Follow-up care compliance among patients diagnosed with unruptured intracranial aneurysms.

OBJECTIVES: Periodic imaging follow-up for patients with unruptured intracranial aneurysms (UIA) is crucial, as studies indicate higher rupture risk with aneurysm growth. However, few studies address patient adherence to follow-up recommendations. This study aims to identify compliance rates and factors influencing follow-up adherence. METHODS: Patients with a UIA were identified from our institution's database from 2011-2021. Follow-up imaging (CT/MR Angiogram) was advised at specific intervals. Patients were categorized into compliant and non-compliant groups based on first-year compliance. Factors contributing to compliance were assessed through multivariate logistic regression. Phone interviews were conducted with non-compliant patients to understand reasons for non-adherence. RESULTS: Among 923 UIA diagnosed patients, 337 were randomly selected for analysis. The median follow-up period was 1.4 years, with a 42% first-year compliance rate. The mean aneurysm size was 3.3 mm. Five patients had a rupture during follow-up, of which 4 died. Compared with patients consulting specialists at the initial diagnosis, those seen by non-specialists exhibited lower compliance (OR 0.25, p < 0.001). Loss to follow-up was greatest during transition from emergency service to specialist appointments. Patients who spoke languages other than English exhibited poorer compliance than those speaking English (OR 0.20, p = 0.01). CONCLUSIONS: Significant amounts of UIA patients at low rupture risk were lost to follow-up before seeing UIA specialists. Main non-compliance factors include inadequate comprehension of follow-up instructions, poor care transfer from non-specialists to specialist, and insurance barriers.

Quantitative Pupillometry in the Intensive Care Unit.

Quantitative pupillometry provides a noninvasive and objective assessment within the neurological examination. This review details the physiology of the pupillary light response, the clinical significance of changes in pupillary reactivity, and the variables that compose the Neurological Pupil index or NPi are discussed. This article reviews the most recent applications and advances in quantitative pupillometry for noninvasive intracranial pressure monitoring, postcardiac arrest prognostication, and subarachnoid hemorrhage. Also discussed are the limitations and confounders of quantitative pupillometry in the modern neurological intensive care unit.

Characteristics and overall survival in pediatric versus adult skull base chordoma: a population-based study.

PURPOSE: Less than 5% of chordomas occur in pediatric patients. While many studies have explored the treatment and outcomes of skull base chordomas, few have focused on the differences between pediatric and adult populations. The aim of this study is to analyze the epidemiological variables and clinical outcomes between pediatric and adult skull base chordomas using a large-sample, population-based cancer database. METHODS: The National Cancer Database was queried between 2004 and 2015 for skull base chordomas. We stratified patients as pediatric (<18 years) and adults (≥18 years). We compared several clinical covariates between the two groups. RESULTS: Our cohort consisted of 658 patients, 61 pediatric (9.3%), and 597 adults (90.7%). Pediatric patients were more likely to have larger tumor size (41.4 ± 15.7 mm versus 34.1 ± 15.8 mm, p < 0.01) and universally treated at academic facilities. There was no significant difference in overall survival. CONCLUSIONS: Pediatric skull base chordomas are rare tumors that are managed with aggressive surgical resection, followed by radiation. While there may be difference between tumor presentation, outcomes between pediatric and adult patients are similar.

Estimating the annual frequency of synchronous brain metastasis in the United States 2010-2013: a population-based study.

Brain metastases (BM) are one of the most common types of brain tumors and are a relatively common event in the disease process for several high-incidence cancer types, including breast and lung cancers. Historically, information on metastases including BM have not been collected as part of national cancer registration in the US, but BM at time of primary cancer diagnosis (SBM), is now collected by the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) system. Using data from 18 SEER registries from 2010 to 2013, we assessed the frequency of SBM at time of primary diagnosis in the US by site, histology group, sex, race, age, and insurance status. There were 1,634,954 total primary cancer cases in SEER from 2010 to 2013, 1.7% of which presented with SBM. The cancer type with the highest proportion of SBM was lung cancer (10.8% of cases with SBM), followed by esophageal (1.5%), kidney (1.4%), and melanoma (1.2%). SBM varied by age, sex, race, and insurance status for most histologies. Our results reflect the high proportion of patients who are diagnosed with lung cancer at late stages and present with SBM, in contrast to other common cancers in the US where SBM is less common. Demographic variation in molecular subtype and risk behavior may influence variation in SBM. BM is a relatively common event in late stage cancer and cause significant morbidity and mortality, and assessment of accurate population-based data is critical to estimate total disease burden.

A Trial Online Educational Melanoma Program Aimed at the Hispanic Population Improves Knowledge and Behaviors.

BACKGROUND: Hispanic individuals who suffer from melanoma are diagnosed later and have a worse prognosis. Because the Hispanic population is one of the fastest growing in the United States, it is important to spread awareness of melanoma. OBJECTIVE: The study aimed to evaluate whether an online educational video about skin cancer could improve knowledge about melanoma and encourage self-skin examinations (SSE). METHODS: The authors directed Hispanic patients to an online survey, which assessed for knowledge about melanoma risk factors and prevention. This was followed by a 5-minute online video about melanoma. A second survey was sent immediately after the video, and a third survey was sent 1 month later. All project materials were in Spanish and available online. RESULTS: Eighty-six participants completed the full experiment. After watching the online video, a significantly higher proportion of participants provided correct answers for melanoma risk factors and prevention techniques. A similar increase was seen in the number of individuals who reported performing SSEs. CONCLUSION: This study provides evidence that an online educational video targeted at the Hispanic population has potential to improve melanoma awareness. This type of intervention may lead to earlier diagnosis and better prognosis for Hispanic individuals.

Embolization of a third ventricular choroid plexus papilloma: illustrative case.

BACKGROUND: Choroid plexus tumors are rare neoplasms that are typically found in the lateral ventricles. They have infrequently been reported in the third ventricle, and treatment strategies have varied. OBSERVATIONS: The authors described a 6-month-old patient who presented with irritability and hypotonia. The patient was found to have a large tumor in the third ventricle with obstructive hydrocephalus. Preoperative angiography revealed a feeding artery from the right medial posterior choroidal artery (MPChA). The feeding artery was effectively embolized, and the patient subsequently received open resection of the tumor. Pathology revealed features consistent with atypical choroid plexus papilloma (CPP). LESSONS: Choroid plexus tumors are often hypervascular, which can often make gross total resection (GTR) difficult. Preoperative angiography of tumors identifies feeding vessels, and embolization has the potential to decrease perioperative blood loss and allow for a higher GTR rate. Third ventricular CPPs appear to invariably receive vascular supply from the MPChA, arising from the right posterior cerebral artery. Embolization followed by resection of a choroid plexus tumor in the third ventricle is an effective treatment strategy.

Telehealth in Neurosurgery: 2021 Council of State Neurosurgical Societies National Survey Results.

OBJECTIVE: Telehealth was rapidly adopted during the COVID-19 pandemic. A survey was distributed to neurosurgeons in the United States (U.S.) to understand its use within neurosurgery, what barriers exist, unique issues related to neurosurgery, and opportunities for improvement. METHODS: A survey was distributed via email and used the SurveyMonkey platform. The survey was sent to 3828 practicing neurosurgeons within the U.S., 404 responses were collected between October 30, 2021 and December 4, 2021. RESULTS: During the pandemic, telehealth was used multiple times per week by 60.65% and used daily by an additional 12.78% of respondents. A supermajority (89.84%) of respondents felt that evaluating patients across state lines with telemedicine is beneficial. Most respondents (95.81%) believed that telehealth improves patient access to care. The major criticism of telehealth was the inability to perform a neurological exam. CONCLUSIONS: Telehealth has been widely implemented within the field of neurosurgery during the COVID-19 pandemic and has increased access to care. It has allowed patients to be evaluated remotely, including across state lines. While certain aspects of the neurological exam are suited for video evaluation, sensation and reflexes cannot be adequately assessed. Neurosurgeons believe that telehealth adds value to their ability to deliver care.

Endovascular retrieval of a broken distal ventriculoatrial shunt catheter within the heart: illustrative case.

BACKGROUND: Displacement of a distal catheter of a ventriculoatrial (VA) shunt is a rare complication and can lead to a challenging extraction requiring endovascular retrieval of the distal catheter. OBSERVATIONS: The authors describe a patient in whom the distal catheter of the VA shunt had become displaced and traveled through the tricuspid valve into the right ventricular outflow tract. LESSONS: In this case report, the authors present a multidisciplinary approach to retrieving a displaced distal catheter from a VA shunt.

The Mini-Craniotomy for cSDH Revisited: New Perspectives.

Background: Chronic subdural hematomas (cSDH) are increasingly prevalent worldwide with the increased aging population and anticoagulant use. Different surgical, medical, and endovascular treatments have had varying success rates. Primary neurosurgical interventions include burr hole drainage of the cSDH and mini-craniotomies/craniotomies with or without fenestration of the inner membrane. A key assessment of the success or failure of cSDH treatments has been symptomatic recurrence rates which have historically ranged from 5 to 30%. Pre-operative prediction of the inner subdural membrane by CT scan was used to guide our decision to perform mini-craniotomies. Release of the inner membrane facilitates the expansion of the brain and likely improves glymphatic flow. Methods: Consecutive mini-craniotomies (N = 34) for cSDH evacuation performed by a single neurosurgeon at a quaternary academic medical center/Level I trauma center from July 2018-September 2020 were retrospectively reviewed. Patient characteristics [age, gender, presenting GCS, GOS, initial CTs noting the inner subdural membrane, midline shift (MLS), cSDH width, inner membrane fenestration, cSDH recurrence, post-operative seizures, infections, length of stay] were extracted from the EMR. Results: Twenty nine patients had mini-craniotomies as primary treatment of the cSDH. Mean age = 68.9 ± 19.7 years (range 22-102), mean pre-operative GCS = 14.5 ± 1.1, mean MLS = 6.75 ± 4.2 mm, and mean maximum thickness of cSDH = 17.7 ± 6.0 mm. Twenty four were unilateral, five bilateral, 34 total craniotomies were performed. Thirty three had inner membrane signs on pre-operative head CTs and an inner subdural membrane was fenestrated in all cases except for the one craniotomy that didn't show these characteristic CT findings. Mean operating time = 79.5 ± 26.0 min. Radiographic and clinical improvement occurred in all patients. Mean improvement in MLS = 3.85 ± 2.69. There were no symptomatic recurrences, re-operations, surgical site infections, or deaths during the 6 months of follow-up. One patient was treated for post-operative seizures with AEDs for 6 months. Conclusion: Pre-operative CT scans demonstrating inner subdural membranes may guide one to target the treatment to allow release of this tension band. Mini-craniotomy with careful fenestration of the inner membrane is very effective for this. Brain re-expansion and re-establishment of normal brain interstitial flow may be important in long term outcomes with cSDH and may be related to the recent interests in brain glymphatics and dural lymphatics.

Ergonomics of Endoscopic Skull Base Surgery: A Systematic Review.

OBJECTIVE: There has been a significant expansion in endonasal endoscopic skull base surgery (EES) that has been used to address a wide range of intracranial and sinonasal pathologies. Although there exists a large amount of literature on approaches and patient outcomes, there is a paucity of data describing ergonomics in this field. Our goal was to evaluate and summarize the literature on ergonomics in EES. METHODS: We systematically reviewed all published, peer-reviewed, English language literature in the PubMed and Web of Science databases as screened by multiple reviewers describing ergonomics as related to EES. RESULTS: A total of 50 articles were found that described significant conclusions and descriptions on ergonomics in EES. We found and summarized the different technical aspects of ergonomics as pertaining to EES and provided evidence-based suggestions on operating room and surgeon setup. CONCLUSIONS: There are several improvements in EES ergonomics that can decrease fatigue, improve efficiency, and overall surgeon well-being.

Stroke Preventability in Large Vessel Occlusion Treated With Mechanical Thrombectomy.

Objective: The preventability of strokes treated by mechanical thrombectomy is unknown. The purpose of this study was to analyze stroke preventability for patients treated with mechanical thrombectomy for large vessel occlusion. Methods: We conducted retrospective analyses of 300 patients (mean ± SE age 69 ± 0.9 years, range 18-97 years; 53% male) treated with mechanical thrombectomy for large vessel occlusion from January 2008 to March 2019. We collected data including demographics, NIH Stroke Scale (NIHSS) at onset, and (beginning in 2015) classified 90-day outcome by modified Rankin Scale (mRS). Patients were evaluated using a Stroke Preventability Score (SPS, 0 to 10 points) based on how well patients had been treated given their hypertension, hyperlipidemia, atrial fibrillation, and prior stroke history. We examined the relationship of SPS with NIHSS at stroke onset and with mRS outcome at 90 days. Results: SPS was calculated for 272 of the 300 patients, with mean ± SE of 2.1 ± 0.1 (range 0-8); 89 (33%) had no preventability (score 0), 120 (44%) had low preventability (score 1-3), and 63 (23%) had high preventability (score 4 or higher). SPS was significantly correlated with age (r = 0.32, p < 0.0001), while NIHSS (n = 267) was significantly higher (p = 0.03) for patients with high stroke preventability vs. low/no preventability [18.8 ± 0.92 (n = 62) vs. 16.5 ± 0.51 (n = 205)]. Among 118 patients with mRS, outcome was significantly worse (p = 0.04) in patients with high stroke preventability vs. low/no preventability [4.7 ± 0.29 (n = 28) vs. 3.8 ± 0.21 (n = 90)]. The vast majority of patients with high stroke preventability had inadequately treated atrial fibrillation (85%, 53/62). Conclusions: Nearly one quarter of stroke patients undergoing mechanical thrombectomy had highly preventable strokes. While stroke preventability showed some relationship to stroke severity at onset and outcome after treatment, preventability had the strongest association with age. These findings emphasize the need for improved stroke prevention in the elderly.

Factors associated with self-reported burnout level in allied healthcare professionals in a tertiary hospital in Singapore.

BACKGROUND: Burnout has adverse implications in healthcare settings, compromising patient care. Allied health professionals (AHPs) are defined as individuals who work collaboratively to deliver routine and essential healthcare services, excluding physicians and nurses. There is a lack of studies on burnout among AHPs in Singapore. This study explored factors associated with a self-reported burnout level and barriers to seeking psychological help among AHPs in Singapore. METHODS: We conducted a cross-sectional study in a sample of AHPs in a tertiary hospital from October to December 2019. We emailed a four-component survey to 1127 eligible participants. The survey comprised four components: (1) sociodemographic characteristics, (2) Maslach Burnout Inventory (MBI-HSS), (3) Areas of Worklife Survey, and (4) Perceived Barriers to Psychological Treatment (PBPT). We performed a multiple logistic regression analysis to identify factors associated with burnout. Adjusted odds ratios (AORs) and associated 95% confidence intervals (CIs) were computed. RESULTS: In total, 328 participants completed the questionnaire. The self-reported burnout level (emotional exhaustion>27 and/or depersonalization>10) was 67.4%. The majority of the respondents were female (83.9%), Singaporean (73.5%), aged 40 years and below (84.2%), and Chinese ethnicity (79.9%). In the multiple logistic regression model, high burnout level was negatively associated with being in the age groups of 31 to 40 (AOR 0.39, 95% CI 0.16-0.93) and 40 years and older (AOR 0.30, 95% CI 0.10-0.87) and a low self-reported workload (AOR 0.35, 95% CI 0.23-0.52). High burnout level was positively associated with a work experience of three to five years (AOR 5.27, 95% CI 1.44-20.93) and more than five years (AOR 4.24; 95% CI 1.16-16.79. One hundred and ninety participants completed the PBPT component. The most frequently cited barriers to seeking psychological help by participants with burnout (n = 130) were 'negative evaluation of therapy' and 'time constraints.' CONCLUSIONS: This study shows a high self-reported burnout level and identifies its associated factors among AHPs in a tertiary hospital. The findings revealed the urgency of addressing burnout in AHPs and the need for effective interventions to reduce burnout. Concurrently, proper consideration of the barriers to seeking help is warranted to improve AHPs' mental well-being.

Noninvasive thermal evaluation for shunt failure in the emergency room.

BACKGROUND: Ventriculoperitoneal shunts (VPSs) have been the mainstay of treating hydrocephalus since the 1950s. However, shunts have a reported complication rate reaching nearly 50%. Devices have been developed that utilize noninvasive thermal transcutaneous diffusion technology. These shunt evaluation devices measure temperature gradients to detect shunt cerebrospinal fluid flow. We assessed the utility using a thermal diffusion technique to work up shunt failure in the emergency room (ER). METHODS: This was a retrospective case series at a single medical center ER. We included consecutive patients with possible VPS malfunction who were evaluated with a thermal sensor. The time period of data collection included September 2015-April 2018. RESULTS: Eight patients were reviewed, including four males and four females. The average age of reviewed patients was 35.1 (+/- ; 16.5). In our case series, three patients had adequate shunt flow as assessed by the shunt evaluation device, and the decision was made to discharge the patient and follow-up in clinic. In two patients, the flow was diminished, but due to other reassuring signs, the patients were still discharged with follow-up. Two patients were noted to have poor flow and were admitted for shunt revision. CONCLUSION: It is important to determine whether a malfunction is present and whether an intervention is necessary for patients who present to the emergency department with possible symptoms of shunt failure. A thermal sensor is a fast and noninvasive tool in the evaluation of shunt flow and helps determine whether it is safe to send a patient home or intervene appropriately.

Protective effect of unilateral vasospasm in the setting of HHH-associated posterior reversible encephalopathy syndrome: case report, review of the literature, and treatment considerations.

BACKGROUND: Hyperdynamic therapy, also called triple-H therapy, is the standard treatment and prophylaxis for aneurysmal-associated vasospasm. In patients who are able to tolerate cardiopulmonary stressors induced by this therapy, it is of benefit as a modality for prevention and treatment of delayed ischemic neurologic deficit. However, it can be a cause of significant cardiopulmonary or neurologic sequelae. In rare cases, it can be associated with posterior reversible encephalopathy syndrome (PRES), secondary to prolonged vasopressor and hypertensive therapies. CASE PRESENTATION: We present the case of a patient with right-sided aneurysmal-associated vasospasm who, after 10 days of triple-H therapy, experienced a seizure and was found to have left-sided PRES. Right-sided vasospasm served as a protective mechanism from triple-H therapy-associated PRES. It presented a treatment conundrum due to contradictory perfusion requirements. Hypertensive therapy was curtailed and in efforts to preserve local cerebral perfusion and vasodilation, local therapy with intrathecal nicardipine was initiated. We present our case, a review of the literature, and management considerations. CONCLUSIONS: Therapies that have conventionally functioned as second line treatments for aneurysmal subarachnoid hemorrhage (intra-arterial vasodilators and intrathecal vasodilators) may be beneficial as earlier treatments in the setting of vasospasm given the systemic difficulties and complications associated with HHH therapy in patients with PRES.

Disseminated cerebral toxoplasmosis in a patient with chronic lymphocytic leukemia.

Infections are one of the most common causes of mortality in immunocompromised patients. In patients diagnosed with hematologic malignancies, treatment with stem cell transplants (SCT) or T-cell suppressing chemotherapy increases the risk of central nervous system (CNS) infections, of which toxoplasmosis is the most common. We report the case of a 63 year-old woman with chronic lymphocytic leukemia (CLL) that presented with gait instability and visual changes. Intracranial lesions were noted on initial neuro-imaging. A rapid decline in the patient's mental status warranted an urgent biopsy of the lesions that revealed tachyzoites consistent with toxoplasmosis. In the presence of diffuse brain lesions that lack a metastatic pattern or contrast enhancement, a common approach is to perform biopsy only after a battery of non-invasive testing. This diagnostic delay may take several days, exposing the patient to a rapidly fatal infection. This report illustrates the utility of early brain biopsy in high-risk patients with hematologic malignancies and CNS lesions.

Adverse Events Following Cervical Disc Arthroplasty: A Systematic Review.

STUDY DESIGN: Systematic review. OBJECTIVES: Cervical arthroplasty is an increasingly popular treatment of cervical radiculopathy and myelopathy. An understanding of the potential adverse events (AEs) is important to help both clinicians and patients. We sought to provide a comprehensive systematic review of the AEs reported in all randomized controlled trials (RCTs) of cervical disc arthroplasty in an attempt to characterize the quality of reporting. METHODS: We conducted a systematic review of MEDLINE and Web of Science for RCTs of cervical disc arthroplasty reporting AEs. We reported the most frequently mentioned AEs, including dysphagia/dysphonia, vascular compromise, dural injury, and infections. We recorded the presence of industry funding and scored the quality of collection methods and reporting of AEs. RESULTS: Of the 3734 identified articles, 29 articles met full inclusion criteria. The quality of AE reporting varied significantly between studies, and a combined meta-analysis was not feasible. The 29 articles covered separate 19 RCTs. Eight studies were US Food and Drug Administration (FDA) investigational device exemption (IDE) trials. Rates were recorded for the following AEs: dysphagia/dysphonia (range = 1.3% to 27.2%), vascular compromise (range = 1.1% to 2.4%), cervical wound infection (range = 1.2% to 22.5%), and cerebrospinal fluid leak (range = 0.8% to 7.1%). CONCLUSIONS: There is a lack of consistency in reporting of AEs among RCTs of cervical arthroplasty. FDA IDE trials scored better in AE event reporting compared to other studies. Standardized definitions for AEs and standardized data collection methodology are needed to improve future studies.

Global incidence of malignant brain and other central nervous system tumors by histology, 2003-2007.

BACKGROUND: Previous reports have shown that overall incidence of malignant brain and other central nervous system (CNS) tumors varied significantly by country. The aim of this study was to estimate histology-specific incidence rates by global region and assess incidence variation by histology and age. METHODS: Using data from the Central Brain Tumor Registry of the United States (CBTRUS) and the International Agency for Research on Cancer's (IARC) Cancer Incidence in Five Continents X (including over 300 cancer registries), we calculated the age-adjusted incidence rates (AAIR) per 100000 person-years and 95% CIs for brain and other CNS tumors overall and by age groups and histology. RESULTS: There were significant differences in incidence by region. Overall incidence of malignant brain tumors per 100000 person-years in the US was 5.74 (95% CI = 5.71-5.78). Incidence was lowest in Southeast Asia (AAIR = 2.55, 95% CI = 2.44-2.66), India (AAIR = 2.85, 95% CI = 2.78-2.93), and East Asia (AAIR = 3.07, 95% CI = 3.02-3.12). Incidence was highest in Northern Europe (AAIR = 6.59, 95% CI = 6.52-6.66) and Canada (AAIR = 6.53, 95% CI = 6.41-6.66). Astrocytic tumors showed the broadest variation in incidence regionally across the globe. CONCLUSION: Brain and other CNS tumors are a significant source of cancer-related morbidity and mortality worldwide. Regional differences in incidence may provide clues toward genetic or environmental causes as well as a foundation for broadening knowledge of their epidemiology. Gaining a comprehensive understanding of the epidemiology of malignant brain tumors globally is critical to researchers, public health officials, disease interest groups, and clinicians and contributes to collaborative efforts in future research.

Enhanced Irrigant Delivery to the Ethmoid Sinuses Directly Following Ethmoid Punch Sinusotomy.

OBJECTIVES: Ethmoid punch sinusotomy (EPS) is a feasible treatment for ethmoid sinusitis in a subset of chronic rhinosinusitis (CRS) patients per a recent report. This adjunctive work investigates the technical characteristics of EPS and determines if EPS measurably alters the topical delivery of irrigant into the ethmoid sinuses in a cadaveric model. METHODS: The sinonasal cavities of 10 human cadaver heads were irrigated with a solution containing methylene blue and radio-opaque contrast prior to and following EPS. Procedural characteristics and irrigant distribution were assessed by endoscopy and computed tomography. RESULTS: Forty EPS procedures were performed through the ethmoid bulla and basal lamella. Compared to controls, EPS enhanced dye distribution into the anterior (90% vs 35%, P < .004) and posterior (90% vs 35%, P < .002) ethmoid sinuses, representing a 157% increase for each of these sites. Contrast was detected in a higher proportion of anterior (65% vs 5%, P < .001) and posterior (60% vs 0%, P < .001) ethmoid sinuses. Endoscopically guided catheter instillation of contrast through the EPS sites achieved radiotracer distribution throughout the ethmoid complex. CONCLUSIONS: Ethmoid punch sinusotomy sites can be reliably created via micro-minimally invasive procedures. Ethmoid punch sinusotomy improves irrigant delivery to the ethmoid sinuses, providing mechanistic understanding for the clinical outcomes observed in CRS patients.

Tau reduction prevents Aß-induced axonal transport deficits by blocking activation of GSK3ß.

Axonal transport deficits in Alzheimer's disease (AD) are attributed to amyloid ß (Aß) peptides and pathological forms of the microtubule-associated protein tau. Genetic ablation of tau prevents neuronal overexcitation and axonal transport deficits caused by recombinant Aß oligomers. Relevance of these findings to naturally secreted Aß and mechanisms underlying tau's enabling effect are unknown. Here we demonstrate deficits in anterograde axonal transport of mitochondria in primary neurons from transgenic mice expressing familial AD-linked forms of human amyloid precursor protein. We show that these deficits depend on Aß1-42 production and are prevented by tau reduction. The copathogenic effect of tau did not depend on its microtubule binding, interactions with Fyn, or potential role in neuronal development. Inhibition of neuronal activity, N-methyl-d-aspartate receptor function, or glycogen synthase kinase 3ß (GSK3ß) activity or expression also abolished Aß-induced transport deficits. Tau ablation prevented Aß-induced GSK3ß activation. Thus, tau allows Aß oligomers to inhibit axonal transport through activation of GSK3ß, possibly by facilitating aberrant neuronal activity.