Automated removal of EKG artifact from EEG data using independent component analysis and continuous wavelet transformation.

The electrical potential produced by the cardiac activity sometimes contaminates electroencephalogram (EEG) recordings, resulting in spiky activities that are referred to as electrocardiographic (EKG) artifact. For a variety of reasons it is often desirable to automatically detect and remove these artifacts. Especially, for accurate source localization of epileptic spikes in an EEG recording from a patient with epilepsy, it is of great importance to remove any concurrent artifact. Due to similarities in morphology between the EKG artifacts and epileptic spikes, any automated artifact removal algorithm must have an extremely low false-positive rate in addition to a high detection rate. In this paper, an automated algorithm for removal of EKG artifact is proposed that satisfies such criteria. The proposed method, which uses combines independent component analysis and continuous wavelet transformation, uses both temporal and spatial characteristics of EKG related potentials to identify and remove the artifacts. The method outperforms algorithms that use general statistical features such as entropy and kurtosis for artifact rejection.

Treatable neurological disorders misdiagnosed as Creutzfeldt-Jakob disease.

OBJECTIVE: Heightened awareness of Creutzfeldt-Jakob disease (CJD) among physicians and the lay public has led to its frequent consideration in the differential diagnosis of patients with rapidly progressive dementia (RPD). Our goal was to determine which treatable disorders are most commonly mistaken for CJD. METHODS: We performed a retrospective clinical and neuropathological review of prion-negative brain autopsy cases referred to the US National Prion Disease Pathology Surveillance Center at Case Western Reserve University from January 2006 through December 2009. RESULTS: Of 1,106 brain autopsies, 352 (32%) were negative for prion disease, 304 of which had adequate tissue for histopathological analysis. Alzheimer disease (n = 154) and vascular dementia (n = 36) were the 2 most frequent diagnoses. Seventy-one patients had potentially treatable diseases. Clinical findings included dementia (42 cases), pyramidal (n = 20), cerebellar (n = 14), or extrapyramidal (n = 12) signs, myoclonus (n = 12), visual disturbance (n = 9), and akinetic mutism (n = 5); a typical electroencephalogram occurred only once. Neuropathological diagnoses included immune-mediated disorders (n = 26), neoplasia (n = 25, most often lymphoma), infections (n = 14), and metabolic disorders (n = 6). INTERPRETATION: In patients with RPD, treatable disorders should be considered and excluded before diagnosing CJD. Misdiagnosed patients often did not fulfill World Health Organization criteria. RPD with positive 14-3-3 cerebrospinal fluid protein should not be regarded as sufficient for the diagnosis of CJD. Adherence to revised criteria for CJD, which include distinctive magnetic resonance imaging features of prion disease, is likely to improve diagnostic accuracy.

Not all stroke units are the same: a comparison of physical activity patterns in Melbourne, Australia, and Trondheim, Norway.

BACKGROUND AND PURPOSE: Very early mobilization may be one of the most important factors contributing to the favorable outcome observed from a stroke unit in Trondheim, Norway. The aims of this study were to (1) describe and compare the pattern of physical activity of patients with stroke managed in a stroke unit with specified mobilization protocols (Trondheim) and those without in Melbourne, Australia; and (2) identify differences in activity according to stroke severity between the 2 sites. METHODS: Melbourne patients were recruited from 5 metropolitan stroke units. Trondheim patients were recruited from the stroke unit at University Hospital, Trondheim. All patients <14 days poststroke were eligible for the study. Patients receiving palliative care were excluded. Consenting participants were observed at 10-minute intervals from 8:00 am to 5:00 pm over a single day. At each observation, patient location, activity, and the people present were recorded. Negative binomial regression analyses were undertaken to assess differences in physical activity patterns between stroke units in the 2 cities. RESULTS: Patients in Melbourne and Trondheim had similar baseline characteristics. Melbourne patients spent 21% more time in bed and only 12.2% undertook moderate/high activity (versus 23.2% in Trondheim, P<0.001). This difference was even more pronounced among patients with greater stroke severity. The incidence rate ratio for time spent doing standing and walking activities in Melbourne was 0.44 (95% CI: 0.32 to 0.62) when compared with Trondheim. CONCLUSIONS: Higher activity levels were observed in Trondheim patients, particularly among those with more severe strokes. A greater emphasis on mobilization may make an important contribution to improved outcome. Further investigation of this is warranted.

Appropriateness of intravenous loading dose of phenytoin treatment in Srinagarind Hospital.

Intravenous loading dose of phenytoin treatment (ILP) is a useful treatment but may cause serious adverse events. The present study assessed the appropriate use of ILP in Srinagarind Hospital. The authors reviewed all charts that ILP was ordered between January 1st, 2000 and December 31st, 2001, about indication, the infusion rate, and side effects. There were 206 cases treated with ILP Thirty-two cases (15.7%) received inappropriate treatment by ILP The most common indication was primary prophylaxis before brain surgery. There were 7 cases that developed side effects with 5 cases of high blood phenytoin level. These data showed that physicians should consider more carefully the use of ILP.