Validation of the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) in Greek population with multiple sclerosis.

BACKGROUND: Cognitive impairment is experienced by about 50% of patients with Multiple Sclerosis (MS) worldwide and affects their employment, disease management and quality of life in general. The Brief International Cognitive assessment for MS (BICAMS) is a brief, practical and potentially universal battery for cognitive impairment in MS patients. It consists of three tests: the Symbol Digit Modalities Test (SDMT), the California Verbal Learning Test-2 (CVLT-2) and the Brief Visuospatial Memory Test-Revised (BVMT-R). OBJECTIVE: The objective of this study was to validate the BICAMS in Greek MS patients and controls. METHODS: Forty four MS patients and seventy nine healthy control (HC) participants were recruited and tested. They were group matched for age, education, gender and also premorbid cognitive reserve. All of them completed the three tests of the BICAMS battery. Instead of CVLT-2, the Greek validated form (Greek Verbal Learning Test, GVLT), was used. In addition, cognitive reserve was assessed using the Cognitive Reserve Index questionnaire (CRIq) standardized for the Greek population. RESULTS: Significant difference was found in the performance of the two groups in all tests (p<0.0001, p<0.02, p<0.009 for SDMT, GVLT and BVMT-R respectively). Test-retest reliability was good for all the tests. Based on the criterion of 1 or more tests below the 5th percentile of healthy controls performance, 47% of patients were found impaired. CONCLUSIONS: The study provides validation of BICAMS in Greek population and therefore facilitates the use of this battery in clinical practice and in future studies of MS patients in Greece.

A non-invasive methodology for fetal monitoring during pregnancy.

OBJECTIVES: This paper describes a methodology for the monitoring of the fetal cardiac health status during pregnancy, through the effective and non-invasive monitoring of the abdominal ECG signals (abdECG) of the mother. METHODS: For this purpose, a three-stage methodology has been developed. In the first stage, the fetal heart rate (fHR) is extracted from the abdECG signals, using nonlinear analysis. Also, the eliminated ECG (eECG) is calculated, which is the abdECG after the maternal QRSs elimination. In the second stage, a blind source separation technique is applied to the eECG signals and the fetal ECG (fECG) is obtained. Finally, monitoring of the fetus is implemented using features extracted from the fHR and fECG, such as the T/QRS ratio and the characterization of the fetal ST waveforms. RESULTS: The methodology is evaluated using a dataset of simulated multichannel abdECG signals: 94.79% accuracy for fHR extraction, 92.49% accuracy in T/QRS ratio calculation and 79.87% in ST waveform classification. CONCLUSIONS: The novel non-invasive proposed methodology is advantageous since it offers automated identification of fHR and fECG and automated ST waveform analysis, exhibiting a high diagnostic accuracy.

Phase resetting in one-dimensional model of the sinoatrial node.

In this paper, we use a one-dimensional model of the rabbit sinoatrial node (SAN), and we investigate the response of the model to hyperpolarizing and depolarizing stimulus. Depending on the stimulus timing, either a delay or an advance in the occurrence of next action potential is produced. This resetting behavior of the model is quantified in terms of phase transition curves (PTCs) for short electrical current pulses of varying amplitude which span the whole period. The main focus of this paper is to compare the dynamic properties of the spatially extended system and the single cell model. The detailed analysis of the results provides new insights in the understanding of the transition from the theoretical single cell models to the spatially extended systems.

Phase response characteristics of sinoatrial node cells.

In this work, the dynamic response of the sinoatrial node (SAN), the natural pacemaker of the heart, to short external stimuli is investigated using the Zhang et al. model. The model equations are solved twice for the central cell and for the peripheral cell. A short current pulse is applied to reset the spontaneous rhythmic activity of the single sinoatrial node cell. Depending on the stimulus timing either a delay or an advance in the occurrence of next action potential is produced. This resetting behavior is quantified in terms of phase transition curves (PTCs) for short electrical current pulses of varying amplitude which span the whole period. For low stimulus amplitudes the transition from advance to delay is smooth, while at higher amplitudes abrupt changes and discontinuities are observed in PTCs. Such discontinuities reveal critical stimuli, the application of which can result in annihilation of activity in central SAN cells. The detailed analysis of the ionic mechanisms involved in its resetting behavior of sinoatrial node cell models provides new insight into the dynamics and physiology of excitation of the sinoatrial node of the heart.

Early, intracoronary growth hormone administration attenuates ventricular remodeling in a porcine model of myocardial infarction.

OBJECTIVE: Ventricular remodeling is a common corollary of myocardial infarction. We hypothesized that this process may be attenuated by growth hormone, administered as a single high-dose, selectively in the infarct zone, early postmyocardial infarction. DESIGN: In 35 pigs (29+/-4 kg), myocardial infarction was generated by inflation of an over-the-wire angioplasty balloon in the circumflex artery for 60 min and 5 further pigs were sham-operated. Ten minutes after reperfusion, the pigs were randomized (2:1) to either growth hormone (1 IU/kg) (n=23) or normal saline (n=12), delivered via the balloon catheter. All survivors were treated with captopril and were sacrificed 4 weeks after myocardial infarction. RESULTS: Compared to controls, growth hormone-treated animals displayed lower heart weight (4.1+/-0.5 g/kg body weight, versus 3.4+/-0.4 g/kg, respectively, p=0.003) and dimensions (left ventricular short axis diameter 46+/-7 mm versus 37+/-6 mm, p=0.01; right ventricular short axis diameter 38+/-7 mm versus 30+/-5 mm p=0.001). Growth hormone increased wall thickness in the infarct (6.0+/-1.8 in controls versus 9.9+/-3.7 in treated animals, p=0.004) and non-infarct zones (10.6+/-1.8 in controls versus 15.5+/-3.8 in treated animals, p=0.0006) and produced higher (p<0.05) microvascular density in both zones. CONCLUSION: Intracoronary administration of growth hormone attenuates left and right ventricular remodeling by inducing hypertrophy and by enhancing angiogenesis.