Large-Scale Cortical Functional Organization and Speech Perception across the Lifespan

Aging is accompanied by substantial changes in brain function, including functional reorganization of large-scale brain networks. Such differences in network architecture have been reported both at rest and during cognitive task performance, but an open question is whether these age-related differences show task-dependent effects or represent only task-independent changes attributable to a common factor (i.e., underlying physiological decline). To address this question, we used graph theoretic analysis to construct weighted cortical functional networks from hemodynamic (functional MRI) responses in 12 younger and 12 older adults during a speech perception task performed in both quiet and noisy listening conditions. Functional networks were constructed for each subject and listening condition based on inter-regional correlations of the fMRI signal among 66 cortical regions, and network measures of global and local efficiency were computed. Across listening conditions, older adult networks showed significantly decreased global (but not local) efficiency relative to younger adults after normalizing measures to surrogate random networks. Although listening condition produced no main effects on whole-cortex network organization, a significant age group x listening condition interaction was observed. Additionally, an exploratory analysis of regional effects uncovered age-related declines in both global and local efficiency concentrated exclusively in auditory areas (bilateral superior and middle temporal cortex), further suggestive of specificity to the speech perception tasks. Global efficiency also correlated positively with mean cortical thickness across all subjects, establishing gross cortical atrophy as a task-independent contributor to age-related differences in functional organization. Together, our findings provide evidence of age-related disruptions in cortical functional network organization during speech perception tasks, and suggest that although task-independent effects such as cortical atrophy clearly underlie age-related changes in cortical functional organization, age-related differences also demonstrate sensitivity to task domains

Unusual complication of condrocostal implant in rhinoplasty.

A 67-year-old patient with a casual diagnosis of a foreign body within the frontal sinus outreaching the frontal cerebral parenchyma was treated. Results of anamnestic examination revealed that the patient underwent rhinoplasty with condrocostal implant of the nasal dorsum fixed to the anterior wall of the frontal sinus using a Kirschner wire 2 years ago. A combined transnasal endoscopic and transcranic approach was performed to remove the foreign bod

Radiation-induced gliomas: report of 10 cases and review of the literature.

BACKGROUND: Radiotherapy and more recently radiosurgery represent important therapeutic methods for the treatment of tumors and arterovenous malformations affecting the central nervous system, even though several significant side-effects have been described (radionecrosis, tumors, etc.). Gliomas induced by radiation therapy are decidedly unusual, and the first descriptions of this association only appeared in the 1960s. METHODS: The pertinent literature was reviewed to yield 116 cases in which a glioma developed after radiotherapy for cranial pathologies (included 10 personal cases treated in our Institution). One of our patients had undergone radiosurgery for a cavernous angioma. RESULTS: Patients who developed a radiation-induced glioma were younger, as a group, than those affected with so-called "spontaneous" gliomas. The tumor originated in the previously irradiated area, after average doses of 32 Gy and an average latency period of 9.6 years in accordance with the findings reported by the authors and in our experience as well. Radiotherapy had most frequently been performed for acute lymphoblastic leukemia. Our Case 10 is the fourth case of intracranial tumor arising after radiosurgery to be described in the literature. CONCLUSIONS: Though rare, gliomas may represent a late complication of radiation treatment. The behavior of the radiation-induced variety of glioma does not seem to differ significantly from that of its "spontaneous" counterpart. Late complications of the radiosurgery are probably underestimated because of the relatively recent introduction of this technique. On the contrary, these should be scrupulously evaluated when deciding whether to employ this method for therapeutic purposes for relatively benign or congenital lesions (which generally affect young patients with a long life expectancy)

Glioblastoma in kidney transplant recipients. Report of five cases.

Five patients who developed an intracranial glioblastoma after a kidney transplant are described. All patients underwent surgical removal of the lesion and eventually radiation therapy, but none of them is still alive at follow-up. The possibility of tumours occurring in transplant recipients is a recognised entity and several series have been reported. Nevertheless, little consideration has been paid to post-transplant gliomas and a precise evaluation of this risk is still lacking. Several hypotheses have been proposed to explain a possible link. One possible factor may be the immunosuppressive state of recipients as a result of post-transplant administration of immunosuppressive drugs, as it is known that gliomas have an higher incidence in HIV-infected patients. However, it is not yet clear whether immunosuppressive drugs function as a direct transforming facto

Unusual exophytic neurocytoma of thoracic spine mimicking meningioma: a case report and review of the literature

Extraventricular neurocytoma (EVN) in the spinal cord is extremely rare and only 15 cases have been reported in the English literature. Fourteen cases presented as an intramedullary lesion with spinal cord enlargement in cervico-thoracic segment and one case presented as an extramedullary lesion originating from cauda equina. Herein, we report an unusual spinal neurocytoma with exophytic growth from the thoracic spinal cord with cord compression mimicking meningioma. To our knowledge, this is the first case of exophytic spinal neurocytoma recorded in the English literature

Drivers of peak sales for pharmaceutical brands

Peak-sales metrics, Brand growth, Econometric models, Market entry, Pharmaceutical marketing, C23, C51, L65, M31,