Tube Feed Necrosis after Major Gastrointestinal Oncologic Surgery: Institutional Lessons and a Review of the Literature.

BACKGROUND: Small bowel necrosis after enteral feeding through a jejunostomy tube (tube feed necrosis, TFN) is a rare, serious complication of major abdominal surgery. However, strategies to reduce the incidence and morbidity of TFN are not well established. Here, in the largest series of TFN presented to date, we report our institutional experience and a comprehensive review of the literature. METHODS: Eight patients who experienced TFN from 2000 to 2014 after major abdominal surgery for oncologic indications at the University of Cincinnati were reviewed. Characteristics of post-operative courses and outcomes were reviewed prior to and after a change in tube-feeding protocol. The existing literature addressing TFN over the last three decades was also reviewed. RESULTS: Patients with TFN ranged from 50 to 74 years old and presented with upper gastrointestinal tract malignancies amenable to surgical resection. Six and two cases of TFN occurred following pancreatectomy and esophagectomy, respectively. Prior to TF protocol changes, which included initiation at a low rate, titrating up more slowly and starting at one-half strength TF, three of six cases of TFN (50%) resulted in mortality. With the new TF protocol, there were no deaths, goal TF rate was achieved 3 days later, symptoms of TFN were recognized 3 days earlier, and re-operation was conducted 1 day earlier. CONCLUSION: This case series describes a change in clinical practice that is associated with decreased morbidity and mortality of TFN. Wider implementation and further refinement of this tube-feeding protocol may reduce TFN incidence at other institutions and in patients with other conditions requiring enteral nutrition.

Vowel perception by adults and children with normal language and specific language impairment: based on steady states or transitions?

The current investigation studied whether adults, children with normally developing language aged 4-5 years, and children with specific language impairment, aged 5-6 years identified vowels on the basis of steady-state or transitional formant frequencies. Four types of synthetic tokens, created with a female voice, served as stimuli: (1) steady-state centers for the vowels [i] and [ae]; (2) voweless tokens with transitions appropriate for [bib] and [baeb]; (3) "congruent" tokens that combined the first two types of stimuli into [bib] and [baeb]; and (4) "conflicting" tokens that combined the transitions from [bib] with the vowel from [baeb] and vice versa. Results showed that children with language impairment identified the [i] vowel more poorly than other subjects for both the voweless and congruent tokens. Overall, children identified vowels most accurately in steady-state centers and congruent stimuli (ranging between 94%-96%). They identified the vowels on the basis of transitions only from "voweless" tokens with 89% and 83.5% accuracy for the normally developing and language impaired groups, respectively. Children with normally developing language used steady-state cues to identify vowels in 87% of the conflicting stimuli, whereas children with language impairment did so for 79% of the stimuli. Adults were equally accurate for voweless, steady-state, and congruent tokens (ranging between 99% to 100% accuracy) and used both steady-state and transition cues for vowel identification. Results suggest that most listeners prefer the steady state for vowel identification but are capable of using the onglide/offglide transitions for vowel identification. Results were discussed with regard to Nittrouer's developmental weighting shift hypothesis and Strange and Jenkin's dynamic specification theory.

HONC measures in 4- to 6-year-old children. Horii Oral Nasal Coupling Index.

OBJECTIVE: To collect normative data using Horii's Oral Nasal Coupling Index (HONC) from 4- to 6-year-old children without cleft palate to be used in the evaluation of young children with cleft palate. In addition, to determine whether HONC values in children are similar to those of adults and thus show that the HONC ratio successfully normalizes nasal accelerometric signals across age, gender, and vocal intensity. DESIGN: Measurement of accelerometric and acoustic signals from novel nasal and nonnasal utterances, which the children repeated after the experimenter. Measurements also included four sustained [m] productions, which were used to calibrate correction factors used to equate nasal and oral signals during a sustained [m] production. SETTING: Laboratory at a state university. PARTICIPANTS: Ten girls and 10 boys, aged 4 to 6 years, with normal speech, language, and hearing. RESULTS: Differences of 13 dB (HONC) were found to separate nasal from nonnasal sentences. No significant difference in HONC score was found across gender for nasal/nonnasal sentences and [m] productions. The correction factors generated during [m] calibration procedures did not differ between girls and boys. CONCLUSIONS: Horii Oral Nasal Coupling Index differences between nasal and nonnasal utterances appear to be valid and reliable measures in both children and adults for detection of disorders of nasal resonance.

Phonetic category structure of [I]: extent, best exemplars, and organization.

The current investigation examined the structure of the phonetic category [I] for 13 listeners. Experiments reported are results from identification, "best exemplar," and discrimination tasks using 105 [I] stimuli. The tokens were synthesized long a mel-spaced vowel continuum that differed in first and second formants. All stimuli ended in a 30 ms [b] sound. Results showed that 10 of 13 listeners demonstrated differing choices of the best exemplars, although most were within 37.5 mels of the central best exemplar chosen in the first experiment. Seven of the participants demonstrated "circular" patterns in identification of the [I] category that appeared to be organized around a central "best exemplar." Six participants showed other identification patterns: "downward," "upward," and "left-extending," with "best exemplars" on an edge or border of the phonetic categories. Graded category structure from a central "best exemplar" was apparent only in the averaged identification results, and not for individual participants. The size of the [I] category was significantly smaller than that surrounding the [i] best exemplar reported in a prior study by Sussman and Lauckner-Morano (1995). Finally, listeners had equivalent or better discrimination sensitivity with the best exemplar as the fixed standard compared to that for a "poor" exemplar token 45 mels away from the best exemplar. Results showed that phonetic category structure for the lax vowel [I] was different from the similar, but tense vowel [i]. The findings question whether prototype theory is generalizable to vowel categories other than [i].

HONC measures in men and women: validity and variability.

Horii's (1980) Oral Nasal Coupling index (HONC) was used in measures of 20 women and 20 men with normal speech to validate procedures used for assessment of disordered nasal resonance. Subjects produced sustained vowels [i] and [a], repeated single word productions of "baby" and "mamie" and nonnasal and nasal sentences. Results showed that the correction factors generated during [m] calibration procedures differed significantly between women and men, but not over time within the single measurement session. Differences were also found for the decibel levels produced in the voice channel during the [m] calibration procedure: the women used higher dB levels, particularly towards the end of the session, than the men. In addition, dB levels differed over time. Differences of 13 dB (HONC) were found to separate nonnasal from nasal sentences supporting the validity of the HONC measure. Smaller differences were found between sustained vowel and repeated single words and nasal sentences. Greater variability found for vowel productions also suggests that the sentence stimuli may be more effective for demonstrating hyper- or hyponasality.

Further tests of the "perceptual magnet effect" in the perception of [i]: identification and change/no-change discrimination.

The present study investigated the existence of a "perceptual magnet" effect [Kuhl, Percept. Psychophys. 50, 93-107 (1991)] in a speech perception experiment. Sixteen subjects experienced in phonetics, transcribed the [i] stimuli used by Kuhl (1991) or identified the stimuli as [i] or not-[i] in experiment 1. In experiments 2 and 3, 50 adults who were not trained in phonetics, participated in an identification task requiring them to decide whether the vowel sounds they heard were the "[i] in 'peep'" or "not the [i] in 'peep'. "They also completed a "change/no change" discrimination task with standards consisting of the "prototype" [i] and other nonprototype stimuli at 67, 75, and 120 mels away from the prototype. Results from the first study showed that listeners did not identify the 120-mel token previously used by Kuhl (1991) as the nonprototype standard stimulus in discrimination experiments as [i]. Sensitivity results from experiments 2 and 3, as measured with d-prime partially supported the "perceptual magnet" hypothesis as suggested by Kuhl (1991) whereas miss results did not. Findings indicated that d-prime, a nonbiased measure of subjects' discrimination ability, better represented the perceptual magnet effect than misses alone. Thus results suggested that subjects were better able to discriminate stimuli surrounding a less "prototypical" [i] vowel as demonstrated by greater sensitivity, faster reaction times for hits and fewer number of misses. However, current results may also be explained by increased auditory resolution rather than prototype-based, "magnet" effects. It was concluded that whereas the perceptual magnet effect may exist for particular vowel categories, more data are needed to better understand the role of prototypes in speech perception.

Articulatory, developmental, and gender effects on measures of fundamental frequency and jitter.

Fundamental frequency (Fo) and jitter were measured in digitized live-voice productions of sustained vowels [a], [i], and [u] from women, men, and 6- through 9-year-old children. Results showed (a) significant developmental differences for mean Fo and for the pattern of jitter by vowel type, (b) significant gender differences in Fo and jitter only for adults, (c) significant differences in Fo and jitter according to vowel type for all subjects, and (d) similar amounts of mean absolute jitter for children and women for all vowels with nonsignificantly different values of jitter for boys and men on [i] and [u] productions. Results are related to Honda's theory of intrinsic Fo for vowels and to Titze's neurologic model of jitter.

Perception of formant transition cues to place of articulation in children with language impairments.

Discrimination and phonetic identification abilities of 5- to 6-year-old children with language impairments were compared to those of 4-year-olds with normally developing language and to previous findings from 5- to 6-year-olds and adults for synthetic stimuli ranging from [ba] to [da]. Results showed similar discrimination sensitivity to the second- and third-formant transition cues of stimuli by all children, with poorest sensitivity by the youngest. Phonetic categorization by children with language impairments was most different from the groups with normal language abilities, evidenced by a difference in the percent of tokens labeled as "BA" and by greater variability in labeling and in placement of phonetic category boundaries. Results support hypotheses by Gathercole and Baddeley (1990) suggesting that the phonological component of working memory may be disordered in children with language impairments. Results are also suggestive of specific difficulties with left-hemisphere processing associated with language learning rather than with problems related to sensitivity to formant transitions of the speech tokens.

Auditory processing in children's speech perception: results of selective adaptation and discrimination tasks.

Five- to six-year-old children and adults participated in discrimination and selective adaptation speech perception tasks using a synthetic consonant-vowel continuum ranging from [ba] to [da]. In one condition of selective adaptation, attention was focused on the adapting stimulus, the continuum-endpoint [ba], with a whispering task. In another condition, attention was focused away from the continuum-endpoint [da] adaptor to contralaterally presented syllables "SHE" and "SEE." Results, compared with two more typical adaptation conditions, indicated that focused attention did not augment selective adaptation effects, particularly for children who showed smaller effects with focused attention on the adaptor. In contrast to adults, children did not significantly change labeling responses after exposure to endpoint-[ba] adaptors, results matching those of Sussman and Carney (1989). However, children did significantly change labeling following exposure to endpoint-[da] adaptors. Discrimination findings with five-formant consonant-vowel and single-formant stimuli supported the importance of acoustic processing for the selective adaptation tasks performed. Together, results support hypotheses of sensory processing differences in younger, normally developing children compared with adults and show that such abilities appear to be related to speech perception skills.

Focused attention during selective adaptation along a place of articulation continuum.

The current investigation manipulated subjects' attention to adaptor tokens in five selective adaptation experiments. All stimuli were synthetic consonant-vowel syllables, with the consonant varying from [b] to [d] by formant frequency transitions. Two distractor conditions (auditory and visual) were compared to a more typical endpoint-[d alpha] adaptor condition. Distraction from endpoint-[d alpha] adaptors to phonetically distinct [si] and [integral of i] was used to observe whether smaller adaptation effects would result when attention was not focused on adaptor stimuli. In contrast, a focused attention condition required subjects to whisper [b alpha] adaptors right after they were heard. Performance in the focused attention condition was compared to a more typical endpoint-[b alpha] adaptation condition. Results indicated that focused attention did not affect the size of the adaptation effect. Asymmetrical adaptation results for [d alpha] vs [b alpha] adaptors, and a larger amount of adaptation with the presence of contralateral "distractor" syllables, resembled findings in psychoacoustic studies of discrimination and loudness adaptation. These results suggest that two levels of auditory processing (not special to speech perception) were responsible for the observed adaptation effects.

Stimulus ratio effects on speech discrimination by children and adults.

This investigation examined the response strategies and discrimination accuracy of adults and children aged 5-10 as the ratio of same to different trials was varied across three conditions of a "change/no-change" discrimination task. The conditions varied as follows: (a) a ratio of one-third same to two-thirds different trials (33% same), (b) an equal ratio of same to different trials (50% same), and (c) a ratio of two-thirds same to one-third different trials (67% same). Stimuli were synthetic consonant-vowel syllables that changed along a place of articulation dimension by formant frequency transition. Results showed that all subjects changed their response strategies depending on the ratio of same-to-different trials. The most lax response pattern was observed for the 50% same condition, and the most conservative pattern was observed for the 67% same condition. Adult response patterns were most conservative across condition. Difference in discrimination accuracy as measured by P(C) were found, with the largest difference in the 5- to 6-year-old group and the smallest change in the adult group. These findings suggest that children's response strategies, like those of adults, can be manipulated by changing the ratio of same-to-different trials. Furthermore, interpretation of sensitivity measures must be referenced to task variables such as the ratio of same-to-different trials.

Effects of transition length on the perception of stop consonants by children and adults.

The purpose of this investigation was to determine whether children with normal linguistic skills demonstrate increasing developmental changes in their perception of place of articulation for stop consonants with short- and long-duration formant transitions. Three experimental paradigms were used with children and adults: discrimination, labeling, and selective adaptation. Two sets of synthetic CV syllables, varying along a seven-step, bilabial-to-alveolar dimension, were used as stimuli. These two synthetic continua differed in the length of the second and third formant transitions. Results showed that children's discrimination abilities gradually approximated those of adults, but did not reach adult levels even at 10 years of age. Differences were not observed in the labeling task. Further, results of the selective adaptation task indicated that only the adult subjects showed a significant boundary shift for any adapting stimuli. The absence of selective adaptation in children was interpreted as a possible reflection of their poorer auditory abilities. Thus, the pattern of speech perception development for children for place of articulation is a complex one with a strong auditory developmental component.