Use of Prolonged Cardiac Rhythm Monitoring to Identify Atrial Fibrillation After Cryptogenic Stroke.

PURPOSE OF REVIEW: Prolonged cardiac monitoring (PCM) improves detection of atrial fibrillation (AF) after cryptogenic stroke. We summarize current research supporting the use of PCM as part of the cryptogenic stroke evaluation, while highlighting areas that require more investigation. RECENT FINDINGS: Despite increased AF detection with longer durations of PCM, more definitive research is needed to demonstrate how PCM improves clinical outcomes. The optimal type, timing, and length of cardiac monitoring after cryptogenic stoke remains unknown. Clinical calculators will be important to risk stratify which cryptogenic stroke patients are most likely to benefit from PCM. Currently, AF detection after cryptogenic stroke should prompt consideration of anticoagulation, but it is unclear if all durations and timing of AF after stroke should be treated the same. PCM remains an important part of the cryptogenic stroke work up, and detection of AF allows for anticoagulation initiation. Additional research is needed to further refine our application of PCM to cryptogenic stroke.

Preoperative antithrombotic treatment in acutely symptomatic carotid artery stenosis.

OBJECTIVES: Early recurrence of cerebral ischemia in acutely symptomatic carotid artery stenosis can precede revascularization. The optimal antithrombotic regimen for this high-risk population is not well established. Although antiplatelet agents are commonly used, there is limited evidence for the use of anticoagulants. We sought to understand the safety and efficacy of short-term preoperative anticoagulants in secondary prevention of recurrent cerebral ischemic events from acutely symptomatic carotid stenosis in patients awaiting carotid endarterectomy (CEA). MATERIALS AND METHODS: A retrospective query of a prospective single institution registry of carotid revascularization was performed. Patients who presented with acute ischemic stroke or transient ischemic attack (TIA) attributable to an ipsilateral internal carotid artery stenosis (ICA) were included. Antiplatelet (AP) only and anticoagulation (AC) treatment arms were compared. The primary outcome was a composite of preoperative recurrent ischemic stroke or TIA. The primary safety outcome was symptomatic intracranial hemorrhage. RESULTS: Out of 443 CEA patients, 342 were in the AC group and 101 in the AP group. Baseline characteristics between groups (AC vs AP) were similar apart from age (71±10.5 vs 73±9.5, p=0.04), premorbid modified Rankin scale (mRS) score (1.0±1.2 vs 1.4±1.3, p=0.03) and stroke as presenting symptom (65.8 vs 53.5%, p=0.02). Patients in the AC group had a lower incidence of recurrent stroke/TIA (3.8 vs 10.9%, p=0.006). One patient had symptomatic intracranial hemorrhage in the AC group, and none in the AP group. In multivariate analysis controlling for age, premorbid mRS, stroke severity, degree of stenosis, presence of intraluminal thrombus (ILT) and time to surgery, AC was protective (OR 0.30, p=0.007). This effect persisted in the cohort exclusively without ILT (OR 0.23, p=0.002). CONCLUSIONS: Short term preoperative anticoagulation in patients with acutely symptomatic carotid stenosis appears safe and effective compared to antiplatelet agents alone in the prevention of recurrent cerebral ischemic events while awaiting CEA.

Musical Sound Quality in Cochlear Implant Users: A Comparison in Bass Frequency Perception Between Fine Structure Processing and High-Definition Continuous Interleaved Sampling Strategies.

OBJECTIVES: Med-El cochlear implant (CI) patients are typically programmed with either the fine structure processing (FSP) or high-definition continuous interleaved sampling (HDCIS) strategy. FSP is the newer-generation strategy and aims to provide more direct encoding of fine structure information compared with HDCIS. Since fine structure information is extremely important in music listening, FSP may offer improvements in musical sound quality for CI users. Despite widespread clinical use of both strategies, few studies have assessed the possible benefits in music perception for the FSP strategy. The objective of this study is to measure the differences in musical sound quality discrimination between the FSP and HDCIS strategies. DESIGN: Musical sound quality discrimination was measured using a previously designed evaluation, called Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA). In this evaluation, participants were required to detect sound quality differences between an unaltered real-world musical stimulus and versions of the stimulus in which various amount of bass (low) frequency information was removed via a high-pass filer. Eight CI users, currently using the FSP strategy, were enrolled in this study. In the first session, participants completed the CI-MUSHRA evaluation with their FSP strategy. Patients were then programmed with the clinical-default HDCIS strategy, which they used for 2 months to allow for acclimatization. After acclimatization, each participant returned for the second session, during which they were retested with HDCIS, and then switched back to their original FSP strategy and tested acutely. Sixteen normal-hearing (NH) controls completed a CI-MUSHRA evaluation for comparison, in which NH controls listened to music samples under normal acoustic conditions, without CI stimulation. RESULTS: Sensitivity to high-pass filtering more closely resembled that of NH controls when CI users were programmed with the clinical-default FSP strategy compared with performance when programmed with HDCIS (mixed-design analysis of variance, p < 0.05). CONCLUSIONS: The clinical-default FSP strategy offers improvements in musical sound quality discrimination for CI users with respect to bass frequency perception. This improved bass frequency discrimination may in turn support enhanced musical sound quality. This is the first study that has demonstrated objective improvements in musical sound quality discrimination with the newer-generation FSP strategy. These positive results may help guide the selection of processing strategies for Med-El CI patients. In addition, CI-MUSHRA may also provide a novel method for assessing the benefits of newer processing strategies in the future.

Clinical Problem-Solving: 72-Year-Old Woman With Multifocal Strokes and an Intracardiac Mass.

We present the case of a 72-year-old female with multifocal strokes found to have multiple, mobile intracardiac masses. We discuss the differential diagnosis and evaluation of intracardiac masses, and the challenges in management of the ultimately diagnosed etiology of stroke in this patient.

Deeper Cochlear Implant Electrode Insertion Angle Improves Detection of Musical Sound Quality Deterioration Related to Bass Frequency Removal.

BACKGROUND: Cochlear implant (CI) electrode arrays typically do not reach the most apical regions of the cochlea that intrinsically encode low frequencies. This may contribute to diminished implant-mediated musical sound quality perception. The objective of this study was to assess the effect of varying degrees of apical cochlear stimulation (measured by angular insertion depth) on musical sound quality discrimination. HYPOTHESIS: Increased apical cochlear stimulation will improve low-frequency perception and musical sound quality discrimination. METHODS: Standard (31.5 mm, n = 17) and medium (24 mm, n = 8) array Med-EL CI users, and normal hearing (NH) listeners (n = 16) participated. Imaging confirmed angular insertion depth. Participants completed a musical discrimination task in which they listened to a real-world musical stimulus (labeled reference) and provided sound quality ratings to versions of the reference, which included a hidden reference and test stimuli with increasing amounts of low-frequency removal. Scores for each CI users were calculated on the basis of how much their ratings differed from NH listeners for each stimulus version. RESULTS: Medium array and standard users had significantly different insertion depths (389.4 ± 64.5 and 583.9 ± 78.5 degrees, respectively; p <  .001). A significant Pearson's correlation was observed between angular insertion depth and the hidden reference scores (p < 0.05). CONCLUSION: CI users with greater apical stimulation made sound quality discriminations that more closely resembled those of NH controls for stimuli that contained low frequencies (< 200 Hz of information). These findings suggest that increased apical cochlear stimulation improves musical low-frequency perception, which may provide a more satisfactory music listening experience for CI users.

Reverberation negatively impacts musical sound quality for cochlear implant users.

OBJECTIVE: Satisfactory musical sound quality remains a challenge for many cochlear implant (CI) users. In particular, questionnaires completed by CI users suggest that reverberation due to room acoustics can negatively impact their music listening experience. The objective of this study was to more specifically characterize of the effect of reverberation on musical sound quality in CI users, normal hearing (NH) non-musicians, and NH musicians using a previously designed assessment method, called Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA). METHODS: In this method, listeners were randomly presented with an anechoic musical segment and five-versions of this segment in which increasing amounts of reverberation were artificially added. Participants listened to the six reverberation versions and provided sound quality ratings between 0 (very poor) and 100 (excellent). RESULTS: Results demonstrated that on average CI users and NH non-musicians preferred the sound quality of anechoic versions to more reverberant versions. In comparison, NH musicians could be delineated into those who preferred the sound quality of anechoic pieces and those who preferred pieces with some reverberation. DISCUSSION/CONCLUSION: This is the first study, to our knowledge, to objectively compare the effects of reverberation on musical sound quality ratings in CI users. These results suggest that musical sound quality for CI users can be improved by non-reverberant listening conditions and musical stimuli in which reverberation is removed.

Use of the Phantom Electrode strategy to improve bass frequency perception for music listening in cochlear implant users.

OBJECTIVES: The Phantom Electrode strategy makes use of partial bipolar stimulation on the two most apical electrodes in an effort to extend the frequency range available to cochlear implant (CI) users. This study aimed to quantify the effect of the Phantom Electrode strategy on bass frequency perception in music listening in CI users. METHODS: Eleven adult Advanced Bionics users with the Fidelity 120 processing strategy and 16 adult normal hearing (NH) individuals participated in the study. All subjects completed the CI-multiple stimulus with hidden reference and anchor (MUSHRA), a test of an individual's ability to make discriminations in sound quality following the removal of bass frequency information. NH participants completed the CI-MUSHRA once, whereas CI users completed the task twice - once with their baseline clinical program and once with the Phantom Electrode strategy, in random order. CI users' performance was assessed in comparison with NH performance. RESULTS: The Phantom Electrode strategy improved CI users performance on the CI-MUSHRA compared with Fidelity 120. DISCUSSION: Creation of a Phantom Electrode percept through partial bipolar stimulation of the two most apical electrodes appears to improve CI users' perception of bass frequency information in music, contributing to greater accuracy in the ability to detect alterations in musical sound quality. CONCLUSION: The Phantom Electrode processing strategy may enhance the experience of listening to music and thus acoustic stimuli more broadly by improving perception of bass frequencies, through direction of current towards the apical portion of the cochlea beyond the termination of the electrode.

Technological, biological, and acoustical constraints to music perception in cochlear implant users.

Despite advances in technology, the ability to perceive music remains limited for many cochlear implant users. This paper reviews the technological, biological, and acoustical constraints that make music an especially challenging stimulus for cochlear implant users, while highlighting recent research efforts to overcome these shortcomings. The limitations of cochlear implant devices, which have been optimized for speech comprehension, become evident when applied to music, particularly with regards to inadequate spectral, fine-temporal, and dynamic range representation. Beyond the impoverished information transmitted by the device itself, both peripheral and central auditory nervous system deficits are seen in the presence of sensorineural hearing loss, such as auditory nerve degeneration and abnormal auditory cortex activation. These technological and biological constraints to effective music perception are further compounded by the complexity of the acoustical features of music itself that require the perceptual integration of varying rhythmic, melodic, harmonic, and timbral elements of sound. Cochlear implant users not only have difficulty perceiving spectral components individually (leading to fundamental disruptions in perception of pitch, melody, and harmony) but also display deficits with higher perceptual integration tasks required for music perception, such as auditory stream segregation. Despite these current limitations, focused musical training programs, new assessment methods, and improvements in the representation and transmission of the complex acoustical features of music through technological innovation offer the potential for significant advancements in cochlear implant-mediated music perception.

Evaluation of a Test Battery to Assess Perception of Music in Children With Cochlear Implants.

IMPORTANCE: A number of studies have investigated music perception in adult cochlear implant (CI) users. However, little is known about how pediatric CI users perceive and process music, in part because suitable methods for assessing music perception in this population are lacking. Therefore, we developed the Music in Children With Cochlear Implants (MCCI) battery to assess music perception in pediatric CI users younger than 9 years. OBJECTIVE: To pilot test the MCCI on a group of pediatric CI users to determine its feasibility for measuring music perception and to compare performance of CI users with that of normal-hearing (NH) control participants. DESIGN, SETTING, AND PARTICIPANTS: The pilot test was conducted in an academic tertiary care center. The MCCI evaluated rhythm, pitch, melody, harmony, and timbre perception. For each section, 10 pediatric CI users and 10 NH controls were presented with a pair of stimuli that possibly varied along a single musical element (eg, rhythm). Participants were required to indicate whether the stimuli in the pair were the same or different. INTERVENTIONS: Administration of the MCCI. MAIN OUTCOMES AND MEASURES: Percentage correct on each section of the MCCI and the aggregate score of all sections by group. RESULTS: The MCCI provided a basic characterization of musical perceptual abilities. In the aggregate, NH controls significantly outperformed CI users in music perception (mean [SD] accuracy for CI users vs NH controls: rhythm, 73% [20%] vs 78% [20%]; pitch, 84% [12%] vs 91% [13%]; melody, 65% [16%] vs 75% [18%]; harmony, 74% [13%] vs 75% [14%]; and timbre, 80% [17%] vs 90% [12%]; repeated-measures analysis of variance, F1,17 = 9.3; P < .01). Despite obtaining lower accuracies than NH controls, however, the CI users achieved above-chance accuracy in all sections of the MCCI (1-sample t test, P < .01), including pitch-based sections that are traditionally difficult for CI users. These results suggest that CI users can make use of temporal and spectral cues to discriminate between musical stimuli, although not to the extent of their NH peers. CONCLUSIONS AND RELEVANCE: The MCCI provided an efficient and user-friendly assessment of music perception in pediatric CI users. This test battery may serve as a valuable tool to evaluate music perceptual abilities of pediatric CI users and measure the effects of interventions.

Assessment of sound quality perception in cochlear implant users during music listening.

BACKGROUND: Although cochlear implant (CI) users frequently report deterioration of sound quality when listening to music, few methods exist to quantify these subjective claims. OBJECTIVE: 1) To design a novel research method for quantifying sound quality perception in CI users during music listening; 2) To validate this method by assessing one attribute of music perception, bass frequency perception, which is hypothesized to be relevant to overall musical sound quality perception. HYPOTHESIS: Limitations in bass frequency perception contribute to CI-mediated sound quality deteriorations. The proposed method will quantify this deterioration by measuring CI users' impaired ability to make sound quality discriminations among musical stimuli with variable amounts of bass frequency removal. METHOD: A method commonly used in the audio industry (multiple stimulus with hidden reference and anchor [MUSHRA]) was adapted for CI users, referred to as CI-MUSHRA. CI users and normal hearing controls were presented with 7 sound quality versions of a musical segment: 5 high pass filter cutoff versions (200-, 400-, 600-, 800-, 1000-Hz) with decreasing amounts of bass information, an unaltered version ("hidden reference"), and a highly altered version (1,000-1,200 Hz band pass filter; "anchor"). Participants provided sound quality ratings between 0 (very poor) and 100 (excellent) for each version; ratings reflected differences in perceived sound quality among stimuli. RESULTS: CI users had greater difficulty making overall sound quality discriminations as a function of bass frequency loss than normal hearing controls, as demonstrated by a significantly weaker correlation between bass frequency content and sound quality ratings. In particular, CI users could not perceive sound quality difference among stimuli missing up to 400 Hz of bass frequency information. CONCLUSION: Bass frequency impairments contribute to sound quality deteriorations during music listening for CI users. CI-MUSHRA provided a systematic and quantitative assessment of this reduced sound quality. Although the effects of bass frequency removal were studied here, we advocate CI-MUSHRA as a user-friendly and versatile research tool to measure the effects of a wide range of acoustic manipulations on sound quality perception in CI users.

Musical sound quality impairments in cochlear implant (CI) users as a function of limited high-frequency perception.

The purpose of this study was to (a) apply the musical sound quality assessment method, Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA), to quantify musical sound quality deficits in CI (cochlear implant) users with respect to high-frequency loss, and (b) assess possible correlations between CI-MUSHRA performance and self-reported musical sound quality, as assessed by more traditional rating scales. Five versions of real-world musical stimuli were created: 8-,4-, and 2-kHz low-pass-filtered (LPF) versions with increasing high-frequency removal, a composite stimulus containing a 1-kHz LPF-filtered version and white noise ("anchor"), and an unaltered version ("hidden reference"). Using the CI-MUSHRA methodology, these versions were simultaneously presented to participants in addition to a labeled reference. Participants listened to all versions and provided ratings based on a 100-point scale that reflected perceived sound quality difference among the versions. A total of 25 musical stimuli were tested. As comparison measures, participants completed four Visual Analogue Scales (VAS) to assess musical sound quality. Overall, compared to normal hearing (NH) listeners, CI users demonstrated an impaired ability to discriminate between unaltered and altered musical stimuli with variable amounts of high-frequency information removed. Performance using CI-MUSHRA to evaluate this parameter did not correlate to measurements of musical sound quality, as assessed by VAS. This study identified high-frequency loss as one acoustic parameter contributing to overall CI-mediated musical sound quality limitations. CI-MUSHRA provided a quantitative assessment of musical sound quality. This method offers the potential to quantify CI impairments of many different acoustic parameters related to musical sound quality in the future.