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1.
J Investig Med ; 62(7): 927-33, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25046178

RESUMEN

BACKGROUND: Accumulating evidence shows that gradual loss of white matter integrity plays an important role in the development of Alzheimer disease (AD). OBJECTIVE: The aim of this research was to study the microstructural integrity of white matter in AD in vivo. METHODS: Global fractional anisotropy, global axial diffusivity (AxD), and global radial diffusivity (RD) were analyzed in subjects with normal controls (NC), mild cognitive impairment (MCI), and AD using Alzheimer's Disease Neuroimaging Initiative data (total N = 210). We further compared specific white matter tracts among the 3 groups. RESULTS: Compared with the NC group, the MCI group had significantly increased global AxD and global RD. Compared with the NC and MCI groups, the AD group had significantly decreased global fractional anisotropy, increased global AxD, and increased global RD. With regard to specific white matter tracts, in the MCI group, we found increased AxD and increased RD in the external capsule, part of the lateral cholinergic pathway, in addition to the tracts connecting the limbic regions, predominantly in the left hemisphere. In the AD group, white matter abnormalities were widespread, including in the external capsule (cholinergic pathway) and limbic region tracts as well as tracts connecting anterior to posterior regions bilaterally. CONCLUSIONS: The radiographic manifestation of damaged white matter microstructural integrity in the cholinergic pathway in MCI patients may provide a rational basis for the use of cholinesterase inhibitor drugs in the MCI stage of AD.


Asunto(s)
Enfermedad de Alzheimer/patología , Disfunción Cognitiva/patología , Sustancia Blanca/patología , Anciano , Anisotropía , Estudios de Casos y Controles , Demografía , Imagen de Difusión Tensora , Femenino , Humanos , Masculino
2.
Seizure ; 19(2): 120-8, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20045354

RESUMEN

Operative treatment of epileptogenic cavernous malformations (CM) continues under debate. Most studies focus on surgery for supratentorial CM in general. For temporal lobe CM, surgical decision-making concerns in particular whether to perform lesionectomy alone or the additional excision of mesial temporal structures. The purpose of this case series was to evaluate operative strategies used to treat epileptogenic temporal CM and to report resultant postoperative seizure outcomes. Twelve consecutive cases of patients with medically intractable epilepsy who underwent operation for temporal CM between 1996 and 2006 were retrospectively reviewed. When the temporal CM directly invaded the hippocampus or amygdala, the affected structures were resected in addition to the lesion; when the CM was located in the superficial temporal cortex, and there was no radiographic evidence of hippocampal sclerosis, lesionectomy alone was done; with CM located between the superficial temporal cortex and the mesial temporal region, other factors were considered in decision-making, such as lesion proximity to the deep mesiotemporal structures and preoperative epilepsy duration. For six of the twelve patients, extended lesionectomy (EL) alone was done; for the other six, tailored anteromedial temporal resection with hippocampectomy and/or amygdalectomy was performed in addition to EL. Postoperatively, 11 patients - all with preoperative VEM demonstrating electroclinical seizure patterns concordant with lesion location - were seizure-free. We conclude that epileptogenic temporal CM are surgically remediable, when approached with the above operative strategies and presurgical VEM. On the basis of these postoperative seizure control results, we recommend consideration of concurrent resection of mesial temporal structures with EL for certain temporal CM.


Asunto(s)
Malformaciones Arteriovenosas/cirugía , Epilepsia/cirugía , Procedimientos Neuroquirúrgicos/efectos adversos , Complicaciones Posoperatorias/fisiopatología , Convulsiones/etiología , Adulto , Algoritmos , Anticonvulsivantes/uso terapéutico , Malformaciones Arteriovenosas/complicaciones , Electroencefalografía/métodos , Epilepsia/complicaciones , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Convulsiones/tratamiento farmacológico , Resultado del Tratamiento , Adulto Joven
3.
Neurosurg Focus ; 22(4): E8, 2007 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-17613197

RESUMEN

OBJECT: Patients with symptomatic isolated fourth ventricle and multicompartmentalized hydrocephalus benefit from operative treatment, but the optimal surgical approach and technique have yet to be established. The authors report on their experience with the treatment of symptomatic adult patients by endoscope-assisted placement of a fourth ventricle shunt catheter via a frontal transventricular approach. METHODS: The authors describe a retrospective series of four patients treated for isolated fourth ventricle. The surgical technique is described in detail: use of a flexible endoscope with dual-port intraventricular access for direct visualization and for mechanical manipulation of a multiperforated panventricular catheter guided by frameless stereotaxy. The transventricular approach allowed optimal catheter placement within the fourth ventricle. The use of the flexible endoscope permitted the neurosurgeon to use the endoscope as a tool to guide the ventricular catheter tip within the third ventricle and through the cerebral aqueduct. Clinical outcomes demonstrated neurological and radiographically verified improvement in all patients. CONCLUSIONS: The endoscope-assisted dual-port technique provides a solution to the technical difficulties of fourth ventricle shunt placement. The multiple advantages of this technique include a single ventricular catheter shunt system that equalizes ventricular pressures, a frontal location for the ventricular catheter that facilitates valve placement and programming, and ventricular catheter placement within the fourth ventricle that does not allow the catheter to impinge on the fourth ventricle floor and makes the catheter less prone to obstruction.


Asunto(s)
Derivaciones del Líquido Cefalorraquídeo/instrumentación , Cuarto Ventrículo/cirugía , Neuroendoscopía , Cirugía Asistida por Computador , Tercer Ventrículo/cirugía , Ventriculostomía , Adulto , Anciano , Diseño de Equipo , Estudios de Seguimiento , Cuarto Ventrículo/patología , Humanos , Imagen por Resonancia Magnética , Persona de Mediana Edad , Resultado del Tratamiento
4.
Hippocampus ; 17(8): 606-17, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17546683

RESUMEN

Recording the activity of neurons is a mainstay of animal memory research, while human recordings are generally limited to the activity of large ensembles of cells. The relationship between ensemble activity and neural firing rate during declarative memory processes, however, remains unclear. We recorded neurons and local field potentials (LFPs) simultaneously from the same sites in the human hippocampus and entorhinal cortex (ERC) in patients with implanted intracranial electrodes during a virtual taxi-driver task that also included a memory retrieval component. Neurons increased their firing rate in response to specific passengers or landmarks both during navigation and retrieval. Although we did not find item specificity in the broadband LFP, both theta- and gamma-band LFPs increased power to specific items on a small but significant percent of channels. These responses, however, did not correlate with item-specific neural responses. To contrast item-specific responses with process-specific responses during memory, we compared neural and LFP responses during encoding (navigation) and retrieval (associative and item-specific recognition). A subset of neurons also altered firing rates nonspecifically while subjects viewed items during encoding. Interestingly, LFPs in the hippocampus and ERC increased in power nonspecifically while subjects viewed items during retrieval, more often during associative than item-recognition. Furthermore, we found no correlation between neural firing rate and broadband, theta-band, and gamma-band LFPs during process-specific responses. Our findings suggest that neuronal firing and ensemble activity can be dissociated during encoding, item-maintenance, and retrieval in the human hippocampal area, likely relating to functional properties unique to this region.


Asunto(s)
Potenciales de Acción/fisiología , Mapeo Encefálico , Encéfalo/patología , Memoria/fisiología , Neuronas/fisiología , Reconocimiento Visual de Modelos/fisiología , Electrodos Implantados , Humanos , Estimulación Luminosa/métodos , Convulsiones/patología
5.
Neurosurg Focus ; 20(6): E8, 2006 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-16819816

RESUMEN

Nongalenic cerebral arteriovenous fistulas (AVFs) are uncommon, high-flow vascular lesions first treated by Walter Dandy and his colleagues by using open surgery with ligation of the feeding artery. Due to advances in endovascular technology over the past four decades that make possible the control of high flow in AVFs, treatment has evolved from the sole option of surgery to include the alternative or adjunct option of endovascular embolization. The authors of this review discuss the history of nongalenic AVF treatment, including techniques of both surgery and interventional neuroradiology and the technological developments underlying them.


Asunto(s)
Técnicas de Diagnóstico Neurológico/historia , Embolización Terapéutica/historia , Malformaciones Arteriovenosas Intracraneales/historia , Neurocirugia/historia , Historia del Siglo XX , Humanos , Malformaciones Arteriovenosas Intracraneales/diagnóstico , Malformaciones Arteriovenosas Intracraneales/terapia , Estados Unidos
6.
Hematol Oncol Clin North Am ; 19(4): 689-703, vii, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16083830

RESUMEN

This article reviews the clinical features of primary central nervous system lymphoma (PCNSL) in immunocompetent and immunocompromised patients. Clinical presentation, differential diagnosis, diagnostic testing, and staging evaluation in both immunocompetent and AIDS patients who have PCNSL are discussed. The differing role of biopsy in these two populations also is addressed.


Asunto(s)
Neoplasias del Sistema Nervioso Central/diagnóstico , Linfoma/diagnóstico , Neoplasias del Sistema Nervioso Central/terapia , Humanos , Linfoma/terapia , Estadificación de Neoplasias
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