Spectral Grouping of Electrically Encoded Sound Predicts Speech-in-Noise Performance in Cochlear Implantees.

OBJECTIVES: Cochlear implant (CI) users exhibit large variability in understanding speech in noise. Past work in CI users found that spectral and temporal resolution correlates with speech-in-noise ability, but a large portion of variance remains unexplained. Recent work on normal-hearing listeners showed that the ability to group temporally and spectrally coherent tones in a complex auditory scene predicts speech-in-noise ability independently of the audiogram, highlighting a central mechanism for auditory scene analysis that contributes to speech-in-noise. The current study examined whether the auditory grouping ability also contributes to speech-in-noise understanding in CI users. DESIGN: Forty-seven post-lingually deafened CI users were tested with psychophysical measures of spectral and temporal resolution, a stochastic figure-ground task that depends on the detection of a figure by grouping multiple fixed frequency elements against a random background, and a sentence-in-noise measure. Multiple linear regression was used to predict sentence-in-noise performance from the other tasks. RESULTS: No co-linearity was found between any predictor variables. All three predictors (spectral and temporal resolution plus the figure-ground task) exhibited significant contribution in the multiple linear regression model, indicating that the auditory grouping ability in a complex auditory scene explains a further proportion of variance in CI users' speech-in-noise performance that was not explained by spectral and temporal resolution. CONCLUSION: Measures of cross-frequency grouping reflect an auditory cognitive mechanism that determines speech-in-noise understanding independently of cochlear function. Such measures are easily implemented clinically as predictors of CI success and suggest potential strategies for rehabilitation based on training with non-speech stimuli.

Neural Correlates of Individual Differences in Speech-in-Noise Performance in a Large Cohort of Cochlear Implant Users.

OBJECTIVES: Understanding speech-in-noise (SiN) is a complex task that recruits multiple cortical subsystems. Individuals vary in their ability to understand SiN. This cannot be explained by simple peripheral hearing profiles, but recent work by our group ( Kim et al. 2021 , Neuroimage ) highlighted central neural factors underlying the variance in SiN ability in normal hearing (NH) subjects. The present study examined neural predictors of SiN ability in a large cohort of cochlear-implant (CI) users. DESIGN: We recorded electroencephalography in 114 postlingually deafened CI users while they completed the California consonant test: a word-in-noise task. In many subjects, data were also collected on two other commonly used clinical measures of speech perception: a word-in-quiet task (consonant-nucleus-consonant) word and a sentence-in-noise task (AzBio sentences). Neural activity was assessed at a vertex electrode (Cz), which could help maximize eventual generalizability to clinical situations. The N1-P2 complex of event-related potentials (ERPs) at this location were included in multiple linear regression analyses, along with several other demographic and hearing factors as predictors of SiN performance. RESULTS: In general, there was a good agreement between the scores on the three speech perception tasks. ERP amplitudes did not predict AzBio performance, which was predicted by the duration of device use, low-frequency hearing thresholds, and age. However, ERP amplitudes were strong predictors for performance for both word recognition tasks: the California consonant test (which was conducted simultaneously with electroencephalography recording) and the consonant-nucleus-consonant (conducted offline). These correlations held even after accounting for known predictors of performance including residual low-frequency hearing thresholds. In CI-users, better performance was predicted by an increased cortical response to the target word, in contrast to previous reports in normal-hearing subjects in whom speech perception ability was accounted for by the ability to suppress noise. CONCLUSIONS: These data indicate a neurophysiological correlate of SiN performance, thereby revealing a richer profile of an individual's hearing performance than shown by psychoacoustic measures alone. These results also highlight important differences between sentence and word recognition measures of performance and suggest that individual differences in these measures may be underwritten by different mechanisms. Finally, the contrast with prior reports of NH listeners in the same task suggests CI-users performance may be explained by a different weighting of neural processes than NH listeners.

Differences in neural encoding of speech in noise between cochlear implant users with and without preserved acoustic hearing.

Cochlear implants (CIs) have evolved to combine residual acoustic hearing with electric hearing. It has been expected that CI users with residual acoustic hearing experience better speech-in-noise perception than CI-only listeners because preserved acoustic cues aid unmasking speech from background noise. This study sought neural substrate of better speech unmasking in CI users with preserved acoustic hearing compared to those with lower degree of acoustic hearing. Cortical evoked responses to speech in multi-talker babble noise were compared between 29 Hybrid (i.e., electric acoustic stimulation or EAS) and 29 electric-only CI users. The amplitude ratio of evoked responses to speech and noise, or internal SNR, was significantly larger in the CI users with EAS. This result indicates that CI users with better residual acoustic hearing exhibit enhanced unmasking of speech from background noise.

Iron-deficiency anemia is a common presenting issue with giant paraesophageal hernia and resolves following repair.

BACKGROUND: A significant percentage of patients with paraesophageal hernia (PEH) will have a co-existing diagnosis of iron-deficiency anemia which will resolve following surgical repair. METHODS: Between 2000 and 2010, 270 patients underwent operative repair of PEH. Of this group, 123 patients (45.6 %) reported a preexisting diagnosis of iron-deficiency anemia. The study group consisted of 77 patients with a documented preoperative hemoglobin level (Hb) consistent with iron-deficiency anemia and a follow-up level at least 3 months following surgery. RESULTS: Of the 77 patients included, 72 underwent elective repair, median age was 75 (39-91) years, and 65 % were female. Cameron erosions were identified preoperatively in 32 %. Mean preoperative hemoglobin was 9.6 (4.4-13.6) g/dl and postoperative hemoglobin was 13.2 (10.7-17) g/dl at 3-12 months and 13.6 (9.7-17.2) g/dl at more than 1 year. Ninety percent of patients had a rise in postoperative hemoglobin level by at least 1 g/dL. Anemia resolved in 55 (71 %) patients, more often in women and younger patients (<70 years). Twenty-nine of 40 (73 %) patients on iron therapy discontinued this postoperatively. CONCLUSION: A significant number of patients who present with giant PEH will present with iron-deficiency anemia. Elective repair will result in resolution of the anemia in more than 70 % of patients. PEH is underappreciated as a source of iron-deficiency anemia, and appropriate patients should be considered for elective repair.

Clinical ramifications of giant paraesophageal hernias are underappreciated: making the case for routine surgical repair.

BACKGROUND: We propose that the symptoms associated with paraesophageal hernia (PEH) are more diverse than previously suggested, and symptoms and clinical manifestations correlate to the anatomy of the hernia. METHODS: Patients undergoing surgery for PEH were reviewed from a prospective, institutional review board-approved, single-center database. Presenting symptoms, anatomy of the PEH, demographics, and outcomes were analyzed from 2000 to 2010. Presenting symptoms were assessed for incidence and improvement after surgery. Size and configuration of the PEH were assessed with respect to presenting symptoms. RESULTS: The study included 270 consecutive patients, 63% were female, and the median age was 70 years (range, 39 to 94 years). The most common presenting symptoms were heartburn in 175 patients (65%), early satiety in 136 patients (50%), chest pain in 130 patients (48%), dyspnea in 130 patients (48%), dysphagia in 129 patients (48%), regurgitation in 128 patients (47%), and anemia in 112 patients (41%). Two hundred sixty-nine patients (99.6%) had at least one symptom; the median number of symptoms was 4 (range, 0 to 10). The type of PEH was II (n=10), III (n=206), and IV (n=54), and the percent intrathoracic stomach was less than 50% (n=33), 50% to 74% (n=86), 75% to 99% (n=55), and 100% (n=96). Paraesophageal hernia type was significantly associated with heartburn (type II/III; p=0.005) and dyspnea (type IV; p=0.007). Significant associations included lower percent intrathoracic stomach with regurgitation (p=0.04); higher percent intrathoracic stomach with early satiety (p=0.02), decreased meal size (p=0.007), and dyspnea (p<0.001); and 50% to 74% intrathoracic stomach with anemia (p=0.001). With a median postoperative follow-up of 103 days, symptoms were subjectively better in patients with dyspnea (67%), early satiety (79%), regurgitation (92%), dysphagia (81%), chest pain (76%), and heartburn (93%). CONCLUSIONS: Paraesophageal hernia is associated with a greater diversity of symptomatic presentation than previously thought. Asymptomatic patients are rare, and size and configuration of the hernia are associated with specific symptoms. Patients with large PEHs should be assessed by an experienced surgeon for elective repair.

Repair of giant paraesophageal hernias routinely produces improvement in respiratory function.

OBJECTIVE: Assessment of the clinical impact of giant paraesophageal hernias have historically focused on upper gastrointestinal symptoms. This study assesses the effect of paraesophageal hernia repair on respiratory function. METHODS: All patients undergoing repair of giant paraesophageal hernia were prospectively entered into a database approved by the institutional review board. Patients had symptoms documented preoperatively, including dyspnea. Pulmonary function tests (PFTs) were done preoperatively and repeated a median of 106 days after repair (range, 16-660 days). RESULTS: Preoperative and postoperative PFTs were obtained in 120 unselected patients treated for paraesophageal hernia between 2000 and 2010. Patients' median age was 74 years (range, 45-91 years), 74 (62%) were female, and median body mass index was 28.0 (range, 16.8-46.6). Median length of stay was 4 days (range, 3-10 days), and perioperative mortality was zero. Hernias were classified as type II in 3 (3%) patients, III in 92 (77%), and IV in 25 (21%). Percent of intrathoracic stomach was assigned from preoperative contrast studies and grouped as less than 50% (n = 6; 5%), 50% to 74% (n = 35; 29%), 75% to 99% (n = 29; 24%), and 100% (n = 50; 42%). Preoperative symptoms included heartburn 71 (59%), early satiety 65 (54%), dyspnea 63 (52%), chest pain 48 (40%), dysphagia 56 (47%), regurgitation 47 (39%), and anemia 44 (37%). PFTs significantly improved after paraesophageal hernia repair (mean volume change, percent reference change): forced vital capacity +0.30 L,+10.3%pred; FEV(1) +0.23 L,+10.4%pred (all P < .001); diffusion capacity of the lung for carbon monoxide +0.58 mL · mm Hg(-1) · min(-1) (P = .004), and +2.9%pred (P = .002). Greater improvements were documented in older patients with significant subjective respiratory symptoms and higher percent of intrathoracic stomach (P < .01). CONCLUSIONS: Paraesophageal hernia has a significant effect on respiratory function, which is largely underappreciated. This study demonstrates that these repairs can be done safely and supports routine consideration for elective repair; older patients with borderline respiratory function may achieve substantial improvements in their respiratory status and quality of life.

Synthesis and biological activity of imidazopyridine anticoccidial agents: part I.

Coccidiosis is the major cause of morbidity and mortality in the poultry industry. Protozoan parasites of the genus Eimeria invade the intestinal lining of the avian host causing tissue pathology, poor weight gain, and in some cases mortality. Resistance to current anticoccidials has prompted the search for new therapeutic agents with potent in vitro and in vivo activity against Eimeria. Antiparasitic activity is due to inhibition of a parasite specific cGMP-dependent protein kinase (PKG). In this study, we present the synthesis and biological activity of imidazo[1,2-a]pyridine anticoccidial agents. From this series, several compounds showed subnanomolar in vitro activity and commercial levels of in vivo activity. However, the potential genotoxicity of these compounds precludes them from further development.

The role of area-level influences on prostate cancer grade and stage at diagnosis.

BACKGROUND: This research explores area-level social influences on prostate cancer, to test whether area-level influences explain disparities in U.S. prostate cancer burden. METHODS: The authors geocoded 23,993 1992-1997 Maryland prostate cancer cases, and linked cases to 1990 census data. The authors examined the effect of 17 area-level social variables, measured at block group, tract, and county, modeling individual and multilevel predictors of later stage and higher tumor grade. RESULTS: Younger age, black race, higher grade or ungraded tumors, and earlier year of diagnosis were associated with later stage. Block group percentage of white-collar workers (O.R. = 0.93, 95% C.I. = 0.89, 0.98), and county resources (O.R. = 0.94, 95% C.I. = 0.89, 0.98), were protective of later stage. Older age, black race, and earlier year of diagnosis were associated with higher grade. Block group income was protective for white men (O.R. = 0.92, 95% C.I. = 0.87, 0.96), but for all men, county resources increased risk of higher grade (O.R. = 1.23, 95% C.I. = 1.16, 1.31). CONCLUSIONS: Social resources did not significantly reduce racial differences. Results suggest tumor biology is related to relative resources, with better outcomes associated with greater small-area wealth in low-resource counties, but stage at diagnosis is associated with absolute resources, with better outcomes associated with higher small-area social class in high-resource counties.