Cochlear Implantation in Cases of Unilateral Hearing Loss: Initial Localization Abilities.

OBJECTIVES: The present study evaluated early auditory localization abilities of cochlear implant (CI) recipients with normal or near-normal hearing (NH) in the contralateral ear. The goal of the study was to better understand the effect of CI listening experience on localization in this population. DESIGN: Twenty participants with unilateral hearing loss enrolled in a prospective clinical trial assessing outcomes of cochlear implantation (ClinicalTrials.gov Identifier: NCT02203305). All participants received the MED-EL Standard electrode array, were fit with an ear-level audio processor, and listened with the FS4 coding strategy. Localization was assessed in the sound field using an 11-speaker array with speakers uniformly positioned on a horizontal, semicircular frame. Stimuli were 200-msec speech-shaped noise bursts. The intensity level (52, 62, and 72 dB SPL) and sound source were randomly interleaved across trials. Participants were tested preoperatively, and 1, 3, and 6 months after activation of the audio processor. Performance was evaluated in two conditions at each interval: (1) unaided (NH ear alone [NH-alone] condition), and (2) aided, with either a bone conduction hearing aid (preoperative interval; bone conduction hearing aid + NH condition) or a CI (postoperative intervals; CI + NH condition). Performance was evaluated by comparing root-mean-squared (RMS) error between listening conditions and between measurement intervals. RESULTS: Mean RMS error for the soft, medium, and loud levels were 66°, 64°, and 69° in the NH-alone condition and 72°, 66°, and 70° in the bone conduction hearing aid + NH condition. Participants experienced a significant improvement in localization in the CI + NH condition at the 1-month interval (38°, 35°, and 38°) as compared with the preoperative NH-alone condition. Localization in the CI + NH condition continued to improve through the 6-month interval. Mean RMS errors were 28°, 25°, and 28° in the CI + NH condition at the 6-month interval. CONCLUSIONS: Adult CI recipients with normal or near-normal hearing in the contralateral ear experienced significant improvement in localization after 1 month of device use, and continued to improve through the 6-month interval. The present results show that binaural acclimatization in CI users with unilateral hearing loss can progress rapidly, with marked improvements in performance observed after only 1 month of listening experience.

Seasonal and Diurnal Variation in Water-Soluble Carbohydrate Concentrations of Repeatedly Defoliated Red and White Clovers in Central Kentucky.

Nonstructural carbohydrates of pasture plants, comprising water-soluble carbohydrates (WSCs) and starch, may contribute to excessive consumption of rapidly fermentable carbohydrates by grazing horses. Seasonal and diurnal variation in WSCs were studied in red (Trifolium pratense L.) and white clovers (Trifolium repens L.) subjected to a typical management regime of rotationally grazed horse pastures. Two red and two white clover cultivars from monoculture plots were harvested after 4 weeks of growth from April to October of 2015, in the morning and afternoon of each harvest date. Water-soluble carbohydrates were quantified for each harvest, and starch was quantified for two harvests. Mean monthly WSC concentrations ranged from 80 to 99 mg/g (freeze-dried weight basis), whereas mean starch concentrations were 31 and 40 mg/g. In September, white clover had 14% more WSCs than red clover (P < .0001). Water-soluble carbohydrate concentrations were 10% higher in the afternoon than in the morning (P < .0001). Starch concentrations were 290% higher in the afternoon than in the morning (P < .0001), and nonstructural carbohydrate concentrations in the afternoon averaged 150 mg/g. Further studies are needed to determine whether the mixed grass-legume pastures of central Kentucky accumulate enough nonstructural carbohydrates to present risk factors for equine metabolic or digestive dysfunction.

Diagnostic comparison of 1.5 Tesla and 3.0 Tesla preoperative MRI of the wrist in patients with ulnar-sided wrist pain.

PURPOSE: The diagnostic sensitivity, specificity, and accuracy of 1.5 Tesla (T) and of 3.0T magnetic resonance imaging (MRI) are correlated with wrist arthroscopy findings in patients presenting with ulnar-sided wrist pain. METHODS: The records and diagnostic MRI scans of 102 patients who presented between 1997 and 2006 with ulnar-sided wrist pain were evaluated. Preoperative MRI scans at 1.5T (n = 70) and 3.0T (n = 32) were evaluated by 2 experienced musculoskeletal radiologists with different levels of experience who were blinded to the arthroscopic findings. Preoperative MRI findings for the triangular fibrocartilage complex (TFCC), scapholunate, ulnotriquetral, and lunotriquetral ligaments were recorded and compared with findings at diagnostic arthroscopy. The sensitivity, specificity, and accuracy were calculated for both the 1.5T and 3.0T preoperative MRI scans. Statistical comparisons were made using chi-square test and JMP 6.0 software. RESULTS: A tear of the TFCC was identified retrospectively on 1.5T images in 49 of 58 patients and on 3.0T images in 15 of 16 patients. Compared with the gold standard of arthroscopy, 1.5T wrist MRI in this patient population had a sensitivity of 85%, a specificity of 75%, and an accuracy of 83% for reader 1 for the detection of a tear of the TFCC. In the same patient population, 3.0T wrist MRI had a sensitivity of 94%, a specificity of 88%, and an accuracy of 91% for reader 1. For reader 2, the improvement in sensitivity for the lunotriquetral ligament between the 1.5T and 3.0T images was statistically significant. CONCLUSIONS: The sensitivity, specificity, and accuracy of 3.0T wrist MRI for the TFCC is consistently higher compared with those of 1.5T wrist MRI. The trend suggests that 3.0T wrist MRI provides improved capability for detection of TFCC injuries. Given the available sample size, however, the confidence intervals around the point estimates are wide and overlapping. Further studies are needed to confirm or refute our results of the estimated sensitivity, specificity, and accuracy parameters.

Clinical comparison of arthroscopic versus open repair of triangular fibrocartilage complex tears.

PURPOSE: To determine whether traumatic triangular fibrocartilage complex (TFCC) tears treated by arthroscopic repair have improved functional outcome scores, range of motion, grip strength, and pain relief compared with those repaired using an open surgical technique. METHODS: From 1997 to 2006, 75 patients had repair of traumatic TFCC tears. Thirty-six patients had arthroscopic TFCC repair, and 39 patients had open repair. One patient was lost to follow-up. Evaluation included range of motion, grip strength, preoperative and postoperative Mayo Modified Wrist Score (MMWS), and patient-reported Disabilities of the Arm, Shoulder, and Hand score and visual analog scale score. Data were analyzed using chi-square tests or 2-sample t-tests; significance was set at p < .05. RESULTS: Mean follow-up was 43 months +/- 11. Mean MMWS improved 6.5 points +/- 19.9 after surgery. Fifty-seven percent of patients improved at least 1 level in the MMWS pain score. No statistical difference was found between open and arthroscopic repair in the improvement of MMWS or visual analog scale pain scores. There was increased postoperative nerve pain (ulnar nerve branch) in the open group (14 out of 39 patients) compared with the arthroscopic group (8 out of 36 patients), but this was not found to be statistically significant. Reoperation for distal radioulnar joint instability was performed in 17% of patients. No statistical association was observed between surgery type and the rate of reoperation for instability. Female gender was significantly associated with a higher rate of total reoperation. CONCLUSIONS: There was no statistical difference in clinical outcomes after open versus arthroscopic TFCC repair. Although not statistically significant, there was an increased rate of postoperative superficial ulnar nerve pain in the open group (14 out of 39 patients) compared with the arthroscopic group (8 out of 36 patients). After TFCC repair, 13 out of 75 patients required reoperation for distal radioulnar joint instability in this sample. A statistically significant association was found between reoperation rate and female gender.

Congruent elbow plate fixation of olecranon fractures.

OBJECTIVES: We hypothesize that clinical results and patient outcomes following treatment of olecranon fractures with a congruent elbow plating system will be comparable to other available plating systems. Our results will be compared to previously published reports. DESIGN: Retrospective study. SETTING: Level 1 academic referral center. PATIENTS/PARTICIPANTS: The trauma registry was reviewed to identify all olecranon fractures treated with open reduction and internal fixation between January 2001 and December 2004 using the Mayo Congruent Elbow Plate system. Thirty-two patients were identified. Postoperative range of motion was initiated within 2 weeks postoperatively. Mean time to follow-up was 2.2 years (0.7-5.1). All patients had follow-up radiographs. Outcome scores were available on 24 of the 32 patients. INTERVENTION: Medical records and radiographs of all patients were reviewed. MAIN OUTCOME MEASUREMENTS: Objective measures included radiographic healing, postoperative range of motion, and complications. Subjective functional results included Mayo Elbow Performance (MEP) score; Disability of the Arm, Shoulder, and Hand (DASH) score; and patient satisfaction. RESULTS: Of the 32 fractures, 30 went on to union. Three patients had symptomatic hardware that was removed. There was 1 infection and 1 failure of fixation also requiring hardware removal. Average arc of motion was 120 degrees. Subjective follow-up was available in 75% of patients. Mean DASH was 32. Mean MEPS was 89, with 92% good or excellent results. CONCLUSIONS: Congruent anatomic plating is a safe, effective option for the treatment of olecranon fractures with a low rate of hardware removal and stability with early motion.

Comparison of two cochlear implant coding strategies on speech perception.

OBJECTIVE: Assess whether differences in speech perception are observed after exclusive listening experience with high-definition continuous interleaved sampling (HDCIS) versus fine structure processing (FSP) coding strategies. METHODS: Subjects were randomly assigned at initial activation of the external speech processor to receive the HDCIS or FSP coding strategy. Frequency filter assignments were consistent across subjects. The speech perception test battery included CNC words in quiet, HINT sentences in quiet and steady noise (+10 dB SNR), AzBio sentences in quiet and a 10-talker babble (+10 dB SNR), and BKB-SIN. Assessment intervals included 1, 3, and 6 months post-activation. RESULTS: Data from 22 subjects (11 with HDCIS and 11 with FSP) were assessed over time. Speech perception performance was not significantly different between groups. DISCUSSION: Speech perception performance was not significantly different after 6 months of listening experience with the HDCIS or FSP coding strategy.

The Compound Action Potential in Subjects Receiving a Cochlear Implant.

HYPOTHESIS: The compound action potential (CAP) is a purely neural component of the cochlea's response to sound, and may provide information regarding the existing neural substrate in cochlear implant (CI) subjects that can help account for variance in speech perception outcomes. BACKGROUND: Measurement of the "total response" (TR), or sum of the magnitudes of spectral components in the ongoing responses to tone bursts across frequencies, has been shown to account for 40 to 50% of variance in speech perception outcomes. The ongoing response is composed of both hair cell and neural components. This correlation may be improved with the addition of the CAP. METHODS: Intraoperative round window electrocochleography (ECochG) was performed in adult and pediatric CI subjects (n = 238). Stimuli were tones of different frequencies (250 Hz-4 kHz) at 90 dB nHL. The CAP was assessed in two ways, as an amplitude and with a scaling factor derived from a function fitted to the response. The results were correlated with consonant-nucleus-consonant (CNC) word scores at 6 months post-implantation (n = 51). RESULTS: Only about half of the subjects had a measurable CAP at any frequency. The CNC word scores correlated weakly with both amplitude (r = 0.20, p < 0.001) and scaling factor (r = 0.25, p < 0.01). In contrast, the TR alone accounted for 43% of the variance, and addition of either CAP measurement in multiple regression did not account for additional variance. CONCLUSIONS: The underlying pathology in CI patients causes the CAP to be often absent and highly variable when present. The TR is a better predictor of speech perception outcomes than the CAP.

Influence of age at revision cochlear implantation on speech perception outcomes.

IMPORTANCE: This study reviewed whether advanced age should be a consideration when revision cochlear implantation is warranted. OBJECTIVE: To examine whether age at revision cochlear implantation is related to postrevision speech perception performance. DESIGN, SETTING, AND PARTICIPANTS: A retrospective analysis was performed in an academic tertiary care center. Participants included 14 younger adults (<65 years) and 15 older adults (≥65 years) who underwent revision cochlear implantation. INTERVENTION: Revision cochlear implantation. MAIN OUTCOMES AND MEASURES: Speech perception performance, as measured with consonant-nucleus-consonant [CNC] words in quiet, at the best prerevision interval as well as the 3- and 6-month postrevision intervals were compared between the 2 cohorts. The CNC word test consists of 10 lists of 50 phonemically balanced monosyllabic words, scored with a range of 0% to 100% correct. RESULTS: Both cohorts experienced a restoration in speech perception scores after revision cochlear implantation compared with their best performance before the revision (mean [SD] CNC word test scores for the younger cohort: 43.9% [25.6%] before revision and 47.7% [21.3%] at 3 months and 47.6% [19.8%] at 6 months after revision; for the older cohort: 36.3% [19.1%] before revision and 35.3% [17.2%] at 3 months and 39.9% [16.3%] at 6 months after revision; F2,54= 0.93; P = .40). There was no interaction between age at revision surgery and speech perception performance at each assessment interval (F2,54= 0.51; P = .60). CONCLUSIONS AND RELEVANCE: In this study, age at revision cochlear implantation was not related to postrevision speech perception performance. Advanced age should not be considered a contraindication to revision cochlear implantation.

Video fluoroscopic analysis of the effects of three commonly-prescribed off-the-shelf orthoses on vertebral motion.

STUDY DESIGN: Fluoroscopic assessment of the effects of commercially available spinal orthotics on lumbar vertebral motion as subjects performed flexion and extension maneuvers. OBJECTIVE: To quantitate the effects of 3 commonly available, off-the-shelf, soft, and semirigid spinal orthoses on lumbar spinal motion. SUMMARY OF BACKGROUND DATA: Commercially available soft and semirigid orthoses are widely prescribed for patients with low back pain and, at times, following surgery. Despite this use, surprisingly little is known about the magnitude of their effects on lumbar vertebral motion. METHODS: Ten subjects (6 men and 4 women) with an average age of 27.0 +/- 5.3 years, underwent videofluoroscopic imaging as they performed a full flexion/extension cycle. Assessments, during which the subjects were unbraced or wearing either a soft lumbrosacral orthosis (LSO), a semirigid LSO, or a semirigid thoracolumbrosacral orthosis (TLSO) were performed in random order. Images were obtained at a rate of 3.75 Hz and digitally processed to determine the sagittal rotation of the L3-L5 vertebral bodies. RESULTS: Each of the braces produced a statistically significant reduction in overall lumbar motion during the flexion maneuver (P = 0.007) but none had a detectable effect during extension. Relative effectiveness varied by vertebral level. At the L3-L4 level, only the TLSO had a statistically significant effect on intervertebral flexion movement (32%, P = 0.003). At the L4-L5 level all the orthoses were effective (and statistically indistinguishable) in their ability to reduce intervertebral flexion movements ranging from 48% for the semirigid TLSO to about 15% to 20% for the 2 LSOs. No effects were noted for any of the orthoses at the L5-S1 level. CONCLUSION: Commercially available soft and semirigid orthotics can have significant effects on lumbar vertebral body motion at the L3-L4 and L4-L5 levels.

The clock face guide to peroneal intraneural ganglia: critical "times" and sites for accurate diagnosis.

OBJECTIVE: The aim of this study is to exploit the normal nature of peroneal nerve anatomy to identify constant magnetic resonance imaging (MRI) patterns in peroneal intraneural ganglia. DESIGN: This study is designed as a retrospective clinical study. MATERIALS AND METHODS: MR images of 25 patients with peroneal intraneural ganglia were analyzed and were compared to those of 25 patients with extraneural ganglia and 25 individuals with normal knees. All specimens were interpreted as left-sided. Using conventional axial images, the position of the common peroneal nerve and either intraneural or extraneural cyst was determined relative to the proximal fibula and the superior tibiofibular joint using a symbolic clock face. In all patients, the common peroneal nerve could be seen between the 4 and 5 o'clock position at the mid-portion of the fibular head. In patients with intraneural ganglia, a single axial image could reproducibly and reliably demonstrate both cyst within the common peroneal nerve at the mid-portion of the fibular head (signet ring sign) between 4 and 5 o'clock and within the articular branch at the superior tibiofibular joint connection (tail sign) between 11 and 12 o'clock; in addition, cyst within the transverse limb of the articular branch (transverse limb sign) was seen at the mid-portion of the fibular neck between the 12 and 2 o'clock positions on serial images. Extraneural ganglia typically arose from more superior joint connections with the epicenter of the cyst varying around the entire clock face without a consistent pattern. There was no significant difference between the visual and template assessment of clock face position for all three groups (intraneural, extraneural, and controls). We believe that the normal anatomic and pathologic relationships of the common peroneal nerve in the vicinity of the fibular neck/head region can be established readily and reliably on single axial images. This technique can provide radiologists and surgeons with rapid and reproducible information for diagnosis and treatment planning. CONCLUSIONS: By using conventional bony anatomy as reference points (namely fibular neck and mid-portion of fibular head), standard axial images can be used to interpret key features of peroneal intraneural ganglia and to establish their accurate diagnosis (rather than extraneural ganglia) and pathogenesis from an articular origin (rather than from de novo formation), a fact that has important therapeutic implications. Because of the relative rarity of peroneal intraneural cysts and physicians' (radiologists and surgeons) inexperience with them and the complexity of their findings, they are frequently misdiagnosed and joint communications are not appreciated preoperatively or intraoperatively. As a result, outcomes are suboptimal and recurrences are common.