Instrumental assessment of velopharyngeal closure for speech.

The presence of a palatal cleft at birth should not prevent good speech production in most children provided they have (1) appropriate surgical intervention to close the palate at or around the child's first birthday, (2) careful monitoring of speech development throughout childhood, (3) speech therapy when needed, and (4) secondary surgical or speech-prosthetic intervention when needed. When managed carefully by an experienced, well-prepared multidisciplinary team that applies the criteria listed above, ~70% of children with nonsyndromic palatal clefts will have no significant difficulties with speech intelligibility or speech quality due to velopharyngeal insufficiency by the time they enter elementary school. Speech assessment is the first step toward comprehensive team management of children with cleft palate. The purpose of this chapter is to describe the use of instrumentation in the evaluation of speech of children with palatal clefts, within the context of a multidisciplinary team. The focus of this article is on instruments that are used to supplement the perceptual assessment to document current speech status and plan management strategies.

Cerebellum structure differences and relationship to speech in boys and girls with nonsyndromic cleft of the lip and/or palate.

OBJECTIVE: To identify regional cerebellar structural differences in boys and girls with nonsyndromic cleft of the lip and/or palate and determine whether these differences are related to speech impairment. DESIGN: Between 2003 and 2007, measures on cerebellar volume were obtained on 43 children with nonsyndromic cleft of the lip and/or palate and 43 age- and sex-matched, healthy controls. Children with the cleft condition also received speech evaluations. Children with nonsyndromic cleft of the lip and/or palate were recruited from clinic records, and controls (screened for medical, psychiatric, speech/language, and behavioral concerns) were recruited from the local community. All tests were administered at a large midwestern hospital. Boys and girls with nonsyndromic cleft of the lip and/or palate were compared with the healthy controls on global and regional measures of cerebellar volume. Areas of significant difference were then correlated with measures of speech to assess relationships in children with nonsyndromic cleft of the lip and/or palate. RESULTS: Boys with nonsyndromic cleft of the lip and/or palate had smaller cerebellums than controls (p = .002); whereas, for girls, only regional reductions in size reached significance (corpus medullare, p = .040). Cerebellum size was correlated with articulation for boys (p = .045). CONCLUSIONS: These findings lend support to previous research documenting abnormal brain structure in children with nonsyndromic cleft of the lip and/or palate and suggest that the cerebellum may play a role in speech deficits along with other structural causes, at least in boys.

Posttreatment FDG-PET uptake in the supraglottic and glottic larynx correlates with decreased quality of life after chemoradiotherapy.

PURPOSE: Inflammation and increased metabolic activity associated with oxidative stress in irradiated normal tissues may contribute to both complications following radiotherapy and increased glucose uptake as detected by posttherapy fluorodeoxyglucose (FDG)-PET imaging. We sought to determine whether increased glucose uptake in normal tissues after chemoradiotherapy is associated with increased toxicity. METHODS AND MATERIALS: Consecutive patients with locoregionally advanced head and neck cancers treated with intensity-modulated radiation therapy and free of recurrence at 1 year were studied. FDG-PET imaging was obtained at 3 and 12 months posttreatment. Standardized uptake value (SUV) levels were determined at various head and neck regions. Functional outcome was measured using a quality of life questionnaire and weight loss and type of diet tolerated 1 year after therapy. A one-tailed Pearson correlation test was used to examine associations between SUV levels and functional outcome measures. RESULTS: Standardized uptake value levels in the supraglottic and glottic larynx from FDG-PET imaging obtained 12 months posttreatment were inversely associated with quality of life measures and were correlated with a more restricted diet 1 year after therapy. SUV levels at 3 months after therapy did not correlate with functional outcome. Increases in SUV levels in normal tissues between 3 and 12 months were commonly found in the absence of recurrence. CONCLUSION: Altered metabolism in irradiated tissues persists 1 year after therapy. FDG-PET scans may be used to assess normal tissue damage following chemoradiotherapy. These data support investigating hypermetabolic conditions associated with either inflammation, oxidative stress, or both, as causal agents for radiation-induced normal tissue damage.

Evaluation of open approach and injection laryngoplasty in revision thyroplasty procedures.

INTRODUCTION: Vocal outcomes after medialization laryngoplasty are variable and may change over time. A revision procedure via open approach or an injection laryngoplasty may be necessary to improve vocal outcomes. METHODS: A retrospective chart review was performed. RESULTS: Twenty-nine subjects were identified and stratified into group 1A (n = 9) if the allograft was repositioned/replaced, group 1B (n = 4) if the allograft was removed, and group 2 (n = 16) if an injection laryngoplasty was performed. Statistically significant differences were found between all data prerevision to postrevision (P < or = 0.05) for group 1A and group 2 when multiple paired-sample t tests were calculated for patient-reported voice severity ratings and voice impact ratings as well as clinician-reported voice ratings of grade, roughness, and breathiness. Results of group 2 were often temporary, with 10 of 16 (62.5%) subjects receiving multiple injections. CONCLUSION: Both open revision laryngoplasty and injection laryngoplasty are successful at providing improved vocal outcomes. Results are often temporary after injection laryngoplasty and often require multiple procedures.

Radiation doses to structures within and adjacent to the larynx are correlated with long-term diet- and speech-related quality of life.

PURPOSE: To test the hypothesis that radiation dose to key sites in the upper aerodigestive tract is associated with long-term functional outcome after (chemo)radiotherapy for head-and-neck cancers. METHODS AND MATERIALS: This study examined the outcome for 27 patients treated with intensity-modulated radiotherapy for definitive management of their head-and-neck cancer who were disease free for at least 1 year after treatment. Head-and-neck cancer-specific quality of life (QoL) was assessed before treatment and at 1 year after treatment. Type of diet tolerated, presence of a feeding tube, and degree of weight loss 1 year after treatment were also used as outcome measures. Radiation doses delivered to various points along the upper aerodigestive tract, including base of tongue, lateral pharyngeal walls, and laryngeal structures, were determined from each treatment plan. Radiation doses for each of these points were tested for correlation with outcome measures. RESULTS: Higher doses delivered to the aryepiglottic folds, false vocal cords, and lateral pharyngeal walls near the false cords correlated with a more restrictive diet, and higher doses to the aryepiglottic folds correlated with greater weight loss (p < 0.05) 1 year after therapy. Better posttreatment speech QoL scores were associated with lower doses delivered to structures within and surrounding the larynx. CONCLUSION: Our data show an inverse relationship between radiation dose delivered to laryngeal structures and speech and diet and QoL outcomes after definitive (chemo)radiation treatment. These findings suggest that efforts to deliver lower doses to laryngeal structures may improve outcomes after definitive (chemo)radiation therapy.

Reliability of clinician-based (GRBAS and CAPE-V) and patient-based (V-RQOL and IPVI) documentation of voice disorders.

This study examined the reliability of two methods for documenting voice quality by clinicians and compared the methods for documenting patients' perceptions of voice quality. It involved a prospective reliability study and a retrospective chart review. Reliability of two clinician-based voice assessment protocols-Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS) and Consensus Auditory Perceptual Evaluation-Voice (CAPE-V)-was evaluated. These two protocols were then compared after use in voice assessments of 42 males and 61 females performed by a certified speech-language pathologist specializing in the assessment of voice disorders. In addition, two patient-based scales (Voice Related Quality of Life, or V-RQOL, and Iowa Patient's Voice Index, or IPVI) obtained from the same patients were compared with each other and with the clinician-based scales. Reliability of clinicians' ratings of overall severity of dysphonia using GRBAS and CAPE-V scales was very good (r>0.80). Agreement between V-RQOL Total scores and IPVI ratings of the patient's perceptions of impact of dysphonia was less strong (Spearman's r=-0.76). There was relatively weak agreement between patient-based and clinician-based scales. Clinician's perceptions of dysphonia appeared to be reliable and unaffected by rating tool, as indicated by the high level of agreement between the two rating systems when they were used together. The CAPE-V system appeared to be more sensitive to small differences within and among patients than the GRBAS system. The V-RQOL and IPVI approaches to documenting patient's perceptions of dysphonia agreed less well possibly due to differences in patient dependence on voice and on interpretation of the rating tool items. The differences between clinician-based and patient-based data support the conclusion that clinicians and patients experience and consider dysphonia very differently.

Quantitative Endoscopic Phototransducer Investigation of Normal Velopharyngeal Physiology.

PURPOSE: The purpose of this research was to learn the extent to which healthy individuals vary in their ability to achieve velopharyngeal closure for speech. METHOD: Twenty healthy adult volunteers (10 women, 10 men) were tested using an endoscopic phototransducer system that tracks variations in velopharyngeal closure during speech production. Each speaker produced multiple repetitions of three utterances that differed in phonetic content. The data were amplitude normalized and averaged for each speaker. RESULTS: Average phototransducer measurements were similar across subjects for utterances containing only oral phonemes. Average percentage of velopharyngeal closure varied considerably among subjects when producing utterances containing both oral and nasal phonemes (54%-95%). Average percentage of velopharyngeal closure levels were significantly lower (p < .05) for utterances that included nasal consonants. CONCLUSIONS: Phototransducer measurements of velopharyngeal closure for speech are sensitive to nasal phoneme content. The findings suggest that motor programming that accomplishes rapid oral-nasal velopharyngeal valving for speech may differ among healthy subjects. However, such variations in motor programming may not perceptually affect typical speakers. If present in individuals with abnormal velopharyngeal mechanisms, these variations may help explain variations among speakers in speech outcomes after physical and behavioral management.

Comparison of clinician judgments and measurements of swallow response time: a preliminary report.

Practicing clinicians frequently offer judgments about aspects of swallowing physiology rather than performing actual measurements. Little is known about the accuracy of those judgments. The purpose of this preliminary study was to explore agreement of clinicians' judgments of pharyngeal swallow response time (PSRT) with temporal measurements of PSRT. In preparation for a larger study, PSRT was measured from the first 3 ml liquid bolus swallow that appeared in each of 20 videofluorographic swallowing evaluations. The same 20 swallows were then shown to 3 clinicians who were instructed to subjectively rate PSRT. The reliability of the PSRT measurements was strong (r > .95). Intrajudge and interjudge agreement was better than chance in all but 1 interjudge comparison. Percentage agreement between clinicians' judgments and the measurements, when the measurements were categorized as either not delayed or delayed, ranged from 60% to 95%. Chi-square and Phi statistics comparing the outcomes of clinicians' ratings with the measurement outcomes were significant, supporting the agreement of the judgments with the measurements. Although the results of tests of agreement were found to be acceptable, clinician experience and training remain important issues whenever clinical judgments are involved. Larger studies are needed to establish the accuracy and importance of clinicians' judgments of PSRT and observations of swallowing physiology.

Resonant voice: spectral and nasendoscopic analysis.

Although resonant voice therapy is a widely used therapeutic approach, little is known about what characterizes resonant voice and how it is physiologically produced. The purpose of this study was to test the hypothesis that resonant voice is produced by narrowing the laryngeal vestibule and is characterized by first formant tuning and more ample harmonics. Videonasendoscopic recordings of the laryngeal vestibule were made during nonresonant and resonant productions of /i/ in six subjects. Spectrums of the two voice types were also obtained. Spectral analysis showed that first formant tuning was exhibited during resonant voice productions and that the degree of harmonic enhancement in the range of 2.0 to 3.5 kHz was related to voice quality: nonresonant voice had the least amount of energy in this range, whereas a resonant-relaxed voice had more energy, and a resonant-bright voice had the greatest amount of energy. Visual-perceptual judgments of the videoendoscopic data indicated that laryngeal vestibule constriction was not consistently associated with resonant voice production.

Laryngeal collagen injection as an adjunct to medialization laryngoplasty.

OBJECTIVES/HYPOTHESIS: Dysphonia associated with laryngeal paralysis may be identified in the short term postoperatively or may develop years after successful medialization laryngoplasty. In selected cases, laryngeal collagen injection permits further medialization of one or both vocal folds by small increments to improve phonation after medialization thyroplasty. The study seeks to determine whether collagen injections result in measurable improvements in voice quality and vocal function when offered to select patients who have received medialization thyroplasty. STUDY DESIGN: Retrospective review of patient charts and voice database. METHODS: Seven patients were treated with Zyderm II collagen using indirect mirror laryngoscopy and a curved injection apparatus. Changes in voice quality and function were assessed by comparing measures obtained before treatment (mean period, 5.6 d), shortly after treatment (mean period, 38.1 d), and in the long term after treatment (mean period, 226 d). RESULTS: Mean self-ratings of the patient, clinician's ratings, and objective measures demonstrated measurable improvement in vocal function after collagen injection. CONCLUSIONS: The office-based procedure offers a simple, efficient adjunct to open techniques of medialization laryngoplasty. Techniques of anesthesia, injection, and patient selection are discussed.

Long-term follow-up of fat injection laryngoplasty for unilateral vocal cord paralysis.

OBJECTIVE: The objective of the study was to evaluate the results of autologous fat injection laryngoplasty in the long-term management of unilateral vocal cord paralysis. STUDY DESIGN: A retrospective chart review and clinical voice re-evaluation of patients treated for unilateral vocal cord paralysis with autologous fat injection at the University of Iowa Hospitals and Clinics (Iowa City, IA) between May 1992 and September 1999. METHODS: The data analyzed included patient demographics, early and long-term vocal outcomes, additional surgical treatments, and patient survival. RESULTS: Fifty patients were treated with fat injection laryngoplasty, which included 44 treated for unilateral vocal cord paralysis. Thirty-one of the patients had fat injection as their primary procedure for permanent voice restoration. Eight patients treated had preoperative and postoperative voice data available. Using the GRBAS subjective voice assessment scale (0, normal; 3, severely abnormal), mean grade improved from 2.1 to 1.3 and breathiness improved from 1.4 to 0.5, at a mean period of 52 days. Thirteen of the 31 patients (41%) required additional procedures to achieve acceptable vocal outcomes. The median time to failure for these patients was 163 days. The initial treatment failure rate at 2 years was 30%, and the rate reached 45% by 4 years. CONCLUSION: Although fat injection laryngoplasty reliably improves the voice over the short term, the long-term voice outcome is unpredictable. Additional surgeries to deal with subsequent vocal deterioration are common. The role of autologous fat injection laryngoplasty in the modern era is limited.

Pharyngeal flap surgery: protocols, complications, and outcomes at the University of Iowa.

OBJECTIVE: We sought to assess complication rates and speech outcomes in patients undergoing pharyngeal flap surgery. Study design and setting We conducted a retrospective chart and database review at a tertiary craniofacial center. PATIENTS: Eighty-seven patients were identified as having pharyngeal flaps between January 1990 and December 2000. RESULTS: Complications were rare, with an overall rate of 3.4% for all children. Craniofacial database records were identified with a follow-up examination between 2 and 5 years. Forty-four patients were identified. Of this group, 81.8% demonstrated no evidence of hypernasality or mild hypernasality, and 84.1% demonstrated no evidence of hyponasality or only mild hyponasality. Preoperative and postoperative assessments showed a statistically significant difference in hypernasality at P < 0.001 with no significant difference in hyponasality. CONCLUSIONS: Although sphincter pharyngoplasty procedures have gained a great deal of attention in the recent otolaryngologic literature, pharyngeal-flap procedures remain a valuable tool in the hands of surgeons dealing with velopharyngeal incompetence.

Pharyngeal flap surgery: long-term outcomes at the University of Iowa.

The pharyngeal flap is the most often used surgical approach to treat the problem of velopharyngeal insufficiency, a common challenge encountered in cleft palate and craniofacial clinics. The authors retrospectively reviewed short-term and long-term measures of children treated with the pharyngeal flap at the University of Iowa Cleft and Craniofacial Center. All patients who underwent pharyngeal flap surgery between January of 1970 and December of 2000, with at least one postoperative speech assessment between 2 and 5 years after the operation, were identified. Both hypernasality and hyponasality were evaluated on a scale from 1 to 6, with 1 indicating no involvement and 6 indicating severe effect on resonance. Velopharyngeal competence was also rated on a scale of 1 to 3, with 1 indicating competence and 3 indicating incompetence. These short-term data were then compared. The results showed that overall resonance performance continues to be adequate and may even improve as the patient continues to grow and mature. These findings support the use of the pharyngeal flap in the treatment of children with velopharyngeal insufficiency.

Perceived phonatory effort and phonation threshold pressure across a prolonged voice loading task: a study of vocal fatigue.

Although the problem of vocal fatigue is not uncommon in people with voice disorders, research on objective quantifiable indicators of vocal fatigue is limited. It has been suggested that a speaker's perception of increased phonatory effort associated with periods of prolonged voice use is related to increased lung pressure required to initiate and sustain phonation. The purpose of this study was to examine the relationship among perceived phonatory effort (PPE), which was used as a subjective index of vocal fatigue, and phonation threshold pressure (PTP), a quantifiable measure defined as the minimal lung pressure required to initiate and sustain vocal fold oscillation. PTP and PPE were recorded before, during, and after five adult male and five adult female speakers engaged in a prolonged oral reading task designed to induce vocal fatigue. The results supported a direct, moderately strong relationship between PTP and PPE, particularly when PTP was measured during speech produced at comfortable and low-speaking pitch levels. No gender effects were found. PTP returned to baseline levels within 1 hour after the fatiguing task. PPE returned to baseline within 1 day. The data support the use of PTP as an objective index of vocal fatigue.

Technical advances toward an endoscopic-phototransducer approach to investigation of velopharyngeal physiology.

PURPOSE: This study aimed to examine the response characteristics of a new generation phototransducer and to test new recording and processing procedures when used with endoscopy to track velopharyngeal closure during normal speech. METHOD: Integrated phototransducer-endoscopy response linearity was laboratory tested using a wide range of simulated velopharyngeal orifice areas. In vivo speech testing was completed to determine the effect of endoscope to light receptor distance on measurements documenting variations in normal velopharyngeal closure. RESULTS: Phototransducer response linearity was excellent (r = .99) provided an indirect (reflected light) orientation was used between the endoscope and the light-sensing fiber coupled with the phototransducer. Phototransducer response time exceeded expected velopharyngeal movement rates by an order of magnitude. In vivo speech measurements were affected by the distance between the light-emitting endoscope and the light-receiving tip of the light-sensing fiber. Data normalization to a light-out condition effectively controlled for this expected phenomenon. Patterns of velopharyngeal valving during speech were found to be stable and appropriate given the phonetic content of the utterance. CONCLUSIONS: Technological and data-processing advances support further exploration of an integrated phototransducer-endoscopic approach to studying velopharyngeal closure for speech. Additional studies involving normal speakers are under way.

Aerodynamic and acoustic effects of ventricular gap.

PURPOSE: Supraglottic compression is frequently observed in individuals with dysphonia. It is commonly interpreted as an indication of excessive circumlaryngeal muscular tension and ventricular medialization. The purpose of this study was to describe the aerodynamic and acoustic impact of varying ventricular medialization in a canine model. METHODS: Subglottal air pressure, glottal airflow, electroglottograph, acoustic signals, and high-speed video images were recorded in seven excised canine larynges mounted in vitro for laryngeal vibratory experimentation. The degree of gap between the ventricular folds was adjusted and measured using sutures and weights. Data were recorded during phonation when the ventricular gap was narrow, neutral, and large. Glottal resistance was estimated by measures of subglottal pressure and glottal flow. RESULTS: Glottal resistance increased systematically as ventricular gap became smaller. Wide ventricular gaps were associated with increases in fundamental frequency and decreases in glottal resistance. Sound pressure level did not appear to be impacted by the adjustments in ventricular gap used in this research. CONCLUSIONS: Increases in supraglottic compression and associated reduced ventricular width may be observed in a variety of disorders that affect voice quality. Ventricular compression may interact with true vocal fold posture and vibration resulting in predictable changes in aerodynamic, physiological, acoustic, and perceptual measures of phonation. The data from this report supports the theory that narrow ventricular gaps may be associated with disordered phonation. In vitro and in vivo human data are needed to further test this association.

Association between severity of dysphagia and survival in patients with head and neck cancer.

BACKGROUND: This study examined risk factors for dysphagia, a common and serious condition in patients with head and neck cancer, and the association between severity of dysphagia and survival. METHODS: Chart reviews were performed on patients diagnosed with head and neck cancer between January 2001 and April 2003, who had dysphagia diagnoses or swallowing evaluations. Regression analyses determined factors associated with dysphagia and the association between observed survival and severity of dysphagia. RESULTS: Almost 50% of the 407 patients had dysphagia. Risk factors included advanced stage, older age, female sex, and hypopharyngeal tumors. The most severe dysphagia ([L.] nil per os or "nothing by mouth" status), which was associated with lower survival rates, was the strongest independent predictor of survival. CONCLUSIONS: Swallowing problems should be considered when determining appropriate cancer-directed treatment and posttreatment care. Because of dysphagia's high incidence rate and association with survival, a speech-language pathologist should be involved to ensure routine diagnostic and therapeutic swallowing interventions.

Outcomes after the use of gastrostomy tubes in patients whose head and neck cancer was managed with radiation therapy.

BACKGROUND: The purpose of this study was to examine the effect of continued oral intake and duration of gastrostomy tube placement on posttreatment nutritional outcomes in patients being irradiated for head and neck cancer. METHODS: Factors associated with continued oral intake and its association with posttreatment outcomes were analyzed. RESULTS: Patients with no oral intake (39.6% of 91) were more likely to have laryngeal tumors, advanced disease, and pretreatment gastrostomy tube placement. Of the 55 patients whose gastrostomy tubes had been removed, those with continued oral intake and shorter gastrostomy tube placement were more likely to maintain their weight and report eating scores in the higher-functioning category, but have more restricted diets. Observed survival was significantly better for the continued-oral-intake group (p = .001). CONCLUSION: The beneficial effects of continued oral intake and shorter gastrostomy tube placement on posttreatment outcomes shown in this study suggest that clinicians involved in these patients' care should emphasize oral intake during treatment.

Tensor veli palatini preservation, transection, and transection with tensor tenopexy during cleft palate repair and its effects on eustachian tube function.

BACKGROUND: During cleft palate repair, levator sling palatoplasty with tensor veli palatini tendon transection significantly improves speech results. However, the procedure may pose a risk to eustachian tube function. This study assesses the impact of three types of palatoplasty techniques on eustachian tube function: no tensor transection, tensor transection alone, and a new addition to the palatoplasty technique, tensor tenopexy. METHODS: A retrospective review was conducted of all patients undergoing cleft palate repair at two institutions between 1997 and 2001. Three cleft palate repair groups were studied: no tensor transection (n = 64), tensor transection alone (n = 31), and tensor tenopexy (n = 52). The percentages of patients requiring myringotomy tubes at each year of age were compared among the three groups. RESULTS: By 7 years of age, there was a significantly decreased need for myringotomy tubes in patients who underwent no tensor transection compared with patients who underwent tensor transection alone (38 percent versus 61 percent, respectively; p = 0.05), as well as for patients who underwent tensor tenopexy compared with patients who underwent tensor veli palatini tendon transection (23 percent versus 61 percent, respectively; p < 0.001). Also, by the age of 7, there was a trend toward a decreased need for myringotomy tubes in patients who underwent tensor tenopexy compared with patients who underwent no tensor transection (23 percent versus 38 percent, respectively; p = 0.11). CONCLUSIONS: No tensor transection and tensor tenopexy significantly decrease the need for myringotomy tubes compared with tensor transection alone. There is a small decrease in the need for myringotomy tubes when comparing tensor tenopexy with no tensor transection.

Health-related quality of life among preadolescent children with oral clefts: the mother's perspective.

OBJECTIVE: The purpose of this study was to evaluate the factors that affect the health-related quality of life of preadolescent children with nonsyndromic oral clefts using the Pediatric Quality of Life Inventory instrument and to evaluate whether there were any differences related to the type of cleft or other factors. METHODS: Data for this study were derived from telephone interviews with the parents of a statewide population of children who were in the Iowa Registry for Congenital and Inherited Disorders, were aged 2 to 12 years, had nonsyndromic oral clefts, and were born in Iowa between January 1, 1990, and December 31, 2000. Twenty-minute interviews were conducted with mothers of 104 children in the spring and summer of 2003; respondents then completed and mailed back Pediatric Quality of Life Inventory surveys 2 to 3 weeks after the interviews (69% participation rate). RESULTS: After controlling for demographic characteristics, children with less severe speech problems had higher total Pediatric Quality of Life Inventory scores as well as higher physical and psychosocial health domain scores. Age and cleft type interacted, with younger children (aged 2-7 years) with a cleft lip or cleft lip and palate having higher health-related quality of life scores than children with an isolated cleft palate; however, this pattern was reversed for older children (aged 8-12 years). CONCLUSIONS: Speech and aesthetic concerns seem to have been important factors affecting the health-related quality of life for children with oral clefts. These factors seem to be more important as children get closer to adolescence (ages 8-12 years) when acceptance by peers becomes more critical.