Long-term prospective on-line real-time seizure prediction

OBJECTIVE

Epilepsy, one of the most common neurological disorders, constitutes a unique opportunity to study the dynamics of spatiotemporal state transitions in real, complex, nonlinear dynamical systems. In this study, we evaluate the performance of a prospective on-line real-time seizure prediction algorithm in two patients from a common database.

METHODS

We previously demonstrated that measures of chaos and angular frequency, estimated from electroencephalographic (EEG) signals recorded at critical sites in the cerebral cortex, progressively converge (i.e. become dynamically entrained) as the epileptic brain transits from the asymptomatic interictal state to the ictal state (seizure) (Iasemidis et al., 2001, 2002a, 2003a). This observation suggested the possibility of developing algorithms to predict seizures well ahead of their occurrences. One of the central points in those investigations was the application of optimization theory, specifically quadratic zero-one programming, for the selection of the critical cortical sites. This current study combines that observation with a dynamical entrainment detection method to prospectively predict epileptic seizures. The algorithm was tested in two patients with long-term (107.54h) and multi-seizure EEG data B and C (Lehnertz and Litt, 2004).

RESULTS

Analysis from the 2 test patients resulted in the prediction of up to 91.3% of the impending 23 seizures, about 89+/-15min prior to seizure onset, with an average false warning rate of one every 8.27h and an allowable prediction horizon of 3h.

CONCLUSIONS

The algorithm provides warning of impending seizures prospectively and in real time, that is, it constitutes an on-line and real-time seizure prediction scheme.

SIGNIFICANCE

These results suggest that the proposed seizure prediction algorithm could be used in novel diagnostic and therapeutic applications in epileptic patients.

Conventional chest physiotherapy compared to other airway clearance techniques for cystic fibrosis

BACKGROUND

Cystic fibrosis is an inherited life-limiting disorder, characterised by pulmonary infections and thick airway secretions. Chest physiotherapy has been integral to clinical management in facilitating removal of airway secretions. Conventional chest physiotherapy techniques (CCPT) have depended upon assistance during treatments, while more contemporary airway clearance techniques are self-administered, facilitating independence and flexibility.

OBJECTIVES

To compare CCPT with other airway clearance techniques in terms of their effects on respiratory function, individual preference, adherence, quality of life and other outcomes.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched CINAHL from 1982 to 2002 and AMED from 1985 to 2002. Date of most recent search: January 2004.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials including those with a cross-over design where CCPT was compared with other airway clearance techniques. Studies of less than seven days duration were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers allocated quality scores to relevant studies and independently extracted data. If we were unable to extract data, we invited authors to submit their data. We excluded studies from meta-analysis when data were lost or study design precluded comparison. For some continuous outcomes, we used the generic inverse variance method for meta-analysis of data from cross-over trials and data from parallel-designed trials were incorporated for comparison. We also examined efficacy of specific techniques and effects of treatment duration.

MAIN RESULTS

Seventy-eight publications were identified by the searches. Twenty-nine of these were included, representing 15 data sets with 475 participants. There was no difference between CCPT and other airway clearance techniques in terms of respiratory function measured by standard lung function tests. Studies undertaken during acute exacerbations demonstrated relatively large gains in respiratory function irrespective of airway clearance technique. Longer-term studies demonstrated smaller improvements or deterioration over time. Ten studies reported individual preferences for technique, with participants tending to favour self-administered techniques. Heterogeneity in the measurement of preference precluded these data from meta-analysis.

AUTHORS' CONCLUSIONS

This review demonstrated no advantage of CCPT over other airway clearance techniques in terms of respiratory function. There was a trend for participants to prefer self-administered airway clearance techniques. Limitations of this review included a paucity of well-designed, adequately-powered, long-term trials.

Video-EEG study in an adult and a child with eyelid myoclonia with absences

Two patients with eyelid myoclonia with absences (EMA) are described. Videotape of the eyelid myoclonia in one patient is presented. An interesting feature in one patient was the induction of clinical seizures only with daylight, and in another the presence of rare, focal, epileptiform discharges during drowsiness. Valproic acid only partially controlled eyelid myoclonia in both cases. Lamotrigine, alone or in combination with valproate, can be used as an alternative but was ineffective in our cases. [Published with video sequences].

Lyme neuroborreliosis

The series on treatable neuromuscular disorders continues with the present article on the peripheral nervous system manifestations of Lyme neuroborreliosis.

Frequency of epilepsy in patients with psychogenic seizures monitored by video-EEG

This study examined the frequency of epilepsy in a consecutive series of patients who received a definitive diagnosis of psychogenic nonepileptic seizures (PNES) after completing inpatient video-EEG (VEEG) monitoring. Of the 1,590 patients receiving definitive diagnosis, 514 (32.3%) were diagnosed with PNES. Twenty-nine (5.3%) of these patients were found to have both PNES and epilepsy. When strict diagnostic criteria are applied, there is little overlap between epileptic seizures and PNES among patients referred for VEEG monitoring.

Neurotoxicity following addition of intravenous valproate to lamotrigine therapy

Reversible neurotoxic symptoms were observed in three adult patients with absence status epilepticus on lamotrigine (LTG) therapy after administration of an IV bolus followed by oral valproic acid (VPA). Neurotoxicity was likely related to elevated serum LTG levels, as improvement correlated with discontinuing or reducing LTG dosage.

Phenylpropanolamine-induced intraventricular hemorrhage

Intracranial hemorrhage is an uncommon complication of phenylpropanolamine. There is an increasing awareness of this complication in the West. However, to the best of our knowledge there have been no cases reported from India. Here we report a patient who developed Intraventricular hemorrhage following ingestion of Phenylpropanolamine, from which he made an uneventul recovery over the next two weeks.

Mediastinal enteric duplication cyst containing aberrant pancreas

OBJECTIVE

The purpose of the study is to report a unique association of clinical and pathological findings in a neonate. Foregut enteric duplication cysts--rare developmental anomalies that are associated with midline vertebral fusion anomalies.

METHODS

We had a neonate with foregut duplication cyst who presented at birth with respiratory distress. The child also had associated communicating hydrocephalus. The patient underwent excision of the duplication cyst along with a ventriculo-peritoneal shunt.

RESULT

The excised specimen revealed a duplication cyst lined by aberrant pancreatic tissue.

CONCLUSION

The present case demonstrates histologically the presence of both pancreatic and gastric tissue.

Natural history and risk factors in fulminant hepatic failure

BACKGROUND

The natural history of fulminant hepatic failure (FHF) without liver transplantation is not well known.

AIMS

To study the natural history and prognostic factors, especially the presence of ascites and spontaneous bacterial peritonitis (SBP), in children with FHF.

METHODS

FHF was defined by the onset of encephalopathy within 12 weeks of onset of jaundice. From August 1997 to December 2000, 67 children (< or =12 years) were diagnosed with FHF. Their clinical features, investigations and outcome were noted. Viral markers A to E (IgM, anti-HAV; IgM, anti-HEV, HBsAg, and anti-HCV) were determined by ELISA. SBP was defined by the presence of > or =250 neutrophils with or without a positive culture in ascitic fluid.

RESULTS

Mean age of the children was 5.8 years with an almost equal sex distribution. Viral markers were positive in 63 (94%) cases: hepatitis A in 34 (54%), E in 17 (27%), A+E in seven (11%), and B in five (8%). Thirty one children presented with grade I or II encephalopathy and all recovered, whereas 17 of 36 children who had grade III or IV encephalopathy died. Ascites was detected (both clinically and ultrasonically) in 34 (51%) cases, nine (26%) of which had SBP. Overall mortality was 25%. Mortality was higher in those who had ascites than in those who did not (32% v 18%); among those with ascites it was maximum in those who had SBP (78% v 16%). Total serum bilirubin and grade of encephalopathy were significantly higher, serum albumin was significantly lower, and prothrombin time was significantly prolonged in those who died than in those who recovered.

CONCLUSION

The natural history of FHF in Indian children depends on age, grade of encephalopathy, ascites, and SBP. SBP depicts worse outcome. In all cases of FHF with ascites, the presence of SBP should be investigated.