensional measure,
might be based in part on the sensory changes associated
with throat dryness, whereas PTP is likely insensitive to
these changes. For purposes of PPE measurement, in
this investigation we used a singing task ostensibly aimed
at sampling a purportedly vulnerable area of the soprano
voice (i.e., the upper passaggio) in a group of singers with
a fairly diverse range of vocal abilities and experience.
On the basis of the results of this study, this task seems
to be more sensitive to changes in PPE, perhaps because
it involves the specific vocal task to which it aims to gen-
eralize (i.e., classical singing) and is therefore more eco-
logically valid.
Singers are believed to have a unique set of vocal
skills that may be used to influence voice production. It
seems intuitive that singers might have greater self-
awareness during vocalization. Perhaps singers are able
to compensate for the physiological changes associated
1562 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
with laryngeal desiccation. An increase in cognitive re-
sources allocation or other psychological factors might
be reflected in PPE measures of the singing voice. Some
evidence for the use of compensatory strategies by trained
versus untrained singers has been reported based on func-
tional magnetic resonance imaging studies of the sensory-
motor feedback loop during singing (Zarate & Zatorre,
2008). Singers demonstrated increased activity in the
anterior cingulate cortex, the auditory cortices, and the
putamen as compared with nonsingers during sing-
ing. The authors hypothesized that these regions of the
brain may be increasingly recruited to facilitate auditory
feedback and vocal motor integration with singing voice
training. Additional evidence for compensatory strate-
gies applied by trained versus untrained singers has been
offered from research involving auditory-motor mapping
of the singing voice (Jones & Keough, 2008). It has been
hypothesized that PPE is likely multidimensional, per-
haps involving additional cognitive processes, such as
resource allocation and learning effects (Sivasankar &
Fisher, 2007; Tanner et al., 2007), which might partially
explain the poor correlation between PPE and PTP. Fur-
ther research involving the nature of PPE measurement
and the tasks used to elicit these perceptual ratings is
necessary. With respect to the present study, however, it
is possible that singers were inherently more aware of
all aspects of voice production and thus more sensitive to
modest increases in vocal effort associated with surface
tissue laryngeal dehydration. In addition, singers may
compensate for modest changes in physiological vocal ef-
fort (i.e., PTP), perhaps accounting for more significant
changes in psychological vocal effort (i.e., PPE) and the
apparent disconnect between these two measures.
Nebulized SW produced some benefit in offsetting
the adverse effects associated with laryngeal desiccation
on the singing voice as compared with the nontreatment
control condition. This finding is also consistent with pre-
vious research involving the nebulized administration
of SW following a laryngeal desiccation challenge in non-
singers (Tanner et al., 2007). Although some studies have
used humidifiers to increase percentage RH in combined
surface and systemic laryngeal hydration studies (e.g.,
Verdolini et al., 1994), different delivery approaches for
SW treatment administration have not been explored.
We presumed in the present study that the nebulization
of SW would optimize its effects on voice production, by
facilitating the delivery of small water particles below
the level of the vocal folds and promoting laryngeal lubri-
cation via mucociliary transport mechanisms. However,
it is possible that more traditional delivery mechanisms
of SW (e.g., humidifiers, vaporizers, facial steamers) might
be more beneficial to voice production. These devices
putatively increase the ambient humidity of the envi-
ronment and likely have some benefit to reducing vo-
cal effort. Future studies should compare these more
traditional delivery mechanisms of SW and their effects
on voice production, particularly given their widespread
use in clinical populations and singing communities.
Qualifications and Caveats
Although this study provides additional evidence to
support nebulized IS as a treatment for surface tissue
dehydration, it does not clarify the specific biological
mechanisms responsible for the effects. Additional re-
search, likely involving both in vitro and in vivo method-
ologies, is warranted to explore the precise mechanisms
that influence surface tissue dehydration and treatment
response. Frequency, timing, duration, method of admin-
istration (e.g., nebulizers, humidifiers, facial steamers),
and dosing effects also should be examined. It is possible
that prophylactic administration of nebulized IS might
offset or prevent the negative effects associated with
laryngeal desiccation. Future research should explore
the potential for preventive hydration treatments and
their effects on voice production. Because of the lack
of an immediate, statistically significant desiccation ef-
fect based on PTP measures, some caution is warranted
when interpreting the findings based on PPE data alone.
More research is needed to examine the long-term ef-
fects of dehydration and rehydration treatments, because
most have been prepost designs, although new research
in parallel areas is moving toward the examination of
temporal effects of topical airway treatments on voice pro-
duction (e.g., Erickson & Sivasankar, 2010). Admittedly,
studies examining the temporal and durational effects of
surface tissue dehydration on the voice will require large
groups of participants because of multiple repeated mea-
sures. However, given the variability of PTP and PPE
measures that has been previously observed (Roy et al.,
2003; Tanner et al., 2007), it seems that this would be a
logical next step to elucidate the effects of rehydration
treatments on voice production.
An additional point regarding both PPE and PTP
measures should be considered. In the present study, we
applied a double-blind, counterbalanced experimental
design to prevent any influence of examiner or partici-
pant bias on the results. However, one could argue that
the singers in this study were not completely blinded to
the desiccation challenge, thereby potentially influenc-
ing postdesiccation PPE measures. However, any par-
ticipant awareness related to the desiccation challenge
presumably would have affected both PPE and PTP mea-
sures similarly. Thus, it is somewhat incongruous that
blinding seemingly failed only for PPE but not for PTP. In
addition, the differential response to the nebulized agents
postdesiccation, with IS outperforming SW, suggests that
the postdesiccation improvements observed in PPE for IS
are real and not merely related to possible placebo effects.
It is also notable that neither PTP nor PPE measures
Tanner et al.: Nebulized Isotonic Saline Versus Water 1563
have been explored or validated with respect to their
generalizability to the singing voice. Particularly in light
of our findings, however, we maintain that double blind-
ing is an essential component to studies involving PTP
and PPE measures of vocal effort.
Summary
Singers often practice regimens seemingly intended
to promote laryngeal lubrication and minimize the pres-
ence of thick mucus, including the avoidance of dairy prod-
ucts, the use of humidifiers, and the drinking of lemon tea,
to name a few. Although research involving the regulation
of hydration in the singing voice has been extremely lim-
ited, singers are considered to be a group at particular risk
for developing voice problems, including those related to
dehydration. This large, double-blind, within-subject ex-
perimental trial provides preliminary evidence that sing-
ers experience significant adverse effects associated with
mouth breathing combined with dry air exposure. These
effects appear to worsen over time without treatment.
Nebulized IS shows promise as a potential laryngeal lu-
bricant, possibly facilitating surface tissue hydration and
reducing perceived vocal effort during singing. Future re-
search should explore frequency, duration, delivery, and
dosing effects associated with laryngeal desiccation and
treatment administration as well as the biological mech-
anisms responsible for regulating surface tissue hydra-
tion in the singing voice. In addition, differences based on
voice type, gender, singing style (e.g., classical, belt, pop),
and the presence of other voice-related problems or com-
plaints should be explored.
Acknowledgments
This work was supported, in part, by the Center for
Interdisciplinary Arts and Technology Research Fellowship
Program at The University of Utah. We thank the Division of
OtolaryngologyHead and Neck Surgery, The University of
Utah, School of Medicine, for the use of the Steven D. Gray,
M.D., Voice Research Memorial Lab. The grand piano used
in this study was generously donated to the Voice Disorders
Center at The University of Utah by Sharon Steele-McGee.
We thank Richard Lutz, John Moody, Rajiv Sharma,
and Raghbir Makhar for their assistance during the prepara-
tion of the experimental protocol for this study. We also thank
university students Jill Sharp, Michelle Monical, Ashley
Chacon, and Leah Glasby for their assistance during data
collection and analysis.
References
Armbrust, R. (2001). Rx: A doctor s prescription for voice
care. Back Stage, 42(28), 2728.
Ayache, S., Ouaknine, M., Dejonckere, P., Prindere, P., &
Giovanni, A. (2004). Experimental study of the effects of
surface mucus viscosity on the glottis cycle. Journal of Voice,
18, 107115.
Behlau, M., & Oliveira, G. (2009). Vocal hygiene for the vocal
professional. Current Opinion in Otolaryngology & Head
and Neck Surgery, 17, 149154.
Broaddus-Lawrence, P. L., Treole, K., McCabe, R. B.,
Allen, R. L., & Toppin, L. (2000). The effects of preventive
vocal hygiene education on the vocal hygiene habits and
perceptual vocal characteristics of training singers. Journal
of Voice, 14, 5871.
Chan, R. W., & Tayama, N. (2002). Biomechanical effects of
hydration in vocal fold tissues. OtolaryngologyHead and
Neck Surgery, 126, 528537.
Chan, R. W., & Titze, I. R. (1999). Viscoelastic shear proper-
ties of human vocal fold mucosa: Measurement methodology
and empirical results. The Journal of the Acoustical Society
of America, 106, 20082021.
Chang, A., & Karnell, M. P. (2004). Perceived phonatory
effort and phonation threshold pressure across a prolonged
voice loading task: A study of vocal fatigue. Journal of Voice,
18, 454466.
David, M. (1996). Designing a program of vocal hygiene for
singers. Journal of Singing, 53, 1520.
Edwin, R. (1995). Voice, how do we abuse thee? Let us count
the ways. Journal of Singing, 52, 6566.
Erickson, E., & Sivasankar, M. (2010). Evidence for adverse
phonatory change following an inhaled combination treat-
ment. Journal of Speech, Language, and Hearing Research,
53, 7583.
Ferreira, A. E. M., & Fujita, R. R. (1999, February). A com-
parison of the parameters of laryngitis sicca for different
methods of hydration. Poster presented at the World Voice
Congress, São Paulo, Brazil.
Finkelhor, B. K., Titze, I. R., & Durham, P. L. (1988). The
effect of viscosity changes in the vocal folds on the range of
oscillation. Journal of Voice, 1, 320325.
Fisher, K. V., Ligon, J., Sobecks, J. L., & Roxe, D. M.
(2001). Phonatory effects of body fluid removal. Journal of
Speech, Language, and Hearing Research, 44, 354367.
Fisher, K. V., & Swank, P. R. (1997). Estimating phonation
threshold pressure. Journal of Speech, Language, and Hearing
Research, 40, 11221129.
Fisher, K. V., Telser, A., Phillips, J. E., & Yeates, D. B.
(2001). Regulation of vocal fold transepithelial water fluxes.
Journal of Applied Physiology, 91, 14011411.
Franca, M. C. R. (2006). Effects of hydration on vocal perfor-
mance (Unpublished doctoral dissertation). Southern Illinois
University, Carbondale.
Gregg, J. W. (1995). On hydration. Journal of Singing, 51, 53.
Hemler, R. J., Wieneke, G. H., van Riel, A. M., Lebacq, J.,
& Dejonckere, P. H. (2001). A new method for measuring
mechanical properties of laryngeal mucosa. European
Archives of Otorhinolaryngology, 258, 130136.
Hemler, R. J. B., Wieneke, G. H., & Dejonckere, P. H.
(1997). The effect of relative humidity of inhaled air on
acoustic parameters of voice in normal subjects. Journal of
Voice, 11, 295300.
Hemler, R. J. B., Wieneke, G. H., Lebacq, J., & Dejonckere,
P. H. (2001). Laryngeal mucosa elasticity and viscosity
1564 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
in high and low relative air humidity. European Archives
of Otorhinolaryngology, 258, 125129.
Henry, J. (2009). Safe singing. Back Stage, 50, 21.
Hillenbrand, J. M., & Gayvert, R. T. (2005). Open source
software for experiment design and control. Journal of
Speech, Language, and Hearing Research, 48, 4560.
Holmberg, E. B., Perkell, J. S., & Hillman, R. E. (1987).
Methods for using a noninvasive technique for estimating
glottal functions from oral measurements. Speech Commu-
nication Group Working Papers, Massachussetts Institute
of Technology, 5, 4758.
Jayaraman, S., Song, Y., & Verkman, A. (2001). Airway
surface liquid osmolarity measured using fluorophore-
encapsulated liposomes. Journal of General Physiology,
117, 423430.
Jiang, J., Ng, J., & Hanson, D. (1999). The effects of rehy-
dration on phonation in excised canine larynges. Journal
of Voice, 13, 5159.
Jiang, J., Verdolini, K., Aquino, B., Ng, J., & Hanson, D.
(2000). Effects of dehydration on phonation in excised canine
larynges. Annals of Otology, Rhinolaryngology, and Laryn-
gology, 109, 568575.
Jones, J. A., & Keough, D. (2008). Auditory-motor mapping
for pitch control in singers and nonsingers. Experimental
Brain Research, 190, 279287.
Kitch, J. A., & Oates, J. (1994). The perceptual features of
vocal fatigue as self-reported by a group of actors and singers.
Journal of Voice, 8, 207214.
LeBorgne, W. D., & Dal Vera, R. (2009). Coaching vocal
athletes. Teaching Theatre, 20(2), 49.
Leydon, C., Sivasankar, M., Falciglia, D. L., Atkins, C., &
Fisher, K. V. (2009). Vocal fold surface hydration: A review.
Journal of Voice, 23, 658665.
Milbrath, R. L., & Solomon, N. P. (2003). Do vocal warm-up
exercises alleviate vocal fatigue? Journal of Speech, Language,
and Hearing Research, 46, 422436.
Miller, R. (1986). The structure of singing: System and art in
vocal technique. New York, NY: Schirmer.
Phyland, D. J., Oates, J., & Greenwood, K. M. (1999). Self-
reported voice problems among three groups of professional
singers. Journal of Voice, 13, 602611.
Roy, N., Tanner, K., Gray, S. D., Blomgren, M., & Fisher,
K. V. (2003). An evaluation of the effects of three laryngeal
lubricants on phonation threshold pressure (PTP). Journal
of Voice, 17, 331342.
Sapir, S., Mathers-Schmidt, B., & Larson, G. W. (1996).
Singersand non-singersvocal health, vocal behaviours, and
attitudes towards voice and singing: Indirect findings from
a questionnaire. European Journal of Disorders of Com-
munication, 31, 193209.
Sivasankar, M., & Blazer-Yost, B. (2009). Effects of long-
acting beta adrenergic agonists on vocal fold ion transport.
The Laryngoscope, 119, 602607.
Sivasankar, M., & Erickson, E. (2009). Short-duration accel-
erated breathing challenges affect phonation. The Laryngo-
scope, 119, 16581663.
Sivasankar, M., Erickson, E., Schneider, S., & Hawes, A.
(2008). Phonatory effects of airway dehydration: Prelimi-
nary evidence for impaired compensation to oral breathing
in individuals with a history of vocal fatigue. Journal of
Speech, Language, and Hearing Research, 51, 14941506.
Sivasankar, M., & Fisher, K. V. (2002). Oral breathing in-
creases Pth and vocal effort by superficial drying of vocal fold
mucosa. Journal of Voice, 16, 172181.
Sivasankar, M., & Fisher, K. V. (2003). Oral breathing chal-
lenge in participants with vocal attrition. Journal of Speech,
Language, and Hearing Research, 46, 14161427.
Sivasankar, M., & Fisher, K. V. (2007). Vocal fold epithelial
response to luminal osmotic perturbation. Journal of Speech,
Language, and Hearing Research, 50, 886898.
Sivasankar, M., & Fisher, K. V. (2008). Vocal folds detect
ionic perturbations on the luminal surface: An in vitro
investigation. Journal of Voice, 22, 408419.
Sivasankar, M., Nofziger, C., & Blazer-Yost, B. (2008).
Cyclic adenosine monophosphate regulation of ion trans-
port in porcine vocal fold mucosae. The Laryngoscope,
118, 15111517.
Smitheran, J. R., & Hixon, T. J. (1981). A clinical method
for estimating laryngeal airway resistance during vowel
production. Journal of Speech and Hearing Disorders, 46,
138146.
Solomon, N. P., & DiMattia, M. S. (2000). Effects of a vocally
fatiguing task and systemic hydration on phonation thresh-
old pressure. Journal of Voice, 14, 341362.
Solomon, N. P., Glaze, L. E., Arnold, R. R., & van
Mersbergen, M. (2003). Effects of a vocally fatiguing task
and systemic hydration on mens voices. Journal of Voice,
17, 3146.
Tanner, K., Roy, N., Merrill, R. M., & Elstad, M. (2007). The
effects of three nebulized osmotic agents in the dry larynx.
Journal of Speech, Language, and Hearing Research, 50,
635646.
Timmermans, B., Vanderwegen, J., & De Bodt, M. S.
(2005). Outcome of vocal hygiene in singers. Current Opinion
in Otolaryngology & Head and Neck Surgery, 13, 138142.
Titze, I. R. (1988). The physics of small-amplitude oscillation
of the vocal folds. The Journal of the Acoustical Society of
America, 83, 15361552.
Verdolini, K., Min, Y., Titze, I. R., Lemke, J., Brown, K.,
van Mersbergen, M., . . . Fisher, K. (2002). Biological
mechanisms underlying voice changes due to dehydration.
Journal of Speech, Language, and Hearing Research, 45,
268281.
Verdolini, K., Titze, I. R., & Fennell, A. (1994). Dependence
of phonatory effort on hydration level. Journal of Speech
and Hearing Research, 37, 10011007.
Verdolini-Marston, K., Sandage, M., & Titze, I. R. (1994).
Effect of hydration treatments on laryngeal nodules and
polyps and related voice measures. Journal of Voice, 8, 3047.
Verdolini-Marston, K., Titze, I. R., & Druker, D. G. (1990).
Changes in phonation threshold pressure with induced
conditions of hydration. Journal of Voice, 4, 142151.
Vintturi, J., Alku, P., Sala, E., Sihvo, M., & Vilkman, E.
(2003). Loading-related subjective symptoms during a
vocal loading test with special reference to gender and
some ergonomic factors. Folia Phoniatrica et Logopaedica,
55, 5569.
Tanner et al.: Nebulized Isotonic Saline Versus Water 1565
Webb, J. L. (2007). Promoting vocal health in the choral
rehearsal. Music Educators Journal, 93(5), 2631.
Welham, N. V., & Maclagan, M. A. (2004). Vocal fatigue in
young trained singers across a solo performance: A prelim-
inary study. Logopedics Phoniatrics Vocology, 29, 312.
Yeates, D. (1991). Mucus rheology. In J. B. West (Ed.), The
lung: Scientific foundations (pp. 197203). New York, NY:
Raven Press.
Yiu, E. M., & Chan, R. M. (2003). Effect of hydration and
vocal rest on the vocal fatigue in amateur karaoke singers.
Journal of Voice, 17, 216227.
Zarate, J. M., & Zatorre, R. J. (2008). Experience-dependent
neural substrates involved in vocal pitch regulation during
singing. NeuroImage, 40, 18711887.
Received November 17, 2009
Revision received February 8, 2010
Accepted March 25, 2010
DOI: 10.1044/1092-4388(2010/09-0249)
Contact author: Kristine Tanner, Department of Communication
Sciences and Disorders and Division of OtolaryngologyHead
& Neck Surgery, The University of Utah, Salt Lake City,
UT 84112. E-mail: kristine.tanner@hsc.utah.edu.
1566 Journal of Speech, Language, and Hearing Research Vol. 53 15551566 December 2010
DOI: 10.1044/1092-4388(2010/09-0249)
2010;
2010;53;1555-1566; originally published online Aug 10, J Speech Lang Hear Res
Sauder, Mark Elstad, and Julie Wright-Costa
Kristine Tanner, Nelson Roy, Ray M. Merrill, Faye Muntz, Daniel R. Houtz, Cara
Challenge in Classically Trained Sopranos
Nebulized Isotonic Saline Versus Water Following a Laryngeal Desiccation
http://jslhr.asha.org/cgi/content/full/53/6/1555#BIBLaccess for free at: The references for this article include 14 HighWire-hosted articles which you can
This information is current as of December 12, 2010
http://jslhr.asha.org/cgi/content/full/53/6/1555
located on the World Wide Web at:
This article, along with updated information and services, is
... 4,8 Dehydration of the vocal folds has been reported to elicit undesirable subjective sensations such as dryness of the throat and increased perceived phonatory effort (PPE). 18,19 Dehydration studies have also reported increased perturbation values and decreased harmonics-to-noise-ratio (HNR) values, 20,21 and an increase in the minimum subglottal pressure needed to initiate and maintain vocal fold vibration (aka phonation threshold pressure, PTP). 19,22,23 Additionally, Hemler and colleagues 7 have stated that sufficient impairment of the vocal-fold oscillatory properties may induce compensatory hypertension during voice production. ...
... 18,19 Dehydration studies have also reported increased perturbation values and decreased harmonics-to-noise-ratio (HNR) values, 20,21 and an increase in the minimum subglottal pressure needed to initiate and maintain vocal fold vibration (aka phonation threshold pressure, PTP). 19,22,23 Additionally, Hemler and colleagues 7 have stated that sufficient impairment of the vocal-fold oscillatory properties may induce compensatory hypertension during voice production. This may further elicit other voice problems, such as muscle tension dysphonia. ...
... However, in the study of Roy and colleagues, 30 PTP did not decrease after superficial hydration, although the lubricant used was a diuretic (Mannitol). Furthermore, Tanner and colleagues 19,31 observed that PTP did not change notably after the superficial hydration intervention when the participants had first breathed dry air. After all, the research results concerning the efficiency of the superficial hydration seem to be quite ambiguous. ...
Article
Full-text available
Objectives This study examined the efficacy of the NHS waterpipe as a superficial hydration treatment in voice production in healthy young women. Study Design This is a prospective, single-blind, within- and between-subject experimental design. Methods Thirty six female university students (mean age 24.6 years, range 19–45 years) were recruited to the study. Participants were randomized to two experimental groups (E1 and E2) and a control group. E1 underwent hydration treatment with the NHS waterpipe filled with 0.9% saline that was immersed in a cup of heated water. E2 underwent a similar treatment but without heated immersion. The control group received no treatment. Acoustic Voice Quality Index (AVQI v03.01) and its subparameters, phonation threshold pressure, self-perceived phonatory effort and sensation of throat dryness was measured at three time points (before the intervention and immediately and 15 minutes after it). Results The Tilt of the AVQI's subparameters increased significantly in the E1 (P = 0.027) and E2 groups (P = 0.027) after the intervention. Furthermore, the E1 group had significantly lower harmonics-to-noise-ratio values at the third measurement point compared to the E2 group (P = 0.023). These findings may result from fluid transported to the vocal fold level. The sensations of throat dryness decreased in the E1 (P = 0.001) and E2 groups (P < 0.0005) after the intervention. Perceived phonatory effort decreased statistically significantly at the final measurement point in the E1 (P = 0.002) and E2 (P = 0.031) groups. No variables changed in the control group. Conclusions The waterpipe seems to be efficient in hydrating vocal folds on single use. It seems to be more efficient when employed with a hot water bath, albeit slightly impairing some acoustic values in the short term. Without the heated fluid, it still seems to decrease sensations of throat dryness and affect acoustic voice quality. The waterpipe does not seem to have an effect on phonation threshold pressure, and it seems to lower self-perceived effort just as efficiently whether the waterpipe is employed using a hot water bath or not. Further research is needed to prove the efficacy of long-term usage and usage with voice patients.
... A hidratação laríngea tem sido descrita como importante recurso para o cuidado com a voz por promover melhora nas características biomecânicas da mucosa das pregas vocais, e consequentemente, na qualidade da emissão vocal (1,2) . A hidratação pode ser realizada na forma sistêmica (3) e/ou diretamente no trato vocal, denominada de hidratação de superfície das pregas vocais (4)(5)(6)(7)(8)(9) . A hidratação laríngea vem sendo estudada em diferentes populações, como profissionais da voz, incluindo cantores (3)(4)(5)10) , professores (7,9) , indivíduos com risco para patologias laríngeas ou queixas vocais (11) e, ainda em sem distúrbios vocais (6) . ...
... A hidratação pode ser realizada na forma sistêmica (3) e/ou diretamente no trato vocal, denominada de hidratação de superfície das pregas vocais (4)(5)(6)(7)(8)(9) . A hidratação laríngea vem sendo estudada em diferentes populações, como profissionais da voz, incluindo cantores (3)(4)(5)10) , professores (7,9) , indivíduos com risco para patologias laríngeas ou queixas vocais (11) e, ainda em sem distúrbios vocais (6) . ...
... Estudos envolvendo a hidratação das pregas vocais abrangem variáveis como, por exemplo, o tipo de solução que melhor hidrata as pregas vocais (4,5) , a umidade do ambiente em que os sujeitos foram expostos (normal ou modificado por umidificadores) (8) e os efeitos da desidratação e reidratação nas pregas vocais (4,7,10) . Para o desfecho dos estudos foram utilizadas diversas formas de avaliação como a autopercepção (4,5,8,9) , pressão de limiar de fonação (4,5) medidas acústicas lineares (5)(6)(7)9,10) e não lineares (8) e, perceptivoauditiva (7)(8)(9)(10) . ...
Article
Full-text available
Objetivo Analisar o efeito imediato da hidratação de superfície laríngea associado à técnica de vibração sonorizada de língua (TVSL) em cantores. Método Participaram 30 cantores, sem queixas vocais ou alterações laríngeas, divididos em grupo controle (GC) e experimental (GE). O GC realizou a TVSL por cinco minutos. O GE foi submetido à nebulização de 3 ml de solução salina seguido da TVSL por cinco minutos. Foram realizadas autoavaliação vocal, análise acústica e avaliação perceptivoauditiva nos momentos pré (PréTVSL) e pós (PTVSL) no GC e no momento pré (PréHTVSL), pós hidratação (PH) e pós hidratação+TVSL (PHTVSL) no GE. Na autoavaliação foram avaliados: qualidade, estabilidade, rouquidão e intensidade vocal. Os parâmetros acústicos analisados foram Frequência Fundamental; Jitter%; Shimmer%, Noise-to-harmonic Ratio e Cepstral Peak Prominence-Smoothed (CPPs). A avaliação perceptivoauditiva foi realizada por uma fonoaudióloga experiente. Resultados Na comparação dos resultados da autoavaliação, entre os grupos, observou-se melhora da percepção de estabilidade e intensidade vocal no PTVSL (GC) em relação ao PH (GE). Na comparação entre os momentos do GE houve diferença estatística na sensação de intensidade vocal, apontando melhor resultado para PHTVSL. Não houve diferença estatística entre os grupos investigados na avaliação perceptivoauditiva e na análise acústica. Conclusão A hidratação laríngea de superfície não potencializa o efeito da TVSL em cantores em condição natural de hidratação com uso de 3ml de nebulização. Para os profissionais da voz com grande demanda vocal, a hidratação de superfície pode ser introduzida durante a utilização da voz, para manutenção da qualidade vocal, sem perda de sua qualidade.
... 26 Although both biological hydration mechanisms are believed to maintain vocal fold vibration and optimal voice quality, the exact processes responsible for their joint influence are not fully understood. 27 When professional singers do not hydrate adequately, dehydration leads to the mucus layer on the vocal folds becoming thick and viscous, simultaneously increasing the weight and dryness of the vocal folds, impeding smooth vibratory patterns, and elevating vulnerability to vocal injury. 28 Lubricated vocal fold mucosa necessitates less subglottic air pressure compared to when the vocal mechanism is dry, thus sufficient surface hydration is essential to optimal vocal fold oscillation. ...
... 31 The application of superficial hydration through the use of nebulisers, humidifiers, and steam inhalation, has been common practice as a means to maintain optimal voice quality over the years. 27 Clinicians recommend the application of nebulisation, humidification and/or steam inhalation to inhibit vocal fold drying. 24 Despite the fact that these recommendations have grown popular amongst professional voice users, the underlying mechanisms contributing to maintaining adequate vocal fold hydration are in question. ...
... 24 Despite the fact that these recommendations have grown popular amongst professional voice users, the underlying mechanisms contributing to maintaining adequate vocal fold hydration are in question. 27,32,33 Thus, the validity of these clinical recommendations must be questioned and substantiated by current evidence-based research. ...
Article
Objective: The aim of this study was to describe the effect of superficial hydration, with or without systemic hydration, on voice quality in future female professional singers by assessing acoustic and perceptual parameters of voice production as well as symptoms of vocal fatigue. Study design: This is an experimental design study. Methods: A study was performed on a sample of 24 female voice majors to ascertain the effect of superficial hydration, with or without systemic hydration, on acoustic parameters and perception of vocal fatigue. The study replicated a prior study by van Wyk et al (2016) with some modifications; we looked at the effect of both systemic and superficial hydration independently and together on voice quality and vocal fatigue. Acoustic measurements including GRBASI, jitter, shimmer, F0 MPT, frequency min and max, intensity min and max, and dysphonia severity index were measured along with perceived vocal fatigue using the Vocal Fatigue Index. Results: A statistically significant increase in MPT values were obtained when comparing pre- and post-test results of the hypo hydrated (P = 0.015) and superficial hydration condition (P = 0.004). A significant increase in frequency min (Hz) within the hypo hydrated condition was also observed (P = 0.019). A significant increase was observed in the intensity min (dB) (P = 0.010) and F0 min (Hz) (P = 0.002) within the combined hydration condition. Also, when superficial hydration was applied, mean shimmer % (P = 0.016), MPT (sec) (P = 0.003) and dysphonia severity index (P = 0.020) scores increased significantly in a between-group, post-test comparison. A significant reduction in mean intensity max (dB) (P = 0.049) and intensity min (dB) (P = 0.018) was also observed. Conclusions: This study demonstrates that the use of superficial hydration results in positive outcomes of perceptual parameters of voice quality and symptoms of vocal fatigue in future female professional singers. However, mixed results were observed regarding the acoustic parameters of voice. The superficial hydration data is compelling enough to warrant implementing in a vocal hygiene protocol for singers.
... [4][5][6][7][8] Although traditionally nebulizers are used to manage conditions of the lower airway, 9 certain nebulized treatments also improve symptoms of the larynx and upper airway. [10][11][12][13][14][15][16] Nebulized hypertonic saline (3% Na + Cl -) has been shown to improve mucociliary clearance in people with cystic fibrosis. 10 Nebulized liquid mannitol was found to improve voice function in healthy speakers. ...
... 11 More recently, nebulized isotonic saline (0.9% Na + Cl -) has been shown to improve voice function and throat dryness in healthy speakers, singers, and people with Sjögren's Syndrome. [12][13][14][15][16] Because people with SGS experience upper airway symptoms that are similar to those with cystic fibrosis and Sjögren's (eg, thick mucus, cough, voice problems), nebulized saline may also improve laryngeal symptoms in this population. The purpose of the present investigation was to examine current nebulizer practices in a large cohort of people with SGS. ...
... A literature base exists regarding the use of nebulized isotonic saline to address dryness and voice symptoms. [12][13][14][15][16] It has been theorized that isotonic saline in particular might improve mucociliary clearance in those with healthy ciliary beat. Furthermore, isotonic saline is believed to thin and increase the spinnability of the mucus blanket while maintaining the depth of the water blanket covering airway epithelial cells. ...
Article
Objective:: People with subglottic stenosis (SGS) may experience laryngeal symptoms that pose significant challenges to management. This study surveyed the use and effects of nebulized treatments on laryngeal symptoms in a large cohort of adults with SGS. Methods:: A survey of nebulized treatment practices was distributed to an online international community of over 2000 members; 316 individuals (298 female, 1 male, 17 declined to specify; age 25+ years) completed the survey. Results:: Nearly half (144) of participants had tried a nebulizer in the past. Among those, half currently used nebulized treatments; the majority used these treatments regularly and for greater than 1 year. The most frequently reported treatments included isotonic saline (0.9% Na+Cl-) or hypertonic saline (3% Na+Cl-). Symptoms improved by these treatments included thick mucus (69%), cough (57%), throat dryness (31%), stridor (28%), and voice (15%). The most frequently reported limitations to nebulizer use included time, noise, and portability. Conclusion:: Among those individuals with SGS who have tried nebulized treatments, nearly half experienced relief from secondary laryngeal symptoms. Additional efficacy research is needed, particularly with respect to treatment type and dosage. The results are encouraging given the adverse impact these laryngeal symptoms can have on activities of daily living and quality of life.
... 19 Several studies have confirmed the adverse voice effects of inhaling air of 0% relative humidity (even for 10 minutes) transorally, essentially desiccating the larynx. [45][46][47][48][49] Likewise, many studies have demonstrated the value of nebulized water and/or saline on voice function following desiccation experiments. [47][48][49] It seems that coupling humidification with PAP attenuates any adverse phonatory effects. ...
... [45][46][47][48][49] Likewise, many studies have demonstrated the value of nebulized water and/or saline on voice function following desiccation experiments. [47][48][49] It seems that coupling humidification with PAP attenuates any adverse phonatory effects. Furthermore, the putative voice benefits of humidified PAP appear related to compliance with PAP rather than the absolute duration of PAP use (ie, in months or years) or the duration of OSA symptoms. ...
Article
Objective: Obstructive sleep apnea (OSA) is characterized by frequent interruptions in breathing related to upper airway collapse during sleep and may adversely affect phonatory function. This study aimed to: (1) establish the prevalence, risks, and quality of life burden of voice disorders in OSA and (2) explore the relation between voice disorders and positive airway pressure (PAP) therapy. Study design: Cross-sectional, descriptive epidemiology study. Methods: Analyses were based on 94 individuals with OSA (53 men, 41 women; mean age = 54.7 ± 12.8 years) who completed a telephone interview. Results: Twenty-eight percent of participants reported having a current voice disorder. Of those with a current voice disorder, 83% had experienced symptoms for at least a year, and 58% had symptoms for at least 4 years. The prevalence of a current voice disorder was greater in women than men (44% vs 15%, P = .0020) but did not vary significantly across different age groups, body mass index (BMI), apnea/hypopnea index (AHI) severity, or medical history. After adjusting for sex, consistent use of PAP therapy (with humidification) was associated with (1) lower occurrence of voice disorders in women (Mantel-Haenszel [MH] χ2P = .0195), (2) reduced snoring severity accompanied by fewer voice disorders in men (MH χ2P = .0101), and (3) fewer reports of acid reflux as a possible trigger for voice problems (MH χ2P = .0226). Patients with OSA who also had a current voice disorder experienced lower overall quality of life compared to those without. Conclusions: Chronic, longstanding voice disorders are common in women with OSA and produce significant adverse effects on quality of life. Nightly PAP use (with humidification) was associated with fewer voice symptoms and reduced severity of snoring and acid reflux as possible contributors. Further research is necessary to better understand the origin of these voice disorders in OSA and their potential response to treatment.
... Similar findings were reported by Tanner et al as PPE was increased after dehydration and statically significant improvement was seen soon after hydration. 27 In case of female participants Max-I was reduced *p=0.017 and p=0.0113 which were revealed that p>0.05 after vocal loading both in VRP and SRP. ...
Article
Full-text available
p> Background: Vocal loading is a phenomenon that affects the vocal folds and voice parameters. Prolonged vocal loading may cause vocal fatigue. Hydration is one of the easiest precautions to reduce the effect of vocal loading. Voice range profile is an analysis of a participant’s vocal intensity and fundamental frequency ranges. Speech range profile is a graphical display of frequency intensity interactions occurring during functional speech activity. Phonetogram software can analyse VRP and SRP. Methods: Total sixty normophonic participants (thirty male and thirty female) were included in this study. Phonetogram, version 4.40 by Tiger DRS, software used to measure the voice range profile and speech range profile. For VRP, participants were asked to produce vowel /a/ and a passage reading task was given for SRP measurement. Results: All sample recording were done at pre vocal loading task, VLT and after hydration. Parameter that were used to measure the effects were Fo-range, semitone, max-F, min-F, SPL range, max-I, min-I, area (dB). Result showed that after VLT all other parameters like Fo-range, semitone, max-F, min-F, SPL range, max-I, min-I, area (dB) in VRP and SRP were reduced except min-F VRP in male, min-I VRP and min-I SRP in both male and female participants. After hydration all other parameters were improved except max-F VRP and min-F VRP in female, max-I VRP, min-F VRP and area VRP. Conclusions: This study concluded that vocal loading has negative impact on vocal fold tissue and mass. </p
... In another study, researchers compared the use of nebulized isotonic saline with nebulized sterile water in classically trained sopranos. 16 There were no statistically significant changed in PTP after the desiccation challenge, however self-perceived phonatory effort (PPE) increased significantly postdesiccation. PPE returned to baseline for those treated with isotonic saline, whereas for sterile water and no intervention, PPE remained above baseline during the two hours postdesiccation. ...
Article
Objective: This study was designed to evaluate the effectiveness of either steam, semi-occluded vocal tract (SOVT) exercises, or a combination of both as a speaking voice warm-up strategy to be used at the start of the day. Methods/design: This prospective study assessed the impact of three different vocal warm-up conditions on phonatory threshold pressure (PTP). The three conditions were: (1) Steam - breathing steam for 3 minutes; (2) SOVT exercise - blowing bubbles through a straw into a cup of water while phonating /u/ for 3 minutes; and (3) Steam + SOVT - both conditions 1 and 2. Participants were 12 females with a mean age of 24. They were assessed on three different mornings, with one condition being tested each morning. Condition order and combination order were counterbalanced. Each morning prior to arriving, participants were asked to be up for about an hour, with no shower, no hot drinks or food, minimal voice-use, and no exercise. PTP was measured prior to each condition and immediately after. Participants also qualitatively described the experience of each condition and provided their subjective impression of how their voice felt after each condition. Results: There were 36 data points, reflecting change in PTP from before to after each condition. Results reflected high variability within each individual and condition. Due to this variability, means and standard deviations for each separate condition are meaningless, requiring deeper investigation into trends in the data. The investigators eliminated all data points where the sound pressure level (SPL) in the pre-experimental measure exceeded 67 dB; this was interpreted as the participant not performing the PTP task as softly as possible. First, data were examined within each participant, excluding all data from any participant who exceeded 67 dB SPL in any of the three pre-experimental measures. Of the seven participants remaining, steam was the best condition for one, SOVT was the best for three, and Steam + SOVT was the best for three. Of these, only two people experienced an improvement in PTP of greater than or equal to 0.5 cm H 2 O, both under the SOVT condition. Of the same seven participants, steam was the worst condition for three, SOVT was the worst for one, and Steam + SOVT was the worst for two. The three participants for whom steam was the worst reported strongly disliking the condition. Only three people experienced a worsening of PTP greater than or equal to 0.5 cm H 2 O: one in the SOVT condition; and two in the Steam + SOVT. It is typically expected that increases or decreases in PTP and SPL will be systematically related. Since the goal of a warm-up is to increase phonatory efficiency, and improve the viscosity of the vocal folds, a reduction in PTP after any condition was interpreted favorably. For the 9 data points across all conditions where PTP and SPL both decreased, there was a mean decrease in PTP of 0.34 cm H2O (SD = 0.28 cm H2O ). Mean decrease in SPL was 2.00 dB (SD = 0.88 dB). This indicates that individuals were able to decrease PTP and SPL as expected after a warm-up strategy. Finally, a trend appeared in six data points, where despite an increase in SPL, PTP decreased, potentially indicating improvement in vocal efficiency. Of these data points the mean decrease in PTP was 0.36 cm H2O ( SD = 0.17 cm H2O ), with a mean increase in SPL of 1.70 dB (SD = 1.21 dB). Of these six data points, indicating increased efficiency, three were with steam, two with Steam + SOVT, and one with SOVT. Conclusion: This study revealed that these strategies are not universally successful, and clinicians should recommend them only after assessing their effectiveness for their client. Clinicians need to be custom tailoring these exercises to their client's goals and proclivities. Another consideration is the importance of teaching proper SOVT technique, so it is done correctly without added tension. Even blowing bubbles into a cup of water with phonation can be done poorly, in some cases yielding counterproductive results. Another interesting trend suggests that the inclusion of steam in vocal warm-up may increase vocal efficiency. Future studies should explore how time of day and vocal condition impact each strategy's effectiveness, and which strategy may be most appropriate for different desired outcomes, such as vocal warmup versus vocal rescue.
... The literature indicates that dehydration may predispose laryngeal tissue to injury or slow recovery from injury, while also increasing the subglottic pressure required for phonation, especially for high pitches. 154,[156][157][158][159] ...
Article
Objective The purpose of this study was to examine the psychometric properties of an ecological vocal effort scale linked to a voicing task. Method Thirty-eight patients with nodules, 18 patients with muscle tension dysphonia, and 45 vocally healthy control individuals participated in a week of ambulatory voice monitoring. A global vocal status question was asked hourly throughout the day. Participants produced a vowel–consonant–vowel syllable string and rated the vocal effort needed to produce the task on a visual analog scale. Test–retest reliability was calculated for a subset using the intraclass correlation coefficient, ICC(A, 1). Construct validity was assessed by (a) comparing the weeklong vocal effort ratings between the patient and control groups and (b) comparing weeklong vocal effort ratings before and after voice rehabilitation in a subset of 25 patients. Cohen's d, the standard error of measurement ( SEM ), and the minimal detectable change (MDC) assessed sensitivity. The minimal clinically important difference (MCID) assessed responsiveness. Results Test–retest reliability was excellent, ICC(A, 1) = .96. Weeklong mean effort was statistically higher in the patients than in controls ( d = 1.62) and lower after voice rehabilitation ( d = 1.75), supporting construct validity and sensitivity. SEM was 4.14, MDC was 11.47, and MCID was 9.74. Since the MCID was within the error of the measure, we must rely upon the MDC to detect real changes in ecological vocal effort. Conclusion The ecological vocal effort scale offers a reliable, valid, and sensitive method of monitoring vocal effort changes during the daily life of individuals with and without vocal hyperfunction.
Article
Full-text available
Purpose Nasal irrigation or nebulizing aerosol of isotonic or hypertonic saline is a traditional method for respiratory or nasal care. A recent small study in outpatients with COVID-19 without acute respiratory distress syndrome suggests substantial symptom resolution. We therefore analyzed pharmacological/pharmacodynamic effects of isotonic or hypertonic saline, relevant to SARS-CoV-2 infection and respiratory care. Methods Mixed search method. Results Due to its wetting properties, saline achieves an improved spreading of alveolar lining fluid and has been shown to reduce bio-aerosols and viral load. Saline provides moisture to respiratory epithelia and gels mucus, promotes ciliary beating, and improves mucociliary clearance. Coronaviruses and SARS-CoV-2 damage ciliated epithelium in the nose and airways. Saline inhibits SARS-CoV-2 replication in Vero cells; possible interactions involve the viral ACE2-entry mechanism (chloride-dependent ACE2 configuration), furin and 3CLpro (inhibition by NaCl), and the sodium channel ENaC. Saline shifts myeloperoxidase activity in epithelial or phagocytic cells to produce hypochlorous acid. Clinically, nasal or respiratory airway care with saline reduces symptoms of seasonal coronaviruses and other common cold viruses. Its use as aerosol reduces hospitalization rates for bronchiolitis in children. Preliminary data suggest symptom reduction in symptomatic COVID-19 patients if saline is initiated within 48 h of symptom onset. Conclusions Saline interacts at various levels relevant to nasal or respiratory hygiene (nasal irrigation, gargling or aerosol). If used from the onset of common cold symptoms, it may represent a useful add-on to first-line interventions for COVID-19. Formal evaluation in mild COVID-19 is desirable as to establish efficacy and optimal treatment regimens.
Article
Full-text available
The airway surface liquid (ASL) is the thin layer of fluid coating the luminal surface of airway epithelial cells at an air interface. Its composition and osmolality are thought to be important in normal airway physiology and in airway diseases such as asthma and cystic fibrosis. The determinants of ASL osmolality include epithelial cell solute and water transport properties, evaporative water loss, and the composition of secreted fluids. We developed a noninvasive approach to measure ASL osmolality using osmotically sensitive 400-nm-diam liposomes composed of phosphatidylcholine/cholesterol/polyethylene glycol-phosphatidylcholine (1:0.3:0.08 molar ratio). Calcein was encapsulated in the liposomes at self-quenching concentrations (30 mM) as a volume-sensitive marker, together with sulforhodamine 101 (2 mM) as a volume-insensitive reference. Liposome calcein/sulforhodamine 101 fluorescence ratios responded rapidly (<0.2 s) and stably to changes in solution osmolality. ASL osmolality was determined from calcein/sulforhodamine 101 fluorescence ratios after addition of microliter quantities of liposome suspensions to the ASL. In bovine airway epithelial cells cultured on porous supports at an air–liquid interface, ASL thickness (by confocal microscopy) was 22 μm and osmolality was 325 ± 12 mOsm. In anesthetized mice in which a transparent window was created in the trachea, ASL thickness was 55 μm and osmolality was 330 ± 36 mOsm. ASL osmolality was not affected by pharmacological inhibition of CFTR in airway cell cultures or by genetic deletion of CFTR in knockout mice. ASL osmolality could be increased substantially to >400 mOsm by exposure of the epithelium to dry air; the data were modeled mathematically using measured rates of osmosis and evaporative water loss. These results establish a ratio imaging method to map osmolality in biological compartments. ASL fluid is approximately isosmolar under normal physiological conditions, but can become hyperosmolar when exposed to dry air, which may induce cough and airway reactivity in some patients.
Article
Full-text available
This article presents the current state of knowledge regarding vocal hygiene for the voice professional. Research regarding vocal hygiene has primarily focused on two areas: vocal hygiene as a preventive strategy, and vocal hygiene as a management technique for individuals with voice disorders. It is difficult to assess the effectiveness of vocal hygiene as a preventive tool as programs are often expensive leading to limited data. Vocal hygiene as a sole strategy for the treatment of voice disorders has shown minimal, but favorable results. As a component of a comprehensive therapeutic program, it is difficult to isolate the influence of vocal hygiene. However, limited components of vocal hygiene including hydration and vocal rest have been associated with improved therapeutic outcomes. In addition, the current literature proposes a paradigm shift away from more restrictive therapy approaches to a holistic approach to vocal well being. Vocal hygiene should be considered only as a component of a broad vocal rehabilitation program. The role of vocal hygiene as a means to prevent voice disorders remains unproven. Additionally, some of the findings may be applied to both dysphonic and healthy individuals in order to facilitate vocal well being.
Article
Combining the physical, technical, and artistic aspects of singing, the author applies current findings in medicine, acoustics, phonetics, and speech therapy to the singer's needs. The text demonstrates the scientific basis of exercises and vocalises, covering all major areas of vocal technique.
Article
Changes in vocal fold oscillation threshold pressure were induced in excised canine larynges by experimentally causing fluid movement into and out of the vocal folds. The transport was facilitated by exposing the vocal folds to various osmotic solutions, and it was assumed that changes in hydration caused changes in the internal tissue viscosity. A range of oscillation threshold pressures was measured for each condition of hydration by varying length and glottal width. The oscillation threshold pressure shifted as predicted. Decreased hydration (increased viscosity) raised the threshold of oscillation, and increased hydration (decreased viscosity) lowered the threshold of oscillation. This apparently represents the first in vitro model for the study of the effect of viscosity changes of the internal environment of the vocal folds on phonation.
Article
A noninvasive technique is used to make acoustic and aerodynamic recordings in an ongoing study whose goal is the objective assessment of vocal function in normal and dysphonic speakers. Intraoral pressure, oral volume velocity (flow), and radiated soundpressure are recorded for strings of repeated productions of the syllable /pae/. A high time resolution pneumothachograph is used to record flow [M. Rothenberg, J. Acoust. Soc. Am. 53, 1632–1645 (1973)]. Transglottal air pressure,glottal air flow, and sound power for the vowel are estimated from the oral measurements, and glottal resistance and vocal efficiency are calculated. Initial results suggest that production mode (smooth versus interrupted) and rate (slow versus fast) may affect the reliability of the aerodynamicmeasures. An interaction between production mode and rate can result in unreliable pressures on one hand and unreliable flows on the other. Results from a separate, methodological study illustrate the importance of control over production mode and rate to obtain oral pressure and flow signals that allow for reliable estimates of glottal functions. [Work supported by The Voice Foundation.]
Article
The purpose of this pilot study was to investigate the relationship between phonation threshold pressure and level of hydration in human subjects. Six adult subjects produced consonant-vowel-consonant strings as quietly as possible at low, medium, and high pitches in no-treatment, hydrated, and slightly dehydrated conditions. Average oral pressures for these trials were used to estimate minimal subglottal pressures required for phonation (phonation threshold pressure). Main effects for hydration and for pitch were significant, as was the interaction of hydration times pitch. Overall, the lowest pressures were seen for the hydrated (or “wet”) condition, and reduction in baseline pressures was greatest for high pitches in this condition. The highest pressures were found for the dry condition, and the greatest increase in pressure relative to the baseline was found at low pitches for this condition. Threshold pressures for intermediate (speaking) pitches were not affected by hydration condition. The findings are consistent with previously reported theoretical predictions regarding the relationship between oscillation threshold pressures and tissue viscosity. They are also consistent with previous empirical reports on the effect of direct hydration of vocal fold tissue in nonhuman subjects.
Article
Voice problems are reported as a frequent side effect of inhaled combination (IC) treatments. The purpose of this experimental study was to investigate whether IC treatments are detrimental to phonation. We hypothesized that IC treatment would significantly increase phonation threshold pressure (PTP) and perceived phonatory effort (PPE), whereas sham treatment would not. Fourteen healthy adults participated in a repeated-measures design in which they received IC and sham treatments in counterbalanced order. PTP and PPE were measured prior to treatments, immediately following treatments, and at 1 and 2 hr following treatments. IC treatment increased PTP, but sham treatment did not. The increase in PTP was maintained for a 2 hr period following administration. PPE ratings were not significantly correlated with PTP. IC treatments can have acute, adverse effects on phonation. Detrimental phonatory effects were elicited in participants with no self-reported voice problems. IC treatments are being increasingly prescribed across the lifespan. The current data increase our understanding of the nature of phonatory deterioration associated with IC treatment and lay the groundwork for increased research effort to develop IC treatments that effectively control respiratory disease while minimizing an adverse effect on phonation.
Article
Inhaled air must be adequately humidified to prevent vocal fold drying, which is detrimental to phonation. The water content of inspired air is reduced by parameters, such as increased breathing rate and oral route. Accelerated oral breathing challenges induce airway dehydration and are posited to affect airway function. The primary objective of this study was to investigate whether accelerated oral breathing challenges are detrimental to phonation. The secondary objective of this study was to determine whether individuals at increased risk for developing voice problems (i.e., smokers) have greater adverse phonatory effects after accelerated breathing challenge than nonsmoking controls. Prospective study with between-subjects, repeated-measures design. Female smokers (n = 12) and nonsmoking controls (n = 12) participated in this experimental study over 2 days that differed in ambient humidity. Phonation threshold pressures (PTP) were collected prior to and following short-term accelerated and habitual breathing challenges. Respiratory measures were collected during the challenges. Short-term accelerated breathing challenges significantly increased PTP. This increase in PTP with accelerated breathing was transient and not significantly influenced by breathing route, ambient humidity, or smoking status. Likewise, respiratory measures were not affected by breathing route, ambient humidity, or smoking status. During daily activities, such as exercise, individuals may engage in accelerated breathing for prolonged durations. This study demonstrates that even extremely short durations of accelerated breathing may affect phonation.