Predicting the onset of Alzheimer's disease and related dementia using Electronic Health Records: Findings from the Cache County Study on Memory in Aging (1995-2008).

Introduction: Clinical notes, biomarkers, and neuroimaging have been proven valuable in dementia prediction models. Whether commonly available structured clinical data can predict dementia is an emerging area of research. We aimed to predict Alzheimer's disease (AD) and Alzheimer's disease related dementias (ADRD) in a well-phenotyped, population-based cohort using a machine learning approach. Methods: Administrative healthcare data (k=163 diagnostic features), in addition to Census/vital record sociodemographic data (k = 6 features), were linked to the Cache County Study (CCS, 1995-2008). Results: Among successfully linked UPDB-CCS participants (n=4206), 522 (12.4%) had incident AD/ADRD as per the CCS "gold standard" assessments. Random Forest models, with a 1-year prediction window, achieved the best performance with an Area Under the Curve (AUC) of 0.67. Accuracy declined for dementia subtypes: AD/ADRD (AUC = 0.65); ADRD (AUC = 0.49). DISCUSSION: Commonly available structured clinical data (without labs, notes, or prescription information) demonstrate modest ability to predict AD/ADRD, corroborated by prior research.

Alzheimer Disease Cerebrospinal Fluid Biomarkers in a Tertiary Neurology Practice.

OBJECTIVE: To evaluate the performance of Alzheimer disease (AD) cerebrospinal fluid (CSF) biomarkers in a tertiary neurology clinic setting with high frequency of non-AD cases, including normal pressure hydrocephalus (NPH). METHODS: There were 534 patients who underwent AD CSF biomarkers (Roche Elecsys Aß42, p-Tau181, total-Tau) from April 1, 2020, through April 23, 2021. A behavioral neurologist blinded to CSF results assigned a clinical diagnosis retrospectively on the basis of consensus criteria, and a neuroradiologist blinded to the diagnosis and CSF studies graded brain magnetic resonance images for indicators of CSF dynamics disorders. Associations between biomarkers, diagnoses, and imaging were assessed by χ2, analysis of covariance, and linear regression methods. RESULTS: Median age at time of testing was 67 years (range, 19 to 96 years), median symptom duration was 2 years (range, 0.4 to 28 years), and median Short Test of Mental Status score was 30 (range, 0 to 38). Clinical diagnoses significantly correlated with different CSF biomarker values (χ2=208.3; P=10e-4). p-Tau181/Aß42 ratios above 0.023 positively correlated with Alzheimer dementia (more than individual measures). This ratio also had the best performance for differentiating Alzheimer dementia from NPH (area under the curve, 0.869). Imaging markers supportive of CSF dynamics disorders correlated with low Aß42, p-Tau181, and total-Tau. CONCLUSION: In a heterogeneous clinical population, abnormal p-Tau181/Aß42 ratios (>0.023) have the strongest association with Alzheimer dementia and probably represent a comorbid AD pathologic component in persons clearly matching non-AD neurodegenerative syndromes. Altered CSF dynamics were associated with lower concentrations of AD CSF biomarkers regardless of clinical diagnosis, but the ratio compensates for these changes. In the appropriate clinical setting, an isolated abnormal Aß42 should prompt consideration of NPH.

Impact of a prospective feedback loop aimed at reducing non-beneficial treatments in older people admitted to hospital and potentially nearing the end of life. A cluster stepped-wedge randomised controlled trial.

OBJECTIVES: To investigate if a prospective feedback loop that flags older patients at risk of death can reduce non-beneficial treatment at end of life. DESIGN: Prospective stepped-wedge cluster randomised trial with usual care and intervention phases. SETTING: Three large tertiary public hospitals in south-east Queensland, Australia. PARTICIPANTS: 14 clinical teams were recruited across the three hospitals. Teams were recruited based on a consistent history of admitting patients aged 75+ years, and needed a nominated lead specialist consultant. Under the care of these teams, there were 4,268 patients (median age 84 years) who were potentially near the end of life and flagged at risk of non-beneficial treatment. INTERVENTION: The intervention notified clinicians of patients under their care determined as at-risk of non-beneficial treatment. There were two notification flags: a real-time notification and an email sent to clinicians about the at-risk patients at the end of each screening day. The nudge intervention ran for 16-35 weeks across the three hospitals. MAIN OUTCOME MEASURES: The primary outcome was the proportion of patients with one or more intensive care unit (ICU) admissions. The secondary outcomes examined times from patients being flagged at-risk. RESULTS: There was no improvement in the primary outcome of reduced ICU admissions (mean probability difference [intervention minus usual care] = -0.01, 95% confidence interval -0.08 to 0.01). There were no differences for the times to death, discharge, or medical emergency call. There was a reduction in the probability of re-admission to hospital during the intervention phase (mean probability difference -0.08, 95% confidence interval -0.13 to -0.03). CONCLUSIONS: This nudge intervention was not sufficient to reduce the trial's non-beneficial treatment outcomes in older hospital patients. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry, ACTRN12619000675123 (registered 6 May 2019).

Structural and practical identifiability of contrast transport models for DCE-MRI.

Contrast transport models are widely used to quantify blood flow and transport in dynamic contrast-enhanced magnetic resonance imaging. These models analyze the time course of the contrast agent concentration, providing diagnostic and prognostic value for many biological systems. Thus, ensuring accuracy and repeatability of the model parameter estimation is a fundamental concern. In this work, we analyze the structural and practical identifiability of a class of nested compartment models pervasively used in analysis of MRI data. We combine artificial and real data to study the role of noise in model parameter estimation. We observe that although all the models are structurally identifiable, practical identifiability strongly depends on the data characteristics. We analyze the impact of increasing data noise on parameter identifiability and show how the latter can be recovered with increased data quality. To complete the analysis, we show that the results do not depend on specific tissue characteristics or the type of enhancement patterns of contrast agent signal.

Model discovery approach enables noninvasive measurement of intra-tumoral fluid transport in dynamic MRI.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a routine method to noninvasively quantify perfusion dynamics in tissues. The standard practice for analyzing DCE-MRI data is to fit an ordinary differential equation to each voxel. Recent advances in data science provide an opportunity to move beyond existing methods to obtain more accurate measurements of fluid properties. Here, we developed a localized convolutional function regression that enables simultaneous measurement of interstitial fluid velocity, diffusion, and perfusion in 3D. We validated the method computationally and experimentally, demonstrating accurate measurement of fluid dynamics in situ and in vivo. Applying the method to human MRIs, we observed tissue-specific differences in fluid dynamics, with an increased fluid velocity in breast cancer as compared to brain cancer. Overall, our method represents an improved strategy for studying interstitial flows and interstitial transport in tumors and patients. We expect that our method will contribute to the better understanding of cancer progression and therapeutic response.

Locoregional delivery of IL-13Rα2-targeting CAR-T cells in recurrent high-grade glioma: a phase 1 trial.

Chimeric antigen receptor T cell (CAR-T) therapy is an emerging strategy to improve treatment outcomes for recurrent high-grade glioma, a cancer that responds poorly to current therapies. Here we report a completed phase I trial evaluating IL-13Rα2-targeted CAR-T cells in 65 patients with recurrent high-grade glioma, the majority being recurrent glioblastoma (rGBM). Primary objectives were safety and feasibility, maximum tolerated dose/maximum feasible dose and a recommended phase 2 dose plan. Secondary objectives included overall survival, disease response, cytokine dynamics and tumor immune contexture biomarkers. This trial evolved to evaluate three routes of locoregional T cell administration (intratumoral (ICT), intraventricular (ICV) and dual ICT/ICV) and two manufacturing platforms, culminating in arm 5, which utilized dual ICT/ICV delivery and an optimized manufacturing process. Locoregional CAR-T cell administration was feasible and well tolerated, and as there were no dose-limiting toxicities across all arms, a maximum tolerated dose was not determined. Probable treatment-related grade 3+ toxicities were one grade 3 encephalopathy and one grade 3 ataxia. A clinical maximum feasible dose of 200 × 106 CAR-T cells per infusion cycle was achieved for arm 5; however, other arms either did not test or achieve this dose due to manufacturing feasibility. A recommended phase 2 dose will be refined in future studies based on data from this trial. Stable disease or better was achieved in 50% (29/58) of patients, with two partial responses, one complete response and a second complete response after additional CAR-T cycles off protocol. For rGBM, median overall survival for all patients was 7.7 months and for arm 5 was 10.2 months. Central nervous system increases in inflammatory cytokines, including IFNγ, CXCL9 and CXCL10, were associated with CAR-T cell administration and bioactivity. Pretreatment intratumoral CD3 T cell levels were positively associated with survival. These findings demonstrate that locoregional IL-13Rα2-targeted CAR-T therapy is safe with promising clinical activity in a subset of patients. ClinicalTrials.gov Identifier: NCT02208362 .

Targeting Wnt signaling for improved glioma immunotherapy.

Introduction: Despite aggressive standard-of-care therapy, including surgery, radiation, and chemotherapy, glioblastoma recurrence is almost inevitable and uniformly lethal. Activation of glioma-intrinsic Wnt/ß-catenin signaling is associated with a poor prognosis and the proliferation of glioma stem-like cells, leading to malignant transformation and tumor progression. Impressive results in a subset of cancers have been obtained using immunotherapies including anti-CTLA4, anti-PD-1, and anti-PD-L1 or chimeric antigen receptor (CAR) T cell therapies. However, the heterogeneity of tumors, low mutational burden, single antigen targeting, and associated antigen escape contribute to non-responsiveness and potential tumor recurrence despite these therapeutic efforts. In the current study, we determined the effects of the small molecule, highly specific Wnt/CBP (CREB Binding Protein)/ß-catenin antagonist ICG-001, on glioma tumor cells and the tumor microenvironment (TME)-including its effect on immune cell infiltration, blood vessel decompression, and metabolic changes. Methods: Using multiple glioma patient-derived xenografts cell lines and murine tumors (GL261, K-Luc), we demonstrated in vitro cytostatic effects and a switch from proliferation to differentiation after treatment with ICG-001. Results: In these glioma cell lines, we further demonstrated that ICG-001 downregulated the CBP/ß-catenin target gene Survivin/BIRC5-a hallmark of Wnt/CBP/ß-catenin inhibition. We found that in a syngeneic mouse model of glioma (K-luc), ICG-001 treatment enhanced tumor infiltration by CD3+ and CD8+ cells with increased expression of the vascular endothelial marker CD31 (PECAM-1). We also observed differential gene expression and induced immune cell infiltration in tumors pretreated with ICG-001 and then treated with CAR T cells as compared with single treatment groups or when ICG-001 treatment was administered after CAR T cell therapy. Discussion: We conclude that specific Wnt/CBP/ß-catenin antagonism results in pleotropic changes in the glioma TME, including glioma stem cell differentiation, modulation of the stroma, and immune cell activation and recruitment, thereby suggesting a possible role for enhancing immunotherapy in glioma patients.

Process evaluation of a tailored nudge intervention to promote appropriate care and treatment of older patients at the end-of-life.

BACKGROUND: Non-beneficial treatment affects a considerable proportion of older people in hospital, and some will choose to decline invasive treatments when they are approaching the end of their life. The Intervention for Appropriate Care and Treatment (InterACT) intervention was a 12-month stepped wedge randomised controlled trial with an embedded process evaluation in three hospitals in Brisbane, Australia. The aim was to increase appropriate care and treatment decisions for older people at the end-of-life, through implementing a nudge intervention in the form of a prospective feedback loop. However, the trial results indicated that the expected practice change did not occur. The process evaluation aimed to assess implementation using the Consolidated Framework for Implementation Research, identify barriers and enablers to implementation and provide insights into the lack of effect of the InterACT intervention. METHODS: Qualitative data collection involved 38 semi-structured interviews with participating clinicians, members of the executive advisory groups overseeing the intervention at a site level, clinical auditors, and project leads. Online interviews were conducted at two times: implementation onset and completion. Data were coded to the Consolidated Framework for Implementation Research and deductively analysed. RESULTS: Overall, clinicians felt the premise and clinical reasoning behind InterACT were strong and could improve patient management. However, several prominent barriers affected implementation. These related to the potency of the nudge intervention and its integration into routine clinical practice, clinician beliefs and perceived self-efficacy, and wider contextual factors at the health system level. CONCLUSIONS: An intervention designed to change clinical practice for patients at or near to end-of-life did not have the intended effect. Future interventions targeting this area of care should consider using multi-component strategies that address the identified barriers to implementation and clinician change of practice. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry (ANZCTR), ACTRN12619000675123p (approved 06/05/2019).

Expansion of endogenous T cells in CSF of pediatric CNS tumor patients undergoing locoregional delivery of IL13R〿2-targeting CAR T cells: an interim analysis.

Outcomes for pediatric brain tumor patients remain poor, and there is optimism that chimeric antigen receptor (CAR) T cell therapy can improve prognosis. Here, we present interim results from the first six pediatric patients treated on an ongoing phase I clinical trial (NCT04510051) of IL13BBζ-CAR T cells delivered weekly into the lateral cerebral ventricles, identifying clonal expansion of endogenous CAR-negative CD8+ T cells in the cerebrospinal fluid (CSF) over time. Additionally, of the five patients evaluable for disease response, three experienced transient radiographic and/or clinical benefit not meeting protocol criteria for response. The first three patients received CAR T cells alone; later patients received lymphodepletion before the first infusion. There were no dose limiting toxicities (DLTs). Aside from expected cytopenias in patients receiving lymphodepletion, serious adverse events possibly attributed to CAR T cell infusion were limited to one episode of headache and one of liver enzyme elevation. One patient withdrew from treatment during the DLT period due to a Grade 3 catheter-related infection and was not evaluable for disease response, although this was not attributed to CAR T cell infusion. Importantly, scRNA- and scTCR-sequence analyses provided insights into CAR T cell interaction with the endogenous immune system. In particular, clonally expanded endogenous CAR- T cells were recovered from the CSF, but not the peripheral blood, of patients who received intraventricular IL13BBζ-CAR T cell therapy. Additionally, although immune infiltrates in CSF and post-therapy tumor did not generally correlate, a fraction of expanded T cell receptors (TCRs) was seen to overlap between CSF and tumor. This has important implications for what samples are collected on these trials and how they are analyzed. These initial findings provide support for continued investigation into locoregionally-delivered IL13BBζ-CAR T cells for children with brain tumors.

Outsmarting trogocytosis to boost CAR NK/T cell therapy.

Chimeric antigen receptor (CAR) NK and T cell therapy are promising immunotherapeutic approaches for the treatment of cancer. However, the efficacy of CAR NK/T cell therapy is often hindered by various factors, including the phenomenon of trogocytosis, which involves the bidirectional exchange of membrane fragments between cells. In this review, we explore the role of trogocytosis in CAR NK/T cell therapy and highlight potential strategies for its modulation to improve therapeutic efficacy. We provide an in-depth analysis of trogocytosis as it relates to the fate and function of NK and T cells, focusing on its effects on cell activation, cytotoxicity, and antigen presentation. We discuss how trogocytosis can mediate transient antigen loss on cancer cells, thereby negatively affecting the effector function of CAR NK/T cells. Additionally, we address the phenomenon of fratricide and trogocytosis-associated exhaustion, which can limit the persistence and effectiveness of CAR-expressing cells. Furthermore, we explore how trogocytosis can impact CAR NK/T cell functionality, including the acquisition of target molecules and the modulation of signaling pathways. To overcome the negative effects of trogocytosis on cellular immunotherapy, we propose innovative approaches to modulate trogocytosis and augment CAR NK/T cell therapy. These strategies encompass targeting trogocytosis-related molecules, engineering CAR NK/T cells to resist trogocytosis-induced exhaustion and leveraging trogocytosis to enhance the function of CAR-expressing cells. By overcoming the limitations imposed by trogocytosis, it may be possible to unleash the full potential of CAR NK/T therapy against cancer. The knowledge and strategies presented in this review will guide future research and development, leading to improved therapeutic outcomes in the field of immunotherapy.

Model discovery approach enables non-invasive measurement of intra-tumoral fluid transport in dynamic MRI.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a routine method to non-invasively quantify perfusion dynamics in tissues. The standard practice for analyzing DCE-MRI data is to fit an ordinary differential equation to each voxel. Recent advances in data science provide an opportunity to move beyond existing methods to obtain more accurate measurements of fluid properties. Here, we developed a localized convolutional function regression that enables simultaneous measurement of interstitial fluid velocity, diffusion, and perfusion in 3D. We validated the method computationally and experimentally, demonstrating accurate measurement of fluid dynamics in situ and in vivo. Applying the method to human MRIs, we observed tissue-specific differences in fluid dynamics, with an increased fluid velocity in breast cancer as compared to brain cancer. Overall, our method represents an improved strategy for studying interstitial flows and interstitial transport in tumors and patients. We expect that it will contribute to the better understanding of cancer progression and therapeutic response.

CAR T cells ignite antitumor immunity.

Broadening immune responses through antigen spreading remains the 'Holy Grail' of cancer immunotherapy. A study by Ma and colleagues reveals that vaccine boosting of chimeric antigen receptor (CAR)-T cells in mice promotes endogenous immunity and elicits antigen spread to eliminate antigenically heterogenous solid tumors through a mechanism crucially dependent on interferon (IFN)γ.

PGE2-EP2/EP4 signaling elicits mesoCAR T cell immunosuppression in pancreatic cancer.

Introduction: For many years, surgery, adjuvant and combination chemotherapy have been the cornerstone of pancreatic cancer treatment. Although these approaches have improved patient survival, relapse remains a common occurrence, necessitating the exploration of novel therapeutic strategies. CAR T cell therapies are now showing tremendous success in hematological cancers. However, the clinical efficacy of CAR T cells in solid tumors remained low, notably due to presence of an immunosuppressive tumor microenvironment (TME). Prostaglandin E2, a bioactive lipid metabolite found within the TME, plays a significant role in promoting cancer progression by increasing tumor proliferation, improving angiogenesis, and impairing immune cell's function. Despite the well-established impact of PGE2 signaling on cancer, its specific effects on CAR T cell therapy remain under investigation. Methods: To address this gap in knowledge the role of PGE2-related genes in cancer tissue and T cells of pancreatic cancer patients were evaluated in-silico. Through our in vitro study, we manufactured fully human functional mesoCAR T cells specific for pancreatic cancer and investigated the influence of PGE2-EP2/EP4 signaling on proliferation, cytotoxicity, and cytokine production of mesoCAR T cells against pancreatic cancer cells. Results: In-silico investigations uncovered a significant negative correlation between PGE2 expression and gene signature of memory T cells. Furthermore, in vitro experiments demonstrated that the activation of PGE2 signaling through EP2 and EP4 receptors suppressed the proliferation and major antitumor functions of mesoCAR T cells. Interestingly, the dual blockade of EP2 and EP4 receptors effectively reversed PGE2-mediated suppression of mesoCAR T cells, while individual receptor antagonists failed to mitigate the PGE2-induced suppression. Discussion: In summary, our findings suggest that mitigating PGE2-EP2/EP4 signaling may be a viable strategy for enhancing CAR T cell activity within the challenging TME, thereby improving the efficacy of CAR T cell therapy in clinical settings.

Uncovering the Role of CD4+ CAR T Cells in Cancer Immunotherapy.

Chimeric antigen receptor (CAR) T-cell therapy has transformed clinical care against blood malignancies and is seeing encouraging progress against solid tumors. While scientific advancement has been rapid, our mechanistic understanding of intrinsic features of CAR-engineered T cells is still evolving. CAR products typically consist of CD4+ and CD8+ T-cell subsets at variable ratios, yet a clear understanding of how each subset contributes together and independently to therapeutic response is lacking. CD8+ CAR T cells are well characterized for their perforin-dependent killing effects; however, the role of CD4+ CAR T cells as "helpers" versus "killers" has been variable across models and warrants more in-depth investigation. A recent study by Boulch and colleagues published in Nature Cancer demonstrates that CD4+ CAR T cells, alone, can exert potent antitumor activity through a mechanism involving IFNγ. CD4+ CAR T-cell production of IFNγ creates a cytokine field that can act at a distance to kill both antigen-positive and -negative tumor cells that are sensitive to the proapoptotic effects of IFNγ. These new findings reveal important insights for the antitumor effects mediated by CD4+ CAR T cells, which could have significant clinical implications.

Architecture of the health system as an enabler of better wellbeing.

INTRODUCTION: Health systems worldwide have heterogenous capacities and financing characteristics. No clear empirical evidence is available on the possible outcomes of these characteristics for population wellbeing. AIM: The study aims to provide empirical insight into health policy alternatives to support the development of health system architecture to improve population wellbeing. METHOD AND RESULTS: We developed an unsupervised neural network model to cluster countries and used the Human Development Index to derive a wellbeing model. The results show that no single health system architecture is associated with a higher level of population wellbeing. Strikingly, high levels of health expenditure and physical health capacity do not guarantee a high level of population wellbeing and different health systems correspond to a certain wellbeing level. CONCLUSIONS: Our analysis shows that alternative options exist for some health system characteristics. These can be considered by governments developing health policy priorities.

Improving difficult peripheral intravenous access requires thought, training and technology (DART3): a stepped-wedge, cluster randomised controlled trial protocol.

BACKGROUND: Peripheral intravenous catheters (PIVCs) are the most used invasive medical device in healthcare. Yet around half of insertion attempts are unsuccessful leading to delayed medical treatments and patient discomfort of harm. Ultrasound-guided PIVC (USGPIVC) insertion is an evidence-based intervention shown to improve insertion success especially in patients with Difficult IntraVenous Access (BMC Health Serv Res 22:220, 2022), however the implementation in some healthcare settings remains suboptimal. This study aims to co-design interventions that optimise ultrasound guided PIVC insertion in patients with DIVA, implement and evaluate these initiatives and develop scale up activities. METHODS: A stepped-wedge cluster randomized controlled trial will be conducted in three hospitals (two adult, one paediatric) in Queensland, Australia. The intervention will be rolled out across 12 distinct clusters (four per hospital). Intervention development will be guided by Michie's Behavior Change Wheel with the aim to increase local staff capability, opportunity, and motivation for appropriate, sustainable adoption of USGPIVC insertion. Eligible clusters include all wards or departments where > 10 PIVCs/week are typically inserted. All clusters will commence in the control (baseline) phase, then, one cluster per hospital will step up every two months, as feasible, to the implementation phase, where the intervention will be rolled out. Implementation strategies are tailored for each hospital by local investigators and advisory groups, through context assessments, staff surveys, and stakeholder interviews and informed by extensive consumer interviews and consultation. Outcome measures align with the RE-AIM framework including clinical-effectiveness outcomes (e.g., first-time PIVC insertion success for DIVA patients [primary outcome], number of insertion attempts); implementation outcomes (e.g., intervention fidelity, readiness assessment) and cost effectiveness outcomes. The Consolidated Framework for Implementation Research framework will be used to report the intervention as it was implemented; how people participated in and responded to the intervention; contextual influences and how the theory underpinning the intervention was realised and delivered at each site. A sustainability assessment will be undertaken at three- and six-months post intervention. DISCUSSION: Study findings will help define systematic solutions to implement DIVA identification and escalation tools aiming to address consumer dissatisfaction with current PIVC insertion practices. Such actionable knowledge is critical for implementation of scale-up activities. TRIAL REGISTRATION: Prospectively registered (Australian and New Zealand Clinical Trials Registry; ACTRN12621001497897).

Cochlear Implantation in Very Young Children With Single-Sided Deafness.

OBJECTIVE: Cochlear implants (CIs) for single-sided deafness (SSD) have only been approved for patients 5 years and older despite data supporting that younger children can also benefit from implantation. This study describes our institution's experience with CI for SSD in children 5 years and younger. STUDY DESIGN: Case series with chart review. SETTING: Tertiary referral center. METHODS: A case series with chart review identified 19 patients up to age 5 years who underwent CI for SSD between 2014 and 2022. Baseline characteristics, perioperative complications, device usage, and speech outcomes were collected. RESULTS: The median age at CI was 2.8 (range, 1.0-5.4) years, with 15 (79%) patients being below age 5 at implantation. Etiologies of hearing loss were idiopathic (n = 8), cytomegalovirus (n = 4), enlarged vestibular aqueduct (n = 3), hypoplastic cochlear nerve (n = 3), and meningitis (n = 1). The median preoperative pure-tone average was 90 (range, 75-120) and 20 (range, 5-35) dB eHL in the poor and better hearing ears, respectively. No patients had postoperative complications. Twelve patients achieved consistent device use (average, 9 h/d). Three of the seven who were not consistent users had hypoplastic cochlear nerves and/or developmental delays. The three patients with available preoperative and postoperative speech testing showed significant benefits, and five patients with available postoperative testing demonstrated speech recognition in the implanted ear when isolated from the better ear. CONCLUSION: CI can safely be performed in younger children with SSD. Patients and families accept early implantation, as evidenced by consistent device use, and derive notable benefits in speech recognition. Candidacy can be broadened to include SSD patients under age five years, particularly individuals without hypoplastic cochlear nerves or developmental delay.