Electrocorticography and functional mapping.

Brain mapping is often critical to the success of epilepsy and brain tumor surgeries. Mapping the cerebral cortex can be performed either extraoperatively or intraoperatively. When considering the optimal venue for a particular patient, a number of important considerations need to be considered including: the intended goals for the mapping, patient factors, anesthetic effects, stimulation parameters, cortical functions of interest, as well as the mapping modalities being considered. In this chapter, we will cover electrocorticography, cortical somatosensory evoked potentials, and the various neurophysiologic techniques used to map sensorimotor and cognitive functions, including language. One of the main uses of electrocorticography in epilepsy surgery is to map the cortical regions associated with epileptiform activity. This information is used to plan resection boundaries. Electrocorticography can also be used to monitor for afterdischarges (ADs) during direct cortical stimulation as well as for mapping high-frequency activity during various cognitive tasks. Cortical somatosensory evoked potentials can identify the central sulcus by mapping the dipolar activation of the primary somatosensory cortex that results from stimulation of the large fiber somatosensory pathway by peripheral nerve stimulation. Motor, sensory, and language cortex can also be identified by direct electrical cortical stimulation.

Electrographic and Clinical Natural History of Lateralized Periodic Discharges.

PURPOSE: The long-term electrographic features of lateralized periodic discharges (LPD) and their impact on clinical management are unclear. The authors investigated routine EEGs (rEEG) to analyze the delayed natural history of LPDs, and studied the clinical care of these patients. METHODS: After IRB approval, the prospectively maintained continuous EEG (cEEG) database was searched to identify patients fulfilling the following criteria: LPDs on cEEG, age ≥18 years, no epilepsy history, and rEEG completed within 1 to 12 months of hospital discharge. Their rEEGs were reviewed followed by clinical data extraction. Appropriate statistical tools were used for data analysis. RESULTS: Thirty-nine patients (20 females) with a mean age of 63.3 ± 16.8 years at the time of cEEG fulfilled the study criteria. Thirty-three (85%) had associated electrographic seizures. rEEG was performed 4.7 ± 3.5 months after cEEG. Seven (18%) patients had interictal epileptiform discharges (IEDs) on the rEEG. The LPDs on cEEG of these patients were more often continuous, with an amplitude >2 times their background compared with 10 (26%) patients with normal rEEGs findings. After a mean follow-up of 19.8 ± 9.9 months, 11 (31%) patients developed epilepsy, but only 3 had IEDs on their rEEG. Majority (86%) of patients were on AEDs at the time of last follow-up. CONCLUSIONS: LPDs lead to markers of epileptogenicity in around 18% of patients. One-third of the study population developed epilepsy. rEEG findings were not found to be good indicators of epilepsy development in our small, retrospective study limited by its sampling bias. Indiscriminate, long-term use of AEDs in these patients is a concerning finding.

Assessment of healthcare personnel knowledge of stroke care at a large referral hospital in sub-Saharan Africa - A survey based approach.

There is no published literature regarding sub-Saharan health-care providers' understanding of stroke management patterns. Understanding current stroke management knowledge is important in formulating future education opportunities for providers to optimize patient outcomes. A cross-sectional survey of acute stroke diagnosis, hospital management, and secondary prevention questions was administered to health-care providers working in one large Kenyan acute referral hospital. Due to the prevalence of medical students (61.8%), an experienced-focused analysis contrasted students with more experienced providers. Providers (n=199) anonymously responded to the surveys. Among the acute diagnosis most respondents stated that stroke scales should always used (58.3% of respondents), 3h was the time period for alteplase (t-PA) (53.8% of respondents), and CT scan should be always be obtained prior to administration of anticoagulant therapy (61.3% of respondents). Neither VTE prophylaxis nor dysphagia/swallowing screening were considered to be done a majority of time. Secondary prevention results were variable. The respondent's level of clinical experience made the most difference in correctly answering the most appropriate IV Fluid to use in stroke patients (adjusted p=0.003) and the ideal initiation time for antithrombotic therapy (adjusted p=0.0017). Healthcare providers demonstrated a wide variability in their responses. Future efforts to improve stroke care in sub-Saharan Africa should include education and process improvement initiatives to focus on more specific aspects of stroke management based on the results from this survey.