A Conceptual Framework and Treatment Taxonomy for Respiratory Lung Volume Training (RLVT).

OBJECTIVES: The purpose of this study was to describe the theoretical and procedural framework of a novel intervention, Respiratory Lung Volume Training (RLVT), and to implement a standardized treatment taxonomy to operationalize the RLVT treatment paradigm. STUDY DESIGN: This study involved a prospective design with a consensus treatment classification process. METHODS: The RLVT paradigm was developed based on biomechanical constructs governing the interactions of the respiratory and phonatory systems in voice production and principles of motor learning theory. In RLVT, higher levels of lung volume (LV) during speech are trained using multiple speech breathing strategies while providing real-time visual biofeedback with superimposed guidelines for desired LV initiation and termination levels. For people with primary muscle tension dysphonia (MTD), RLVT can capitalize on nonmuscular respiratory forces to increase efficiency of voice production with reduced speaking effort. To define and operationalize the treatment components of RLVT, six investigators with training in RLVT used the Rehabilitation Treatment Specification System to delineate the treatment targets, mechanisms of action, ingredients and dosing through a multistage, consensus decision-making process. RESULTS: The finalized taxonomy for RLVT included four treatment targets, with three addressing the area of Respiratory Function and one addressing Somatosensory Function. For each treatment target, three categories of ingredients were defined: (1) provide opportunities to practice breathing during voicing/speech, (2) provide feedback, and (3) provide volition ingredients. Within each ingredient category, three to seven specific ingredients were ultimately defined to further operationalize RLVT. CONCLUSIONS: The RLVT paradigm is a theoretically driven approach for optimizing speech breathing patterns to increase efficient voice production in people with primary MTD. By applying a standardized, systematic treatment taxonomy system to specify the components of RLVT, future researchers and clinicians can implement RLVT with improved fidelity and consistency to optimize treatment outcomes.

Isolated and Combined Respiratory Training for Muscle Tension Dysphonia: Preliminary Findings.

PURPOSE: The purpose of this study was to determine the feasibility of altering speech breathing patterns and dysphonia severity through training increased levels of lung volume use during speech. It was hypothesized that respiratory-based training would increase lung volume levels during speech as well as improve acoustic voice measures, and that the addition of laryngeal-based treatment would further improve voice acoustics by treatment completion. METHOD: A multiple baseline, single subject design was replicated over six participants with primary muscle tension dysphonia as a preliminary investigation of novel respiratory treatment methods. Following four baseline probes (1-4), two phases of treatment were implemented over 6 weeks. Respiratory lung volume-based training (RLVT) and subsequent performance was probed at sessions 5 to 7 and laryngeal-based training was added to the RLVT and probed at sessions 8 to 10. Visual biofeedback was used during RLVT to assist the motor learning process. Respiratory outcome measures of lung volume initiation, termination and excursion were objectively measured using respiratory plethysmography (InductoTrace), and cepstral and spectral-based acoustic measures were also determined at each time point. RESULTS: All participants showed improvement in one or more respiratory measures as well as reduced acoustic dysphonia severity following phase 1 of RLVT alone. Two participants achieved further marked improvement in acoustic voice measures after laryngeal-based training was added in phase 2 of treatment, but this was generally also accompanied by further improvement or stabilization of respiratory measures. CONCLUSION: Results from this preliminary study support the feasibility of RLVT for improving speech breathing behavior, and suggest that RLVT alone can improve objectively measured dysphonia severity.

Clinical Features of Essential Voice Tremor and Associations with Tremor Severity and Response to Octanoic Acid Treatment.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to characterize the clinical features, tremor variability, and factors related to octanoic acid (OA) treatment response in essential voice tremor (EVT). STUDY DESIGN: Prospective, double blind, placebo-controlled, crossover study with secondary analysis. METHODS: Clinical tremor features in 16 individuals with EVT were comprehensively assessed, and correlations with acoustic tremor severity were determined. Intrasubject and intersubject variability measures were analyzed from 18 repeated measures for each acoustic tremor variable. Clinical correlates of treatment response were evaluated, and cumulative effects over a 2-week period of OA drug dosing were assessed. RESULTS: Participants with EVT were 90% female with a mean age of 70.31 (±8.68) years at the time of testing. Neurologist-rated body tremor beyond the vocal tract region was present in 69% of participants, and multiple vocal tract regions contributed to the voice tremor. The mean frequency of amplitude tremor was 4.67 Hz (±0.88). Respiratory tremor was evident in 50% of participants. Participants experienced moderate voice-related disability as assessed on the Voice Handicap Index-10 (19.38, ±8.50), and increased speaking effort. Acoustic tremor severity was significantly associated with severity of tremor affecting vocal tract structures. Overall intrasubject consistency was strong (single measures intraclass correlation coefficient = 0.701, P < .01), with high intersubject variability. Acoustic tremor severity was significantly, positively associated with treatment response, and results suggested a cumulative OA benefit for magnitude of amplitude tremor. CONCLUSIONS: This study identified common clinical correlates of EVT and demonstrated positive associations between acoustic tremor severity, severity of affected vocal tract structures, and response to treatment. LEVEL OF EVIDENCE: 2 Laryngoscope, 131:E2792-E2801, 2021.

Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations.

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

The Effect of Octanoic Acid on Essential Voice Tremor: A Double-Blind, Placebo-Controlled Study.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to determine the effects of octanoic acid on acoustic, perceptual, and functional aspects of essential voice tremor (EVT). STUDY DESIGN: Prospective, double-blind, placebo-controlled, crossover study. METHODS: Sixteen participants with a diagnosis of EVT were randomized to a 3-week dosing condition of octanoic acid or placebo, followed by a 2-week washout period and crossover to the other condition for an additional 3 weeks. Baseline and post-testing sessions were completed before and at the completion of each condition. Primary outcome measures were the magnitude of amplitude and frequency tremor, measured from the acoustic signal. Secondary outcomes were auditory-perceptual ratings of tremor severity and self-ratings of voice handicap. RESULTS: Magnitude of amplitude and frequency tremor were significantly lower after 3 weeks of octanoic acid dosing as compared to the placebo condition. Auditory-perceptual ratings of tremor severity did not show significant differences between conditions. A trend toward better voice was seen for the sustained vowel ratings, but not the sentence-level ratings. No significant differences between conditions were seen on self-reported voice disability as assessed on the Voice Handicap Index-10. CONCLUSIONS: The results of this controlled investigation support the potential utility of octanoic acid for reducing the magnitude of tremor in people with EVT. Further research is needed to determine whether different dosing or treatment combinations can improve functional communication in EVT. LEVEL OF EVIDENCE: 1 Laryngoscope, 129:1882-1890, 2019.

The effect of anchors on reliability of endoscopic tremor ratings.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to determine the effects of anchors and training on intrarater and inter-rater reliability for visual-perceptual, endoscopic tremor ratings. STUDY DESIGN: Prospective cohort study. METHODS: Nasoendoscopy recordings of 10 participants with a diagnosis of essential voice tremor were evaluated by five voice specialists using the Vocal Tremor Scoring System. Ratings were performed before, immediately after, and 4 weeks after implementation of a training program with anchor stimuli. Immediate and long-term post-training ratings were performed with simultaneous use of anchor samples for each rating. RESULTS: Intrarater reliability showed significant improvement from pretraining to immediate and long-term post-training. Mean correlation coefficients (Spearman's rho) increased from 0.71 at pretraining to 0.84 and 0.90 at immediate and long-term post-training, respectively. Inter-rater reliability was not affected by training with anchors, with mean correlation coefficients ranging from 0.62 at pretraining to 0.58 and 0.64 at immediate and long-term post-training, respectively. CONCLUSIONS: Consistent, reproducible ratings are critical for the interpretation and comparison of endoscopic tremor data. Reliability findings from this study indicate that the use of anchor samples as referents for making ordinal judgments about the severity of tremor in oropharyngeal and laryngeal regions was helpful for improving internal standards and consistency but less useful for calibrating across different raters. LEVEL OF EVIDENCE: 4 Laryngoscope, 2016 127:411-416, 2017.

A Preliminary Quantitative Comparison of Vibratory Amplitude Using Rigid and Flexible Stroboscopic Assessment.

STUDY OBJECTIVE: The purpose of this study was to establish preliminary, quantitative data on amplitude of vibration during stroboscopic assessment in healthy speakers with normal voice characteristics. Amplitude of vocal fold vibration is a core physiological parameter used in diagnosing voice disorders, yet quantitative data are lacking to guide the determination of what constitutes normal vibratory amplitude. METHODS/STUDY DESIGN: Eleven participants were assessed during sustained vowel production using rigid and flexible endoscopy with stroboscopy. Still images were extracted from digital recordings of a sustained /i/ produced at a comfortable pitch and loudness, with F0 controlled so that levels were within ±15% of each participant's comfortable mean level as determined from connected speech. Glottal width (GW), true vocal fold (TVF) length, and TVF width were measured from still frames representing the maximum open phase of the vibratory cycle. To control for anatomic and magnification differences across participants, GW was normalized to TVF length. GW as a ratio of TVF width was also computed for comparison with prior studies. RESULTS: Mean values and standard deviations were computed for the normalized measures. Paired t tests showed no significant differences between rigid and flexible endoscopy methods. Interrater and intrarater reliability values for raw measurements were found to be high (0.89-0.99). CONCLUSIONS: These preliminary quantitative data may be helpful in determining normality or abnormality of vocal fold vibration. Results indicate that quantified amplitude of vibration is similar between endoscopic methods, a clinically relevant finding for individuals performing and interpreting stroboscopic assessments.

The Use of TOC Reconciliation as a Means of Establishing the Degree to Which Chromatographic Screening of Plastic Material Extracts for Organic Extractables Is Complete.

Extracts of plastic packaging, manufacturing, and delivery systems (or their materials of construction) are analyzed by chromatographic methods to establish the system's extractables profile. The testing strategy consists of multiple orthogonal chromatographic methods, for example, gas and liquid chromatography with multiple detection strategies. Although this orthogonal testing strategy is comprehensive, it is not necessarily complete and members of the extractables profile can elude detection and/or accurate identification/quantification. Because the chromatographic methods rarely indicate that some extractables have been missed, another means of assessing the completeness of the profiling activity must be established. If the extracts are aqueous and contain no organic additives (e.g., pH buffers), then they can be analyzed for their total organic carbon content (TOC). Additionally, the TOC of an extract can be calculated based on the extractables revealed by the screening analyses. The measured and calculated TOC can be reconciled to establish the completeness and accuracy of the extractables profile. If the reconciliation is poor, then the profile is either incomplete or inaccurate and additional testing is needed to establish the complete and accurate profile. Ten test materials and components of systems were extracted and their extracts characterized for organic extractables using typical screening procedures. Measured and calculated TOC was reconciled to establish the completeness of the revealed extractables profile. When the TOC reconciliation was incomplete, the profiling was augmented with additional analytical testing to reveal the missing members of the organic extractables profile. This process is illustrated via two case studies involving aqueous extracts of sterile filters. LAY ABSTRACT: Plastic materials and systems used to manufacture, contain, store, and deliver pharmaceutical products are extracted and the extracts analyzed to establish the materials' (or systems') organic extractables profile. Such testing typically consists of multiple chromatographic approaches whose differences help to ensure that all organic extractables are revealed, measured, and identified. Nevertheless, this rigorous screening process is not infallible and certain organic extractables may elude detection. If the extraction medium is aqueous, the process of total organic carbon (TOC) reconciliation is proposed as a means of establishing when some organic extractables elude detection. In the reconciliation, the TOC of the extracts is both directly measured and calculated from the chromatographic data. The measured and calculated TOC is compared (or reconciled), and the degree of reconciliation is an indication of the completeness and accuracy of the organic extractables profiling. If the reconciliation is poor, then the extractables profile is either incomplete or inaccurate and additional testing must be performed to establish the complete and accurate profile. This article demonstrates the TOC reconciliation process by considering aqueous extracts of 10 different test articles. Incomplete reconciliations were augmented with additional testing to produce a more complete TOC reconciliation.

Aerodynamic and acoustic features of vocal effort.

OBJECTIVES: The purpose of this study was to determine the aerodynamic and acoustic features of speech produced at comfortable, maximal and minimal levels of vocal effort. STUDY DESIGN: Prospective, quasi-experimental research design. METHOD: Eighteen healthy participants with normal voice were included in this study. After task training, participants produced repeated syllable combinations at comfortable, maximal and minimal levels of vocal effort. A pneumotachometer and vented (Rothenberg) mask were used to record aerodynamic data, with simultaneous recording of the acoustic signal for subsequent analysis. Aerodynamic measures of subglottal pressure, translaryngeal airflow, maximum flow declination rate (MFDR), and laryngeal resistance were analyzed, along with acoustic measures of cepstral peak prominence (CPP) and its standard deviation (SD). RESULTS: Participants produced significantly greater subglottal pressure, translaryngeal airflow, and MFDR during maximal effort speech as compared with comfortable vocal effort. When producing speech at minimal vocal effort, participants lowered subglottal pressure, MFDR, and laryngeal resistance. Acoustic changes associated with changes in vocal effort included significantly higher CPP during maximal effort speech and significantly lower CPP SD during minimal effort speech, when each was compared with comfortable effort. CONCLUSIONS: For healthy speakers without voice disorders, subglottal pressure, translaryngeal airflow, and MFDR may be important factors that contribute to an increased sense of vocal effort. Changes in the cepstral signal also occur under conditions of increased or decreased vocal effort relative to comfortable effort.

Predictive value and discriminant capacity of cepstral- and spectral-based measures during continuous speech.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to determine the relative strength of various cepstral- and spectral-based measures for predicting dysphonia severity and differentiating voice quality types. STUDY DESIGN: Prospective, quasi-experimental research design. METHODS: Twenty-eight dysphonic speakers and 14 normal speakers were included in this study. Among the dysphonic speakers, 14 had a predominant voice quality of breathiness and 14 had a predominant voice quality of roughness. Cepstral and spectral analyses of the first and second sentences of the Rainbow passage were performed, along with perceptual ratings of overall dysphonia severity. Linear regression was performed to determine the predictive capacity of each variable for dysphonia severity, and discriminant analysis determined the combination of variables that optimally differentiated the three voice quality types. RESULTS: A four-factor model that incorporated the cepstral- and spectral-based measures produced an R value of 0.899, explaining 81% of the variance in auditory-perceptual dysphonia severity. Cepstral peak prominence (CPP) showed the greatest predictive contribution to dysphonia severity in the regression model. The discriminant analysis produced two discriminant functions that included both CPP and its standard deviation (CPP SD) as significant contributors (P < 0.001), with an overall classification accuracy for the combined functions of 79%. CONCLUSIONS: Acoustic measures reflecting the distribution of harmonic energy and low- to high-frequency energy in continuous speech, along with the variability (standard deviations) of each, were highly predictive of dysphonia severity when combined in a multivariate linear model. Cepstral-based measures showed the highest capacity to discriminate voice quality types, with better classification accuracy for normal and dysphonic-breathy than for dysphonic-rough voices.

Spectral- and cepstral-based acoustic features of dysphonic, strained voice quality.

OBJECTIVES: We sought to determine whether spectral- and cepstral-based acoustic measures were effective in distinguishing dysphonic-strained voice quality from normal voice quality and whether these measures were related to auditory-perceptual ratings of strain severity. METHODS: Voice samples from 23 speakers with dysphonia characterized predominantly by strained voice quality and 23 speakers with normal voice were acoustically analyzed. Measures related to the prominence of the cepstral peak and the ratio of low- to high-frequency spectral energies, as well as the variation of each, were computed from continuous speech and a sustained vowel. Correlations to perceptually rated strain severity were determined. RESULTS: Measures related to the cepstrum were the strongest discriminators between dysphonic-strained voice and normal voice. Variation in the ratio of low- to high-frequency spectral energies also significantly differentiated the two speaker groups. All measures were significantly correlated with perceptually rated strain severity, including an acoustic severity index that incorporated both cepstral- and spectral-based measures. CONCLUSIONS: Cepstral- and spectral-based measures that have been previously studied in dysphonia characterized by breathiness and roughness are effective in distinguishing strained dysphonia from normal voice quality. The utility of these acoustic measures is supported by their moderate-to-high relationship with perceptually rated strain severity.

Position of the hyoid and larynx in people with muscle tension dysphonia.

OBJECTIVES/HYPOTHESIS: To determine whether radiographic measures of hyoid position, laryngeal position, and hyolaryngeal space during phonation were different for people with primary muscle tension dysphonia (MTD) as compared to control participants without voice disorders. STUDY DESIGN: Prospective, quasi-experimental research design. METHODS: Twenty participants, 10 with primary MTD and 10 without voice disorders who were age and sex matched were studied radiographically while producing phonation. Lateral x-ray images were obtained for each participant during three tasks: resting state, sustained phonation, and a swallow-hold maneuver. Vertical positions of the hyoid and larynx were measured on a Cartesian coordinate system and were normalized to reflect change from rest during phonation. RESULTS: Normalized, vertical hyoid, and laryngeal positions during phonation were significantly higher for people with MTD than for control participants. Normalized hyolaryngeal space during phonation did not show differences between groups. A low to moderate significant correlation for radiographically measured hyoid and laryngeal position and the total score from a subjective laryngeal palpatory scale were evidenced, but no relationship was evidenced for radiographic laryngeal position and the laryngeal position subscore of the palpatory examination. CONCLUSIONS: Objective determinants of physiology are critical for the differential diagnosis of MTD and its effective treatment. Radiographic findings from this study indicate that hyoid and laryngeal positions during phonation are higher in people with primary MTD as compared to people without voice disorders.

Spectral moment analysis of unilateral vocal fold paralysis.

Many acoustic measures have been used to assess and track the voices of patients with voice problems. Some of these measures rely on the accurate measurement of fundamental frequency to produce reliable results. Patients with voice disorders often produce voices with considerable quasiperiodicity or aperiodicity. There are other measurements that do not depend on the accurate tracking of fundamental frequency by computing the spectrum of the sound and comparing different parts of the spectrum. The moments of the spectral distribution may also be important measurements to use in patients with voice problems. Several studies have reported good results using these measures to track treatment progress. In this study, spectral moments were used to assess the effectiveness of two treatment approaches in patients with unilateral vocal fold paralysis (UVFP). Twenty-six patients with UVFP and dysphonia (16 female and 10 male patients) were studied. Thirteen underwent surgery to improve their voice, whereas the other 13 received voice therapy. The patients were recorded at three time intervals: before the start of treatment, about 1 month after treatment has been completed, and at 3 months after treatment. They produced three types of speech material, vowels /ah/ and /oo/ and a simple sentence. The first four spectral moments (mean, standard deviation, skewness, and kurtosis) were computed from the long-term average spectrum. Severity of voice dysphonia was rated on a 11-point scale ranging from 0 (normal) to 10 (aphonic). There were no statistical differences between males and females for any of the four moments. There was also no difference between the two treatment types. There were differences among the three types of speech material for moments 1 and 3. There were also differences for moments 1, 2, and 3 for the three treatment conditions with most of the differences occurring between the pretreatment and first posttreatment condition. Severity of dysphonia decreased significantly from the pretreatment to either of the two posttreatment conditions. Spectral moments appear to be viable acoustic measurements to use to assess the effects of treatment on the voice of patients with UVFP.

Spectral- and cepstral-based measures during continuous speech: capacity to distinguish dysphonia and consistency within a speaker.

Spectral- and cepstral-based acoustic measures are preferable to time-based measures for accurately representing dysphonic voices during continuous speech. Although these measures show promising relationships to perceptual voice quality ratings, less is known regarding their ability to differentiate normal from dysphonic voice during continuous speech and the consistency of these measures across multiple utterances by the same speaker. The purpose of this study was to determine whether spectral moments of the long-term average spectrum (LTAS) (spectral mean, standard deviation, skewness, and kurtosis) and cepstral peak prominence measures were significantly different for speakers with and without voice disorders when assessed during continuous speech. The consistency of these measures within a speaker across utterances was also addressed. Continuous speech samples from 27 subjects without voice disorders and 27 subjects with mixed voice disorders were acoustically analyzed. In addition, voice samples were perceptually rated for overall severity. Acoustic analyses were performed on three continuous speech stimuli from a reading passage: two full sentences and one constituent phrase. Significant between-group differences were found for both cepstral measures and three LTAS measures (P<0.001): spectral mean, skewness, and kurtosis. These five measures also showed moderate to strong correlations to overall voice severity. Furthermore, high degrees of within-speaker consistency (correlation coefficients ≥0.89) across utterances with varying length and phonemic content were evidenced for both subject groups.

Evaluation of stroboscopic signs.

OBJECTIVE: Clinicians interpret the stroboscopic examination by systematically rating several parameters or "signs." This can be time consuming and experience dependent. The significance of each of these signs is unknown. Some signs may be redundant, whereas others may be more independent, thus reflecting a unique aspect of the exam assessment. We wanted to determine which stroboscopic signs are more independent and clinically relevant. This may lead to a more efficient and reliable method of stroboscopic exam evaluation. STUDY DESIGN: Retrospective. METHOD: One hundred and eighty one consecutive adult patients with dysphonia of various pathologies were studied. Severity of dysphonia was judged, and a set of seven stroboscopic signs for each stroboscopic exam was rated by our voice team. A principal component factor analysis was performed, and the two factors that accounted for the most variance in the original rating data were determined. These two independent factors were then investigated for clinical usefulness. RESULTS: Several individual stroboscopic signs of vocal fold vibration correlated with the "Vibration Factor" (VF) (mucosal wave, amplitude, vibratory behavior, and periodicity) and the vocal fold edge correlated with the "Edge Factor" (EF). Scores for VF and EF were used to differentiate between general categories of vocal fold pathology and related to the severity of dysphonia. Severity of dysphonia correlated with the VF to a greater degree than the EF. Furthermore, these two factor scores could be accurately estimated using only three stroboscopic signs (amplitude, vibratory behavior, and edge). CONCLUSION: The results of the study support the concept that a small set of stroboscopic ratings is an adequate representation of the information derived from the original, more comprehensive sign rating protocol. A focused rating system may provide an efficient method for stroboscopic evaluation, contributing to the differentiation of various vocal fold pathologies and correlating to clinician ratings of severity of dysphonia.

Study of protein adsorption effects on crossflow filtration using BSA and milk protein.

Three membrane materials were tested under similar conditions to determine the effects of membrane material on the performance and cleanability of the filters. The membrane materials investigated were stabilized cellulose (Hydrosart, Sartorius Corporation), cellulose triacetate, and polyethersulfone; all having a 10 kilodalton molecular weight cutoff. Stabilized cellulose is a cellulose-based membrane material, modified for low non-specific protein adsorption combined with high pH-resistance. When analyzing the data, three phenomena were considered: adsorption of protein to the membrane, gel layer formation, and osmotic pressure due to concentration polarization. Throughout these studies, the effects of a gel layer and the osmotic pressure were approximately equivalent in all cassettes. However, the stabilized cellulose was resistant to protein adsorption while the other two membranes exhibited significant decreases in permeate flux due to adsorption. Using a 0.2% BSA (MW = 67,000 kD) solution with a crossflow rate of 5 L/min and transmembrane pressure of 35 psi, the permeate flux through the stabilized cellulose membrane was 3% lower than the baseline saline flux, whereas the cellulose triacetate and polyethersulfone membranes lost 33% and 60% of baseline flux, respectively. The decrease in flux occurring in the latter two membranes is due to adsorption. Another study evaluated adsorption by alternating between crossflow and static operation. After three cycles, the stabilized cellulose maintained the original crossflow flux level. The polyethersulfone lost cumulatively 17% of its crossflow flux after three cycles and the cellulose triacetate lost 13%. The stabilized cellulose and polyethersulfone membranes were also evaluated using a milk solution. The results indicate that the stabilized cellulose is not susceptible to adsorption of any of the milk components while the polyethersulfone permeate flux was limited by adsorption. The saline flux of the stabilized cellulose immediately after testing with the milk solution was 3% lower than the baseline flux, while the polyethersulfone membrane saline flux was 81% lower. The results consistently indicated that, unlike the cellulose triacetate and polyethersulfone membranes, the stabilized cellulose membrane was not subject to adsorption.