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Predicting cognitive decline from neuropsychiatric symptoms and Alzheimer\u27s disease biomarkers: A machine learning approach to a population-based data
No full textBACKGROUND: The aim of this study was to examine the potential added value of including neuropsychiatric symptoms (NPS) in machine learning (ML) models, along with demographic features and Alzheimer\u27s disease (AD) biomarkers, to predict decline or non-decline in global and domain-specific cognitive scores among community-dwelling older adults. OBJECTIVE: To evaluate the impact of adding NPS to AD biomarkers on ML model accuracy in predicting cognitive decline among older adults. METHODS: The study was conducted in the setting of the Mayo Clinic Study of Aging, including participants aged ≥ 50 years with information on demographics (i.e., age, sex, education), NPS (i.e., Neuropsychiatric Inventory Questionnaire; Beck Depression and Anxiety Inventories), at least one AD biomarker (i.e., plasma-, neuroimaging- and/or cerebrospinal fluid [CSF]-derived), and at least 2 repeated neuropsychological assessments. We trained and tested ML models using a stepwise feature addition approach to predict decline versus non-decline in global and domain-specific (i.e., memory, language, visuospatial, and attention/executive function) cognitive scores. RESULTS: ML models had better performance when NPS were included along with a) neuroimaging biomarkers for predicting decline in global cognition, as well as language and visuospatial skills; b) plasma-derived biomarkers for predicting decline in visuospatial skills; and c) CSF-derived biomarkers for predicting decline in attention/executive function, language, and memory. CONCLUSIONS: NPS, added to ML models including demographic and AD biomarker data, improves prediction of downward trajectories in global and domain-specific cognitive scores among community-dwelling older adults, albeit effect sizes are small. These preliminary findings need to be confirmed by future cohort studies
Effects of genetic knockdown of the serotonin transporter on established L-DOPA-induced dyskinesia and gene expression in hemiparkinsonian rats
No full textParkinson\u27s disease (PD) is a neurodegenerative disorder typified by the loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) leading to motor symptoms including resting tremor, rigidity, akinesia, and postural instability. DA replacement therapy with levodopa (L-DOPA) remains the gold-standard treatment for the motor symptoms of PD. Unfortunately, chronic use of L-DOPA leads to the development of side effects known as L-DOPA-induced dyskinesia (LID). The mechanisms underlying LID are multifaceted, but accumulating research has strongly implicated maladaptive neuroplasticity within the raphe-striatal serotonin (5-HT) circuit. The 5-HT transporter (SERT) has emerged as an intriguing therapeutic target as it is upregulated in the brains of dyskinetic patients and animal models of LID, and pharmacological blockade of SERT alters L-DOPA\u27s effects. Therefore, the current study employed an interventional genetic knockdown of SERT (SERT-KD) to investigate its role in LID expression and LID-associated transcription factors. To do so, hemiparkinsonian, stably dyskinetic rats (N = 68) received adeno-associated virus 9 (AAV9) expressing either a short-hairpin RNA against SERT (SERT-shRNA) or a scrambled control shRNA (SCR-shRNA) after which LID reinstatement and motor performance were assayed over 2 weeks. Dorsal raphe and striatal tissue were collected for the expression analyses of known parkinsonian and LID-associated genes. Results demonstrated that SERT-KD significantly and durably reduced LID and L-DOPA-induced striatal cFOS mRNA without altering L-DOPA efficacy. Such findings point to SERT-mediated adaptations as a 5-HT mechanism by which L-DOPA exerts its actions and therapeutic target for LID
Applied microanatomy of the petrous internal carotid artery, greater superficial petrosal nerve, and tensor tympani muscle to improve safety during middle fossa surgery: laboratory cadaveric investigation
No full textBACKGROUND: Middle cranial fossa surgery is challenging due to the proximity of several neurovascular structures, such as the otic capsule, greater superficial petrosal nerve (GSPN), and petrous internal carotid artery (pICA). The concept of middle fossa triangles aids in the recognition of landmarks and increases the safety of middle fossa surgery. However, a definitive description of the microanatomical interrelationship between the pICA, tensor tympani, and GSPN in middle fossa surgery is lacking. METHODS: This study investigates the relationship between the GSPN, pICA, and tensor tympani to improve the safety of pICA exposure during surgery of the middle fossa. The middle fossae of 5 cadaveric heads (10 sides) were drilled to expose the GSPN, pICA, and tensor tympani. The crossing points between the pICA, GSPN, and tensor tympani were recorded for the proximal and distal pICA using a stereotactic navigation system. Distances between the crossing points and the borders of the horizontal pICA were calculated. The GSPN and pICA crossed in all specimens. RESULTS: The mean (SD) distance between the GSPN and pICA was 3.0 (4.9) mm proximally and 5.3 (2.8) mm distally. The tensor tympani was lateral to the pICA with a mean (SD) distance of 4.2 (1.9) mm in all specimens (proximally and distally), except in 1 specimen in which it crossed only the proximal pICA. CONCLUSIONS: Drilling the Kawase triangle on the medial side of the GSPN is not universally safe because the pICA and GSPN frequently cross along the course of the horizontal pICA. The tensor tympani muscle may be used as a reliable landmark to systematically localize the pICA
Development and Validation of a 3-Dimensionally Printed Craniotomy Simulation Model for Under-resourced Healthcare Systems: A Technical Note
No full textBACKGROUND AND OBJECTIVES: Cadaver-based simulations are limited by financial and legal constraints, particularly in low- and middle-income countries (LMICs). Three-dimensional (3D) printing-based alternatives are often limited in scope and prohibitively expensive. This report describes a 3D-printed model that addresses these concerns by simulating a variety of craniotomy approaches in a cost-effective manner. METHODS: A craniotomy model was developed using medical imaging, 3D printing, and foam molding. Detailed manufacturing information for the model is provided. The model was assessed by 40 neurosurgery residents and young attendings in a Latin American LMIC with a questionnaire administered after they performed simulated craniotomies using the model. RESULTS: The total cost of the model was 47.52 USD, and it took 6 hours to produce. Thirty-four (85%) participants agreed that the simulated tissue elastance allowed for using the model to teach surgical approaches. Twenty-six (65%) participants agreed that the model provided realistic haptic feedback. All participants felt the model was useful in learning how to perform emergent craniotomies and that training with the model was transferable to clinical practice. Thirty-seven (93%) participants felt use of the model would help prevent serious intraoperative complications. Thirty-six (90%) participants agreed that the model would be useful in educating patients and families about their neurosurgical problem and the planned surgical approach. CONCLUSION: Most participants found that the craniotomy model provided clinically translatable neurosurgical skills, and it may be a viable alternative to cadaver-based training in LMICs
Management and outcomes for thoracic anterior spinal artery aneurysms: illustrative case
No full textBACKGROUND: Anterior spinal artery (ASA) aneurysms are uncommon and difficult to diagnose due to their variable presentation and limited visibility with traditional imaging. They often present with severe back pain from rupture and spinal subarachnoid hemorrhage (SAH). There are few published studies and no established treatment recommendations. This study reports a ruptured thoracic ASA aneurysm treated with clip reconstruction and reviews the literature. OBSERVATIONS: A man in his late 40s presented with sudden, intense interscapular pain that progressed to paraplegia and sensory loss below T5. He regained neurological function within 6 hours, with residual back pain. Imaging showed SAH and an aneurysm from the left ASA at T5. After a left T4 costotransversectomy, the aneurysm was clipped, and postoperative angiography confirmed ASA patency and aneurysm occlusion. A review of 31 patients (mean [SD] age 43.4 [17.8] years) showed varied treatments: microsurgery (n = 13, 42%), endovascular embolization (n = 3, 10%), conservative management (n = 13, 42%), and surgical exploration followed by conservative management (n = 1, 3%). Complete symptom resolution occurred in 45% (n = 14) of cases. LESSONS: Thoracic ASA aneurysms present diagnostic and treatment challenges. This case illustrates that open microsurgical treatment can successfully decompress the spinal cord and occlude the aneurysm while preserving parent artery flow. https://thejns.org/doi/10.3171/CASE24649
The Cochlear Dimple: A Novel Landmark for Cochlear Protection During Middle Fossa Surgery-A Cadaveric Laboratory Investigation
No full textBACKGROUND AND OBJECTIVES: Cochlear safety is paramount during middle fossa surgery because of the proximity of the cochlea to adjacent potential surgical targets such as the internal auditory canal (IAC). Several proposed methods are based on general anatomical relationships and distance averages between the cochlea and adjacent structures or reconstruction of lines drawn between other structures around the cochlea. We assessed the feasibility and safety of using the cochlear dimple as a direct cochlear localization landmark during a middle fossa approach to the IAC. METHODS: The middle fossa approach was simulated in 13 fresh cadaveric temporal bone specimens and 2 intact heads (4 sides). The middle fossa rhomboid was drilled to expose the anterior and superior aspects of the IAC and the cochlear dimple. RESULTS: The cochlear dimple was identified as a triangular depression in the distal dura of the anterior IAC with a mean distance of 3.2 mm from the laterally located cochlea. In no specimen did exposure of the cochlear dimple violate the cochlea. The cochlear dimple was identifiable in all specimens, and it was created by the divergence of the distal intracanalicular course of the facial and cochlear nerves near the IAC fundus. CONCLUSION: The cochlear dimple is a direct anatomical landmark that can be used to localize the cochlea. It is the only landmark whose establishment is not contingent on the identification of any other structure. It may be used as an additional measure to protect the cochlea during middle fossa surgery
Comparative meta-analysis of microsurgery versus endovascular therapy and bypass versus nonbypass techniques for blister-like aneurysms: enigmas of the supraclinoid internal carotid artery
No full textOBJECTIVE: Blister aneurysms of the internal carotid artery (ICA) have high associated mortality rates and are challenging due to their friable wall and poorly defined neck. Microsurgical and endovascular treatment options have been suggested, including bypass of the parent vessel to exclude the aneurysm. The goal of this study was to evaluate the safety and efficacy of microsurgical versus endovascular interventions. Additionally, for patients treated with open surgery, the outcomes of bypass were compared to nonbypass techniques. METHODS: Three databases were systematically queried for primary studies comparing microsurgery to endovascular therapy and assessing bypass versus nonbypass treatment modalities for blister aneurysms of the ICA. All relevant studies published between 2000 and 2023 were eligible for inclusion. All articles were screened against title and abstract by 2 authors, as were those eligible for full-text assessment. Ultimately, relevant data from all included studies were pooled for meta-analysis in which the Mantel-Haenszel method with random-effects modeling was used. RESULTS: Among the 504 cases reported across 24 studies, 182 (35.1%) blister aneurysms of the ICA were surgically treated, whereas 337 (64.9%) involved endovascular treatment. There were 235 (46.6%) female patients in the cohort. Functional outcomes were comparable between groups, with 83% of surgically treated patients and 85% of endovascularly treated patients achieving a favorable outcome (p \u3e 0.05). Among the 7 studies (178 patients) comparing bypass to nonbypass microsurgery, rates of postoperative bleeding, ischemic infarct, vasospasm, recurrence, favorable outcomes, and mortality were comparable for bypass (n = 54, 30.3%) and nonbypass groups (n = 124, 69.7%). CONCLUSIONS: Blister aneurysms of the ICA are rare intracranial aneurysms that are difficult to treat with microsurgical and endovascular techniques. Considering only patients treated with open surgery, there appears to be no significant difference in complication profile or functional outcomes between patients undergoing bypass or alternative microsurgical techniques. However, it must be noted that the complex nature of bypass procedures means that much of the data granularity is lost on meta-analysis, suggesting that additional investigations comparing bypass to other open microsurgical techniques may be merited. Similarly, future studies should determine the limitations of dual antiplatelet therapy in endovascular treatment and the efficacy of different numbers and types of overlapping, flow-diverting devices
History and current state of neurosurgery in Greece
No full textThere is a global deficit in access to neurosurgical care. Although most of the deficit occurs in low- and middle-income countries, high-income countries can also face similar problems. Greece has experienced challenges in the provision of neurosurgical care due to diverse terrains, socioeconomic inequalities, and deficient health systems. Discussions with key individuals involved in neurosurgical care were conducted to characterize the history and current state of neurosurgery in Greece. Data were collected from Greek hospitals with neurosurgical services and the archives of the Hellenic Neurosurgical Society. A summary of the background of Greece is provided. Then, the ancient and modern history of neurosurgery and the current state of neurosurgery in Greece is described, underscoring important moments and individuals in Greek neurosurgery. This article describes the history and current state of neurosurgery in Greece and yields critical insights to guide the neurosurgical community in developing neurosurgical care in countries that experience similar challenges as Greece
