Perfusion network shift during seizures in medial temporal lobe epilepsy.

BACKGROUND: Medial temporal lobe epilepsy (MTLE) is associated with limbic atrophy involving the hippocampus, peri-hippocampal and extra-temporal structures. While MTLE is related to static structural limbic compromise, it is unknown whether the limbic system undergoes dynamic regional perfusion network alterations during seizures. In this study, we aimed to investigate state specific (i.e. ictal versus interictal) perfusional limbic networks in patients with MTLE. METHODS: We studied clinical information and single photon emission computed tomography (SPECT) images obtained with intravenous infusion of the radioactive tracer Technetium- Tc 99 m Hexamethylpropyleneamine Oxime (Tc-99 m HMPAO) during ictal and interictal state confirmed by video-electroencephalography (VEEG) in 20 patients with unilateral MTLE (12 left and 8 right MTLE). Pair-wise voxel-based analyses were used to define global changes in tracer between states. Regional tracer uptake was calculated and state specific adjacency matrices were constructed based on regional correlation of uptake across subjects. Graph theoretical measures were applied to investigate global and regional state specific network reconfigurations. RESULTS: A significant increase in tracer uptake was observed during the ictal state in the medial temporal region, cerebellum, thalamus, insula and putamen. From network analyses, we observed a relative decreased correlation between the epileptogenic temporal region and remaining cortex during the interictal state, followed by a surge of cross-correlated perfusion in epileptogenic temporal-limbic structures during a seizure, corresponding to local network integration. CONCLUSIONS: These results suggest that MTLE is associated with a state specific perfusion and possibly functional organization consisting of a surge of limbic cross-correlated tracer uptake during a seizure, with a relative disconnection of the epileptogenic temporal lobe in the interictal period. This pattern of state specific shift in metabolic networks in MTLE may improve the understanding of epileptogenesis and neuropsychological impairments associated with MTLE.

Cognitive impairment is associated with reduced bone mass in multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) has been associated with reduced bone mineral density (BMD), yet the underlying causes are not fully known. The recent discovery that bone homeostasis is directly regulated by the brain led us to hypothesize that it may be impaired by MS pathology. As cognitive impairment (CI) is a well-documented correlate of MS-related brain pathology, we tested the hypothesis that it is associated with reduced BMD. OBJECTIVE: We aimed to determine if CI is associated with reduced BMD in patients with MS. METHODS: We retrospectively studied the medical records of 56 patients with MS, ≤50 years old, with Expanded Disability Status Scale score ≤4.5 and with dual X-ray absorptiometry (DEXA) BMD measurement within 1 year of neuropsychological testing with a standard battery (MACFIMS). RESULTS: In total, 23 (41.1%) MS patients had osteopenia or osteoporosis. Mean femur BMD was significantly lower in patients with MS with CI (0.89±0.12 g/cm(2)) compared with intact patients (0.99±0.17 g/cm(2), p=0.009). In the cognitively impaired group, 59.3% had either osteopenia or osteoporosis, compared with 24.1% in the non-cognitively impaired group (odds ratio=4.57, p=0.008). CONCLUSION: CI is associated with reduced BMD in patients with MS, suggesting that central mechanisms involved in bone homeostasis may be directly impaired by MS-related inflammatory and neurodegenerative processes.

Development of communities of practice to facilitate quality improvement initiatives in surgical oncology.

BACKGROUND: The process of developing clinical guidelines and standards for cancer treatment and screening is well established in the Ontario health care system; however, the dissemination and implementation of such guidelines and standards are more recent undertakings. Traditional implementation strategies to improve surgical practice and the delivery of cancer care have not been consistently effective. There is a recognized need to develop integrated models that offer direct support for implementation strategies. Such a model should be feasible, adaptable, and open to evaluation across diverse surgical settings. DISCUSSION: Research suggests that successful implementation should consider tools and expertise from other disciplines. This article considers a community of practice (COP) model to provide a supportive infrastructure for quality improvements in cancer surgery. The COP model was adapted for cancer surgeons. It is supported by 5 enablers referred to as tools: communication system, project development support, access to data, access to evidence review, and accreditation with continued medical education and continued professional development. These tools need to be part of an infrastructure that is both provided and supported by a team of administrators and health care professionals, who have active roles and responsibilities. Therefore, the primary objective of this article is to describe our COP model in cancer surgery including the key success factors necessary for providing the infrastructure and tools. The secondary objective is to offer the integrated COP model as a basis for future research and the evaluation of various collaborative improvement projects. SUMMARY: Building on knowledge management concepts, we identified the 4 essential processes that should be targeted by implementation strategies. A common COP evaluation framework uses the outcomes of 4 knowledge conversion modes-organizational memory, social capital, innovation, and knowledge transfer-as proxies for actual provider and organizational behavior. Insights from different collaborative improvement projects described in a consistent way could inform future research and assist in the collation of systematic reviews on this topic.