Carbodicarbene-Stibenium Ion-Mediated Functionalization of C(sp3)-H and C(sp)-H Bonds.

Main-group element-mediated C-H activation remains experimentally challenging, and the development of clear concepts and design principles have been limited by the increased reactivity of relevant complexes, especially for the heavier elements. Herein, we report that the stibenium ion [(pyCDC)Sb][NTf2]3 (1) (pyCDC = bis-pyridyl carbodicarbene; NTf2 = bis(trifluoromethanesulfonyl)imide) reacts with acetonitrile in the presence of the base 2,6-di-tert--butylpyridine to enable C(sp3)-H bond breaking to generate the stiba-methylene nitrile complex [(pyCDC)Sb(CH2CN)][NTf2]2 (2). Kinetic analyses were performed to elucidate the rate dependence for all the substrates involved in the reaction. Computational studies suggest that C-H activation proceeds via a mechanism in which acetonitrile first coordinates to the Sb center through the nitrogen atom in a κ1 fashion, thereby weakening the C-H bond which can then be deprotonated by base in solution. Further, we show that 1 reacts with terminal alkynes in the presence of 2,6-di-tert--butylpyridine to enable C(sp)-H bond breaking to form stiba-alkynyl adducts of the type [(pyCDC)Sb(CCR)][NTf2]2 (3a-f). Compound 1 shows excellent specificity for the activation of the terminal C(sp)-H bond even across alkynes with diverse functionality. The resulting stiba-methylene nitrile and stiba-alkynyl adducts react with elemental iodine (I2) to produce iodoacetonitrile and iodoalkynes, while regenerating an Sb trication.

Pd(II) and Rh(I) Catalytic Precursors for Arene Alkenylation: Comparative Evaluation of Reactivity and Mechanism Based on Experimental and Computational Studies.

We combine experimental and computational investigations to compare and understand catalytic arene alkenylation using the Pd(II) and Rh(I) precursors Pd(OAc)2 and [(η2-C2H4)2Rh(µ-OAc)]2 with arene, olefin, and Cu(II) carboxylate at elevated temperatures (>120 °C). Under specific conditions, previous computational and experimental efforts have identified heterotrimetallic cyclic PdCu2(η2-C2H4)3(µ-OPiv)6 and [(η2-C2H4)2Rh(µ-OPiv)2]2(µ-Cu) (OPiv = pivalate) species as likely active catalysts for these processes. Further studies of catalyst speciation suggest a complicated equilibrium between Cu(II)-containing complexes containing one Rh or Pd atom with complexes containing two Rh or Pd atoms. At 120 °C, Rh catalysis produces styrene >20-fold more rapidly than Pd. Also, at 120 °C, Rh is ∼98% selective for styrene formation, while Pd is ∼82% selective. Our studies indicate that Pd catalysis has a higher predilection toward olefin functionalization to form undesired vinyl ester, while Rh catalysis is more selective for arene/olefin coupling. However, at elevated temperatures, Pd converts vinyl ester and arene to vinyl arene, which is proposed to occur through low-valent Pd(0) clusters that are formed in situ. Regardless of arene functionality, the regioselectivity for alkenylation of mono-substituted arenes with the Rh catalyst gives an approximate 2:1 meta/para ratio with minimal ortho C-H activation. In contrast, Pd selectivity is significantly influenced by arene electronics, with electron-rich arenes giving an approximate 1:2:2 ortho/meta/para ratio, while the electron-deficient (α,α,α)-trifluorotoluene gives a 3:1 meta/para ratio with minimal ortho functionalization. Kinetic intermolecular arene ethenylation competition experiments find that Rh reacts most rapidly with benzene, and the rate of mono-substituted arene alkenylation does not correlate with arene electronics. In contrast, with Pd catalysis, electron-rich arenes react more rapidly than benzene, while electron-deficient arenes react less rapidly than benzene. These experimental findings, in combination with computational results, are consistent with the arene C-H activation step for Pd catalysis involving significant η1-arenium character due to Pd-mediated electrophilic aromatic substitution character. In contrast, the mechanism for Rh catalysis is not sensitive to arene-substituent electronics, which we propose indicates less electrophilic aromatic substitution character for the Rh-mediated arene C-H activation.

Life-Course Brain Health as a Determinant of Late-Life Mental Health: American Association for Geriatric Psychiatry Expert Panel Recommendations.

This position statement of the Expert Panel on Brain Health of the American Association for Geriatric Psychiatry (AAGP) emphasizes the critical role of life course brain health in shaping mental well-being during the later stages of life. Evidence posits that maintaining optimal brain health earlier in life is crucial for preventing and managing brain aging-related disorders such as dementia/cognitive decline, depression, stroke, and anxiety. We advocate for a holistic approach that integrates medical, psychological, and social frameworks with culturally tailored interventions across the lifespan to promote brain health and overall mental well-being in aging adults across all communities. Furthermore, our statement underscores the significance of prevention, early detection, and intervention in identifying cognitive decline, mood changes, and related mental illness. Action should also be taken to understand and address the needs of communities that traditionally have unequal access to preventive health information and services. By implementing culturally relevant and tailored evidence-based practices and advancing research in geriatric psychiatry, behavioral neurology, and geroscience, we can enhance the quality of life for older adults facing the unique challenges of aging. This position statement emphasizes the intrinsic link between brain health and mental health in aging, urging healthcare professionals, policymakers, and a broader society to prioritize comprehensive strategies that safeguard and promote brain health from birth through later years across all communities. The AAGP Expert Panel has the goal of launching further activities in the coming months and years.

Dimensions of internalizing symptoms are stable across early adolescence and predicted by executive functions: Longitudinal findings from the Adolescent Brain and Cognitive Development (ABCD) study.

Early adolescence is characterized by rapid changes in executive function and increased vulnerability to internalizing difficulties. The aim of this study was to explore whether internalizing symptoms are stable across early adolescence and to identify possible links with executive function. Using data from the Adolescent Brain and Cognitive Development Study (ABCD), we identified four dimensions of internalizing symptoms from item-level ratings on the Child Behavior Checklist at ages 10 (n = 10,841) and 12 (n = 5,846), with an invariant factor structure across time. These dimensions corresponded to anxiety, depression, withdrawal, and somatic problems. We then examined associations between these dimensions and three aspects of executive function at age 10 measured by the NIH Toolbox: inhibition, shifting and working memory. Worse shifting and inhibition at age 10 was associated with elevated symptoms of anxiety and withdrawal cross-sectionally, while poor inhibition was also uniquely associated with symptoms of depression. Longitudinal associations were more limited: Worse inhibition at age 10 predicted greater symptoms of withdrawal at age 12, while worse shifting predicted fewer symptoms of anxiety 2 years later. These findings suggest that poor executive function in early adolescence is associated with greater internalizing difficulties and poor inhibition may contribute to later social withdrawal.

Reducing fear and avoidance of memory loss improves mood and social engagement in community-based older adults: a randomized trial.

BACKGROUND: Alzheimer's disease and related dementias (ADRD) are among the most feared age-related conditions. The aim of this study was to evaluate a brief psychological intervention to promote adaptive coping in older adults experiencing heightened fear of ADRD and investigate positive downstream effects on health-related secondary outcomes, including frequency of reported memory failures, psychosocial functioning, and quality of life. METHODS: Eighty-one older adults were recruited and randomized into REFRAME or active control intervention arms. Both groups received psycho-education and training in mindful monitoring of fears related to ADRD. The REFRAME group received an additional behavioral activation component intended to disrupt maladaptive avoidant coping (i.e., avoidance) strategies. Both groups completed 3-weeks of intervention exercises with accompanying questionnaires (baseline, mid- and post-intervention and 4-week follow-up). RESULTS: Adherence was strong (> 75%). We observed a significant reduction in ADRD-related fear and avoidance in both groups. Significant reductions were also observed for frequency of self-reported memory failures, anxiety, and depression. Depression was significantly reduced in the REFRAME group compared to the control group. Significant increases in participants' ability to participate in social activities and well-being were also observed. CONCLUSIONS: Findings suggest that a brief psychological intervention can mitigate ADRD-related fears and avoidant coping in older adults, and that benefits extend to broader health-related outcomes including anxiety, depression, social functioning, and well-being. Addressing ADRD-related fear has implications for healthy aging and risk reduction, as individuals may be more likely to engage in activities that are protective against ADRD but were previously avoided. TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT04821960 .

Susceptibility to prosocial and antisocial influence in adolescence following mindfulness training.

Mindfulness training programmes have shown to encourage prosocial behaviours and reduce antisocial tendencies in adolescents. However, less is known about whether training affects susceptibility to prosocial and antisocial influence. The current study investigated the effect of mindfulness training (compared with an active control) on self-reported prosocial and antisocial tendencies and susceptibility to prosocial and antisocial influence. 465 adolescents aged 11-16 years were randomly allocated to one of two training programmes. Pre- and post-training, participants completed a social influence task. Self-reported likelihood of engaging in prosocial and antisocial behaviours did not change post-training, and regardless of training group, participants showed a higher propensity for prosocial influence than for antisocial influence. Finally, participants were less influenced by antisocial ratings following both training programmes.

Aberrant reward prediction errors in young adult at-risk alcohol users.

Previous studies suggest that individuals with substance use disorder have abnormally large responses to unexpected outcomes (reward prediction errors [RPEs]). However, there is much less information on RPE in individuals at risk of alcohol misuse, prior to neurobiological adaptations that might result from sustained alcohol use. Here, participants (mean age 23.77 years, range 18-32 years) performed the electrophysiological monetary incentive delay task. This task involved responding to a target stimulus following reward incentive cues to win, or avoid losing, the cued reward while brain activity was recorded under 64-channel EEG. The Alcohol Use Disorders Identification Test (AUDIT) was used to quantify at-risk alcohol use, with high (n = 22, mean AUDIT score: 13.82) and low (n = 22, mean AUDIT score: 5.77) alcohol use groups. Trial-by-trial RPEs were estimated using a Rescorla-Wagner reinforcement model based on behavioral data. A single-trial analysis revealed that the feedback-related negativity (FRN) and feedback P3 (fb-P3) event-related potential components were significantly modulated by RPEs. There was increased RPE-related fb-P3 amplitude for those in the high alcohol use group. Next, the mean amplitude of ERPs elicited by positive and negative RPEs were compared between groups. We found that high alcohol use participants had attenuated FRN amplitude in contrast with low alcohol use participants for both positive and negative RPEs but enhanced fb-P3 for both positive and negative RPE. These results, with differences in RPE in an at-risk group, suggest that RPE a potential vulnerability marker for alcohol use disorder.

Management of vestibular dysfunction and hearing loss in intralabyrinthine schwannomas.

PURPOSE: Intralabyrinthine schwannomas (ILS) are rare, benign, slow-growing tumors arising from schwann cells of the cochlear or vestibular nerves within the bony labyrinth. This study provides insight into the management of this rare tumor through a large case series. MATERIALS AND METHODS: After Institutional Review Board approval, a retrospective chart review was performed of all ILS patients treated at our institution between 2007 and 2019. RESULTS: 20 patients (9 male, 11 female) with ILS were managed at our institution. The right ear was affected in 9 patients (45%) and the left in 11 (55%). Subjective hearing loss was endorsed by all 20 patients. Average pure tone average at presentation was 72 dB nHL. Nine tumors (45%) were intravestibular, 6 (30%) were intracochlear, 4 (20%) were transmodiolar and 1 (5%) was intravestibulocochlear. Hearings aids were used in 3 patients (15%), BiCROS in 2 (10%), CI in 2 (10%), and bone conduction implant in 1 (5%). Vestibular rehabilitation was pursued in 5 patients. Surgical excision was performed for one patient (5%) via translabyrinthine approach due to intractable vertigo. No patients received radiotherapy or intratympanic gentamicin injections. CONCLUSION: ILS presents a diagnostic and management challenge given the similarity of symptoms with other disorders and limited treatment options. Hearing loss may be managed on a case-by-case basis according to patient symptoms while vestibular loss may be mitigated with vestibular therapy. Surgical excision may be considered in patients with intractable vertigo, severe hearing loss with concurrent CI placement, or in other case-by-case situations.

Contralateral delay activity is not a robust marker of cognitive function in older adults at risk of mild cognitive impairment.

Contralateral delay activity (CDA) has been proposed as a pre-clinical neural marker for mild cognitive impairment (MCI). However, existing evidence is limited to one study with a small sample size (n = 24). Our aim was to extend previous work by investigating the relationship between the CDA and MCI risk in a large sample of older adults (n = 76). We used a regression approach to determine whether (and when) CDA amplitude predicted MCI risk, as indexed by the Montreal Cognitive Assessment (MoCA). CDA amplitude from ~300-500 and ~800-900 ms predicted MoCA performance. However, significant effects were only observed for specific electrodes (P5/P6 and CP3/CP4, but not PO7/PO8) and the nature of the relationship between the CDA and MoCA scores differed across time and according to set size. Bayesian regression analysis indicated partial evidence in favour of the null hypothesis (BF10 values = 4-1.18). Contrary to previous results, our findings suggest that the CDA may not a robust marker of MCI risk. More broadly, our results highlight the difficulty in identifying at-risk individuals, particularly as MCI is a heterogeneous, unstable condition. Future research should prioritise longitudinal approaches in order to track the progression of the CDA and its association with cognitive decline in later life.

EEG spectral power, but not theta/beta ratio, is a neuromarker for adult ADHD.

Adults with attention-deficit/hyperactivity disorder (ADHD) have been described as having altered resting-state electroencephalographic (EEG) spectral power and theta/beta ratio (TBR). However, a recent review (Pulini et al. 2018) identified methodological errors in neuroimaging, including EEG, ADHD classification studies. Therefore, the specific EEG neuromarkers of adult ADHD remain to be identified, as do the EEG characteristics that mediate between genes and behaviour (mediational endophenotypes). Resting-state eyes-open and eyes-closed EEG was measured from 38 adults with ADHD, 45 first-degree relatives of people with ADHD and 51 unrelated controls. A machine learning classification analysis using penalized logistic regression (Elastic Net) examined if EEG spectral power (1-45 Hz) and TBR could classify participants into ADHD, first-degree relatives and/or control groups. Random-label permutation was used to quantify any bias in the analysis. Eyes-open absolute and relative EEG power distinguished ADHD from control participants (area under receiver operating characteristic = 0.71-0.77). The best predictors of ADHD status were increased power in delta, theta and low-alpha over centro-parietal regions, and in frontal low-beta and parietal mid-beta. TBR did not successfully classify ADHD status. Elevated eyes-open power in delta, theta, low-alpha and low-beta distinguished first-degree relatives from controls (area under receiver operating characteristic = 0.68-0.72), suggesting that these features may be a mediational endophenotype for adult ADHD. Resting-state EEG spectral power may be a neuromarker and mediational endophenotype of adult ADHD. These results did not support TBR as a diagnostic neuromarker for ADHD. It is possible that TBR is a characteristic of childhood ADHD.

Mapping adolescent reward anticipation, receipt, and prediction error during the monetary incentive delay task.

The functional neuroanatomy and connectivity of reward processing in adults are well documented, with relatively less research on adolescents, a notable gap given this developmental period's association with altered reward sensitivity. Here, a large sample (n = 1,510) of adolescents performed the monetary incentive delay (MID) task during functional magnetic resonance imaging. Probabilistic maps identified brain regions that were reliably responsive to reward anticipation and receipt, and to prediction errors derived from a computational model. Psychophysiological interactions analyses were used to examine functional connections throughout reward processing. Bilateral ventral striatum, pallidum, insula, thalamus, hippocampus, cingulate cortex, midbrain, motor area, and occipital areas were reliably activated during reward anticipation. Bilateral ventromedial prefrontal cortex and bilateral thalamus exhibited positive and negative activation, respectively, during reward receipt. Bilateral ventral striatum was reliably active following prediction errors. Previously, individual differences in the personality trait of sensation seeking were shown to be related to individual differences in sensitivity to reward outcome. Here, we found that sensation seeking scores were negatively correlated with right inferior frontal gyrus activity following reward prediction errors estimated using a computational model. Psychophysiological interactions demonstrated widespread cortical and subcortical connectivity during reward processing, including connectivity between reward-related regions with motor areas and the salience network. Males had more activation in left putamen, right precuneus, and middle temporal gyrus during reward anticipation. In summary, we found that, in adolescents, different reward processing stages during the MID task were robustly associated with distinctive patterns of activation and of connectivity.

Electron Localization and Transport in SnO2/TiO2 Mesoporous Thin Films: Evidence for a SnO2/SnxTi1-xO2/TiO2 Structure.

A study of SnO2/TiO2 core/shell films was undertaken to investigate the influences of shell thickness and post deposition sintering on electron localization and transport properties. Electrochemical reduction of the materials resulted in the appearance of a broad visible-near IR absorbance that provided insights into the electronic state(s) within the core/shell structures. As the shell thickness was increased from 0.5 to 5 nm, evidence for the presence of a SnxTi1-xO2 interfacial state emerged that was physically located between the core and the shell. The lifetime of photoinjected electrons increased with the shell thickness. Electron transport occurred through the SnO2 core; however, when materials with shell thicknesses ≥2 nm were annealed at 450 °C, a new electron transport pathway through the shell was evident. The data indicate that these materials are best described as SnO2/SnxTi1-xO2/TiO2 where electrons preferentially localize in a SnxTi1-xO2 interfacial state and transport through SnO2 and annealed TiO2 (if present). The implications of these results for applications in solar energy conversion are discussed.

Development and Preliminary Findings of the Dizziness Symptom Profile.

OBJECTIVES: Dizziness, vertigo, and unsteadiness are common complaints of patients who present to primary care providers. These patients often are referred to otology for assessment and management. Unfortunately, there are a small number of specialists to manage these patients. However, there are several dizziness disorders that can be successfully managed by primary care providers if the disorder is properly identified. To assist in the identification of several of the most common dizziness disorders, we developed the dizziness symptom profile (DSP). The DSP is a self-report questionnaire designed to generate one or more differential diagnoses that can be combined with the patient's case history and physical examination. DESIGN: This report describes three investigations. Investigations 1 and 2 (i.e., exploratory and confirmatory investigations, N = 514) describe the development of the DSP. Investigation 3 (N = 195) is a validation study that describes the level of agreement between the DSP completed by the patient, and, the differential diagnosis of the otologist. RESULTS: The final version of the DSP consists of 31 items. Preliminary findings suggest that the DSP is in agreement with the differential diagnoses of ear specialists for Meniere's disease (100% agreement), vestibular migraine (95% agreement), and benign paroxysmal positional vertigo (82% agreement). CONCLUSIONS: Early results suggest that DSP may be useful in the creation of differential diagnoses for dizzy patients that can be evaluated and managed locally. This has the potential to reduce the burden on primary care providers and reduce delays in the diagnosis of common dizziness and vertigo disorders.

Bending rules: the shape of the perceptual generalisation gradient is sensitive to inference rules.

Generalising what is learned about one stimulus to other but perceptually related stimuli is a basic behavioural phenomenon. We evaluated whether a rule learning mechanism may serve to explain such generalisation. To this end, we assessed whether inference rules communicated through verbal instructions affect generalisation. Expectancy ratings, but not valence ratings, proved sensitive to this manipulation. In addition to revealing a role for inference rules in generalisation, our study has clinical implications as well. More specifically, we argue that targeting inference rules might prove to be an effective strategy to affect the excessive generalisation that is often observed in psychopathology.

Facial nerve repair after operative injury: Impact of timing on hypoglossal-facial nerve graft outcomes.

PURPOSE: Reanimation of facial paralysis is a complex problem with multiple treatment options. One option is hypoglossal-facial nerve grafting, which can be performed in the immediate postoperative period after nerve transection, or in a delayed setting after skull base surgery when the nerve is anatomically intact but function is poor. The purpose of this study is to investigate the effect of timing of hypoglossal-facial grafting on functional outcome. MATERIALS AND METHODS: A retrospective case series from a single tertiary otologic referral center was performed identifying 60 patients with facial nerve injury following cerebellopontine angle tumor extirpation. Patients underwent hypoglossal-facial nerve anastomosis following facial nerve injury. Facial nerve function was measured using the House-Brackmann facial nerve grading system at a median follow-up interval of 18months. Multivariate logistic regression analysis was used determine how time to hypoglossal-facial nerve grafting affected odds of achieving House-Brackmann grade of ≤3. RESULTS: Patients who underwent acute hypoglossal-facial anastomotic repair (0-14days from injury) were more likely to achieve House-Brackmann grade ≤3 compared to those that had delayed repair (OR 4.97, 95% CI 1.5-16.9, p=0.01). CONCLUSIONS: Early hypoglossal-facial anastomotic repair after acute facial nerve injury is associated with better long-term facial function outcomes and should be considered in the management algorithm.

From bad to worse: Symbolic equivalence and opposition in fear generalisation.

The present study compared the impact of symbolic equivalence and opposition relations on fear generalisation. In a procedure using nonsense words, some stimuli became symbolically equivalent to an aversively conditioned stimulus while others were symbolically opposite. The generalisation of fear to symbolically related stimuli was then measured using behavioural avoidance, retrospective unconditioned stimulus expectancy and stimulus valence ratings. Equivalence relations facilitated fear generalisation while opposition relations constrained generalisation. The potential clinical implications of symbolic generalisation are discussed.

Predictive properties of the video head impulse test: measures of caloric symmetry and self-report dizziness handicap.

OBJECTIVES: The purpose of this investigation was to determine whether a predictable relationship existed between self-reported dizziness handicap and video Head Impulse Test (vHIT) results in a large sample of patients reporting to a dizziness clinic. Secondary objectives included describing the characteristics of the vHIT ipsilesional and contralesional vestibulo-ocular reflex slow-phase velocity in patients with varying levels of canal paresis. Finally, the authors calculated the sensitivity and specificity of the vHIT for detecting horizontal semicircular canal impairment using the caloric test as the "gold standard." DESIGN: Participants were 115 adults presenting to a tertiary medical care center with symptoms of dizziness. Participants were administered a measure of self-report dizziness handicap (i.e., Dizziness Handicap Inventory) and underwent caloric testing and vHIT at the same appointment. RESULTS: Results showed that (1) there were no significant group differences (i.e., vHIT normal versus vHIT abnormal) in the Dizziness Handicap Inventory total score, (2) both ipsilesional and contralateral velocity gain decreased with increases in caloric paresis, and (3) a caloric asymmetry of 39.5% was determined to be the cutoff that maximized discrimination of vHIT outcome. CONCLUSIONS: The level of self-reported dizziness handicap is not predicted by the outcome of the vHIT, which is consistent with the majority of published reports describing the poor relationship between quantitative tests of vestibular function and dizziness handicap. Further, the study findings have demonstrated that vHIT and caloric data are not redundant, and each test provides unique information regarding the functional integrity of the horizontal semicircular canal at different points on the frequency spectrum. The vHIT does offer some advantages over caloric testing, but at the expense of sensitivity. The vHIT can be completed in less time, is not noxious to the patient, and requires very little laboratory space. However, the study data show that a caloric asymmetry of 39.5% is required to optimize discrimination between an abnormal and normal vHIT. It is the authors' contention that the vHIT is a complementary test to the balance function examination and should viewed as such rather than as a replacement for caloric testing.

Retrosigmoid craniotomy for resection of acoustic neuroma with hearing preservation: a video publication.

In this publication, video format is utilized to review the operative technique of retrosigmoid craniotomy for resection of acoustic neuroma with attempted hearing preservation. Steps of the operative procedure are reviewed and salient principles and technical nuances useful in minimizing complications and maximizing efficacy are discussed. The video can be found here: http://youtu.be/PBE5rQ7B0Ls .

Factors associated with recurrence of squamous cell carcinoma involving the temporal bone.

OBJECTIVE: This study aimed to better identify factors associated with recurrence of squamous cell carcinoma (SCC) involving the temporal bone. METHODS: A retrospective study was conducted at a tertiary hospital. Sixty patients who were diagnosed over a 10-year period with SCC involving the temporal bone and underwent surgical resection were analyzed. All patients were staged based on the University of Pittsburgh staging system. Demographic, intraoperative, and pathologic data were analyzed with respect to recurrence. RESULTS: Thirteen (21.7%) patients were T1, 8 (13.3%) T2, 7 (11.7%) T3, and 32 (53.3%) T4. Eighteen patients (30.0%) recurred in the study period. The mean time to recurrence was 5.8 months. Tumors originating in the skin overlying the parotid gland and the external auditory canal had higher recurrence rates than those from the auricle/postauricular skin and temporal bone (P = .05). Direct parotid and perineural spread accounted for 15.0% of all routes of temporal invasion but resulted in 22.2% of all recurrences (P = .04). Increased N stage was statistically associated with increased risk of recurrence (P = .01). Cervical, as compared to perifacial and parotid, lymph node involvement was associated with increased risk of recurrence (odds ratio = 6.91; 95% confidence interval, 1.11-42.87). CONCLUSION: We have identified multiple factors that are associated with increased recurrence of SCC involving the temporal bone.

The limitations of computed tomography in adult cochlear implant evaluation.

OBJECTIVE: To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation. PATIENTS: Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation. INTERVENTIONS: Temporal bone CT and MRI. MAIN OUTCOME MEASURE: Diagnosis of NF2. RESULTS: Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI. CONCLUSIONS: Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.